電器蓋注塑模具設(shè)計(jì)【含CAD圖紙+三維UG+文檔】
電器蓋注塑模具設(shè)計(jì)【含CAD圖紙+三維UG+文檔】,含CAD圖紙+三維UG+文檔,電器,注塑,模具設(shè)計(jì),cad,圖紙,三維,ug,文檔
English translation in injection mold
Abstract: According to the requirements of the plastic products, understand the use of plastic parts, technical requirements, analysis of dimensional accuracy and other technical considerations of plastic parts, plastic parts size. We used a mold two cavity, the side gate, injection machine uses the Haitian 110X 1A models, equipped with a cooling system, CAD and UG drawing two-dimensional assembly drawing and parts drawing, choose the reasonable processing method of mould. Attach a statement, the systematic use of a brief text, analysis and calculation of plastic parts and concise, so as to make reasonable mold design.
Key Words：Mechanical design;?mold design;?CAD?UG to draw the?3D?drawing two-dimensional map.
1、Introduction
Many types of mold, the structure and varieties of plastic, plastic injection molding machine and the complexity of the types and other factors, its basic structure is composed of the movable mould and the fixed mould is composed of two parts. The fixed mould part arranged on the fixing plate of the machine, dynamic part is installed in the mobile injection molding machine, in the injection molding process with the clamping system of injection molding machine's movement. Part of mold and die part guided by a guide post and a closed dynamic injection molding. General injection molding parts, the clamping mechanism, gating system, side parting and core pulling mechanism, pushing mechanism, a heating and cooling system, exhaust system and the supporting parts.
At present, the mould manufacturing technology in China has been from the past can only make simple mold to mold can produce large, sophisticated, complex, long life. In the plastic mold design and manufacturing, to bumper and the whole panel of large injection mold. With the rapid development of computer technology, the mold design and manufacturing technology is moving in the direction of the development of digital. On the one hand, the domestic market will continue to mold growth; on the other hand, mold manufacturing is gradually transferred to China and the multinational corporations to China's purchases tend to die is also very obvious. China's economy is still in a stage of rapid development, the international development trend of economic globalization is increasingly obvious, which provides good conditions and opportunities for the rapid development of mold industry in our country.
2、 Mold-Filling Simulation
2.1 Calculation of the interface locations
The mold filling velocity and the shape of the melt front in LFC are quite different from those in the conventional empty mold casting．The velocity at the melt front is restricted by the foam degradation，gas elimination，pressure building-up in the mold，etc，and ．1t is affected by the original process parameters，such as the vacuum degree，the pattern density and the metallic static head ． The melt—pattern interface develops in a radiate manner．Due to the foam degradation caused by the heat transfer between the molten metal and the foam pattern in LFC．The influence of the gravity on the mold filling velocity and the interface morphology in LFC is minor compared with that in the conventional empty mold gravity casting[5 ~7]． According to the mechanism of the melt front
movement during the mold filling process of LFC．the artificial neural network technique is proposed to calculate the locations of the melt—pattern interface．
The whole casting(including the gating and feeding system) is meshed into the cubic cells of appropriate size．Each cell is regarded as a neuron and can be in one of three states during the mold filling, empty, interfacial or ful1. A neural network is formed through the interconnecting links between the cells，in which each cell is connected only to its neighboring cells and has no connections to the others．The architecture of the network is similar to the cellular neural network
(CNN)in the way of cell connecting，I,E, with locally interconnecting
linkage and pre-designed link values(weights)．According to the mode of linkage，each cell except for the cell located at the boundary of the casting is connected to its 26 neighboring cells．
Let C(i，j，k)denote a cell and Nr(i，j, k)the aggregation of ceils connected to C(i，j，k)，then：
From the initial time t0，each cell of the network changes its state of activation at the end of every time interval Δt according to its activation function an d produces an output value of 1 or 0．For a time intervaleach cell accepts the outputs from the 26 neighboring cells as its input．Using a 26-dimeusional vector to denote the input of C(i，j ，k)，the components of the vector are：
in which， is the output of C(l，m，n)and represents the distance of interface movement from C(l，m，n)to the un-filled cell C(i，j，k)in the time interval of At with unit velocity．
The summed input of the un-filled cell c(i，J，k)is：
