【正文】 (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)。39。對這些問題的研究分析可以為避免這些問題的出現指明方向。當然，這些新材料可能降低成本、改進產品的性能。設計工程師最好能在這一階段完全完成材料的分析、選擇和確定工作，而不是將其留到生產設計階段去做。 在功能設計和工程設計階段，要做出一個切實可行的設計。由于材料選用不當造成的產品責任訴訟，已經產生了深刻的影響。這些事例恰好說明了設計是一個動態(tài)過程。這一般是通過口頭討論，草圖和文字材料進行的。只有這樣，才不致于堵塞創(chuàng)新的思路。一個全新的設計，要求屏棄許多陳舊的，為人們所熟知的方法。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要這種產品。機械設計理論 機械設計是一門通過設計新產品或者改進老產品來滿足人類需求的應用技術科學。 應當把機械設計看成是機械設計人員運用創(chuàng)造性的才能進行產品設計、系統分析和制定產品的制造工藝學的一個良機。由于許多人墨守成規(guī)，這樣做并不是一件容易的事。通常，要提出幾套設計方案，然后加以比較。為了進行有效的交流 ，需要解決下列問題： （ 1） 所設計的這個產品是否真正為人們所需要？ （ 2） 此產品與其他公司的現有同類產品相比有無競爭能力？ （ 3） 生產這種產品是否經濟？ （ 4） 產品的維修是否方便？ （ 5） 產品有無銷路？是否可以盈利？ 只有時間能對上述問題給出正確答案。總是存在著更好的方法來完成設計工作，設計人員應該不斷努力，尋找這些更好的方法。此外，材料與材料加工之間的相互依賴關系已經被人們認識得更清楚。在這個階段要繪制出相當完整的圖紙，選擇并確定各種零件的材料。因為，在生產設計階段材料的更換是由其他人進行的，這些人對產品的所有功能的了解不如設計工程師。但是，必須對新材料進行認真的評價，以確保其所有性能都滿足要求。盡管采用最好的材料選擇方法也不能避免發(fā)生產品責任訴訟，設計人員和工業(yè)界按照適當的程序進行材料選擇，可以大大減少訴訟的數量。s health and security frequently can attach the new limiting condition to the choice of material. In order to reduce the weight or saves the energy, possibly can request the use different material. Comes from domestic and international petition, to product service maintenance convenience request enhancement and customer39。 (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。 If no, whether has a bigger assurance all permits in the cost and the time in the limit develops one kind of new material. In the functional design and the engineering design stage, needs to make a practical feasible design. Must draw up the quite plete blueprint in this stage, chooses and determines each kind of ponents the material. Usually must make the prototype or the working model, and carries on the experiment to it, the appraisal product function, the reliability, the outward appearance and the service maintenance and so on. Although this kind of experiment possibly can indicate, enters in the product to the production base in front of, should replace certain materials, but, absolutely cannot this point take not earnestly chooses the material the excuse. Should unify the product the function, earnestly carefully considers the product the outward appearance, the cost and the reliability. Has the achievement very much the pany when manufacture all prototypes, selects the material should the material which uses with its production in be same, and uses the similar manufacture technology as far as possible. Like this has the advantage very much to the pany. The function plete prototype if cannot act according to the anticipated sales volume economically to make, or is prototypical and the official production installment has in the quality and the reliable aspect is very greatly different, then this kind of prototype does not have the great value. Project engineer is best can pletely plete the material in t