淺析使用有限元分析的注射模具設(shè)計(jì)（doc 14頁）.doc

1、使用有限元分析的注射模具設(shè)計(jì)摘要?dú)w功于電腦模擬分析運(yùn)用，通過Moldflow模流分析仿真系統(tǒng)幾個(gè)步驟就可以對(duì)塑件及模具進(jìn)行開發(fā)?；谧⑺苣＞叩姆抡娼Y(jié)果是在Pro/E 三維輔助設(shè)計(jì)的幫助下完成的。計(jì)算機(jī)輔助工程的運(yùn)用產(chǎn)品的開發(fā)階段尤為突出，這也使得工具及模具的成本減少。關(guān)鍵詞：注射模具，CAE仿真，Moldflow1.介紹塑料的最常見的處理方法之一是注塑。這一進(jìn)程的主要優(yōu)點(diǎn)包括其在塑造的各種產(chǎn)品的多功能性，它的自動(dòng)化可以引進(jìn)，高的生產(chǎn)率和較小的物件公差與制造的可能性。 注射成型件的生產(chǎn)與注塑機(jī)和注塑模具一起進(jìn)展。相對(duì)于形狀復(fù)雜的零件等的生產(chǎn)方法，這個(gè)過程運(yùn)行在相對(duì)短的周期。注塑標(biāo)準(zhǔn)的要求是： 高

2、精確度和型腔表面光潔度 最大剛度，模具組件的強(qiáng)度，整個(gè)注射模具可抵抗夾緊力，注塑壓力 適當(dāng)?shù)臐沧⑾到y(tǒng)，注射系統(tǒng)，排氣系統(tǒng)和冷卻系統(tǒng) 最佳生命周期。 注射模具設(shè)計(jì)師的任務(wù)是： 分析成型零件的設(shè)計(jì)，考慮形狀、尺寸、澆口位置和零件回彈 確定分型面，考慮功能和成型零件的外觀，定義型腔草圖 確定模腔數(shù)，模腔尺寸及布局和考慮收縮，幾何公差，及注塑機(jī) 選擇適當(dāng)?shù)臐沧⑾到y(tǒng)，冷卻和通風(fēng)系統(tǒng) 對(duì)模架選擇材料和其他研究過程中加載的條件和模具組件注塑周期。 選擇合適的注塑機(jī)。 現(xiàn)在注射成型技術(shù)的制圖不適合用二維繪圖來描述復(fù)雜的形狀。使用三維CAD模型的確切原因是確切描述部件形狀，很容易看到剖面圖及細(xì)節(jié)圖。更重要的原因

3、，使用三維CAD模型可以利用CAM軟件對(duì)注塑和模具制造的過程仿真。 （2）為CAM使用三維CAD模型已成為模具制造的一個(gè)組成部分。 （4）輔助工程的注射成型過程模擬，逐步成為了模具制造過程的組成部分。隨著CAE模擬模具設(shè)計(jì)人員的幫助可以測試未經(jīng)注塑模具的使用前需要解決的各種費(fèi)用及耗時(shí)模具的更正。2.注射模具過程仿真這部分是描述在Mlodflow模流分析6.0的幫助下的頂部注射情況。這次仿真的材料是Cycoloy C2100HF。分析準(zhǔn)備的是有限元網(wǎng)格模型。常規(guī)計(jì)算來決定開始的模型尺寸。下一步的工作是執(zhí)行流道優(yōu)化分析，以減少流道系統(tǒng)的體積和重量。2.1由列線圖決定分流道系統(tǒng)的尺寸這種方法屬于常規(guī)

4、的電腦計(jì)算方法。輸入型腔布置，部件材料與體積大小數(shù)據(jù)來決定分流道截面尺寸。型腔布置設(shè)計(jì)決定了分流道的形狀，同樣知道重量也決定了截面的尺寸。圖2-1展示了型腔布置的地方： L 主流道的長度 L1 主分流道的一半長度 L2 副分流道的一半長度 L3 澆口長度圖2-1. 型腔布置單個(gè)型腔的流道系統(tǒng)總長度：LC= L1+L2+L3 = 55 + 33, 5 + 15, 5 = 94 mm成型零件體積：V = 61000 mm3分流道系統(tǒng)的體積：VCA = 4298, 96 mm3材料密度(Cycoloy C2100HF): = 1,075 g.cm-3成型零件重量：G = Vk. = 61. 1,07

5、5 = 65, 57 g成型零件的壁厚：s = 2mm有了這些參數(shù)和列線圖就可以確定梯形分流道截面尺寸。D的值是與分流道連接的主流道的直徑，在圖2-2用直線列表定義。Lf是分流道尺寸計(jì)算的修正因素。圖2-2. 分流道尺寸確定列圖數(shù)值線圖：D= 3,8 mm , Lf=1,1, D= D. Lf = 3,8. 1,1 = 4,18 mm2.2為仿真準(zhǔn)備模型基于這些有限元網(wǎng)格計(jì)算準(zhǔn)備，為了在MPI 6.0（圖2-3）中仿真。在模型中包含型腔、分流道系統(tǒng)、冷卻流道和鑲塊。圖2-3. 仿真模型分流道系統(tǒng)的優(yōu)化由MPI/Flow模型來展示。分流道平衡分析被用來分流道系統(tǒng)體積的優(yōu)化，當(dāng)使用足夠填充時(shí)的平衡

