注塑工艺手册.doc

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1、工艺注塑手册Injection process handbook一. 基本理念：Basic opinion:1. 什么是最佳的流动状态：What is the best flow state: 流体流动状态应该是喷泉状的，最佳的流动状态是流体前端的流动速度在型腔内处处相等。由于流动方向上截面积的不同，在其变化的位置应进行注射速度的调节（注意：机床上所能设定的注射速度是指螺杆的前进速度）。 The flow state should be like fountain, and the best is that the speed of the front melt is the same eve

2、rywhere in the cavities. For different areas in the direction that is vertical with the flow way, we must adjust the injection speed.(Attention: The injection speed, which we can set on the machine, is the screw forward speed)2. 什么是最佳的压力,温度分布状态：What is the best pressure and temperature state:最佳的压力和温

3、度分布状态是压力和温度分布在型腔内部处处相等，并且随着熔体地逐步冷却而下降并使最终产品的内应力为零。The best pressure and temperature state should be like this that the pressure and temperature everywhere in cavities are the same, and make the force of the part inside be zero finally as the melt solidified.实际压力分布状况是浇口附近最大并随着距离的增加而降低。（记住：螺杆头处的熔体和流动着

4、的熔体前端存在压力差是使熔体发生流动的根本原因）The actual pressure around the gate is the highest and as the distance goes its getting lower and lower。(Remember: Its the pressure in front of the flowing melt is lower than in cylinder that makes the melt flow.) 所以,综合来讲,参数设定的一般准则:(1) 尽量选用高的注射速度(螺杆前进速度)(2) 尽量选用高的料筒温度(3) 尽量选用

5、高的模具温度So the general principles when setting parameters are:(1) As fast injection speed as possible (Screw forward speed)(2) As high cylinder temperature as possible(3) As high mold temperature as possible二. 基本概念：Basic conception:1. 收缩：Shrinkage:（1）收缩的原因：.a.热胀冷缩；.b.熔体结晶；(结晶度越高，熔体收缩越严重).c.分子取向；（一般来说，

6、分子总是沿着流动方向取向的。对于未增强型材料，其熔体在流动方向上的收缩总是大于垂直方向；对于增强型材料，正好相反）. d.状态变化 The reasons of shrinkage: a. Chang from hot to cold; b. Crystallization ;( The more crystallization, the more shrinkage)c. Molecule orientation; (For non-strengthen material, the shrinkage in the flowing direction is more than that, w

7、hich is vertical with the flowing direction; and for the strengthen material, the result is just reverse,) d. Form changing（2）收缩的阶段： The stages of shrinkage: 收缩从注射开始就随着熔体的逐步冷却而开始 The shrinkage starts from injection to forever. 它包括三个阶段：a.从注射开始到保压结束；b.从冷却时 间开始到脱模前；c.脱模后 It contains three stages: a. Fr

8、om injection stage to end of holding stage; b. From cooling stage to demold stage; c. After demold.（3）变形： Deformation 变形的根本原因时收缩的不均匀。造成收缩不均匀的原因有：The root cause of deformation is inhomogeneous shrinkage. The causes of inhomogeneous shrinkage are as follows:a. 冷却(即温度分布)不均匀Inhomogeneous coolingb. 壁厚不均匀

9、Different wall thicknessc. 压力分布不均匀Not average location of pressure location d. 分子取向Molecule orientatione. 脱模受力不均Inhomogeneous forces when demolding 2. 结晶Crystallization: （1）什么是结晶： What is crystallization: 简单的说，结晶就是指分子的有序排列 In a short word, it means to make the molecule in order. （2）结晶的影响因素： Factors

10、affecting crystallization: 结晶的影响因素：冷却速度。冷却速度越快，结晶程度越低。 The cooling speed affects the crystallization. The faster cooling speed the more crystallization （3）结晶对产品性能的影响： How does crystallization affect the parts: 结晶度越高：密度越高 收缩越大 光洁度越好 强度越高 韧性变差 The more crystallization: The higher density The more shri

