Page 22 - 2019-22

橡塑技术与装备（塑料） CHINA RUBBER/PLASTICS TECHNOLOGY AND EQUIPMENT （PLASTICS）

h—塑件孔深，mm ； 度的选用原则如下所示 ：
K p —平均收缩率，%。 a. 塑料制件收缩率大，以及其形状复 杂、不易脱
（2）中等精度塑件当塑件为中等精度要求时，其 模的，应选取较大的脱模斜度。
脱模斜度值的选择应保证 在 2/3 配合面的长度内满足 b. 热固性塑料件的脱模斜度，比相似条件下的热
塑件公差要求，如图 28 所示，其脱模斜度值一般 可 塑性制件斜度小些，但最小脱模斜度一般不小于 0.5°。
取 a=10′ ~ 20′。 对于酚醛塑料制件的脱模斜度取 1° 为好。热塑性塑
料制件壁面脱模斜度一般取 0.5° ~3°。刚性大的塑料
制件脱模斜度，应比刚性小的塑料制件适当小些。
c.— 般情况下，塑料制件因收缩产生的对型芯包
紧力大于其附着于型腔的黏附力。因此，塑料制件内
表面的脱模斜度，应大于塑件制件外表面的脱模斜 度，
而侧孔的脱模斜度，应比处于开闭方向的塑料制件内
外表面的脱模斜度稍大。
图 28 中等精塑件的脱模斜度 d. 在满足塑料制件尺寸公差要求的前提下，脱模
斜度可适当取大些。取斜度方向的规定 ：以塑料制
（3）粗级精度塑件 当塑件为粗级精度时，脱模
件为轴，应保证其大端尺寸，斜度向小的方向取 ；
斜度值可取下列数值 ： a=20′、30′、1°、1°30′、2°、3°。
以塑料制件为孔，应保证其小端尺寸，斜度向大的
脱模斜度的选择，应根据材料的性质、制件的形状与
方向取。
大小以及模具的结构，并结合实际经验而定。脱模斜
Pressing technology and mold design
—— Part I Plastic press molding

Lecture 2 Introduction (1)Ḥ
ḤḤḤ
Hong Shenzhang
(Shanghai Jiaotong University of Plastic Forming Technology and Equipment Institute, Shanghai 200030,China)
Abstract: Compression and injection molding use different types of plastics, the former using thermosetting
plastics, the latter using thermoplastic plastics. Compression molding technology and mold design is
a developing comprehensive science. It not only improves with the improvement of polymer synthesis
technology, the renewal of molding equipment and the maturity of molding technology, but also with the
development of computer technology, rapid molding technology, numerical simulation technology, digital
application technology, intelligent technology, etc. The main contents of this lecture include: compressing
molding technology and classification, compressing molding parts design, compressing mold structure design
and parts design, compressing molding equipment, quality control and defect analysis of compressing
molded parts, application examples of compressing molds, principle and process of injection-compression
molding, structure design of injection-compression mold, calculation of injection-compression molding
pressure, selection of injection-compression molding equipment, quality and defect analysis of injection-
compression molded parts, application examples of injection-compression molds.
Key words: design and forming of compression molded part; compression molding technology and mold
structure design; compressing molding equipment; quality and defect of compressing molded part; selection
of injection-compression molding technology and equipment; structure design of injection-compression mold;
quality and defect analysis of injection-compression molded part
（未完待续）
(R-03)

·6· 第 45 卷 第 22 期