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景德鎮(zhèn)陶瓷學(xué)院
本科生畢業(yè)設(shè)計(jì)
Φ350真空練泥機(jī)
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目 錄
1 真空練泥機(jī)結(jié)構(gòu)概述 3
2 真空練泥機(jī)技術(shù)參數(shù) 4
3 真空練泥機(jī)的安裝 5
4 真空練泥機(jī)試車前的檢查 5
5 真空練泥機(jī)的試車 5
6 真空練泥機(jī)的使用規(guī)程 6
7 真空泵的操作程序 6
8 真空泵的注意事項(xiàng) 7
9 真空練泥機(jī)常見故障及排除方法 7
10 真空泵常見故障及排除方法 8
1 真空練泥機(jī)結(jié)構(gòu)概述
1、傳動部分
多軸式真空練泥機(jī)的傳動形式分為：集中驅(qū)動：指電動機(jī)通過聯(lián)軸器或離合器經(jīng)齒輪減速器帶動上軸和下軸轉(zhuǎn)動，結(jié)構(gòu)緊湊，占地面積小，但運(yùn)動鏈較長，裝配和維修較困難，多用于中小型真空練泥機(jī)。分散驅(qū)動：指上、下軸的運(yùn)轉(zhuǎn)分別由兩臺電動機(jī)和兩套傳動機(jī)構(gòu)驅(qū)動，操作比較靈活，多用于大型真空練泥機(jī)，可采用效率高、體積小、重量輕的行星擺線針輪減速器直接驅(qū)動上、下軸。
2、攪泥部分
由加料槽、攪泥螺旋、梳子板、擠泥筒等組成，作用是原泥喂入、破碎、攪拌混合、輸送，最后將初練的泥料擠壓入真空室，并從用泥料本身形成對真空室的密封。
在加料槽內(nèi)壁的螺旋絞刀向上轉(zhuǎn)的一側(cè)安裝梳子板，以阻止泥料隨絞刀轉(zhuǎn)動，并把泥料擋回進(jìn)料槽內(nèi)。
不連續(xù)螺旋刀片按截面形式不同，可分為矩形截面刀片和六角形截面刀片兩種。矩形截面的刀片容易制造，有刀片粘泥現(xiàn)象；六角形截面刀片使用效果好，但制造較困難。
3、擠泥部分
由連續(xù)螺旋絞刀、擠泥筒、機(jī)頭和機(jī)嘴等組成。
1)連續(xù)螺旋絞刀
有圓柱形或圓錐形，作用除了輸送泥料外，還能對泥料進(jìn)行捏練、混合和擠壓。
螺旋面各點(diǎn)的升角是不同的，外緣的螺旋升角最小，與軸轂聯(lián)接處螺旋升角最大。螺旋升角的最大值與最小值之差稱為側(cè)滑角，使螺旋槽中的泥料有沿著半徑向遠(yuǎn)心方向滑動的趨勢。通常螺旋升角指平均半徑處的螺旋升角。
螺旋葉片的斷面形狀 根據(jù)螺旋面母線傾角β的不同情況，葉片的斷面形狀有三種，其中Pn為正壓力，P1 、P2 、P3為軸向、周向和徑向分力。
2) 擠泥筒
1、擠泥筒的作用：應(yīng)保證落入真空室的泥料被順利地輸送至擠出螺旋處。
2、擠泥筒的結(jié)構(gòu)：一般采用鑄鐵制成，內(nèi)壁都開有軸向凹槽。為方便裝拆維修，常將擠泥筒分節(jié)制造，再用法蘭盤聯(lián)接。擠泥筒內(nèi)壁和螺旋絞刀的徑向間隙是影響練泥機(jī)工作的重要因素。對于塑性良好、含水量高的泥料，間隙應(yīng)當(dāng)小些；對于塑性較差、含水量低的泥料，間隙可大些，該間隙一般要求是不大于3mm～5mm，擠泥筒的工作長度一般取L=（2.5～3）h。
3、擠泥筒的形狀
（1）、圓柱形：制造容易，在輸送泥料時阻力小。易出現(xiàn)回泥現(xiàn)象，并造成泥料產(chǎn)生層裂。
（2）、圓錐形：對泥料有壓緊和揉練作用，但泥料在移動時阻力大，使之發(fā)熱，影響出泥。
（3）、圓柱、圓錐組合式：上述兩種形狀的折衷方法，多用。
本設(shè)計(jì)采用第三種方法制作。采用Q235鋼板制作。具體結(jié)構(gòu)詳見零件圖。
3) 機(jī)頭
機(jī)頭的形狀: 為空心筒體
機(jī)頭的作用：螺旋運(yùn)動、軸向流動；改善泥料質(zhì)量(練泥后的處理——消除缺陷)； 保證泥料受壓(進(jìn)一步揉練、擠壓致密)；準(zhǔn)備出泥(過渡)。
其形狀有：由圓柱形和圓錐形兩部分組合的機(jī)頭：適用于擠制直徑比絞刀小得多的泥段。鼓形機(jī)頭：用于擠制直徑大于或接近于絞刀直徑的泥段。本設(shè)計(jì)采用鼓形機(jī)頭進(jìn)行制作。具體結(jié)構(gòu)詳見附件圖。
4) 機(jī)嘴
機(jī)嘴的作用：擠出泥料(切割成泥段)，使之符合規(guī)定，且致密均勻，缺陷最少，阻力小。使擠出的泥段具有一定的形狀、尺寸和密度。
