注塑工艺参数优化

叮叮小文库培训课程 2 工艺参数的优化受训者手册德马格注塑机工艺参数优化的步骤指导页面周期分析3注塑工艺参数优化6步骤 1: 找出转压点7步骤 1结果8步骤 2: 找出保压时间(浇口冷凝时间)9步骤 2 结果10步骤 3: 优化注射速度11步骤 3 结果12步骤 4: 采用正确的螺杆转速13步骤 4 结果14步骤 5: 优化多级螺杆转速和背压曲线15步骤 5 结果16步骤 6: 优化松退17步骤 6 结果18步骤 7: 优化保压曲线19步骤 7 结果20TABULATED RESULTS21步骤 8: 优化锁模力22步骤 8 结果22步骤 9: 设定注射压力23步骤 9 结果23典型工艺参数公差设定24成型周期分析采用下面表格估计注塑过程中的每一阶段对周期的影响. 然后去机床看正在运行的模具, 写下实际的时间并计算出百分比.哪一阶段在整个周期中占最多的时间? 那里可以是最有效的缩短成型周期? 模具 1估计 %实际实际%评价 合模射台前进和后退注射时间保压时间冷却时间开模顶出整个成型周期100%seconds100%模具 2估计 %实际实际%评价合模射台前进和后退 注射时间保压时间冷却时间开模顶出整个成型周期100%seconds100%工艺参数优化目标: 一步步改进工艺过程稳定性. 评估各个参数的更改对工艺过程稳定性的影响 to demonstrate the cumulative improvemnt in the process and product consistency 方法:At each stage, after the process has been given sufficient time to stabilise, a run of sixteen consecutive mouldings is to be made. These mouldings will be assessed for consistency by weight (a dimension, a physical property or some other attribute could equally well be used, weight is simply the most widely applicable).稳定性通过计算重量的标准偏差来衡量. 同时打印出机床IBED上的过程统计数据. 1. 找出转压点2. 找出浇口冷却时间3. 优化注射速度4. 采用正确的螺杆转速5. 优化多级预塑曲线6. 优化松推7. 优化多级保压曲线8. 优化锁模力9. 设定注射压力限定 步骤 1 找出转压点在没有保压压力和保压时间的基础上填满产品95% -98%, 然后设定一定的保压和保压时间生产16模. 初始设置时的指导1采用行程切换2设定切换位置为10-12mm (逐步增加预塑量直到产品打满95% - 98% 的位置) 3设置注射压力为最大值4设定保压压力和保压时间均为05设定注射速度 60 mm s-1 6设定松推速度为最大值7设定锁模力为最大值8选择适当的螺杆转速9根据材料物性表, 设定料桶温度10配置过程统计控制11设定保压压力和保压时间生产完整的产品称12 模产品的重量, 计算标准偏差打印:页面 20 工艺参数优化页面 50 工艺过程统计步骤 1 结果输入实际值平均值范围最小最大没保压时的重量有保压后的重量填充的百分比%标准偏差 (16 模)g料垫 (平均值和范围)预塑时间 (平均值和范围)螺杆停止位置 (平均值和范围)注射时间 (平均值和范围)注射压力峰值, P inj. max转压压力, PN press.转压位置 步骤 2 找出浇口冷凝时间设定保压压力为步骤1 上找出的注射压力峰值的50% 左右. 设定保压时间为 1 s .生产数模产品使过程稳定后连续取5模产品称出每模重量和平均值 增加保压时间至2 s, 生产数模产品使过程稳定后连续取5模产品称出每模重量.在保压时间3s, 4s 5s . . . 时重复上述过程直到产品重量不再增加 作出产品重量和保压时间的关系图. 记录Record the TCU setting and the actual mould temperature.打印:页面 30 温度XL Spreadsheet graph为什么记录模具温度很重要?还有什么因素会影响浇口冷凝时间?步骤 2 结果输入实际值TCU settingFH temperatureMH temperatureCCC重量 1重量2重量3重量4重量5平均重量时间保压重量1重量2重量3重量4重量5平均重量时间保压所需的保压时间s 步骤 3 优化注射速度采用多级注射曲线, 使注射行程最后的10-20% 采用逐步降低的注射速度. 每次更改注射速度, 必须重新建立转压点. (注意每次保压和保压时间都设定为0.)连续取16模, 计算出标准偏差. 打印:页面 24 MWE 使用和没使用多级保压时的曲线页面 26 多级注射页面50 工艺过程统计为什么转压点要更改?注射压力发生了什么?为什么在数社的末端采用逐步降低的注射速度是有用的?步骤 3 结果输入实际值平均值范围最小最大没有保压时的重量采用保压的重量填充百分比%标准偏差 (16 模)g料垫 (平均值和范围)预塑时间 (平均值和范围)螺杆停止位置(平均值和范围)注射时间 (平均值和范围)注射压力峰值, P inj. max转压压力, PN press.转换位置 步骤 4 采用正确的螺杆转速Select the correct, optimum screw speed for the material being processed (see T.01 notes, Section 5 ). Use this single speed for the whole plasticising strokeSet a back pressure of 5 to 10 bar (hydraulic).Readjust dosing stroke to achieve 95-98% fillTake sixteeen consecutive mouldings and determine the standard deviation of the weights.Print out:Page 50 Process StatisticsWhy is it important to use the manufacturers recommended screw speed?STEP FOUR RESULTSInsert actual values in the relevant boxesMean valueRangeminmaxWeight without holding pressureWeight with holding pressurePercentage fill%Standard deviation (16 shots)gMelt cushion (mean and range)Dosing time (mean and range)Screw stop position (mean and range)Injection time (mean and range)Peak injection pressure, P inj. maxInjection pressure at changeover, PN press.Changeover stroke STEP FIVEOptimise screw speed and back-pressure profileUse the Dosing Profile page to slow down the screw rotation speed for the last 10% of the metering stroke.Readjust dosing stroke to achieve 95-98% fillTake sixteeen consecutive mouldings and determine the standard deviation of the weights.Print out:Page 21 Dosing ProfilesPage 50 Process StatisticsWhat has happened to the Dosing Stop position?STEP FIVE RESULTSInsert actual values in the relevant boxesMean valueRangeminmaxWeight without holding pressureWeight with holding pressurePercentage fill%Standard deviation (16 shots)gMelt cushion (mean and range)Dosing time (mean and range)Screw stop position (mean and range)Injection time (mean and range)Peak injection pressure, P inj. maxInjection pressure at changeover, PN press.Changeover stroke STEP SIXOptimise decompressionFind the decompression speed which gives best screw stroke and melt cushion consistency. Set a decompression stroke of 5mm.Check that you still achieve 95-98% fill.Take sixteeen consecutive mouldings and determine the standard deviation of the weights.Print out:Page 21 Dosing ProfilesPage 50 Process StatisticsWhat