Professional Hospital Furnishers Sialkot

Professional Hospital Furnishers (PHF) was established in 1972. Clear vision, fair practices and passion to succeed has led PHF to grow into a highly professional international company that reached clients across the world.


Business Philosophy:


The hallmark of our business philosophy is to ensure total customer satisfaction. For us our customers are our strategic partners with whom we develop a special relationship in order to ensure success at both ends. We enjoy a brand presence in 60 countries where we are represented by very strong regional distributors. Our distributors and the end-users of our products state to be fully satisfied with our products and services.


Product Range & Quality:


The primary basis for the success of any product is its ability to satisfy the purpose for which it is manufactured. Not only should it be designed to meet specifications, the specifications or "need" must be clearly identified for the design to be result oriented. The acumen for the understanding these 'needs' is the hallmark of our successful business.


We have complete confidence in the quality of our products. With clients in more than 60 countries, our high-grade, theatre quality instruments are being primarily sold under our own brand name and are used and recommended by doctors and surgeons around the world.


Our manufacturing program covers over 10,000 types of instruments for general as we all special surgeries.


Address:
19-A(N),Industrial Estate, P.O. Box 2095
Sialkot
Category(ies):
Surgical Instruments Mfrs./ Exporters , Dental Equipment & Instruments , ISO Certified Organizations
Contact Info:
Phone: 052-3256441
Phone: 052-3559980
Fax: 052-3552939
Email: info@phfworld.com
Website: www.phfworld.com
Contact Person:
Syed Waseem Abbas
Marketing Director

Special Relationship

Special Relationship is a phrase used to describe the exceptionally close political, diplomatic, cultural, economic, military and historical relations between the United Kingdom and the United States, following its use in a 1946 speech by British statesman Winston Churchill. Although both the United Kingdom and United States have close relationships with many other nations, the level of cooperation between them in economic activity, trade and commerce, military planning, execution of military operations, nuclear weapons technology and intelligence sharing has been described as "unparalleled" among major powers.
The United Kingdom and United States have been close allies in numerous military and political conflicts including World War I, World War II, the Korean War, the Cold War, the Gulf War, the Iraq War and the Afghanistan War.



Churchillian emphasis


A poster from World War I showing Britannia arm-in-arm with Uncle Sam symbolizing the Anglo-American alliance.
Although the special relationship between the two governments was especially emphasised by British Prime Minister Winston Churchill, its existence had been recognised since the 19th century, not least by rival powers. Their troops had been fighting side by side—sometimes spontaneously—in skirmishes overseas since 1859, and the two democracies shared a common bond of sacrifice in World War I.
Prime Minister Ramsay MacDonald's visit to the United States in 1930 confirmed his own belief in the 'special relationship', and for this reason he looked to the Washington Treaty rather than a revival of the Anglo-Japanese alliance as the guarantee of peace in the Far East. However, as David Reynolds observes: ‘For most of the period since 1919, Anglo-American relations had been cool and often suspicious. America’s “betrayal” of the League of Nations was only the first in a series of US actions—over war debts, naval rivalry, the 1931-2 Manchurian crisis and the Depression—that convinced British leaders that the United States could not be relied on.’ Equally, as President Truman's secretary of state, Dean Acheson, recalled: 'Of course a unique relation existed between Britain and America—our common language and history ensured that. But unique did not mean affectionate. We had fought England as an enemy as often as we had fought by her side as an ally.'
Arguably, 'the fall of France in 1940 was decisive in shaping the pattern of international politics', leading the special relationship to displace the entente cordiale as the pivot of the international system.[11] During World War II, as an observer noted, 'Great Britain and the United States integrated their military efforts to a degree unprecedented among major allies in the history of warfare.' 'Each time I must choose between you and Roosevelt,' Churchill shouted at General Charles de Gaulle, leader of the Free French, in 1945, 'I shall choose Roosevelt.'
Churchill's mother was American, and he felt keenly the links between the English-speaking peoples. He first used the term 'special relationship' in 1945 to describe not the Anglo-American relationship alone, but the United Kingdom's relationship with both the United States and Canada. The New York Times Herald quoted Churchill in November 1945:
We should not abandon our special relationship with the United States and Canada about the atomic bomb and we should aid the United States to guard this weapon as a sacred trust for the maintenance of peace.
Churchill used the phrase again a year later, at the onset of the Cold War, this time to note the special relationship between the United States on the one hand, and the English-speaking nations of the British Commonwealth and Empire under the leadership of the United Kingdom on the other. The occasion was his 'Sinews of Peace Address' in Fulton, Missouri, on 5 March 1946:
Neither the sure prevention of war, nor the continuous rise of world organization will be gained without what I have called the fraternal association of the English-speaking peoples ...a special relationship between the British Commonwealth and Empire and the United States. Fraternal association requires not only the growing friendship and mutual understanding between our two vast but kindred systems of society, but the continuance of the intimate relationship between our military advisers, leading to common study of potential dangers, the similarity of weapons and manuals of instructions, and to the interchange of officers and cadets at technical colleges. It should carry with it the continuance of the present facilities for mutual security by the joint use of all Naval and Air Force bases in the possession of either country all over the world.
There is however an important question we must ask ourselves. Would a special relationship between the United States and the British Commonwealth be inconsistent with our over-riding loyalties to the World Organisation? I reply that, on the contrary, it is probably the only means by which that organisation will achieve its full stature and strength.
In the opinion of one international relations specialist: 'the United Kingdom's success in obtaining US commitment to cooperation in the postwar world was a major triumph, given the isolation of the interwar period. A senior British diplomat in Moscow, Thomas Brimelow, admitted: 'The one quality which most disquiets the Soviet government is the ability which they attribute to us to get others to do our fighting for us ... they respect not us, but our ability to collect friends.'[16] Conversely, 'the success or failure of United States foreign economic peace aims depended almost entirely on its ability to win or extract the co-operation of Great Britain'. Reflecting on the symbiosis, a later champion, former prime minister Margaret Thatcher, declared: 'The Anglo-American relationship has done more for the defence and future of freedom than any other alliance in the world.'






Military cooperation


The intense level of military co-operation between the United Kingdom and United States began with the creation of the Combined Chiefs of Staff in December 1941, a military command with authority over all American and British operations. Following the end of the Second World War the joint command structure was disbanded, but close military cooperation between the nations resumed in the early 1950s with the start of the Cold War.
[edit]Shared military bases
Since the Second World War and the subsequent Berlin Blockade, the United States has maintained substantial forces in Great Britain. In July 1948, the first American deployment began with the stationing of B-29 bombers. Currently, an important base is the radar facility RAF Fylingdales, part of the US Ballistic Missile Early Warning System, although this base is operated under British command and has only one USAF representative for largely administrative reasons. Several bases with a significant US presence include RAF Menwith Hill (only a short distance from RAF Fylingdales), RAF Lakenheath and RAF Mildenhall.
During the Cold War, critics of the special relationship jocularly referred to the United Kingdom as the "biggest aircraft carrier in the world."
Following the end of the Cold War, which was the main rationale for their presence, the number of US facilities in the United Kingdom has been reduced in number in line with the US military worldwide. Despite this, these bases have been used extensively in support of various peacekeeping and offensive operations of the 1990s and early 21st century.
The two nations also jointly operate on the British military facilities of Diego Garcia in the British Indian Ocean Territory and on Ascension Island, a dependency of Saint Helena in the Atlantic Ocean.