11、nkage The better surface The stronger of the parts 3. 粘度：（1）什么是粘度： What is viscosity: 粘度是流体本身的一种性能，它的大小是流体流动性能的一种衡量。数值越大，流体的流动性能越差。 Viscosity is a character of the flowing material. Its value is used to measure the flowing character. The bigger value it is, the worse flowing character it is.（2）粘度的影响

12、因素： What affect the viscosity: a.温度 Temperature b.剪切速度 Shear rate c.压力 Pressure 千万注意：往往粘度是三者共同作用的结果。不同的材料对温度，剪切速度和压力的敏感程度是不同的，并且在不同的注射速度下哪一个起主导作用也是不同的 Attention: The three factors affect the viscosity together all the time. Different material are differently sensitive to temperature, shear rate and

13、pressure, and which factor will be the main factor in different phase is also different. 通常：（A）对温度敏感：PA；PC Normally: Sensitive to temperature: PA, PC 对剪切速度敏感：POM；PP；PE Sensitive to shear rate: POM, PP, PE 对压力敏感：PP；PE Sensitive to pressure: PP, PE( B ) 在高速注射的情况下，剪切速度起主导作用(所以,对于薄壁 产品或含薄壁部分的产品宜采用高速注射)。

14、 In high injection speed situation, the shear rate is the main factor. (So use high injection speed for thin wall thickness parts)4. 止回阀:Non-return valve:a. 止回阀的功能是什么:Function of non-return valve:在注射，保压时防止熔体倒流，从而给予熔体我们所需的压力和速度。To prevent the melt flowing back when injection and packing.b. 怎么判断止回阀或料筒

15、损坏How to recognize the non-return valve is broken:初步判断：经常性的出现料垫不稳，或无料垫。Recognize presumedly: Melt cushion is not stable usually or no cushion.准确判断：延长保压时间，如果出现零料垫则说明止回阀损坏或料筒损坏。Recognize precisely: Prolong the holding time, if there is no melt cushion, the non-return valve is broken or the cylinder is

16、 broken. c. 怎么区别止回阀损坏还是料筒损坏How to recognize the non-return valve is broken or the cylinder is broken:方法一：换上新的止回阀，延长保压时间依然没有料垫，则说明料筒损坏。Method 1: Change into a new non-return valve; prolong the holding time, if there is still no melt cushion, it means the cylinder is broken.方法二：放大料垫，延长保压时间依然没有料垫，则说明止回

17、阀损坏；反之则说明料筒损坏。Method 2: Make the melt cushion big enough; prolong the holding time. If there is still no melt cushion, it means the non-return valve is broken; if there is melt cushion, it means the cylinder is broken.三.基本参数： Basic parameters:1. 注射速度：Injection speed:（1）什么是注射速度： What is injection spe

18、ed: 通常我们所设定的注射速度是指螺杆前进的速度。但是真正重要的是 熔体在型腔里前进的速度，它与流动方向的截面积大小有关。 The injection speed, which we can set on the machine, is the screw forward speed. But what is very important is the melt forward speed in cavities（2）怎么确定注射速度： How to set the injection speed: 作为原则，注射速度应越快越好。 As a rule, the injection speed

19、 should be the faster the better. 它的确定取决于熔体的冷却速度和熔体粘度： 冷却速度快的或粘度高的熔体采用高的注射速度。注意：冷却速度的快慢取决于材料本身的性能，壁厚以及模具温度高低。 The injection speed is determined by the cooling speed and the viscosity of melt: To the melt, which cooling speed is very fast and the viscosity is high, we d better use fast injection spee

20、d. Attention that the cooling speed is determined by the material character itself, wall thickness and mold temperature（3）注射速度太快：易出现焦斑，飞边，内部气泡或造成熔体喷射 Too fast injection speed: burns, flash, air bubble inside or melt jet. 注射速度太慢：易出现流动痕， 熔接痕，并且造成表面粗糙，无光泽 Too slow injection speed: Flow line; weld line,