對錐形機(jī)嘴有如下經(jīng)驗(yàn)數(shù)據(jù)：錐角α＝20°～40°，L＝（1～1.5）D，l＝L/3；也有采用板式機(jī)嘴的，便于更換擠制泥料的截面尺寸。
機(jī)嘴的結(jié)構(gòu)采用錐形機(jī)嘴。
2 真空練泥機(jī)技術(shù)參數(shù)
生產(chǎn)能力：4~ 6t/h
加料部分鉸刀轉(zhuǎn)速：18r/min
出料鉸刀轉(zhuǎn)速：18r/min
擠出刀直徑：350mm。
加料電機(jī)：Y280M-8三相異步電動機(jī)，其異步轉(zhuǎn)速為740r/min，電機(jī)功率為45KW。
擠出電機(jī)：Y160L-8三相異步電動機(jī)，滿載轉(zhuǎn)速為720r/min，螺旋軸的轉(zhuǎn)速：=18r/min。
加料減速器：上海尊翔減速機(jī)有限公司生產(chǎn)的“F平行軸標(biāo)準(zhǔn)圓柱齒輪減速器”， FA107減速器。輸入功率為45KW，速比為20.5。
擠出減速器：上海尊翔減速機(jī)有限公司生產(chǎn)的“F平行軸標(biāo)準(zhǔn)圓柱齒輪減速器”，F(xiàn)A77減速器。輸入功率為7.5KW，速比為20。
3 真空練泥機(jī)的安裝
1、擠出螺旋主軸要和機(jī)筒同心，不得有任何卡阻現(xiàn)象；
2、真空室密封要可靠；
3、加料螺旋主軸轉(zhuǎn)動時，不得有任何卡阻現(xiàn)象；
4、全部傳動齒輪正常嚙合，所有傳動件無異常，潤滑良好；
5、對分段安裝的螺旋組件，各段的銜接部位均應(yīng)圓滑過渡；
6、抽真空系統(tǒng)要安裝準(zhǔn)確，泵及相關(guān)儀表等要有合格證。
4 真空練泥機(jī)試車前的檢查
1、加料槽、真空室及機(jī)筒內(nèi)雜物應(yīng)除盡；
2、進(jìn)行設(shè)備外觀和電氣檢查；
3、各傳動件及軸承的潤滑狀況；
4、整機(jī)的動、靜密封檢查；
5、抽真空系統(tǒng)，包括真空泵及各元件、管道的密封檢查；
6、加料、擠出用主軸是否竄動。；
5 真空練泥機(jī)的試車
1、先點(diǎn)動無誤，再點(diǎn)動運(yùn)轉(zhuǎn)，同時查各電氣控制的靈敏度及離合器的可靠性；
2、在手動、點(diǎn)動確認(rèn)無故障后，再開機(jī)連續(xù)空轉(zhuǎn)2小時，無異常雜音和發(fā)熱；
3、見到泥段從機(jī)嘴擠出時，方可開動泵，讓抽真空系統(tǒng)運(yùn)行，真空室真空度要保持在720mmHg以上。
6 真空練泥機(jī)的使用規(guī)程
1、檢查練泥機(jī)和泥料真空處理裝置的完好情況，按使用說明書的規(guī)定對各潤滑點(diǎn)加足潤滑油；
2、開動真空泵，待真空表達(dá)到規(guī)定的真空度讀數(shù)后，方可啟動練泥機(jī)(先開擠出螺旋用電機(jī)，再開加料螺旋用電機(jī))；
3、如真空練泥機(jī)有離合器裝置，應(yīng)先使離合器處于分離狀態(tài)下開動電機(jī)，待電機(jī)啟動后，才能合上離合器，驅(qū)動練泥機(jī)；
4、加料時要均勻且量不宜過多(以真空室不堵泥為限)；
5、開始擠出的泥段未經(jīng)完善的真空處理，不能使用，要重新加入輥槽內(nèi)。練泥機(jī)在工作過程中，應(yīng)經(jīng)常對擠出的泥料切片作質(zhì)量檢查，以保證泥料中沒有氣孔、裂紋和夾層等缺陷，并能使泥料的含水量合乎工藝要求。
6、應(yīng)經(jīng)常檢查篩板出泥情況(如堵泥應(yīng)卸下清理)、軸承和機(jī)殼的溫升情況，注意齒輪嚙合的聲響，發(fā)現(xiàn)不正?，F(xiàn)象，應(yīng)立即停機(jī)檢查和修理。
7、發(fā)現(xiàn)擠泥筒過分發(fā)熱或真空度達(dá)不到要求時，應(yīng)及時停機(jī)檢查。
8、練泥機(jī)停機(jī)前應(yīng)先停止加料，待機(jī)中泥料盡可能都擠出后，方可停機(jī)，以減小下次啟動時的載荷。
9、練泥機(jī)停止后，關(guān)閉真空泵，蓋上加料槽的蓋子，用濕布包住機(jī)嘴。
7 真空泵的操作程序
1、本機(jī)外殼必須接地，并保持良好的接觸，以保證操作人員的安全，特別是包裝含水份的物品時，更需注意接地情況。
2、根據(jù)機(jī)器標(biāo)明的電源要求，接能相應(yīng)電源，一般單室機(jī)型采用AC220V/50HZ