Nuclear weapons development


The Quebec Agreement of 1943 paved the way for the two countries to develop atomic weapons side by side, the United Kingdom handing over vital documents from its own Tube Alloys project and sending a delegation to assist in the work of the Manhattan Project. The United States later kept the results of the work to itself under the postwar McMahon Act, but after the United Kingdom developed its own thermonuclear weapons, the United States agreed to supply delivery systems, designs and nuclear material for British warheads through the 1958 US-UK Mutual Defence Agreement.
The United Kingdom purchased first Polaris and then the American Trident system which remains in use today. The 1958 agreement gave the United Kingdom access to the facilities at the Nevada Test Site, and from 1963 it conducted a total of 21 underground tests there before the cessation of testing in 1991.The agreement under which this partnership operates was updated in 2004; anti-nuclear activists claimed renewal may breach the 1968 Nuclear Non-Proliferation Treaty. The United States and the United Kingdom jointly conducted subcritical nuclear experiments in 2002 and 2006, to determine the effectiveness of existing stocks, as permitted under the 1998 Comprehensive Nuclear Test Ban Treaty.




Military procurement

The United Kingdom is the only collaborative, or Level One, international partner in the largest US aircraft procurement project in history, the F-35 Lightning II program. The United Kingdom was involved in writing the specification and selection and its largest defense contractor, BAE Systems, which is a partner of the American prime contractor Lockheed Martin. BAE Systems is also the largest foreign supplier to the United States Defense Department and has been permitted to buy important US defense companies such as Lockheed Martin Aerospace Electronic Systems and United Defense.
The US operates several British designs including Chobham Armour, the RAF Harrier GR9 or United States Marine Corps AV-8B Harrier II and the US Navy T-45 Goshawk. The UK also operates several American designs, including the Javelin anti-tank missile, M270 rocket artillery, the Apache gunship, C-130 Hercules and C-17 Globemaster transport aircraft.

Business philosophy

Development of management theory and philosophy considers the fundamental principles that underlie the formation and operation of a business enterprise; the nature and purpose of a business, for example, is it primarily property or a social institution; its role in society; and the moral obligations that pertain to it. The subject is important to business and management, and is closely related to business ethics and political economy. It is influenced significantly by philosophy, ethics, and economic theory.
One must draw an important distinction between the philosophy of business and business philosophy, which is an appellation that one often hears in the business world. More often than not, the latter designation is intended to denote a way of doing business or a business outlook, a popular use of the term philosophy, instead of its more formal, academic meaning, using the concepts and methods employed by philosophers. The latter meaning applies to the philosophy of business in this article. The phrase philosophy of business also might be used in the same way as business philosophy, for example, "Risk taking represents my philosophy of business." However, this is not the same sense that philosophy is used in this article.



Development of Management Theory and Philosophy


It is a somewhat curious truism that despite the fact that business touches nearly every aspect of our lives, few thinkers have shown an interest in it from a rules or philosophical perspective until relatively recently. Indeed, few philosophers can be said to have paid much attention to the business enterprise, itself, prior to the latter part of the 20th century. Many philosophers tended to look askance at commercial activity, believing, as Plato did, that only the worst sort of people are involved in such matters. Plato is not unlike many academics throughout history, even today, who tend to think of business as a necessary evil in society, and not as something worthy of serious philosophical consideration. To the extent philosophers were concerned with business, they were primarily interested in it from an economic or political standpoint, and not as a primary object of attention.
Although there have been few "philosophers of business", per se, business and economics has not developed in a vacuum. It is built on many tacit philosophical principles and assumptions that we can examine. As a general rule, business practitioners and theorists tend to accept the principles that are current in their society. In the European Middle Ages, for example, the dominant Christian influence resulted in a pricing practice known as just price, and in the Enlightenment the dominant view of economic decision making was one of rationality.
The formative years in the development of the modern philosophy of business and economics was the 17th and 18th century. At that time, thinkers like Hobbes, Locke, Rousseau, Shaftesbury, and Smith created the intellectual foundation upon which modern business and capitalism was built. A basic principle subsumed within business practice and economic theory alike is the notion of free will. Thomas Hobbes, John Locke, and Jean-Jacques Rousseau all accepted that we are free moral agents, able to make decisions, control our own destiny, and engage in a social contract. This notion would later be celebrated in the idea of the entrepreneur, someone that freely decides to pursue a risky venture in the hope of receiving great rewards. It is also at the core of utility theory, a model of consumer behaviour in economics in which consumers freely choose what to purchase.
Another philosophic principle that would become part of business theory and practice is rationality. The general philosophic predilection of the enlightenment was that people were fundamentally rational. Philosophers such as René Descartes and Spinoza had built whole systems of thought on this assumption. Capitalism would do the same. For two hundred years economics was founded on the assumption of Homo economicus. This assumption has recently been challenged by Herbert Simon, among others.
Another key philosophic assumption is atomism. It was John Locke's view of society as an aggregation of independent, autonomous individuals, rather than Jean-Jacques Rousseau's vision of society as an organic collective that would become an integral part of business philosophy. The key ethical unit is the individual. Social institutions are merely constructs that individuals can use for their own purposes. Many years later, Milton Friedman used this assumption in arguing that corporations have no moral responsibility because, he contended, they are not individuals capable of responding to moral claims. Only the individuals within the business enterprise have a moral responsibility.
Modern business practice and theory developed in the age of scientific discovery, and this gave it a mechanistic orientation. In particular, Newton had just discovered classical physics. This would influence business and economics in ways that we are just beginning to understand. Early writers dealing with economic topics, such as Adam Smith, borrowed many of their techniques and terminology from classical physics. They would use terms like "equilibrium", "labor force", "elasticity", and "income accelerator". Today a few theorists are starting to question the mechanistic approach and model business on biological principles or chaos theory. Newton's law of inertia has found its way into marketing where it is claimed that consumers will continue in their current state unless they are encouraged to act otherwise. Thus advertising is claimed to perform the valuable role of helping people experience a more variegated and interesting life.
John Locke also contributed an important attitude towards the private ownership of property. He claimed that individuals have certain inalienable, natural rights. One of these is the right of ownership. He said that if we toil on the land and mix our sweat with the soil, we become the rightful owners of the land. This argument was extended to other assets including the factors of production, a conclusion that many, including Karl Marx, would challenge.
Another key concept that underlies modern business is psychological egoism. This states that the core moral obligation is to oneself. Thomas Hobbes saw all action as motivated out of self-interest. A group of philosophers including Mandeville, Butler, Shaftsebury, Hutcheson, and Smith (sometimes referred to as the "enlightened self-interest school") developed this into one of the core concepts of modern business theory. Bernard Mandeville claimed that private vices are actually public benefits. In The Fable of the Bees (1714) he laments that the "bees of social virtue are buzzing in mans bonnet". Civilized man has stigmatized his private appetites and the result is the retardation of the common good. Bishop Butler claimed that pursuing the public good was the best way of advancing one's own good since the two were necessarily identical. Lord Shaftesbury turned the convergence of public and private good around, claiming that acting in accordance with ones self interest will produce socially beneficial results. An underlying unifying force that Shaftesbury called the "Will of Nature" maintains equilibrium, congruency, and harmony. This force, if it is to operate freely, requires the individual pursuit of rational self-interest, and the preservation and advancement of the self. Francis Hutcheson also accepted this convergence between public and private interest, but he attributed the mechanism, not to rational self interest, but to personal intuition which he called a "moral sense". Adam Smith developed a version of this general principle in which six psychological motives combine in each individual to produce the common good. He called it the invisible hand. In The Theory of Moral Sentiments, vol II, page 316, he says: By acting according to the dictates of our moral faculties, we necessarily pursue the most effective means for promoting the happiness of mankind. Since Smith's time, the principle of the invisible hand has been further incorporated into economic theory. Leon Walras developed a four equation general equilibrium model which concludes that individual self interest operating in a competitive market place produce the unique conditions under which a society's total utility is maximized. Vilfredo Pareto used an edgeworth box contact line to illustrate a similar social optimality.
A link can also be made between utilitarianism and the fundamental principles of the philosophy of business, however this is more theoretical than practical. Economists use utility theory to model human actions. Like Jeremy Bentham, modern economists assume that people are hedonists, that is they prefer more satisfaction to less satisfaction. The amount of satisfaction can be expressed in terms of the utility a person derives from the satisfaction. Social welfare functions used in modern welfare economics are an outgrowth of John Stuart Mill's utilitarian calculation of obtaining the greatest good for the greatest number. The grounding of business principles on teleological ethics has been challenged by many deontological philosophers. John Rawls' maxmin criterion also provides an alternative.