has happened to the screw stop position?What is happening to the check ring? STEP SIX RESULTSInsert actual values in the relevant boxesMean valueRangeminmaxWeight without holding pressureWeight with holding pressurePercentage fill%Standard deviation (16 shots)gMelt cushion (mean and range)Dosing time (mean and range)Screw stop position (mean and range)Injection time (mean and range)Peak injection pressure, P inj. maxInjection pressure at changeover, PN press.Changeover stroke STEP SEVENOptimise holding pressure profileUse the Holding Profile page to set a holding pressure profile which ensures a smooth transition from injection to the holding pressure phase and use a high enough pressure to pack the part properly.Add a step which reduces holding pressure gradually to zero.Take sixteeen consecutive mouldings and determine the standard deviation of the weights.Print out:Page 24 MWEPage 27 Holding ProfilePage 50 Process StatisticsWhy do you need a smooth transition from injection to holding pressure?Why bother to reduce the pressure gradually if the gate has already frozen? STEP SEVEN RESULTSInsert actual values in the relevant boxesMean valueRangeminmaxWeight without holding pressureWeight with holding pressurePercentage fill%Standard deviation (16 shots)gMelt cushion (mean and range)Dosing time (mean and range)Screw stop position (mean and range)Injection time (mean and range)Peak injection pressure, P inj. maxInjection pressure at changeover, PN press.Changeover stroke TABULATED RESULTS Insert actual values in the relevant boxesThe range value, R, is the maximum minus the minumum, taken from the seven steps.1234567meanRmeanRmeanRmeanRmeanRmeanRmeanRMelt cushionDosing timeScrew end positionInjection timeInjection pressure P hyd maxInection pressure PN hydraulicChangeover strokeStandard deviation (16 shots)Can you see a trend?Which step had the greatest effect on the consistency of the moulding?STEP EIGHTOptimising the clamp forceReduce the clamp force by steps of 50 kN (100 kN for machines over 100 tonnes) using the settings far optimised in the seven steps above.Allow the process to stabilise each time and then weigh five mouldings.Tabulate your results below and plot a graph of tonnage against part weight.Does the mould require the expected clamp force?What are the advantages of running at reduced tonnage?STEP EIGHT RESULTSInsert actual values in the relevant boxesEnter results in XL spreadsheet. Print out graph.Weight 1Weight 2Weight 3Weight 4Weight 5Mean weightClamp forceRequired clamp forcekNSTEP NINESet injection pressureUntil now the injection pressure has been set to the machines maximum value. From the Process Statistcs page it can be seen that the machine does not need all that pressure to fill the mould.Gradually decrease the set injection pressure until the injection time starts to increase. Increase the pressure again until the previous injection time is established with a consistency of 0.08 s or better preferably 0.02 to 0.03 s variation.What is the purpose of limiting the injection pressure?STEP NINE RESULTSActual peak injection pressurebarSet injection pressurebarAppendix 1TYPICAL PROCESS TOLERANCESShot-weight deviation0.05%0.1%0.2%0.4%Plasticising time 0.04s 0.06s0.08s0.13sInjection time 0.02s 0.02s 0.04s 0.06sCycle time 0.5% 0.5% 1% 1%Screw position, dosing stop 0.1mm 0.1mm 0.2mm 0.3mmMelt cushion 0.1mm 0.1mm 0.2mm 0.3mmMelt temperature 2C 2C 3C 5CMould temperature 1C 1C 2C 4CBarrel temperature 1C 1C 2C 4CFeed zone temperature 1C 2C 3C 4CHot runner temperature 1C 2C 3C 4CHydraulic oil temperature 1C 1C 2C 2CRoom temperature 2C 2C 3C 4CMould cavity pressure 3 bar 4 bar 6 bar 8 barPressure integral 200 300 600 900Injection filling pressure 1 bar 2 bar 3 bar 4 barHolding pressure 1 bar 1 bar 1.5 bar 2 barBack pressure 0.5 bar 0.5 bar 1 bar 1 barFilling differences (Balance of fill for each cavity) on multi-cavity tools 1% 1% 2% 5%Mould breathe0.01mm0.01mm0.02mm0.04mmChange over pressure (Pn Value) 1 bar 2 bar 3 bar 4 barScrew surface speed 10mms-1 15mms-1 20mms-1 30mms-1Melt temperature peak value 0.3C 0.4C 0.5C 0.6CMelt temperature value at changeover 0.3C 0.4C 0.5C 0.6CThe achievable part quality is much influenced by the condition of the material processed.It is important that moisture content, pro