3、機(jī)器應(yīng)水平安裝，周圍環(huán)境無腐蝕性氣體，總保持通風(fēng)良好。
4、開機(jī)前應(yīng)按真空泵使用說明所規(guī)定的要求，加注真空泵專用機(jī)油至油窗高度的1/2，但也不可多。
5、按設(shè)定各項(xiàng)參數(shù)選擇合適的抽氣時間，抽氣時間越長真空度越高。
7、確認(rèn)上述調(diào)整工作已經(jīng)正確無誤，真空泵開始工作。
8、真空泵對工作室開始抽氣，系統(tǒng)產(chǎn)生負(fù)壓，上蓋自動被吸住。
8 真空泵的注意事項(xiàng)
1、真空泵運(yùn)轉(zhuǎn)時，其油位高度應(yīng)為油窗高度的3/4為宜，如低于1/2油窗高度，應(yīng)及時加注高速真空泵油，油位過高或過低均對真空泵電機(jī)造成不利。
2、機(jī)器因?yàn)樗椒胖?，環(huán)境地點(diǎn)要通風(fēng)良好，周圍無腐蝕性氣體、及較大灰層。
3、機(jī)器必須安裝保護(hù)接地線，并經(jīng)常檢查連接點(diǎn)是否接觸良好，以保障人生安全。
4、機(jī)器工作前必須將加熱時間及加熱溫度設(shè)置在合適的位置，應(yīng)掌握從低到高的原則，切不可一下子將熱封時間及熱封溫度設(shè)置得很長或過高，以免燒壞電熱部件或聚四氟乙烯封口漆布。
5、上蓋壓下時，真空泵即可開始工作，此時如果上蓋尚未吸合到位，用戶應(yīng)在稍用力將上蓋用手壓下。
6、經(jīng)常檢查封口部件的聚四氟乙烯漆布表面是否有異物、或不平整，以確保封口質(zhì)量，如有損壞應(yīng)及時更換。
7、如需單獨(dú)作程序運(yùn)行或真空度測驗(yàn)時，可將溫度選擇開關(guān)置于0檔，此時加熱部分停止工作，以利于封口袋等部件不受損。
8、機(jī)器工作時遇緊急情況，按急停按鈕，機(jī)蓋可自行打開。
9、機(jī)器工作結(jié)束后，應(yīng)切斷總電源。
9 真空練泥機(jī)常見故障及排除方法
故障現(xiàn)象
產(chǎn)生原因
排除方法
生產(chǎn)能力下降
1.絞刀與機(jī)殼的間隙由于磨損而增大，造成泥料大量回流；
1.修理絞刀和機(jī)殼襯套，減小間隙；
2.篩板堵塞；
2.拆下篩板清理；
3.加料量不足；
3.適當(dāng)增大進(jìn)料量；
4.泥料過干。
4.適當(dāng)搭配加入部分含水量較高的泥料。
真空室堵塞
1.由于間隙過大，泥料大量回流到真空室；
1.修理絞刀和機(jī)殼襯套，減小間隙；
2.出料部分絞刀輸送能力降低；
2.修理或調(diào)整絞刀、壓料滾筒或梳子板；
3.泥料水分不均勻。
3.加料時注意干濕泥料的均勻搭配。
泥料發(fā)熱
1.泥料大量回流；
1.按上面有關(guān)辦法處理；
2.絞刀葉片之間夾有大塊異物；
2.拆機(jī)清除；
3.泥料過干，與絞刀轉(zhuǎn)速不適應(yīng)
3.適當(dāng)搭配或降低絞刀轉(zhuǎn)速。
真空度降低
1.真空泵性能變差；
1.檢查真空泵；
2.真空裝置大量漏氣。
2.查出漏氣的地方予以修復(fù)；
3.濾氣器過濾介質(zhì)太臟。
3.清洗或更換過濾介質(zhì)。
10 真空泵常見故障及排除方法
故障現(xiàn)象
產(chǎn)生原因
解決方法
不能抽真空
接觸器損壞
更換
行程開關(guān)損壞或未到位
更換或調(diào)整
上、下蓋未吻合
在機(jī)蓋上稍用力下壓
真空泵電機(jī)不良
檢查、更換
真空度不夠
管路連接部位松動
檢查
真空室或電氣閥漏氣
檢查或更換
管子泄漏
更換
真空室密封圈破損
更換
抽真空時間不夠
延長時間
真空室上蓋不能打開
放氣電磁閥損壞或接觸不良
檢查或更換
不能封口
熱封選擇開關(guān)處于0檔
重新設(shè)置
封口變壓器損壞
更換
封口電熱部件燒斷
更換
封口部分保險(xiǎn)熔斷
更換
封口時間繼電器處于0檔或損壞
調(diào)整、更換
封口時接觸器接觸不良或損壞
調(diào)整、更換
封口不良
封口電磁閥未打開或損壞J
檢查
氣囊漏氣
更換
封口時間或熱風(fēng)溫度不合適
重新設(shè)置
封口處平面有污物
清楚
封口活動部分卡死或不靈活
調(diào)整
聚四氟漆布表面硬碳化、破損
更換
封口電熱帶皺折、變形
更換
封口部分冒煙
封口平面有油污或其他殘留物
清除
封口時間過長或熱風(fēng)溫度過高
重新調(diào)整
機(jī)器程序運(yùn)行不正常
電器線路松動或接觸不良
檢查、測試
時間繼電器不良
檢查、測試
外文原文：
Machine design theory
The machine design is through designs the new product or improves the old product to meet the human need the application technical science. It involves the project technology each domain, mainly studies the product the size, the shape and the detailed structure basic idea, but also must study the product the personnel which in aspect the and so on manufacture, sale and use question.
Carries on each kind of machine design work to be usually called designs the personnel or machine design engineer. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, engineerig material, materials mechanics and machine manufacture technology has the deep elementary knowledge.
If front sues, the machine design goal is the production can meet the human need the product. The invention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product the benefit. Thus, should realize to carries on before the design in a specific product, must first determine whether the people do need this kind of product
Must regard as the machine design is the machine design personnel carries on using creative ability the product design, the system analysis and a formulation product manufacture technology good opportunity. Grasps the project elementary knowledge to have to memorize some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point position, also can cause the correct design to turn wrongly.
A good design personnel should dare to propose the new idea, moreover is willing to undertake the certain risk, when the new method is not suitable, use original method. Therefore, designs the personnel to have to have to have the patience, because spends the time and the endeavor certainly cannot guarantee brings successfully. A brand-new design, the request screen abandons obsoletely many, knows very well the method for the people. Because many person of conservativeness, does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after the confirmation new idea.