Modern philosophers of business


It is fair to say that most modern philosophers of business are involved in other philosophical or scholarly pursuits, and that they come to the philosophy of business as a sub-specialty, or only indirectly because it relates to another area of interest. Thus, they are primarily philosophers dealing with other subjects, economists, or business management theorists. If one were to examine the philosophy departments in most universities, today, one would find precious few courses in the philosophy of business (as opposed to a growing number of business ethics or applied ethics courses). There are indications that a growing number of philosophers with formal training in academic philosophy will come to specialize in the philosophy of business.
Perhaps the best known modern philosopher of business is Peter Drucker, whose publications have had a profound influence on management and organizational theory, generally, and on how we think of the business enterprise. More often than not, people who think about business issues are considering it from an applied perspective, which is to say, what is the best or most effective means of transacting commerce or managing the enterprise, with some goal in mind, usually profitability, improving employee relations, or marketing. While Drucker has dealt with these issues and many more in numerous publications over his long life, he also inquires into the principles and concepts that underlie commercial activity and organizational structure, and he asks what ought the mission of a business to be, and, in particular, how can we reconcile a business mission with conflicting interests in the marketplace and society.
One of the most frequently discussed topics is the matter of organizational change in a complex environment. Paul R. Lawrence has dealt primarily with organizational change, organization design, and the relationship between the structural characteristics of complex organizations and the technical, market and other conditions of their immediate environment. His 1967 book, Organization and Environment (written with Professor Jay Lorsch), added contingency theory to the vocabulary of students of organizational behavior.
Other philosophers of business, for example, Geoffrey Klempner, are principally interested in examining how business is even possible, which is to say, how can an enterprise function in society as a whole. Klempner states that theories of ethics and business are often at odds, and that one might even have to suspend the normal ethical considerations that would apply outside of business in order for a business to be possible. This is reminiscent of Albert Z. Carr's famous and controversial Harvard Business Review article on bluffing, where he said business was similar to playing poker, and that deception is a necessary part of business.
Of course, there is a close relationship between the philosophy of business and business ethics. Philosophers specializing in business ethics are primarily interested in how business people ought to conduct themselves in the marketplace and in society. Philosopher Norman E. Bowie adopts Kant's three versions of the categorical imperative for ensuring ethical business conduct, and he pays particular attention to the third variation, whereby the people within a business must be seen as a kingdom of ends, and not merely treated as means to an end.
The "invisible hand" is a favorite metaphor for practitioners of modern-day Western capitalism, the ideology driving globalization and, for the most part, business as we know it today. What many of the bottom-line fundamentalists may ignore is the degree to which the so-called "free market" has been skewed and maneuvered in ways Adam Smith never envisioned. Thus the question of ethics and conscience runs deeper yet. With exponential increases in government laws, regulations and court decisions regarding business in the past century, ethical practice has morphed from doing "the right thing" as conscience would dictate to doing what complies with the law or isn't explicitly illegal. Thus there's been a gradual relaxation of internal moral compass and greater reliance on external parameters, as in "if it isn't illegal, it must be all right," as well as a new skillset in finding "legal loopholes" in stretching the boundaries of compliance.




Some important philosophical topics and questions


The purpose of a business


Most would argue that the main purpose of a business is to maximize profits for its owners, or in the case of a publicly-traded company, its stockholders. The late economist Milton Friedman was a proponent of this view. Others would say that its principal purpose is to serve the interests of a larger group of stakeholders, including employees, customers, and even society as a whole. Most philosophers would agree, however, that business activities ought to comport with legal regulations. One proponent of a broader view which includes a moral component has been U.S. businessman-turned-futurist John Renesch  who writes, "Corporations are human-made organisms, associations of human beings. To see this association as having one solitary purpose and responsibility, to grow only in economic terms, is such an extreme view that implosions like what happened to Enron, WorldCom and other corporate collapses will become more and more commonplace." Anu Agha, ex-chairperson of Thermax Limited, once said, "We survive by breathing but we can't say we live to breathe. Likewise, making money is very important for a business to survive, but money alone cannot be the reason for business to exist". Profit maximization is extremely relevant when top management is mandated with the job of selecting the right strategy for the business. According to Jackson Mullane, the primary goal for any business strategy exercise must be that of maximizing profitability.
Peter Drucker defined the very purpose of business as creating a satisfied customer. This definition is also useful in evaluating to what extent a business is succeeding in fulfilling its stated purpose.
Many observers would hold that concepts such as economic value added (EVA) are useful in balancing profit-making objectives with other ends. They argue that sustainable financial returns are not possible without taking into account the aspirations and interests of other stakeholders (customers, employees, society, environment). This conception suggests that a principal challenge for a business is to balance the interests of parties affected by the business, interests that are sometimes in conflict with one another.
Spiritual capital theory is a new emerging approach to business purpose, and becomes more and more influenctial due to the recent financial crisis.




Contract theory


Advocates of business contract theory believe that a business is a community of participants organized around a common purpose. These participants have legitimate interests in how the business is conducted and, therefore, they have legitimate rights over its affairs. Most contract theorists see the enterprise being run by employees and managers as a kind of representative democracy.