6、填充方式。3.分析結(jié)論主要的分析是47, 92%的分流道系統(tǒng)體積的減少輸出。這也減少了材料的成本和周期。在圖3-1，3-2中，是填充始時(shí)間與冷卻時(shí)間的輸出?；谶@些數(shù)據(jù)是在模具沒有制造與修復(fù)的前提下，在設(shè)計(jì)階段中所必要的。圖3-1. 填充時(shí)間分析圖3-2. 冷卻時(shí)間的分析4.模具結(jié)構(gòu)在想要的流道分析輸出后，基于有限元網(wǎng)格劃分的3D CAD 模型被準(zhǔn)備好（圖4-1）。這個(gè)模型被輸入CAM系統(tǒng)然后在CNC機(jī)床中制造模具。圖4-1.3D CAD 模具裝配Design of Injection Mould Using CAEAbstractThe contribution deals with sev

7、eral steps computer simulation application by means of CAE system Moldflow MPI in mould development for mold plastic part. Based on result of simulation design of injection mould is made with help of Pro/Engineer CAD system. Application of the CAE methods is accentuated in the development phase of t

8、he product, which redounds to cost reducing on tools and moulds development.Keywords: injection moulding, CAE simulation, Moldflow1 IntroductionOne of the most common processing methods for plastics is injection moulding. The major advantages of the process include its versatility in moulding a wide

9、 range of products, the ease with which automation can be introduced, the possibility of high production rates and the manufacture of articles with close tolerances.Production of injection molded parts is in progress with injection molding machine and injection mould. This process is running in rela

10、tively short cycles compared to other production methods for complex shape parts. Standard demands on injection mould are: High accuracy and cavity surface finish Maximal stiffness and strength of mould components and whole injection mould to resist clamping and injection pressures proper runner, ej

11、ection , venting and cooling system optimal life-time.Tasks for injection mould designer are: Analyze molded part design considering shape, dimensions, gate location and ejection of part define parting plane considering function and appearance of molded part, define drafts in cavity determine number

12、 of cavities, cavity layout and cavity dimensions considering shrinkage, geometry tolerance, wear of cavity and used injection molding machine select proper design of ejection, cooling and venting system select material for mould base and other mould components considering conditions and load during

13、injection molding cycle. choose tightening of mould on injection molding machine.Nowadays technical drawing of injection molded part is not sufficient to describe complex shapes in 2D drawing. Reason for using 3D CAD model are wide opportunities to exact describe shape of part, easy making of cut vi

14、ews and detail views. More important reason to use 3D CAD model is CAE process simulation of injection molding and mold manufacturing with CAM software. (2) Using 3D CAD model for CAM software has become integral part of mould manufacturing. (4) CAE process simulation of injection molding is becomin

15、g stepwise integral part of mould manufacturing process. With help of CAE simulation mould designer can test various construction solution of injection mould without need cost a time consuming mould corrections.2 Injection Molding Process SimulationIn this part of contribution is described analysis

16、of molded part injection (top part-hosuing) with help Moldflow Plastics Insight 6.0. Material proposed for this simulation is Cycoloy C2100HF. For analysis is prepared mould finite element mesh model. Start model dimensions is determined conventional calculation. In next step is performed runner opt

17、imization analysis, to reduce volume and weight of runner system.2.1 Determining dimension of runner system by nomogramsThis method belongs to conventional way of computing. Input data for determining runner cross section dimensions are cavity layout, material of molded part and volume of molded par

18、t. Cavity layout designed upon determines length of runner channels and with known weight are determined cross section dimensions. (1) Fig. 1 shows cavity layout where: L sprue length L1 half length of main runner L2 half length of secondary runner L3 gate length.Fig. 1 Cavity layoutOverall length o

19、f runner system to single cavity is:LC= L1+L2+L3 = 55 + 33, 5 + 15, 5 = 94 mmMolded part volume: V = 61000 mm3Runner system volume: VCA = 4298, 96 mm3Material density (Cycoloy C2100HF): = 1,075 g.cm-3Molded part volume: G = Vk. = 61. 1,075 = 65, 57 gWall thickness of molded part: s = 2mmWith this pa

20、rameters and nomograms are determined dimensions of trapezoidal cross section of runner channel.Value D is the diameter of sprue at hne connection with runner and is defined in nomogram (fig.2). Lf is correction factor for calculation of dimension of runner.Fig. 2 Nomograms for dimension determinati

21、on of runnerValues from nomograms: D= 3,8 mm , Lf=1,1, D= D. Lf = 3,8. 1,1 = 4,18 mm2.2 Preparing model for simulationBased on these calculations is prepared finite element mesh for simulation in MPI 6.0 (fig.3). This model involves cavity, runner system cooling channels and mold block.Fig. 3 Model for simulationRunner system optimization is performed by MPI/Flow module. Runner balance analysis is used for runner system volume optimization, determine balanced filling pattern when using family moulds and sufficient filling and packing pressure. During analysis dimensio