Newly designs itself can have the question occurrence which many flaws and has not been able to expect, only has after these flaws and the question are solved, can manifest new goods come into the market the product superiority. Therefore, a performance superior product is born at the same time, also is following a higher risk. Should emphasize, if designs itself does not request to use the brand-new method, is not unnecessary merely for the goal which transform to use the new method.
In the design preliminary stage, should allow to design the personnel fully to display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the innovation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts.
How does the psychologist frequently discuss causes the machine which the people adapts them to operate. Designs personnel''s basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because certainly does not have to all people to say in fact all is the most superior operating area and the operating process.
Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and the consultation on the preliminary design with the administrative personnel, and is approved. This generally is through the oral discussion, the schematic diagram and the writing material carries on. In order to carry on the effective exchange, needs to solve the following problem:
(1) designs whether this product truly does need for the people? Whether there is competitive ability
(2) does this product compare with other companies'' existing similar products?
(3) produces this kind of product is whether economical?
(4) product service is whether convenient?
(5) product whether there is sale? Whether may gain?
Only has the time to be able to produce the correct answer to above question. But, the product design, the manufacture and the sale only can in carry on to the above question preliminary affirmation answer foundation in. Project engineer also should through the detail drawing and the assembly drawing, carries on the consultation together with the branch of manufacture to the finally design proposal.
Usually, can have some problem in the manufacture process. Possibly can request to some components size or the common difference makes some changes, causes the components the production to change easily. But, in the project change must have to pass through designs the personnel to authorize, guaranteed cannot damage the product the function. Sometimes, when in front of product assembly or in the packing foreign shipment experiment only then discovers in the design some kind of flaw. These instances exactly showed the design is a dynamic process. Always has a better method to complete the design work, designs the personnel to be supposed unceasingly diligently, seeks these better method.
Recent year, the engineerig material choice already appeared importantly. In addition, the choice process should be to the material continuously the unceasing again appraisal process. The new material unceasingly appears, but some original materials can obtain the quantity possibly can reduce. The environmental pollution, material recycling aspect and so on use, worker''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 competition, to product service maintenance convenience request enhancement and customer''s aspect the and so on feedback pressure, can urge the people to carry on to the material reappraises. Because the material does not select when created the product responsibility lawsuit, has already had the profound influence. In addition, the material and between the material processing interdependence is already known by the people clearly. Therefore, in order to can and guarantees the quality in the reasonable cost under the premise to obtain satisfaction the result, project engineer makes engineers all to have earnestly carefully to choose, the determination and the use material.
Makes any product the first step of work all is designs. Designs usually may divide into several explicit stages: (a) preliminary design; (b) functional design; (c) production design. In the preliminary design stage, the designer emphatically considered the product should have function. Usually must conceive and consider several plans, then decided this kind of thought is whether feasible; If is feasible, then should makes the further improvement to or several plans. In this stage, the question which only must consider about the choice of material is: Whether has the performance to conform to the request material to be possible to supply the choice; 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 complete blueprint in this stage, chooses and determines each kind of components 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 company 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 company. The function complete 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 completely complete the material in this stage the analysis, the choice and the determination work, but is not remains it to the production design stage does. Because, is carries on in the production design stage material replacement by other people, these people are inferior to project engineer to the product all functions understanding. I
n the production design stage, is should completely 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 common 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 long-term operational performance causes.
The product responsibility lawsuit forces designs the personnel and the company when the choice material, uses the best procedure. In the material process, five most common 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.
In recent 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 long-term 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 completely is not competent 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 comprehensive and the basic understanding.
