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1、工艺注塑手册Injection process handbook一一.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）f ffrT-nhrr力：:vn： n左訓轴f的剋心功2. 什么是最佳的压力，温度分布 状态：What is the best pressure a
3、nd temperature state: 最佳的压力和温度分布状态 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
4、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: Itthe 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
5、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；
6、.b.熔体结晶；(结晶度越咼，熔体收缩越严重 c分子取向；(一般来说，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, themore shrinkagec. Molecule orientation;(For non-strengthen material, the shrinkage in the . flow
7、ing direction is more than that, which 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；
8、c.脱模后It contains three stages: a. From injection stage to end of holding stage;b. From cooling stage to demoldstage;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
9、）不均匀Inhomogeneous coolingb. 壁厚不均匀Different wall thicknessc. 压力分布不均匀Not average location of pressure locationd. 分子取向Molecule orientatione. 脱模受力不均 Inhomogeneous forces when demolding2. 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
10、in order.（2）结晶的影响因素：Factors 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 hig
11、her densityThe more shrinkageThe better surfaceThe stronger of the parts3. 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 char
12、acter it is.（2）粘度的影响因素：What affect the viscosity:a. 温度 Temperatureb. 剪切速度 Shear rateC.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 temperatu
13、re, shear rate and pressure, and which . factor will be the main factor in different phase is also different.通常：（A）对温度敏感：PA; PCNormallySensitive to temperature: PA, PC对剪切速度敏感:POM； PP； PESensitive to shear rate: POM, PP, PE 对压力敏感：PP； PESensitive to pressure: PP, PE（B ）在高速注射的情况下，剪切速度起主导作（所以对于薄壁 产品或含薄壁
14、部分的产品宜采用高速注射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.
15、b. 怎么判断止回阀或料筒损坏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 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
