塑料件尺寸公差

1． 范围

本标准规定了注射、压制、挤塑等成型的热塑性和热固性塑料（不包括二次加工和发泡成型的塑料件）尺寸公差、偏差、公差等级的选用、测量条件和测量方法。

本标准主要适用于电子产品用塑料件尺寸公差，其他产品用塑料件尺寸公差，亦可参照采用。 2． 引用标准

下列标准所包含的条文，通过在标准中引用而构成本标准的条文。在标准出版时，所示版本均为有效。所有标准都会被修订，使用标准的各方应探讨使用下列标准最新版本的可能性。

GB1800-79 公差与配合 总论 标准公差与基本偏差 GB3177-82 光滑工件尺寸的检验 机械制图 尺寸公差与配合注法 3． 定义

基本尺寸 basic size

设计给定的尺寸。 实际尺寸 actral size 通过测量所得的尺寸。 尺寸公差 dimensional tolerance

允许尺寸的变动量。

尺寸偏差 dimensional deviation

某一尺寸减去基本尺寸所得的代数差。 塑料收缩率 plastic shringkage

塑料件尺寸与相应模具尺寸之差的绝对值与相应模具尺寸之比。 径向收缩率 radial shringkage 指料流方向的塑料收缩率。 切向收缩率 tangential shringkage 指垂直于料流方向的塑料收缩率。 收缩特性值 contraction chararcteristic value

表示料流方向和垂直于料流方向的塑料综合收缩能力，以2倍径向减去切向收缩的绝对值之差表示。

受模具活动部分影响的尺寸 size effected movable parts of mould

由模具活动零件决定的塑料件尺寸。 尺寸公差、偏关的规定

基本尺寸范围为~3至600mm。基本尺寸分段~3至120mm。采用不均匀递增数列：140~1600mm，采用R20优先数系。

2 公差等级及数值

公差等级分为10级，每一级公差数值按表1规定。

表1

差等级 1 2 3 4 5 6 7 8 9 10 公差数值 ~3 >3~6 >6~10 >10~14 >14~18 >18~24 >24~30 >30~40 >40~50 040 >50~65 >65~80 >80~100 120 140 160 180 200 225 250 280 315 355 400 450 500 560 630 710 800 900 1000 1200 5 7 10 14 1400 6 8 11 16 1600 7 9 13 18 注：表中公差值用于基准孔或非基准孔时取（+）号；用于基准轴或非配合轴取（-）值，用于非配合长度取半值冠以正负（±）号 4．3 偏差的规定

本标准只规定公差，而基本尺寸的上下偏差，可按需要分配。例如：Φ60mm基本尺寸 公的6级公差为，其上下偏差可分配为：

Φ60错误!mm，Φ60错误!mm，Φ60错误!mm，Φ60错误!mm，Φ60错误!mm 4．4 受模具活动部分影响的尺寸公差 受模具活动部分影响的尺寸公差，为本标准规定的公差值与附加值之和。1、2级附加值为：3、4级附加值为：5至7级附加值为：8、10级附加值为： 5 未注公差

尺寸未注公差，按表1规定的7~10级公差选用。 公差等级的选用

公差等级的选用，按表2规定。 材收缩特性值 代号 ABS AS GRD HIPS MF PBTP PC PETP PF PMMA PPE PPO PPS PS PSU PA PVC PE POM PP PE PVC 料 名称 苯乙烯-丁二烯-丙烯腈共聚物 丙烯腈-苯乙烯共聚物 30%玻璃纤维增强塑料 高冲击强度聚苯乙烯 氨基塑料 聚对苯酸丁二酯 聚碳酸酯 聚对苯酸丁二酯 酚醛塑料 聚甲基丙烯酸甲酯 聚苯硫醚（增强） 聚苯醚 聚苯醚砜 聚苯乙烯 聚砜 聚酰胺6、66、610、9、1010 氯化聚醚 聚氯乙烯（硬） 聚乙烯（高密度） 聚甲醛 聚丙烯 聚乙烯（低密度） 聚氯乙烯（软） 相应的公差等级 一般精高精度 低精度 度 0~1 3 4 5 1~2 4 5 6 2~3 3~4 6 8 7 9 8 10 注 ：1、其他材料，可按加工尺寸的稳定性，参照表2选取公差等级。 2、1、2级为精密级，只有在特殊条件下才采用。 3、当沿脱模方向两端尺寸均在要求时，应考虑脱模斜度对公差的影响。 4、其他增强塑料的收缩特性性值，应比表2 中规定的小，或由试验结果定。 6 测量方法