21、 or bad surface.* 注射速度和注射时间设定的一般原则: General principles when setting injection speed or injection time:注射体积Injection Volume (ccm)注射时间 Injection Time (s)低粘度Low Viscosity中粘度Mid Viscosity高粘度High Viscosity1-80.2-0.40.25-0.50.3-0.68-150.4-0.50.5-0.60.6-0.7515-300.5-0.60.6-0.750.75-0.930-500.6-0.80.75-1.00

22、.9-1.250-800.8-1.21.0-1.51.2-1.880-1201.2-1.81.5-2.21.8-2.7120-1801.8-2.62.2-3.22.7-4.0180-2502.6-3.53.2-4.44.0-5.4250-3503.5-4.64.4-6.05.4-7.2350-5504.6-6.56.0-8.07.2-9.5塑料PlasticPE, PP, PA6, PA66, POM, PET, PBT, PPSPE, PP, PA12, ABS, PSPC, PMMA2. 转压点：Switch point:（1）怎么确定转压点： How to set switch poin

23、t: 一般来说，转压点是指在零保压压力的情况下把产品打到95满时， 由注射到保压的切换点。 Normally the switch is the changing point of screw from injection phase to holding phase, when the parts are 95% of their volume. 对于薄壁产品（如：扎带）：一般打到产品的98 To the thin wall thickness parts (Example: Cable strap): Up to 98% of their volume. 对于非平衡流道：一般为70-80，

24、应视具体情况而定。并建议采 用慢-快-慢多级注射。 To non-balance runners: Normally its up to 70% to 80%. It should be determined by the reality. We suggest using step injection speed (Slow- Fast- Slow).（2）转压点太高：产品充模不足，熔接痕，凹陷，尺寸偏小等 Too high switch point: empty part, weld line, sink mark, and small dimension 转压点太低：飞边，脱模困难,尺寸

25、偏大等 Too low switch: flash, difficult to demold， big dimension.3. 保压压力：Holding pressure:（1）怎么确定保压压力： How to set the holding pressure: 优化的保压压力一般为最低保压压力和最高保压压力的中间值。 The optimized holding pressure is in the middle of the maximum and minimum normally. 最低保压压力：在准确的转压点基础上，给予一定的保压压力，当产品刚出现充模不足时的保压压力。Minimum

26、holding pressure: based on the correct switch point, the pressure when the parts start to be empty . 最高保压压力：在准确的转压点基础上，给予一定的保压压力，当产品刚出 现毛刺时的保压压力。Minimum holding pressure: based on the correct switch point, the pressure when the parts start to have flash.（从最低和最高保压压力我们可以看到产品工艺波动的安全范围）(From the maximum

27、 holding pressure and minimum holding pressure, we can see the safe extension of the parts when the process is a little bit fluctuate)（2）一般来说： Normally: PA保压压力=50% 注射压力 POM 保压压力= 80% 注射压力；对于尺寸要求高的产品可达到 100注射压力PP/PE 保压压力=30-50 注射压力PA Holding pressure = 50% Injection pressurePOM Holding pressure = 80%

28、 Injection pressure; 100% Injection pressure to high dimension requirement partsPP / PE Holding pressure = 30-50% injection pressure4. 保压时间：Holding time:（1）怎么确定保压时间： How to set holding time: 保压时间的确定以浇口冷凝为依据。通过产品称重来确定。 Holding time is determined by the solidification time of the gate. We decide it ac

29、cording to the weight.（2）保压时间太长： 影响周期 Too long holding time: Waste time 保压时间太短：重量不足，产品内部空洞，尺寸偏小 Too short holding time: Not enough weight, empty inside, small dimension * 注意：保压压力会影响保压时间的长短。保压压力越大保压时间越长。 Attention: The holding pressure will affects the holding time. The higher holding pressure the lo