where， is the input function and represents the 26_dimensional weight vector．Each component of the weight vector is set according to the velocities of the neighboring cell and their relative of nations．that is：
where， denotes the relative orientation to the neighboring cells，and ， is the evaporating velocity of the foam pattern at the corresponding location．From the related experimental study it has been found that is determined by the process parameters of the metallic static head h，the vacuum degree ，the pattern density d，the pouring temperature and the factor of coating property For this specially designed network，the operation 0f the input function is to calculate the relative interface moving distances from the neighboring cells to cell C(i,j,k).The detailed calculation process is as follows:
(1)By multiplying the corresponding components of the input vector and weight vector，a new 26-dimensional vector is obtained，and the accumulation of the components of the new vector with time is：
And ，when C(i，J，k )is empty．
(2)By summing the two components of vector ，m，along which the filling directions confront with each other，a 13-dimensional vector is obtained：
Let
then，the states of activation of the cells are defined as:
when ，k=0，C(i，j，k )is an empty cell；
when ，j， ≥0，C(i，j，k )is a full cell；
when ， <0，C(i，j，k)is an interface cel1．
The output of the neuron is a threshold function：
where is the threshold value of the neuron and it equals to
the side length of the meshed cel1．
Fig．1 Flow chart of LFC mold filling solution procedure
The algorithm was realized by C++ computing language，as its computation flow chart shown in Fig．1、At the beginning of the calculation．The cells in the top layer of the meshed sprue of casting were set to be fu11 (if the sprue was hollow，all the cells between the top layer of sprue and the ingate were set to be ful1)．According to the calculation process，all the cells would be full after filling for a certain time, and the system would be stable.
2.2 Calculation on the fluid flow and temperature distribution during mold filling
According to the above solution algorithm，the locations of melt—pattern interface at any moment are obtained． So the fluid flow and the temperature distribution during the mold filling can be calculated by solving the N—S equation and the energy equation within the known computational domain．
The governing equations are expressed as the following
general form ：
where φ is a dependent variable，Γrepresents the diffusion coefficient and S is the source term．The equation represents the continuity equation，the N—S equation or the energy equation，when the dependent variable is 1，uj, or T，respectively．For a certain φ，there are correspondingΓ and S．
SOLA technique was applied to calculate the fluid flow in the N—S equation．The velocity boundary condition at the melt—pattern interface in LFC is different from that at the free surface in the conventional empty mold casting．In the lost foam casting ，the melt front velocity is restricted by the evaporating velocity of the foam pattern．So the melt front velocity could be set as the evaporating velocity of the foam pattern，and the direction is determined according to the relative orientation between the molten metal and the foam pattern．For a full cell C(i，j，k )，for example，if the output value， is 0，then the boundary velocity can be set as :．
The temperature boundary condition at the melt front in LFC is also quite different from that in the conventional empty mold casting．In the lost foam casting，the melt front is remarkably chilled due to the evaporation an d the decomposition of the foam pattern．Generally ,so me researchers used an equivalent heat transfer coefficient to deal with the chilling effect ．In this paper ,the boundary condition is treated by giving the relationship between the heat flow an d the time at the interface．
3、Check the stiffness and strength of die
Die strength of common sense in mold strength, stiffness. Requirements of various molding parts and components have the strength, the stiffness of the die, enough strength can ensure mold can work normally.
Because the mold form is more, the calculation is different and more complex, in actual production, using the method of experience design and strength check of the combination of the strength check, adjust the design, to ensure the normal work of the mould can be.
Die strength calculation is relatively complex, generally use the simplified calculation method, to take a conservative approach, the calculation principle is: select the most unfavorable loading structure, selection of safety coefficient, and then optimizing the structure of the mold, improve the mold strength. In order to ensure that the mold can work normally, the overall strength is not only to check the mold, to check the strength of the local structure of die.
The overall strength of the main for the cavity wall thickness, cavity thickness of base plate, several pressure mold surface can bear, the actual choice of size should be larger than the size and integral calculation. Check the strength and bending from the two aspects of calculation, select a larger size.