6．1 公差测量条件

a. 标准测量温度为20±2℃；

b. 相对湿度为（65±5）%；

c. 待塑料件成型后24h及“后处理”后进行测量。 6．2 公差的测量方法

公差的测量方法和量具，按GB3177的规定。 7 公差的注法

公差的注法，按的规定。

4． 5．

TABLE 1 : DIMENSIONAL TOLERANCES - GROUP 1 MATERIALS NOMINAL DIMENSIONS (mm) Up to 1 Over 1 Over 3 Over 6 Over 10 Over 15 Over 22 Over 30 Over 40 Over 55 Over 70 Over 90 Over 120 Over 160 Over 200 Over 250 Over 315 Over 400 Over 500 Over 650 Over 800 Over 1000 Over 1200 Over 1400 Over 1600 Over 1800 up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc 3 6 10 15 22 30 40 55 70 90 120 160 200 250 315 400 500 650 800 1000 1200 1400 1600 1800 2000 TOLERANCES ± (mm) Fine Commercial

TABLE 2 : DIMENSIONAL TOLERANCES - GROUP 2 MATERIALS

NOMINAL DIMENSIONS (mm) Up to 1 Over 1 Over 3 Over 6 Over 10 Over 15 Over 22 Over 30 Over 40 Over 55 Over 70 Over 90 Over 120 Over 160 Over 200 Over 250 Over 315 Over 400 Over 500 Over 650 Over 800 Over 1000 Over 1200 Over 1400 Over 1600 Over 1800 up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc 3 6 10 15 22 30 40 55 70 90 120 160 200 250 315 400 500 650 800 1000 1200 1400 1600 1800 2000 TOLERANCES ± (mm) Fine Commercial

TABLE 3 : DIMENSIONAL TOLERANCES - GROUP 3 MATERIALS

NOMINAL DIMENSIONS (mm) Up to 1 Over 1 Over 3 Over 6 Over 10 Over 15 Over 22 Over 30 Over 40 Over 55 Over 70 Over 90 Over 120 Over 160 Over 200 Over 250 Over 315 Over 400 Over 500 Over 650 Over 800 Over 1000 Over 1200 Over 1400 Over 1600 Over 1800 up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc up to and inc 3 6 10 15 22 30 40 55 70 90 120 160 200 250 315 400 500 650 800 1000 1200 1400 1600 1800 2000 TOLERANCES ± (mm) Fine Commercial

MOULD SHRINKAGE AND COEFFICIENTS OF LINEAR EXPANSION

MATERIAL ABS ABS - 30% glass filled Acetal Acetal - 30% glass filled Acrylic Cellulose Acetate Cellulose Acetate Butyrate Diallyl Phthalate Ethylene Vinyl Acetate Melamine Formaldehyde Nylon 6 Nylon 6-30% glass filled Nylon 66 Nylon 66 - 30% glass filled Nylon 11 Nylon 11 - 30% glass filled Nylon 12 Nylon 12 - 30% glass filled Phenol Formaldehyde Polycarbonate Polycarbonate - 30% glass filled Polycarbonate / ABS (Bayblend) Polyester, laminates Polyester, thermoplastic Polybutylene Terephthalate Polybutylene Terephthalate - 30% glass filled Polyethylene Terephthalate Polyethylene Terephthalate - 30% glass filled Polyester, thermoplastic elastomer Polyethylene, low density Polyethylene, high density Polyethylene Oxide-mod-(Noryl) Polyethylene Oxide-mod-30% - glass filled Polypropylene Polypropylene - 20% talc filled Polypropylene - 20% glass filled Polypropylene - asbestos filled Polypropylene - rubber modified Polystyrene Mould Shrinkage - - - - - - - - - - - - - - - - - - - - - - - per cent 10Coeff . linear expansion °K 50 - 110 35 - 50 90 - 150 35 - 80 50 - 90 80 - 160 110 170 - 10 - 60 230 250 - 10 - 50 70 - 170 15 - 30 60 - 110 15 - 30 90 - 150 10 - 40 90 - 130 30 - 70 15 - 30 20 - 70 20 - 30 70 - 85 10 - 50

- 80 - 180 - - 30 - 70 - 60 150 - - - - - 20 - 140 - 200 - 150 - 60 - 40 210 250 200 70 - - - - - - - 20 - 110 - 70 - 60 - 20 - 50 - 35 - 30 170 110 140 40 140 100

MATERIAL Polyurethane thermoplastic greater than 50 Shore D equal or less than 50 Shore D Polyurethane, RIM Polyurethane, RRIM Polyvinyl Chloride - rigid Polyvinyl Chloride - flexible Styrene Acrylonitrile Urea Formaldehyde Mould Shrinkage per cent expansion °K-1 - - - - - - - - 130 - 120 150 - 225 90 - 150 30 - 180 50 – 100 70 - 250 50 - 110 30 - 50

Note :

The mould shrinkage and coefficient of expansion of f directions parallel and perpendicular to the flow.

ibre filled mater

ials will vary in