30、nger holding time.5. 螺杆转速Rotation Speed:预塑的目标是：获得均一稳定的熔体（即塑化均匀，无冷料，无降解，无过 多气体）Target of plastification: To get homogeneous melt.（1）怎么确定螺杆转速： How to set the rotation speed: 作为原则，螺杆转速的确定必须使螺杆的预塑时间，回吸时间与射台 的回退时间之和略短于冷却时间。As a rule, the rotation speed is determined by that the total dosing time, retract

31、 of screw and retract of injection unit must be a little bit shorter than the cooling time.（2）螺杆转速太快：塑化不均（从而造成产品冷料，充模不足和断裂 等），材料分解（从而造成焦斑，色差，断裂等） Too fast rotation speed: Inhomogeneous melt (which cause empty parts, broken), material decomposed (which cause burns, different color, broken etc) 螺杆转速太慢

32、：影响周期 Too slow rotation speed: Waste time.6. 冷却时间：Cooling time:作为原则，冷却时间的设定应越短越好，以产品不变形，不粘模，无过深的顶出痕为基本要求。并且：螺杆转速： PA1.0m/s; POM 0.7 m/s; PP/PE/PS 1.3m/s; ABS/PC/PMMA 0.6m/sAs a rule, the cooling is the shorter the better based on the parts are not deformed, not sticky and without too deep impressed

33、by ejectors. And the rotation speed: PA1.0m/s; POM 0.7m/s; PP/PE 1.3m/s* 推荐的脱模温度如下:Suggested demolding temperature is as follows:塑料 Plastics脱模温度C Demolding Temperature低限 Mini中间值 Mid高限 MaxPC60-8585-110110-130PE Soft300-4040-5050-65PE Rigid40-5050-6060-75PP45-5555-6565-80PA650-7070-9090-110PA6675-9090

34、-120120-150PA1240-6060-8080-100POM60-8080-100100-130PS20-3535-4545-60ABS35-5555-7575-90PBT60-7575-9090-120PPS120-145145-170170-190PMMA50-7070-9090-1107. 背压：Backpressure:（1）什么是背压： What is backpressure: 背压是指螺杆预塑时，液压缸阻止螺杆后退的力，其大小等于螺杆前 端熔体对螺杆的反作用力。 Backpressure is the hydraulic force preventing the scre

35、w going back as dosing, the value is equal to the force that the melt in front of the cylinder to the screw.（2）怎么确定背压： Ho to set the backpressure: 背压的确定取决于不同材料的性能，通常由材料供应商提供。 一般来说：PA: 20-80 Bar ; POM : 50-100 Bar ; PP/PE : 50-200 Bar The backpressure is determined by the material character and its v

36、alue is offered by the supplier. Normally: PA: 20-80 Bar; POM: 50-100 Bar; PP/PE: 50-200 Bar（2）背压太高：材料分解；流涎；需要更长的预塑时间 Too high backpressure: material decomposed, material escaping from the nozzle; need more dosing time 背压太低：塑化不均（特别对于含色母料），塑化不实（从而造成产 品气泡，焦斑等）Too low backpressure: Inhomogeneous melt (

37、especially for material with pigment etc.), not packed enough (Which cause air bubbles, burns etc.)8. 回吸量：Retract：（1） 如何确定回吸量：How to decide retract:回吸量的确定（结合背压的确定）以不流涎为原则The retract is determined by the principle that there is no melt escaping from nozzle.（2） 回吸量太大：气泡，焦斑, 料垫不稳Too much retract: Air b

38、ubble, burns, and unstable melt cushion回吸量太小： 流涎， 料垫不稳（由于止回阀关不住）Too little retract: Melt escaping from nozzle, unstable melt cushion (Because of the non-return valve not closed)9. 锁模力：Clamping force: （1） 锁模力的确定：锁模力的大小取决于型腔投影面积和注射压力的大小How to decide the clamping force: Its determined by the projection acreage of the cavities and the injection pressure （2） 锁模力太大：排气不畅（焦斑，充模不足），模具变形 Too much clamping force: Bad vent(burns, incomplete), mold deformation. 锁模力太小：飞边 Too low clamping force: flash10. 熔体温度：Melt temperature:（1）怎么确定熔体温度：