中文譯文：
機(jī)械設(shè)計(jì)理論
機(jī)械設(shè)計(jì)是一門通過設(shè)計(jì)新產(chǎn)品或者改進(jìn)老產(chǎn)品來滿足人類需求的應(yīng)用技術(shù)科學(xué)。它涉及工程技術(shù)的各個領(lǐng)域，主要研究產(chǎn)品的尺寸、形狀和詳細(xì)結(jié)構(gòu)的基本構(gòu)思，還要研究產(chǎn)品在制造、銷售和使用等方面的問題。
進(jìn)行各種機(jī)械設(shè)計(jì)工作的人員通常被稱為設(shè)計(jì)人員或者機(jī)械設(shè)計(jì)工程師。機(jī)械設(shè)計(jì)是一項(xiàng)創(chuàng)造性的工作。設(shè)計(jì)工程師不僅在工作上要有創(chuàng)造性，還必須在機(jī)械制圖、運(yùn)動學(xué)、工程材料、材料力學(xué)和機(jī)械制造工藝學(xué)等方面具有深厚的基礎(chǔ)知識。
如前所訴，機(jī)械設(shè)計(jì)的目的是生產(chǎn)能夠滿足人類需求的產(chǎn)品。發(fā)明、發(fā)現(xiàn)和科技知識本身并不一定能給人類帶來好處，只有當(dāng)它們被應(yīng)用在產(chǎn)品上才能產(chǎn)生效益。因而，應(yīng)該認(rèn)識到在一個特定的產(chǎn)品進(jìn)行設(shè)計(jì)之前，必須先確定人們是否需要這種產(chǎn)品。
應(yīng)當(dāng)把機(jī)械設(shè)計(jì)看成是機(jī)械設(shè)計(jì)人員運(yùn)用創(chuàng)造性的才能進(jìn)行產(chǎn)品設(shè)計(jì)、系統(tǒng)分析和制定產(chǎn)品的制造工藝學(xué)的一個良機(jī)。掌握工程基礎(chǔ)知識要比熟記一些數(shù)據(jù)和公式更為重要。僅僅使用數(shù)據(jù)和公式是不足以在一個好的設(shè)計(jì)中做出所需的全部決定的。另一方面，應(yīng)該認(rèn)真精確的進(jìn)行所有運(yùn)算。例如，即使將一個小數(shù)點(diǎn)的位置放錯，也會使正確的設(shè)計(jì)變成錯誤的。
一個好的設(shè)計(jì)人員應(yīng)該勇于提出新的想法，而且愿意承擔(dān)一定的風(fēng)險(xiǎn)，當(dāng)新的方法不適用時，就使用原來的方法。因此，設(shè)計(jì)人員必須要有耐心，因?yàn)?所花費(fèi)的時間和努力并不能保證帶來成功。一個全新的設(shè)計(jì)，要求屏棄許多陳舊的，為人們所熟知的方法。由于許多人墨守成規(guī)，這樣做并不是一件容易的事。一位機(jī)械設(shè)計(jì)師應(yīng)該不斷地探索改進(jìn)現(xiàn)有的產(chǎn)品的方法，在此過程中應(yīng)該認(rèn)真選擇原有的、經(jīng)過驗(yàn)證的設(shè)計(jì)原理，將其與未經(jīng)過驗(yàn)證的新觀念結(jié)合起來。
新設(shè)計(jì)本身會有許多缺陷和未能預(yù)料的問題發(fā)生，只有當(dāng)這些缺陷和問題被解決之后，才能體現(xiàn)出新產(chǎn)品的優(yōu)越性。因此，一個性能優(yōu)越的產(chǎn)品誕生的同時，也伴隨著較高的風(fēng)險(xiǎn)。應(yīng)該強(qiáng)調(diào)的是，如果設(shè)計(jì)本身不要求采用全新的方法，就沒有必要僅僅為了變革的目的而采用新方法。
在設(shè)計(jì)的初始階段，應(yīng)該允許設(shè)計(jì)人員充分發(fā)揮創(chuàng)造性，不受各種約束。即使產(chǎn)生了許多不切實(shí)際的想法，也會在設(shè)計(jì)的早期，即繪制圖紙之前被改正掉。只有這樣，才不致于堵塞創(chuàng)新的思路。通常，要提出幾套設(shè)計(jì)方案，然后加以比較。很有可能在最后選定的方案中，采用了某些未被接受的方案中的一些想法。