Stakeholder theory


Stakeholder theorists believe that people who have legitimate interests in a business also ought to have voice in how. The obvious non-owner, stakeholders are the employees. However, stakeholder theorists take contract theory a step further, maintaining that people outside of the business enterprise ought to have a say in how the business operates. Thus, for example, consumers, even community members who could be affected by what the business does, for example, by the pollutants of a factory, ought to have some control over the business.




Business as property


Some philosophers believe that a business is essentially someone's property, and, as such, that its owners have the right to dispose of it as they see fit, within the confines of the law and morality. They do not believe that workers or consumers have special rights over the property, other than the right not to be harmed by its use without their consent. In this conception, workers voluntarily exchange their labor for wages from the business owner; they have no more right to tell the owner how he will dispose of his property than the owner has to tell them how to spend their wages, which is property belonging to the workers. Similarly, assuming the business has purveyed its goods honestly and with full disclosure, consumers have no inherent rights to govern the business, which belongs to someone else.
Philosophers who subscribe to this view generally point out that a property owner's rights are nevertheless not unlimited, and that they are constrained by morality. Thus, a home owner cannot burn down his home and thereby jeopardize the entire neighborhood. Similarly, a business does not have an unlimited right to pollute the air in the manufacturing process.
Followers of John Locke would suggest that the first instance of property is the property that one has in himself, and that one's labor is an extension of this. The labor theory of value suggests that when one mixes his labor with an object, he thereby makes it his property, and that his labor is the principal means of measuring value. Many classical economists and Marxists both subscribe to this view. Marxists also believe that modern production, which involves many inputs, makes an equitable division of this property impossible, which, among other reasons, necessitates that the state hold property and the factors of production in common for everyone. They assert that labor value provides an objective measure of economic activity, compared to price and other measures which they see as subjective and fluctuating.
Many neo-classical thinkers, for example, Ludwig von Mises, believe that value is subjective and that labor is incommensurable (e.g., comparing the labor of a house painter to the labor of Picasso). They return to the classical belief in practice but assert that price is objective, the product of multiple, albeit subjective, valuations. Moreover, they assert that what really matters for assigning ownership is whether or not property was acquired or exchanged legally (see Robert Nozick), which is known as the historical entitlement theory, whereas Marxists assert that there are no property rights in the means of production.
Libertarian socialists, sometimes known as left-anarchists, hold that, as Proudhon said, "Property is theft" — that is, in reference to the ownership of productive resources, property is not the right to use, but the right to keep others from using. Advocates of this philosophy therefore hold the "institution of property", as they sometimes call it, to be immoral in itself, so the accumulation of wealth that includes productive resources, especially land, is also immoral. This means that no business can really be ethical, since the very foundation of business as we know it is private property.




A mini-republic or modern village


Some philosophers see the business enterprise as a means of transmitting social justice, as a kind of mini-republic. This is especially true of contract and stakeholder theorists. Those who view a business as being primarily someone's property reject this view. While they might believe that the net effect of people disposing and exchanging their property freely will benefit society as a whole, they would argue, even if this were not the case, if there were no utilitarian advantage, one ought not to limit another's freedom, that is, unless it is harmful to others.
Regardless of how one thinks about these matters, it is undeniable that a business enterprise represents an increasingly important part of people's lives, especially the employees working there, for, in many ways, the business constitutes a person's principal social group, and it amounts to a replacement for the village or tribe that was the central social setting for our ancestors. In many ways, one's affiliation with a business is the most important social institution most of us have outside of the family.




The ontology of the business enterprise


What makes a business a business? We take for granted that a business is a profit-making entity. How, then, are we to characterize a business that is run only for the benefit of the people who buy from it, for example, a so-called co-operative? Similarly, how might we characterize an insurance business that is owned by its clients, as in the case of a mutual insurance company? Do the owners of insurance policies buy them primarily for a profit? What about charitable enterprises, such as Goodwill Industries, or religious organizations such as Trinity Broadcasting Network? Are all of these organizations businesses in the same sense as, say, General Motors is?
What is it that fundamentally distinguishes a business from other kinds of organizations, say, governmental organizations? For example, how could we characterize quasi-governmental organizations such as the U.S. Post Office and Amtrak, which are supposed to be self-sustaining, even profitable (for reinvestment, reducing or eliminating taxpayer subsidy, reserves)? Would we call such organizations businesses? One might suggest that these are run for the benefit of society, whereas a business is to satisfy the interests of its owners. However, is it not the case that society owns the government? One also would have to ask, how is one entity's satisfying the various interests of some segment of society substantially different from another entity's making a profit that also satisfies various interests, sometimes even the same ones?
What about a person who trades his labor in return for a wage? Is he also in business? After all, he is putting up risk capital, in the sense that he's giving up his time...an opportunity cost...and even making an investment of himself, his labor. He is performing a service, just as a business does. His employer is, in a sense, a customer, someone whom he must satisfy. And the employee markets himself, his skills, either to get a job or to get ahead. He has either an explicit or implicit performance agreement, a contract. He even hopes that his revenues will exceed his expenses, which is to say, that his efforts will be profitable. Does this, therefore, make every laborer a business person?
In other words, a philosopher might reasonably ask, what elements constitute the essential and distinguishing characteristics of a business enterprise? Perhaps it ends up being something as simple as being one or more persons engaged in any number of possible exchanges that satisfies any number of possible interests in an intentional, organized, planned manner. In any case, these are at least some of the questions one might ask about the ontology of a business.




The epistemology and logic of business


In the epistemology of business, we ask what are business facts and how do we come to know them? What constitutes business knowledge versus mere belief? As in other aspects of life, in business we acquire our knowledge through empirical study, from which we draw conclusions using inductive or deductive methods. We test our hypotheses, using them as long as they are not empirically falsified, and thereby develop business theories, organized explanations of the facts. To what extent is what we purport to be business knowledge...other than that which is relatively trivial...reliable or veridical?
Business relies heavily on inductive reasoning, which assumes a uniformity of nature, such that the future is assumed to resemble the past. This, of course, is problematic, especially when considering the complexity involved in adequately factoring in the effects of customers, competitors, legislative and regulatory encumbrances, employees, environmental and climatic hazards, war, new technology, and so forth, into useful quantitative formulae. It is impossible to bind all of the variables for making probabilistic judgments on many of the most important business problems with a high degree of confidence. For this reason (among others)...because of the number of variables and the sheer unpredictability of outcomes...there is a rather considerable risk of failure in business; conversely, there would seem to be a rather high degree of luck in achieving success, or putting it in the vernacular, being at the right place at the right time. This relates to the simple fact that business knowledge is highly tentative, and subject to error or obsolescence.
The philosopher of business might also reasonably ask, to what extent does intuition play a role in our business knowledge. What does it mean to have "a gut feeling" about a business matter, and how is it useful. Is there even such a thing as business intuition, or is it simply a matter of internalizing knowledge through a variety of experiences, such that it seems intuitive. At the very least, a great many managers and marketers would say that they operate using their intuition a great deal, perhaps especially in dealing with people, which, of course, leads us to inquire into the role of psychology.