4、Design and calculation of cooling system
Mold temperature have influence on the mold filling of plastic melt flow, solidification, the production efficiency and the product's shape and size precision, for any plastic products, mold temperature fluctuation is negative. The mold temperature is too high will make the plastic deformation occurs in the release, to extend the cooling time and make the productivity decline. Mold temperature too low will reduce the flow of plastic, making it difficult to filling, increased stress products and obvious weld marks. Due to the requirements of performance and process all kinds of plastic, the mold temperature requirements are not the same. Plastic powder injection to the general mold temperature, melt solidified into the plastic parts, reduce the mold, mold temperature from the left and right are dependent on the cooling water inlet in the mold, the heat away. For the requirement of low temperature (less than) plastic, only need to set up the cooling system can be, because can be adjusted by the flow of water to adjust the mould temperature
5、Conclusions
The mold design project, through the analysis of plastic parts of the process, determine the overall design of the mold, and the design of each subsystem. The design of the mould can meet the quality requirements of the working state, the use of safe and reliable, easy to repair, a molding cycle is short in injection molding, forming a long service life, reasonable mould manufacturing process.
Through the above work, I on a mold from design to the whole process of knowledge are clear and intuitive, understanding the working principle of injection mold, with the experience and knowledge will determine the design and accuracy of the main parts of the die cavity and so on, can be a reasonable solution to the problems in the design of the mould often appear the proposed, to select the injection molding machine, mold, determine the structure and size of the cavity number, the choice of parting surface, gating system design, core pulling mechanism etc.. Due to the lack of knowledge and experience, in the design process to determine the machining accuracy of parts, there are still many shortcomings, still need to be improved in the future work, study.
References
[1] Chen Xiaokang, Zhou Xinglong. Practical Mould Technology Handbook [M]. Beijing: China Light Industry Press, 2001