心理學(xué)家經(jīng)常談?wù)撊绾问谷藗冞m應(yīng)他們所操作的機(jī)器。設(shè)計(jì)人員的基本職責(zé)是努力使機(jī)器來適應(yīng)人們。這并不是一項(xiàng)容易的工作，因?yàn)閷?shí)際上并不存在著一個對所有人來說都是最優(yōu)的操作范圍和操作過程。
另一個重要問題，設(shè)計(jì)工程師必須能夠同其他有關(guān)人員進(jìn)行交流和磋商。在開始階段，設(shè)計(jì)人員必須就初步設(shè)計(jì)同管理人員進(jìn)行交流和磋商，并得到批準(zhǔn)。這一般是通過口頭討論，草圖和文字材料進(jìn)行的。為了進(jìn)行有效的交流 ，需要解決下列問題：
（1） 所設(shè)計(jì)的這個產(chǎn)品是否真正為人們所需要？
（2） 此產(chǎn)品與其他公司的現(xiàn)有同類產(chǎn)品相比有無競爭能力？
（3） 生產(chǎn)這種產(chǎn)品是否經(jīng)濟(jì)？
（4） 產(chǎn)品的維修是否方便？
（5） 產(chǎn)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。但是， 產(chǎn)品的設(shè)計(jì)、制造和銷售只能在對上述問題的初步肯定答案的基礎(chǔ)上進(jìn)行。設(shè)計(jì)工程師還應(yīng)該通過零件圖和裝配圖，與制造部門一起對最終設(shè)計(jì)方案進(jìn)行磋商。
通常 ，在制造過程中會出現(xiàn)某個問題。可能會要求對某個零件尺寸或公差作一些更改，使零件的生產(chǎn)變得容易。但是，工程上的更改必須要經(jīng)過設(shè)計(jì)人員批準(zhǔn)，以保證不會損傷產(chǎn)品的功能。有時，在產(chǎn)品的裝配時或者裝箱外運(yùn)前的試驗(yàn)中才發(fā)現(xiàn)設(shè)計(jì)中的某種缺陷。這些事例恰好說明了設(shè)計(jì)是一個動態(tài)過程?？偸谴嬖谥玫姆椒▉硗瓿稍O(shè)計(jì)工作，設(shè)計(jì)人員應(yīng)該不斷努力，尋找這些更好的方法。
近些年來，工程材料的選擇已經(jīng)顯得重要。此外，選擇過程應(yīng)該是一個對材料的連續(xù)不斷的重新評價過程。新材料不斷出現(xiàn)，而一些原有的材料的能夠獲得的數(shù)量可能會減少。環(huán)境污染、材料的回收利用、工人的健康及安全等方面經(jīng)常會對材料選擇附加新的限制條件。為了減輕重量或者節(jié)約能源，可能會要求使用不同的材料。來自國內(nèi)和國際競爭、對產(chǎn)品維修保養(yǎng)方便性要求的提高和顧客的反饋等方面的壓力，都會促使人們對材料進(jìn)行重新評價。由于材料選用不當(dāng)造成的產(chǎn)品責(zé)任訴訟，已經(jīng)產(chǎn)生了深刻的影響。此外，材料與材料加工之間的相互依賴關(guān)系已經(jīng)被人們認(rèn)識得更清楚。因此，為了能在合理的成本和確保質(zhì)量的前提下獲得滿意的結(jié)果，設(shè)計(jì)工程師的制造工程師都必須認(rèn)真仔細(xì)地選擇、確定和使用材料。
制造任何產(chǎn)品的第一步工作都是設(shè)計(jì)。設(shè)計(jì)通?？梢苑譃閹讉€明確的階段：（a）初步設(shè)計(jì)；（b）功能設(shè)計(jì)；（c）生產(chǎn)設(shè)計(jì)。在初步設(shè)計(jì)階段，設(shè)計(jì)者著重考慮產(chǎn)品應(yīng)該具有的功能。通常要設(shè)想和考慮幾個方案，然后決定這種思想是否可行；如果可行，則應(yīng)該對其中一個或幾個方案作進(jìn)一步的改進(jìn)。在此階段，關(guān)于材料選擇唯一要考慮的問題是：是否有性能符合要求的材料可供選擇；如果沒有的話，是否有較大的把握在成本和時間都允許的限度內(nèi)研制出一種新材料。