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SWISSPO MANUFACTURING GROUP established in 1978 an ISO-9001 approved BSCI & SA-8000 certified. Manufacturers of wide range of Gloves, Apparel, Sports Balls & Fitness accessories.We are also specialized in Police & Military Gloves & Apparel, Government contracts, Customs designs and Private Label programs.


More than 30 years experience in the manufacturing business has allowed us to produce and develop methods that ensure quality services.


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Faisal Sanitary fittings Industries (pvt) Ltd

By the grace of Allah Faisal Sanitary fittings Industries (pvt) Ltd, is currently operating in an integrated range of manufacturing concerns. Faisal Sanitary fittings Industries (pvt) Ltd is manufacturing an integrated range of sanitary fittings. The combination of state-of art technology,


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Die casting process

Die casting is a metal casting process that is characterized by forcing molten metal under high pressure into a mold cavity. The mold cavity is created using two hardened tool steel dies which have been machined into shape and work similarly to an injection mold during the process. Most die castings are made from non-ferrous metals, specifically zinc, copper, aluminium, magnesium, lead, pewter and tin based alloys. Depending on the type of metal being cast, a hot- or cold-chamber machine is used.
The casting equipment and the metal dies represent large capital costs and this tends to limit the process to high volume production. Manufacture of parts using die casting is relatively simple, involving only four main steps, which keeps the incremental cost per item low. It is especially suited for a large quantity of small to medium sized castings, which is why die casting produces more castings than any other casting process. Die castings are characterized by a very good surface finish (by casting standards) and dimensional consistency.
Two variants are pore-free die casting, which is used to eliminate gas porosity defects; and direct injection die casting, which is used with zinc castings to reduce scrap and increase yield.



History


Die casting equipment was invented in 1838 for the purpose of producing movable type for the printing industry. The first die casting-related patent was granted in 1849 for a small hand operated machine for the purpose of mechanized printing type production. In 1885, Otto Mergenthaler invented the linotype machine, an automated type casting device which became the prominent type of equipment in the publishing industry. Other applications grew rapidly, with die casting facilitating the growth of consumer goods and appliances by making affordable the production of intricate parts in high volumes.
In 1966, General Motors released the acurad process,




Cast metals


The main die casting alloys are: zinc, aluminium, magnesium, copper, lead, and tin; although uncommon, ferrous die casting is possible.[5] Specific dies casting alloys include: ZAMAK; zinc aluminium; aluminium to, e.g. The Aluminum Association (AA) standards: AA 380, AA 384, AA 386, AA 390; and AZ91D magnesium. The following is a summary of the advantages of each alloy:
Zinc: the easiest alloy to cast; high ductility; high impact strength; easily plated; economical for small parts; promotes long die life.
Aluminium: lightweight; high dimensional stability for complex shapes and thin walls; good corrosion resistance; good mechanical properties; high thermal and electrical conductivity; retains strength at high temperatures.
Magnesium: the easiest alloy to machine; excellent strength-to-weight ratio; lightest alloy commonly die cast.
Copper: high hardness; high corrosion resistance; highest mechanical properties of alloys die cast; excellent wear resistance; excellent dimensional stability; strength approaching that of steel parts.
Lead and tin: high density; extremely close dimensional accuracy; used for special forms of corrosion resistance. Such alloys are not used in foodservice applications for public health reasons.
Maximum weight limits for aluminium, brass, magnesium, and zinc castings are approximately 70 pounds (32 kg), 10 lb (4.5 kg), 44 lb (20 kg), and 75 lb (34 kg), respectively.
The material used defines the minimum section thickness and minimum draft required for a casting as outlined in the table below. The thickest section should be less than 13 mm (0.5 in), but can be greater.
Metal Minimum section Minimum draft
Aluminium alloys 0.89 mm (0.035 in) 1:100 (0.6°)
Brass and bronze 1.27 mm (0.050 in) 1:80 (0.7°)
Magnesium alloys 1.27 mm (0.050 in) 1:100 (0.6°)
Zinc alloys 0.63 mm (0.025 in) 1:200 (0.3°)






Equipment


There are two basic types of die casting machines: hot-chamber machines and cold-chamber machines. These are rated by how much clamping force they can apply. Typical ratings are between 400 and 4,000 st (2,500 and 25,000 kg).




Hot-chamber machines




Schematic of a hot-chamber machine
Hot-chamber machines, also known as gooseneck machines, rely upon a pool of molten metal to feed the die. At the beginning of the cycle the piston of the machine is retracted, which allows the molten metal to fill the "gooseneck". The pneumatic or hydraulic powered piston then forces this metal out of the gooseneck into the die. The advantages of this system include fast cycle times (approximately 15 cycles a minute) and the convenience of melting the metal in the casting machine. The disadvantages of this system are that high-melting point metals cannot be utilized and aluminium cannot be used because it picks up some of the iron while in the molten pool. Due to this, hot-chamber machines are primarily used with zinc, tin, and lead based alloys.




Cold-chamber machines


A schematic of a cold-chamber die casting machine.
These are used when the casting alloy cannot be used in hot-chamber machines; these include aluminium, zinc alloys with a large composition of aluminium, magnesium and copper. The process for these machines start with melting the metal in a separate furnace.[10] Then a precise amount of molten metal is transported to the cold-chamber machine where it is fed into an unheated shot chamber (or injection cylinder). This shot is then driven into the die by a hydraulic or mechanical piston. This biggest disadvantage of this system is the slower cycle time due to the need to transfer the molten metal from the furnace to the cold-chamber machine.