[2] Peng Jiansheng. Mold design and Processing Handbook [M]. Beijing: Mechanical Industry Press, 2005
[3] Shen Kai Chi. Plastic mould [M]. Beijing: China Light Industry Press, 2002
[4] Liu Shouyong machinery manufacturing technology and machine tool fixture [M]. Beijing: Mechanical Industry Press, 2000
[5] Zhang Zheng. Die manufacturing technology [M]. Beijing: Publishing House of electronics industry, 2002
[6] Ding Wen. The utility of plastic mold design manual [M]. Xi'an: Xi'an Jiao Tong University press, 1993
[7] Li Zhigang, Xia Ju Chen. China Mold Design Canon [M]. China society of mechanical engineering, 2003
[8] pan Baoquan. Die manufacturing technology [M]. Beijing: Mechanical Industry Press, 2004
[9] Wang Boping, interchangeability and measurement technology [M]. Beijing: Mechanical Industry Press, 2002
[10] Li Yimin. Mechanical manufacturing process design handbook [M]. Beijing: Mechanical Industry Press, 1993
[11] Li Yuncheng. Die manufacturing technology [M]. Beijing: Mechanical Industry Press, 2002
[12] Huang Chengju, Li Eqin. Reverse engineering project training tutorial [M]. Beijing: Publishing House of electronics industry, 2004
[13] Liu Yanguo, Yan Huiping. The quantity of injection molding cavity of the selection of [J]. electromachining & mould, 2006
[14] Wilson, F.W.Die Design Handbook MaGraw Hill 1990.6
[15] Q.C.Li, Z.Huang.Mobility Analysis of a novel 3-5R Parallel Mechanism Family.DOI: 10.1115/1.1637651
注塑模中英文翻譯
摘要：根據(jù)塑料制品的要求，了解塑件的用途，分析塑件的工藝性、尺寸精度等技術(shù)要求，考量塑件制件尺寸。本模具采用一模兩腔，側(cè)澆口進(jìn)料，注射機(jī)采用海天110X 1A型號(hào)，設(shè)置冷卻系統(tǒng)，CAD和UG繪制二維總裝圖和零件圖，選擇模具合理的加工方法。附上說(shuō)明書，系統(tǒng)地運(yùn)用簡(jiǎn)要的文字，簡(jiǎn)明的示意圖和和計(jì)算等分析塑件，從而作出合理的模具設(shè)計(jì)。
關(guān)鍵詞：機(jī)械設(shè)計(jì)；模具設(shè)計(jì)；CAD繪制二維圖；UG繪制3D圖。
1 、介紹
注塑模的種類很多，其結(jié)構(gòu)與塑料品種、塑件的復(fù)雜程度和注塑機(jī)的種類等很多因素有關(guān)，其基本結(jié)構(gòu)都是由動(dòng)模和定模兩大部分組成的。定模部分安裝在注塑機(jī)的固定板上，動(dòng)模部分安裝在注塑機(jī)的移動(dòng)模板上，在注射成型過(guò)程中它隨注塑機(jī)上的合模系統(tǒng)運(yùn)動(dòng)。注塑成型時(shí)動(dòng)模部分與定模部分由導(dǎo)柱導(dǎo)向而閉合。一般注塑模由成型零部件、合模導(dǎo)向機(jī)構(gòu)、澆注系統(tǒng)、側(cè)向分型與抽芯機(jī)構(gòu)、推出機(jī)構(gòu)、加熱和冷卻系統(tǒng)、排氣系統(tǒng)及支承零部件組成。
