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1. Introduction

In the recent years many die casting companies have gone bankrupt (Doehler-Jarvis and Shelby to name a few) and many other die casting companies have been sold (St. Paul Metalcraft, Tool Products, OMC etc.). What is/are the reason/s for this situation? Some blame poor management. Others blame bad customers (which is mostly the automobile industry). Perhaps there is something to these claims. Nevertheless one can see that the underlying reasons is the missing knowledge of how to calculate the when profits are made and how to design so that costs will be minimized. To demonstrate how the absurd situation is the fact that there is not even one company today that can calculate the actual price of any product that they are producing. Moreover, if a company is able to produce a specific product, no one in that company looks at the redesign (mold or process) in order to reduce the cost systematically. If there is a company which does such A thing, the author will be more then glad to learn about it.

In order to compete with other industries, the die casting industry must reduce cost as much as possible (20% to 40%) and lead time significantly (by 1/2 or more). To achieve these goals, the engineer must learn to connect mold design to the cost of production (charged to the customer) and to use the correct scientific principals involved in the die casting process to reduce/eliminate the guess work. This book is part of the revolution in die casting by which science is replacing the black art of design. For the first time, a link between the cost and the design is spelled out. Many new concepts, based on scientific principles, are introduced. The old models, which plagued by the die casting industry for many decades, are analyzed, their errors are explained and the old models are superseded.

``Science is good, but it is not useful in the floor of our plant!!'' George Reed, the former president of SDCE, recently announced in a meeting in the local chapter (16) of NADCA. He does not believe that there is A relationship between ``science'' and what he does with the die casting machine. He said that because he does not follow NADCA recommendations, he achieves good castings. For instance, he stated that in the conventional recommendation in order to increase the gate velocity, plunger diameter needs to be decreased. He said that because he does not follow this recommendation, and/or others, that is the reason he succeeds in obtaining good castings. He is right and wrong. He is right not to follow the conventional recommendations since they violate many basic scientific principles. One should expect that models violating scientific principles would produce unrealistic results. When such results occur, this should actually strengthen the idea that science has validity. The fact that models which appear in books today are violating scientific principals and therefore do not work should actually convince him, and others, that science does have validity. Mr. Reed is right (in certain ranges) to increase the diameter in order to increase the gate velocity as will be covered in Chapter [*].

The above example is but one of many of models that are errant and in need of correction. To date, the author has not found so much as a single ``commonly'' used model that has been correct in its conclusions, trends, and/or assumptions. The wrong models/methods that have plagued the industry are: 1) critical slow plunger velocity, 2) diagram, 3) plunger diameter calculations, 4) runner system design, 5) vent system design, etc. These incorrect models are the reasons that ``science'' does not work. The models presented in this book are here for the purpose of answering the questions of design in a scientific manner which will result in reduced costs and increased product quality.

Once the reasons to why ``science'' did not work are clear, one should learn the correct models for improving quality, reducing lead time and reducing production cost. The main underlying reason people are in the die casting business is to make money. One has to use science to examine what the components of production cost/scrap are and how to minimize or eliminate each of them to increase profitability. The underlying purpose of this book it to help the die caster to achieve this target. = 110 mm

Figure: The profits as a function of the amount of the scrap



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Genick Bar-Meir ||| www.potto.org
copyright Dec , 2006

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