Dies


The ejector die half


The cover die half
Two dies are used in die casting; one is called the "cover die half" and the other the "ejector die half". Where they meet is called the parting line. The cover die contains the sprue (for hot-chamber machines) or shot hole (for cold-chamber machines), which allows the molten metal to flow into the dies; this feature matches up with the injector nozzle on the hot-chamber machines or the shot chamber in the cold-chamber machines. The ejector die contains the ejector pins and usually the runner, which is the path from the sprue or shot hole to the mold cavity. The cover die is secured to the stationary, or front, platen of the casting machine, while the ejector die is attached to the movable platen. The mold cavity is cut into two cavity inserts, which are separate pieces that can be replaced relatively easily and bolt into the die halves.
The dies are designed so that the finished casting will slide off the cover half of the die and stay in the ejector half as the dies are opened. This assures that the casting will be ejected every cycle because the ejector half contains the ejector pins to push the casting out of that die half. The ejector pins are driven by an ejector pin plate, which accurately drives all of the pins at the same time and with the same force, so that the casting is not damaged. The ejector pin plate also retracts the pins after ejecting the casting to prepare for the next shot. There must be enough ejector pins to keep the overall force on each pin low, because the casting is still hot and can be damaged by excessive force. The pins still leave a mark, so they must be located in places where these marks will not hamper the castings purpose.
Other die components include cores and slides. Cores are components that usually produce holes or opening, but they can be used to create other details as well. There are three types of cores: fixed, movable, and loose. Fixed cores are ones that are oriented parallel to the pull direction of the dies (i.e. the direction the dies open), therefore they are fixed, or permanently attached to the die. Movable cores are ones that are oriented in any other way than parallel to the pull direction. These cores must be removed from the die cavity after the shot solidifies, but before the dies open, using a separate mechanism. Slides are similar to movable cores, except they are used to form undercut surfaces. The use of movable cores and slides greatly increases the cost of the dies. Loose cores, also called pick-outs, are used to cast intricate features, such as threaded holes. These loose cores are inserted into the die by hand before each cycle and then ejected with the part at the end of the cycle. The core then must be removed by hand. Loose cores are the most expensive type of core, because of the extra labor and increased cycle time. Other features in the dies include water-cooling passages and vents along the parting lines. These vents are usually wide and thin (approximately 0.13 mm or 0.005 in) so that when the molten metal starts filling them the metal quickly solidifies and minimizes scrap. No risers are used because the high pressure ensures a continuous feed of metal from the gate.
The most important material properties for the dies are thermal shock resistance and softening at elevated temperature; other important properties include hardenability, machinability, heat checking resistance, weldability, availability (especially for larger dies), and cost. The longevity of a die is directly dependent on the temperature of the molten metal and the cycle time. The dies used in die casting are usually made out of hardened tool steels, because cast iron cannot withstand the high pressures involved, therefore the dies are very expensive, resulting in high start-up costs. Metals that are cast at higher temperatures require dies made from higher alloy steels.
Die and component material and hardness for various cast metals
Die component Cast metal
Tin, lead & zinc Aluminium & magnesium Copper & brass
Material Hardness Material Hardness Material Hardness
Cavity inserts P20[note 1] 290–330 HB H13 42–48 HRC DIN 1.2367 38–44 HRC
H11 46–50 HRC H11 42–48 HRC H20, H21, H22 44–48 HRC
H13 46–50 HRC
Cores H13 46–52 HRC H13 44–48 HRC DIN 1.2367 40–46 HRC
DIN 1.2367 42–48 HRC
Core pins H13 48–52 HRC DIN 1.2367 prehard 37–40 HRC DIN 1.2367 prehard 37–40 HRC
Sprue parts H13 48–52 HRC H13
DIN 1.2367 46–48 HRC
44–46 HRC DIN 1.2367 42–46 HRC
Nozzle 420 40–44 HRC H13 42–48 HRC DIN 1.2367
H13 40–44 HRC
42–48 HRC
Ejector pins H13[note 2] 46–50 HRC H13[note 2] 46–50 HRC H13[note 2] 46–50 HRC
Plunger shot sleeve H13[note 2] 46–50 HRC H13
DIN 1.2367[note 2] 42–48 HRC
42–48 HRC DIN 1.2367
H13[note 2] 42–46 HRC
42–46 HRC
Holder block 4140 prehard ~300 HB 4140 prehard ~300 HB 4140 prehard ~300 HB
The main failure mode for die casting dies is wear or erosion. Other failure modes are heat checking and thermal fatigue. Heat checking is when surface cracks occur on the die due to a large temperature change on every cycle. Thermal fatigue is when surface cracks occur on the die due to a large number of cycles.
Typical die temperatures and life for various cast materials
Zinc Aluminium Magnesium Brass (leaded yellow)
Maximum die life [number of cycles] 1,000,000 100,000 100,000 10,000
Die temperature [C° (F°)] 218 (425) 288 (550) 260 (500) 500 (950)
Casting temperature [C° (F°)] 400 (760) 660 (1220) 760 (1400) 1090 (2000)




Process


The following are the four steps in traditional die casting, also known as high-pressure die casting,[4] these are also the basis for any of the die casting variations: die preparation, filling, ejection, and shakeout. The dies are prepared by spraying the mold cavity with lubricant. The lubricant both helps control the temperature of the die and it also assists in the removal of the casting. The dies are then closed and molten metal is injected into the dies under high pressure; between 10 and 175 megapascals (1,500 and 25,400 psi). Once the mold cavity is filled, the pressure is maintained until the casting solidifies. The dies are then opened and the shot (shots are different from castings because there can be multiple cavities in a die, yielding multiple castings per shot) is ejected by the ejector pins. Finally, the shakeout involves separating the scrap, which includes the gate, runners, sprues and flash, from the shot. This is often done using a special trim die in a power press or hydraulic press. Other methods of shaking out include sawing and grinding. A less labor-intensive method is to tumble shots if gates are thin and easily broken; separation of gates from finished parts must follow. This scrap is recycled by remelting it. The yield is approximately 67%.
The high-pressure injection leads to a quick fill of the die, which is required so the entire cavity fills before any part of the casting solidifies. In this way, discontinuities are avoided, even if the shape requires difficult-to-fill thin sections. This creates the problem of air entrapment, because when the mold is filled quickly there is little time for the air to escape. This problem is minimized by including vents along the parting lines, however, even in a highly refined process there will still be some porosity in the center of the casting.
Most die casters perform other secondary operations to produce features not readily castable, such as tapping a hole, polishing, plating, buffing, or painting.




Inspection


Casting defect


After the shakeout of the casting it is inspected for defects. The most common defects are misruns and cold shuts. These defects can be caused by cold dies, low metal temperature, dirty metal, lack of venting, or too much lubricant. Other possible defects are gas porosity, shrinkage porosity, hot tears, and flow marks. Flow marks are marks left on the surface of the casting due to poor gating, sharp corners, or excessive lubricant.




Lubricants


Water-based lubricants, called emulsions, are the most commonly used type of lubricant, because of health, environmental, and safety reasons. Unlike solvent-based lubricants, if water is properly treated to remove all minerals from it, it will not leave any by-product in the dies. If the water is not properly treated, then the minerals can cause surface defects and discontinuities. There are four types of water-based lubricants: oil in water, water in oil, semi-synthetic, and synthetic. Oil in water is the best, because when the lubricant is applied the water cools the die surface by evaporating while depositing the oil, which helps release the shot. A common mixture for this type of lubricants is thirty parts water to one part oil, however in extreme cases a ratio of 100:1 is used.
Oils that are used include heavy residual oil (HRO), animal fats, vegetable fats, and synthetic fats. HROs are gelatinous at room temperature, but at the high temperatures found in die casting, they form a thin film. Other substances are added to control the emulsions viscosity and thermal properties; these include graphite, aluminium, and mica. Other chemical additives are used to inhibit rusting and oxidation. Emulsifiers are added to water-based lubricants, so that oil based additives can be mixed into the water; these include soap, alcohol esters, and ethylene oxides.
Historically, solvent-based lubricants, such as diesel fuel and kerosene, were commonly used. These were good at releasing the part from the dies, but a small explosion occurred during each shot, which led to a build-up of carbon on the mold cavity walls. However, they were easier to apply evenly than water-based lubricants.




