【導讀】它涉及工程技術的各個領域，主要研究產品的尺寸、形狀和詳細結構的基本。構思，還要研究產品在制造、銷售和使用等方面的問題。進行各種機械設計工作的人員通常被稱為設計人員或者機械設計工程師。計是一項創(chuàng)造性的工作。圖、運動學、工程材料、材料力學和機械制造工藝學等方面具有深厚的基礎知識。如前所訴，機械設計的目的是生產能夠滿足人類需求的產品。發(fā)明、發(fā)現(xiàn)和科技。因而，應該認識到在一個特定的產品進行設計之前，必須先確定人們是否需。和制定產品的制造工藝學的一個良機。置放錯，也會使正確的設計變成錯誤的。的時間和努力并不能保證帶來成功。人們所熟知的方法。由于許多人墨守成規(guī)，這樣做并不是一件容易的事。在設計的初始階段，應該允許設計人員充分發(fā)揮創(chuàng)造性，不受各種約束。所有人來說都是最優(yōu)的操作范圍和操作過程。階段，設計人員必須就初步設計同管理人員進行交流和磋商，并得到批準。以保證不會損傷產品的功能。長期使用性能而引起的。

　　

【正文】 n design stage, is should pletely determine with the material related main question the material, causes them to adapt with the existing equipment, can use the existing equipment economically to carry on the processing, moreover the material quantity can quite be easy to guarantee the supply. In the manufacture process, inevitably can appear to uses the material to make some changes the situation. The experience indicated that, may use certain cheap materials to take the substitute. However, in the majority situation, in will carry on the production later to change the material to have in to start before the production to change the price which the material will spend to have to be higher than. Completes the choice of material work in the design stage, may avoid the most such situations. Started after the production manufacture to appear has been possible to supply the use the new material is replaces the material the most mon reason. Certainly, these new materials possibly reduce the cost, the improvement product performance. But, must carry on the earnest appraisal to the new material, guarantees its all performance all to answer the purpose. Must remember that, the new material performance and the reliable very few pictures materials on hand such understood for the people. The majority of products expiration and the product accident caused by negligence case is because in selects the new material to take in front of substitution material, not truly understood their longterm operational performance causes. The product responsibility lawsuit forces designs the personnel and the pany when the choice material, uses the best procedure. In the material process, five most mon questions are: (a) did not understand or cannot use about the material application aspect most newly the best information paper。 (b) has not been able to foresee and to consider the dusk year possible reasonable use (for example to have the possibility, designs the personnel also to be supposed further to forecast and the consideration because product application method not when creates consequence. ecent years many products responsibilities lawsuit case, because wrongly uses the plaintiff which the product receives the injury to accuse produces the factory, and wins the decision)。 (c) uses the material data not entire perhaps some data are indefinite, works as its longterm performance data is the like this time in particular。 (d) the quality control method is not suitable and not after the confirmation。 (e) the personnel which pletely is not petent for the post by some chooses the material. Through to the above five questions analysis, may obtain these questions is does not have the sufficient reason existence the conclusion. May for avoid these questions to these questions research analyses the appearance indicating the direction. Although uses the best choice of material method not to be able to avoid having the product responsibility lawsuit, designs the personnel and the industry carries on the choice of material according to the suitable procedure, may greatly reduce the lawsuit the quantity. May see from the above discussion, the choice material people should to the material nature, the characteristic and the processing method have prehensive and the basic understanding.