在功能設(shè)計(jì)和工程設(shè)計(jì)階段，要做出一個切實(shí)可行的設(shè)計(jì)。在這個階段要繪制出相當(dāng)完整的圖紙，選擇并確定各種零件的材料。通常要制造出樣機(jī)或者實(shí)物模型，并對其進(jìn)行試驗(yàn)，評價產(chǎn)品的功能、可靠性、外觀和維修保養(yǎng)性等。雖然這種試驗(yàn)可能會表明，在產(chǎn)品進(jìn)入到生產(chǎn)階段之前，應(yīng)該更換某些材料，但是，絕對不能將這一點(diǎn)作為不認(rèn)真選擇材料的借口。應(yīng)該結(jié)合產(chǎn)品的功能，認(rèn)真仔細(xì)地考慮產(chǎn)品的外觀、成本和可靠性。一個很有成就的公司在制造所有的樣機(jī)時，所選用的材料應(yīng)該和其生產(chǎn)中使用的材料相同，并盡可能使用同樣的制造技術(shù)。這樣對公司是很有好處的。功能完備的樣機(jī)如果不能根據(jù)預(yù)期的銷售量經(jīng)濟(jì)地制造出來，或者是樣機(jī)與正式生產(chǎn)的裝置在質(zhì)量和可靠性方面有很大不同，則這種樣機(jī)就沒有多大的價值。設(shè)計(jì)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(chǎn)設(shè)計(jì)階段去做。因?yàn)?，在生產(chǎn)設(shè)計(jì)階段材料的更換是由其他人進(jìn)行的，這些人對產(chǎn)品的所有功能的了解不如設(shè)計(jì)工程師。
在生產(chǎn)設(shè)計(jì)階段中，與材料有關(guān)的主要問題是應(yīng)該把材料完全確定下來，使它們與現(xiàn)有的設(shè)備相適應(yīng)，能夠利用現(xiàn)有設(shè)備經(jīng)濟(jì)地進(jìn)行加工，而且材料的數(shù)量能夠比較容易保證供應(yīng)。
在制造過程中，不可避免地會出現(xiàn)對使用中的材料做一些更改的情況。經(jīng)驗(yàn)表明，可采用某些便宜材料作為替代品。然而，在大多數(shù)情況下，在進(jìn)行生產(chǎn)以后改換材料要比在開始生產(chǎn)前改換材料所花費(fèi)的代價要高。在設(shè)計(jì)階段做好材料選擇工作，可以避免多數(shù)這樣的情況。在生產(chǎn)制造開始后出現(xiàn)了可供使用的新材料是更換材料的最常見的原因。當(dāng)然，這些新材料可能降低成本、改進(jìn)產(chǎn)品的性能。但是，必須對新材料進(jìn)行認(rèn)真的評價，以確保其所有性能都滿足要求。應(yīng)當(dāng)記住，新材料的性能和可靠性很少像現(xiàn)有材料那樣為人們所了解。大部分的產(chǎn)品失效和產(chǎn)品責(zé)任事故案件是由于在選用新材料作為替代材料之前，沒有真正了解它們的長期使用性能而引起的。
產(chǎn)品的責(zé)任訴訟迫使設(shè)計(jì)人員和公司在選擇材料時，采用最好的程序。在材料過程中，五個最常見的問題為：（a）不了解或者不會使用關(guān)于材料應(yīng)用方面的最新最好的信息資料；(b)未能預(yù)見和考慮擦黑年品可能的合理用途（如有可能，設(shè)計(jì)人員還應(yīng)進(jìn)一步預(yù)測和考慮由于產(chǎn)品使用方法不當(dāng)造成的后果。在近年來的許多產(chǎn)品責(zé)任訴訟案件中，由于錯誤地使用產(chǎn)品而受到傷害的原告控告生產(chǎn)廠家，并且贏得判決）；(c)所使用的材料的數(shù)據(jù)不全或是有些數(shù)據(jù)不確定，尤其是當(dāng)其長期性能數(shù)據(jù)是如此的時候；(d)質(zhì)量控制方法不適當(dāng)和未經(jīng)驗(yàn)證；(e)由一些完全不稱職的人員選擇材料。
通過對上述五個問題的分析，可以得出這些問題是沒有充分理由存在的結(jié)論。對這些問題的研究分析可以為避免這些問題的出現(xiàn)指明方向。盡管采用最好的材料選擇方法也不能避免發(fā)生產(chǎn)品責(zé)任訴訟，設(shè)計(jì)人員和工業(yè)界按照適當(dāng)?shù)某绦蜻M(jìn)行材料選擇，可以大大減少訴訟的數(shù)量。
從以上的討論可以看出，選擇材料的人們應(yīng)該對材料的性質(zhì)，特點(diǎn)和加工方法有一個全面而基本的了解。