Advantages and disadvantages


Advantages:


Excellent dimensional accuracy (dependent on casting material, but typically 0.1 mm for the first 2.5 cm (0.005 inch for the first inch) and 0.02 mm for each additional centimeter (0.002 inch for each additional inch).
Smooth cast surfaces (Ra 1–2.5 micrometres or 0.04–0.10 thou rms).
Thinner walls can be cast as compared to sand and permanent mold casting (approximately 0.75 mm or 0.030 in).
Inserts can be cast-in (such as threaded inserts, heating elements, and high strength bearing surfaces).
Reduces or eliminates secondary machining operations.
Rapid production rates.
Casting tensile strength as high as 415 megapascals (60 ksi).
The main disadvantage to die casting is the very high capital cost. Both the casting equipment required and the dies and related components are very costly, as compared to most other casting processes. Therefore to make die casting an economic process a large production volume is needed. Other disadvantages include: the process is limited to high-fluidity metals and casting weights must be between 30 grams (1 oz) and 10 kg (20 lb). In the standard die casting process the final casting will have a small amount of porosity. This prevents any heat treating or welding, because the heat causes the gas in the pores to expand, which causes micro-cracks inside the part and exfoliation of the surface.




Variants


Acurad


Acurad was a die casting process developed by General Motors in the late 1950s and 1960s. The name is an acronym for accurate, reliable, and dense. It was developed to combine a stable fill and directional solidification with the fast cycle times of the traditional die casting process. The process pioneered four breakthrough technologies for die casting: thermal analysis, flow and fill modeling, heat treatable and high integrity die castings, and indirect squeeze casting.
The thermal analysis was the first done for any casting process. This was done by creating an electrical analog of the thermal system. A cross-section of the dies were drawn on teledeltos paper and then thermal loads and cooling patterns were drawn onto the paper. Water lines were represented by magnets of various sizes. The thermal conductivity was represented by the reciprocal of the resistivity of the paper.
The Acurad system employed a bottom fill system that required a stable flow-front. Logical thought processes and trial and error were used because computerized analysis did not exist yet; however this modeling was the precursor to computerized flow and fill modeling.
The Acurad system was the first die casting process that could successfully cast low-iron aluminum alloys, such as A356 and A357. In a traditional die casting process these alloys would solder to the die. Similarly, Acurad castings could be heat treated and meet the U.S. military specification MIL-A-21180.
Finally, the Acurad system employed a patented double shot piston design. The idea was to use a second piston (located within the primary piston) to apply pressure after the shot had partially solidified around the perimeter of the casting cavity and shot sleeve. While the system was not very effective, it did lead the manufacturer of the Acurad machines, Ube Industries, to discover that it was just effective to apply sufficient pressure at the right time later in the cycle with the primary piston; this is indirect squeeze casting,




Pore-free


When no porosity is required for a casting then the pore-free casting process is used. It is identical to the standard process except oxygen is injected into the die before each shot to purge any air from the mold cavity. This causes small dispersed oxides to form when the molten metal fills the dies, which virtually eliminates gas porosity. An added advantage to this is greater strength. Unlike standard die castings, these castings can be heat treated and welded. This process can be performed on aluminium, zinc, and lead alloys.




Heated-manifold direct-injection


Heated-manifold direct-injection die casting, also known as direct-injection die casting or runnerless die casting, is a zinc die casting process where molten zinc is forced through a heated manifold and then through heated mini-nozzles, which lead into the molding cavity. This process has the advantages of lower cost per part, through the reduction of scrap (by the elimination of sprues, gates and runners) and energy conservation, and better surface quality through slower cooling cycles.

Shot penning

Shot peening is a cold working process used to produce a compressive residual stress layer and modify mechanical properties of metals. It entails impacting a surface with shot (round metallic, glass, or ceramic particles) with force sufficient to create plastic deformation. It is similar to sandblasting, except that it operates by the mechanism of plasticity rather than abrasion: each particle functions as a ball-peen hammer. In practice, this means that less material is removed by the process, and less dust created.




Details


Peening a surface spreads it plastically, causing changes in the mechanical properties of the surface. Shot peening is often called for in aircraft repairs to relieve tensile stresses built up in the grinding process and replace them with beneficial compressive stresses. Depending on the part geometry, part material, shot material, shot quality, shot intensity, shot coverage, shot peening can increase fatigue life up to 1000%.


Plastic deformation induces a residual compressive stress in a peened surface, along with tensile stress in the interior. Surface compressive stresses confer resistance to metal fatigue and to some forms of stress corrosion. The tensile stresses deep in the part are not as problematic as tensile stresses on the surface because cracks are less likely to start in the interior.
A study done through the SAE Fatigue Design and Evaluation Committee showed what shot peening can do for welds compared to welds that didn't have this operation done. The study claimed that the regular welds would fail after 250,000 cycles when welds that had been shot peened would fail after 2.5 million cycles, and outside the weld area. This is part of the reason that shot peening is a popular operation with aerospace parts. However, the beneficial prestresses can anneal out at higher temperatures.
Intensity is a key parameter of the shot peening process. After some development of the process, an analog was needed to measure the effects of shot peening. John Almen noticed that shot peening made the side of the sheet metal that was exposed begin to bend and stretch. He created the Almen strip to measure the compressive stresses in the strip created by the shot peening operation. One can obtain what is referred to as the "intensity of the blast stream" by measuring the deformation on the Almen strip that is in the shot peening operation. As the strip reaches a 10% deformation, the Almen strip is then hit with the same intensity for twice the amount of time. If the strip deforms another 10%, then one obtains the intensity of the blast stream.
Coverage, the percentage of the surface indented once or more, is subject to variation due to the angle of the shot blast stream relative to the workpiece surface. The stream is cone-shaped, thus, shot arrives at varying angles. Processing the surface with a series of overlapping passes improves coverage, although variation in "stripes" will still be present. Alignment of the axis of the shot stream with the axis of the Almen strip is important. A continuous compressively stressed surface of the workpiece has been shown to be produced at less than 50% coverage but falls as 100% is approached. Optimizing coverage level for the process being performed is important for producing the desired surface effect.
SAE International's includes several standards for shot peening in aerospace and other industries.