目前，我國(guó)的模具制造技術(shù)已從過(guò)去只能制造簡(jiǎn)單模具發(fā)展到可以制造大型、精密、復(fù)雜、長(zhǎng)壽命的模具。在塑料模具方面，能設(shè)計(jì)制造汽車保險(xiǎn)杠及整體儀表盤大型注塑模。隨著計(jì)算機(jī)技術(shù)的發(fā)展應(yīng)用，模具設(shè)計(jì)與制造技術(shù)正朝著數(shù)字化方向發(fā)展。一方面，國(guó)內(nèi)模具市場(chǎng)將繼續(xù)高速發(fā)展；另一方面，模具制造也逐漸向我國(guó)轉(zhuǎn)移以及跨國(guó)集團(tuán)到我國(guó)進(jìn)行模具采購(gòu)趨向也十分明顯。我國(guó)經(jīng)濟(jì)仍處于高速發(fā)展階段，國(guó)際上經(jīng)濟(jì)全球化發(fā)展趨勢(shì)日趨明顯，這為我國(guó)模具工業(yè)高速發(fā)展提供了良好的條件和機(jī)遇。
2、模具充模仿真
2.1界面定位的計(jì)算
在消失模鑄造中, 模具充模的速度和熔化前面的形狀與傳統(tǒng)空模鑄造是十分不同的.在模具中, 熔化前面的速率受到泡抹降解,天然氣揮發(fā)和應(yīng)力集中等等的限制。它還受到源工藝參數(shù)的影響,例如真空度,模型密度和金屬的靜止端,熔化模式的界面是按放射模式展開(kāi)的。在消失模鑄造中，由于泡沫降解導(dǎo)致熱量在熔融金屬與泡沫之間傳遞。在消失模鑄造中，模具沖模速率與界面形態(tài)學(xué)相對(duì)與傳統(tǒng)的空模具重力影響是很小的。根據(jù)熔融前面的運(yùn)動(dòng)機(jī)理，在消失模鑄造過(guò)程中，人工神經(jīng)網(wǎng)絡(luò)技術(shù)很可能計(jì)算出熔融形式界面的定位。
整個(gè)鑄造（包括開(kāi)啟和進(jìn)給系統(tǒng)）結(jié)網(wǎng)成恰當(dāng)形式的的立方單元。每個(gè)單元被認(rèn)為是一個(gè)神經(jīng)元，在模具沖模中處于三種狀態(tài)，空的，接口的，滿的。通過(guò)單元之間的內(nèi)部連接，一個(gè)神經(jīng)網(wǎng)絡(luò)就形成了，其中每個(gè)單元只是與它相鄰的單元相連，不與其它的單元相連。在單元連接形式上，通過(guò)固定的連接鏈和預(yù)定的設(shè)定鏈連接重力。由于模型的收縮率，除了固定在鑄模邊緣的單元，每個(gè)單元都與26維相鄰單元連接。
如果C(i，j，k)代表一個(gè)單元，Nr(i，j, k)代表連接C(i，j，k)的單元，那么：
從開(kāi)始時(shí)間T0，根據(jù)它的活動(dòng)功能和產(chǎn)生1或0的量，在相距一定的時(shí)間間隔下，每個(gè)網(wǎng)絡(luò)單元改變它的活動(dòng)狀態(tài)。在相距一定的時(shí)間間隔下，每個(gè)單元連接26維相鄰單元的輸出量作為輸入量。用這26維矢量來(lái)表示C(i，j，k)的輸入量，其矢量式是：
在這里，是C(l，m，n)的輸出量，在單位速度相同的時(shí)間內(nèi)，代表了界面運(yùn)動(dòng)從C(l，m，n)到未填充的C(i，j，k)的距離。
總共未填充的單元c(i，J，k 是：
其中，是輸入功能，代表26維重力矢量。根據(jù)相鄰單元的速率和它們相對(duì)的特性，每個(gè)組件的重力矢量設(shè)置如下：
其中，說(shuō)明了相對(duì)與相鄰單元的方向，也是在相對(duì)應(yīng)的位置泡沫形式的蒸發(fā)速率。從相關(guān)實(shí)驗(yàn)研究中，我們發(fā)現(xiàn)，金屬靜止端，真空度，模型密度，澆注溫度和鑄造特性因素的工藝參數(shù)決定了。
為了這個(gè)特殊的網(wǎng)絡(luò)設(shè)計(jì),輸入功能的作用是用來(lái)計(jì)算相對(duì)的界面從相鄰的單元到C運(yùn)動(dòng)的距離,其詳細(xì)的計(jì)算過(guò)程如下:
(1) 通過(guò)相乘相應(yīng)的組件的輸入量和重力矢量,一個(gè)新的26維矢量就得到了,這個(gè)累加的組件的新的矢量是:
當(dāng)C(i，J，k )是空的時(shí)候，
(2) 通過(guò)相加兩個(gè)組件矢量,由于填充方向相互面對(duì),一個(gè)新的13維矢量就得到了:
如果
那么所以單元的活動(dòng)狀態(tài)定義如下:
當(dāng)，k=0，C(i，j，k )是空單元
當(dāng)，j， ≥0，C(i，j，k )是滿單元
當(dāng)， <0，C(i，j，k)是接口單元
神經(jīng)元的輸出具有閾功能:
當(dāng)神經(jīng)元的閾值是θ是時(shí),它等同于結(jié)網(wǎng)單元的邊長(zhǎng)度:
通過(guò)C++程序語(yǔ)言可以實(shí)現(xiàn)這種算法,計(jì)算流程如圖1所示.在計(jì)算開(kāi)始的時(shí)候,鑄模網(wǎng)絡(luò)的頂層的網(wǎng)格單元設(shè)置為滿(如果尖端是凹的,在頂層和入口的所有單元都設(shè)置為滿).根據(jù)這個(gè)計(jì)算程序,通過(guò)一定時(shí)間的填充,所以的單元都是滿的,這個(gè)系統(tǒng)就是穩(wěn)定的。
2.2在模具充模過(guò)程中液體流動(dòng)和溫度分布的計(jì)算
根據(jù)上面的算法,熔化模式界面的定位在任何時(shí)候都可以得到.所以在一定的計(jì)算范圍內(nèi),通過(guò)求解N-S方程和能量方程,模具充模中的液體流動(dòng)和溫度分布都可以計(jì)算出來(lái).調(diào)節(jié)方程的表示如下：
一般形式為：
其中φ是因變量,Γ代表擴(kuò)散系數(shù),?代表原條件.而且這個(gè)方程是一個(gè)連續(xù)性的方程,可以是N-S方程或者能量方程.當(dāng)因變量是1或T時(shí),各不相關(guān).在一定的情況下,都有相應(yīng)的Γ和 ?。
在N-S方程中,SOLA技術(shù)用來(lái)計(jì)算液體流動(dòng),在消失模鑄造中,邊界條件的速率與傳統(tǒng)的空模鑄造的速率是不相同的. 在消失模鑄造中,熔融前面的速率受到泡沫模式的速率的限制.所以前面熔化速率應(yīng)該設(shè)置為泡沫模式的蒸發(fā)速率,根據(jù)熔融狀金屬和泡沫方式之間的相對(duì)方向來(lái)決定其方向.所以一個(gè)滿單元C(i，j，k )為例,如果輸出值為0,那么邊界速率設(shè)置為：
在消失模鑄造中,熔融物前面的邊界狀態(tài)下的溫度是不同與傳統(tǒng)空模鑄造的溫度。在消失模鑄造中,由于泡沫模式的蒸發(fā)和分解, 熔融物前面的溫度顯著劇烈.通常,我們的研究者用等效的轉(zhuǎn)換系數(shù)來(lái)處理劇烈效應(yīng)。在這篇文章中,通過(guò)在熱量流與界面之間給定的關(guān)系來(lái)處理邊界情況。
3、模具強(qiáng)度與剛度校核
普通意義上的模具強(qiáng)度包括模具的強(qiáng)度、剛度。模具的各種成型零部件和結(jié)構(gòu)零部件均有強(qiáng)度、剛度的要求，足夠的強(qiáng)度才可以保證模具能正常工作。
由于模具形式較多，計(jì)算也不盡相同且較復(fù)雜，實(shí)際生產(chǎn)中，采用經(jīng)驗(yàn)設(shè)計(jì)和強(qiáng)度校核相結(jié)合的方法，通過(guò)強(qiáng)度校核來(lái)調(diào)整設(shè)計(jì)，保證模具能正常工作。
模具強(qiáng)度計(jì)算較為復(fù)雜，一般采用簡(jiǎn)化的計(jì)算方法,計(jì)算時(shí)采取保守的做法，原則是：選取最不利的受力結(jié)構(gòu)形式，選用較大的安全系數(shù)，然后再優(yōu)化模具結(jié)構(gòu)，充分提高模具強(qiáng)度。為保證模具能正常工作，不僅要校核模具的整體性強(qiáng)度，也要校核模具局部結(jié)構(gòu)的強(qiáng)度。
整體性強(qiáng)度主要針對(duì)型腔側(cè)壁厚度，型腔底板厚度，合模面所能承受的壓力等幾個(gè)方面，實(shí)際選用尺寸應(yīng)大于計(jì)算尺寸并取整。校核時(shí)應(yīng)從強(qiáng)度與彎曲兩個(gè)方面分別計(jì)算，選取較大的尺寸。
4、冷卻系統(tǒng)的設(shè)計(jì)與計(jì)算
注塑模的溫度對(duì)于塑料熔體的充模流動(dòng)、固化成型、生產(chǎn)效率以及制品的形狀和尺寸精度都有影響，對(duì)于任一個(gè)塑料制品，模具溫度波動(dòng)過(guò)大都是不利的。過(guò)高的模溫會(huì)使塑件在脫模后發(fā)生變形，若延長(zhǎng)冷卻時(shí)間又會(huì)使生產(chǎn)率下降。過(guò)低的模溫會(huì)降低塑料的流動(dòng)性，使其難于充模，增加制品的內(nèi)應(yīng)力和明顯的熔接痕等缺陷。由于各種塑料的性能和成型工藝要求不同，對(duì)模具溫度的要求也不相同。一般注射到模具內(nèi)的塑料粉體的溫度為 左右，熔體固化成為塑件后，從 左右的模具中脫模、溫度的降低是依靠在模具內(nèi)通入冷卻水，將熱量帶走。對(duì)于要求較低模溫（一般小于 ）的塑料，僅需要設(shè)置冷系統(tǒng)即可，因?yàn)榭梢酝ㄟ^(guò)調(diào)節(jié)水的流量就可以調(diào)節(jié)模具的溫度。
5、總結(jié)
本次模具設(shè)計(jì)課題，通過(guò)對(duì)塑件的工藝分析，確定模具的總體設(shè)計(jì)，并進(jìn)行各個(gè)子系統(tǒng)的設(shè)計(jì)。所設(shè)計(jì)的模具能滿足其工作狀態(tài)的質(zhì)量要求，使用時(shí)安全可靠，易于維修，在注塑成型時(shí)有較短的成型周期，成型后有較長(zhǎng)的使用壽命，具有合理的模具制造工藝性。
通過(guò)以上工作，我對(duì)一套模具從設(shè)計(jì)到加工的全過(guò)程有了清醒而直觀的認(rèn)識(shí)，了解了注塑模的工作原理，對(duì)模具中型腔等主要零件的設(shè)計(jì)及精度的確定具備了一定的經(jīng)驗(yàn)知識(shí)，能夠?qū)δ＞咴O(shè)計(jì)中常出現(xiàn)的問(wèn)題提出了合理的解決方法，能夠正確地選取注塑機(jī)、確定模架的結(jié)構(gòu)及尺寸、確定型腔數(shù)、選擇分型面、設(shè)計(jì)澆注系統(tǒng)、抽芯機(jī)構(gòu)等。由于知識(shí)及實(shí)踐經(jīng)驗(yàn)的缺乏，在設(shè)計(jì)過(guò)程中，零件加工精度的確定尚存在許多不足之處，在以后的工作、學(xué)習(xí)中還有待改進(jìn)。
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