Process and equipment


Popular methods for propelling shot media include air blast systems and centrifugal blast wheels. In the air blast systems, media is introduced by various methods into the path of high pressure air and accelerated through a nozzle directed at the part to be peened. The centrifugal blast wheel consists of a high speed paddle wheel. Shot media is introduced in the center of the spinning wheel and propelled by the centrifugal force by the spinning paddles towards the part by adjusting the media entrance location, effectively timing the release of the media. Other methods include ultrasonic peening, wet peening, and laser peening (which does not use media).
Media choices include spherical cast steel shot, ceramic bead, glass bead or conditioned (rounded) cut wire. Cut wire shot is preferred because it maintains its roundness as it is degraded, unlike cast shot which tends to break up into sharp pieces that can damage the workpiece. Cut wire shot can last five times longer than cast shot. Because peening demands well-graded shot of consistent hardness, diameter, and shape, a mechanism for removing shot fragments throughout the process is desirable. Equipment is available that includes separators to clean and recondition shot and feeders to add new shot automatically to replace the damaged material.
A popular method for sorting damaged/out-of-spec shot media is the use of shot separators. Production sized separators consist of various levels of precision wire mesh, from 1 or more sizes to sort, and is mechanically shaken. Some applications require a maximum and minimum level of shot diameter. To maintain specifications, shot is slowly introduced where the large shot/contamination will be sorted in the first stage, then shot within specifications are sorted in the second level, then degraded shot below specifications is sorted last. The openings on the wire mesh progressively get smaller in this instance. It is possible to attach a production separator to a shot peener for continuous control of shot quality. Testing methods use a similar concept in a much smaller package, where a technician takes a sample of shot and then sorts the various sizes. Further testing of the samples verifies the quality of the shot media.
Wheel blast systems include satellite rotation models, rotary throughfeed components, and various manipulator designs. There are overhead monorail systems as well as reverse-belted models. Workpiece holding equipment includes rotating index tables, loading and unloading robots, and jigs that hold multiple workpieces. For larger workpieces, manipulators to reposition them to expose features to the shot blast stream are available.




Coverage


Factors affecting coverage density include: number of impacts (shot flow), exposure time, shot properties (size, chemistry), and work piece properties. Coverage is monitored by visual examination to determine the percent coverage (0-100%). Coverage beyond 100% cannot be determined. The number of individual impacts is linearly proportional to shot flow, exposure area, and exposure time. Coverage is not linearly proportional because of the random nature of the process (chaos theory). When 100% coverage is achieved, with an exposure time of 1T, locations on the surface have been impacted multiple times. At 150% coverage (1.5T), 5 or more impacts occur at 52% of locations. At 200% coverage (2T), 5 or more impacts occur at 84% of locations.
Coverage is effected by shot geometry and the shot and workpiece chemistry. The size of the shot controls how many impacts there are per pound, where smaller shot produces more impacts per pound therefore requiring less exposure time. Soft shot impacting hard material will take more exposure time to reach acceptable coverage compared to hard shot impacting a soft material (since the harder shot can penetrate deeper, thus creating a larger impression).
Coverage and intensity (measured by Almen strips) can have a profound effect on fatigue life. This can effect a variety of materials typically shot peened. Incomplete or excessive coverage and intensity can result in reduced fatigue life. Overpeening will cause excessive cold working of the surface of the workpiece, which can also cause fatigue cracks.[5]. Be diligent when developing parameters for coverage and intensity, especially when using materials with different properties (ie softer metal to harder metal). Testing fatigue life over a range of parameters would result in a "sweet-spot" where there is near exponential growth to a peak fatigue life (x = peening intensity or media stream energy, y = time-to-crack or fatigue strength) and rapidly decay fatigue life as more intensity or coverage is added. The "sweet-spot" will directly correlate with the kinetic energy transferred and the material properties of the shot media and workpiece.






Applications


Shot peening is used on gear parts, cams and camshafts, clutch springs, coil springs, connecting rods, crankshafts, gearwheels, leaf and suspension springs, rock drills, and turbine blades. It is also used in foundries for sand removal, decoring, descaling, and surface finishing of castings such as engine blocks and cylinder heads. Its descaling action can be used in the manufacturing of steel products such as strip, plates, sheets, wire, and bar stock.
Shot peening is a crucial process in spring making. Types of springs include leaf springs, extension springs, and compression springs. The most widely used application are for engine valve springs (compression springs) due to high cyclic fatigue. In an OEM valve spring application, the mechanical design combined with some shot peening ensures longevity; however, automotive makers are shifting to more high performance higher stressed valve spring designs as modern engines evolve. In aftermarket high performance valve spring applications, the need for controlled and multi-step shot peening is a requirement to withstand extreme surface stresses that sometimes exceeds material specifications! The fatigue life of an extreme performance spring (NHRA, IHRA) can be as short as two passes down a 1/4 mile drag racing track before relaxation or failure occurs.
Shot peening may be used for cosmetic effect. The surface roughness resulting from the overlapping dimples causes light to scatter upon reflection. Because peening typically produces larger surface features than sand-blasting, the resulting effect is more pronounced.
Shot peening and abrasive blasting can apply materials on metal surfaces. When the shot or grit particles are blasted through a powder or liquid containing the desired surface coating, the impact plates or coats the workpiece surface. The process has been used to embed ceramic coatings, though the coverage is random rather than coherent. 3M developed a process where a metal surface was blasted with particles with a core of alumina and an outer layer of silica. The result was fusion of the silica to the surface. The process known as peen plating was developed by NASA. Fine powders of metals or non-metals are plated onto metal surfaces using glass bead shot as the blast medium. The process has evolved to applying solid lubricants such as molybdenum disulphide to surfaces. Biocompatible ceramics have been applied this way to biomedical implants. Peen plating subjects the coating material to high heat in the collisions with the shot and also must be available in powder form, limiting the range of materials that can be used. To overcome the problem of heat, a process called temperature moderated-collision mediated coating (TM-CMC) has allowed the use of polymers and antibiotic materials as peened coatings. The coating is presented as an aerosol directed to the surface at the same time as a stream of shot particles. The TM-CMC process is still in the R&D phase of development.




Compressive residual stress (metal alloy)


A sub-surface compressive residual stress profile is measured using techniques such as x-ray diffraction and hardness profile testing. The X-axis is depth in mm or inches and the Y-axis is residual stress in ksi or MPa. The maximum residual stress profile can be affected by the factors of shot peening, including: part geometry, part material, shot material, shot quality, shot intensity, and shot coverage. For example, shot peening a hardened steel part with a process and then using the same process for another unhardened part could result in overpeening; causing a sharp decrease in surface residual stresses, but not affecting sub-surface stresses. This is critical because max stresses are typically at the surface of the material. Mitigation of these lower surface stresses can be accomplished a multi-stage post process with varied shot diameters and other surface treatments that remove the low residual stress layer.
The compressive residual stress in a metal alloy is produced by the transfer of kinetic energy (K.E.) from a moving mass (shot particle or ball peen) into the surface of a material with the capacity to plastically deform. The residual stress profile is also dependent on coverage density. The mechanics of the collisions involve properties of the shot hardness, shape, and structure; as well as the properties of the workpiece. Factors for process development and the control for K.E. transfer for shot peening are: shot velocity (wheel speed or air pressure/nozzle design), shot mass, shot chemistry, impact angle and work piece properties. Example: if you needed very high residual stresses you would likely want to use large diameter cut-wire shot, high-intensity process, direct blast onto the workpiece, and a very hard workpiece material.




History of peening


It was common practice for blacksmiths to hammer peen the concave side of leaf springs, which enhanced their life, although the exact mechanism was unknown. The maximum tensile stresses are located on the surface of the concave portion of leaf springs; the peening effectively offset the maximum tensile stresses, also located on the surface, when the compressive stresses were induced by peening with a ball peen hammer.
Shot peening was independently invented in Germany and the United States in the late 1920s and early 1930s. The first commercial implementation was done in the United States on automotive valve springs.