Reference Tables

Plastic Shrinkage Values
Material	Shrink in/in
ABS High Impact	0.005 – 0.007
ABS Heat Resistant	0.004 – 0.005
ABS Medium Impact	0.005
Acetal	0.020 – 0.035
Acrylic General Purpose	0.002 – 0.009
Acrylic Heat Resistant	0.003 – 0.010
Acrylic High Impact	0.004 – 0.008
Ethylene Vinyl Acetate	0.010 – 0.030
Ionomer	0.003 – 0.020
Nylon 6/6	0.010 – 0.025
Nylon 6/6	0.007 – 0.015
Nylon 6/10	0.010 – 0.025
Nylon 11	0.010 – 0.025
Nylon 12	0.008 – 0.020
Nylon Glass Filled	0.005 – 0.010
Polybutylene	0.020 (molded)
Polybutylene	0.040 (aged)
Polycarbonate	0.005 – 0.007
PET (Amorphous, petg, pctg)	0.003 – 0.005
Polyester .025 – .050 THICK	0.006 – 0.012
Polyester .050 – .100 THICK	0.012 – 0.017
Polyster .100 – .180 THICK	0.016 – 0.022
Polyester PBT	0.010 – 0.020
Polyester PET 30% GF	0.001 – 0.002
Polyester PBT 30% GF	0.003 – 0.005
POLYETHERIMIDE	0.005 – 0.007
Polyethylene Low Density	0.015 – 0.035
Polyethylene High Density	0.015 – 0.030
PPO/Styrene CO (NORYL)	0.005 – 0.007
Polypropylene	0.010 – 0.030
PPO/Styrene G.P.	0.002 – 0.008
PPO/Styrene Heat Resistant	0.002 – 0.008
PPO/Styrene Impact Mod	0.003 – 0.006
Polysulfone	0.008
Polyurethane	0.010 – 0.020
PVC Rigid	0.002 – 0.004
PVC Semi-Rigid	0.005 – 0.025
PVC Flexible	0.015 – 0.030
SAN	0.002 – 0.006

Density of Plastic Values – Selected Resins
Material	70°F DENSITY gr/cc	MELT DENSITY gr/cc
ABS (Injection Grade)	1.05	0.97
ABS 30% GR	1.28
Acetal	1.42	1.17
Acetal 20% GF	1.55
Acrylic General Purpose)	1.16	1.04
Cellulose Acetate	1.26	1.13
Cellulose Butyrate	1.20	1.07
Cellulose Propionate	1.22	1.10
Ethylene Vinyl Acetate	0.95
Ionomer	0.95	0.73
Nylon 6/6	1.14	0.97
Nylon 6	1.13	0.97
Nylon 6/10	1.08	0.97
Nylon 6/12	1.07	0.97
Nylon 11	1.04	0.97
Nylon 12	1.02	0.97
Nylon 30% GF	1.36
Polybutylene	0.92
Polycarb/Ester Alloy	1.20
Polycarbonate	1.20	1.02
Polycarbonate 30% GF	1.42
Co-Polyester PETG	1.27	1.12
Co-Polyester PCTG	1.24	1.08
Polyester PBT	1.34	1.11
Polyester PBT/PET 30% GF	1.58
Polyester PET (Bottle)	1.40	1.20
Polytherimide	1.27
Polyethylene Low Density	0.92	0.76
Polyethylene Medium Density	0.92-0.94	0.74
Polyethylene High Density	0.94-0.97	0.72
Polythyl 30% GF HDPE	1.18
PPO/Styrene (NORYL)	1.07	0.90
PolyphenYlene Sulfide	1.35-1.80
Polyphen Sulfide 40% GF	1.65
Polypropylene	0.90	0.70
Polypropylene 30% GF	1.13
POLYStyrene GP	1.05	0.97
POLYStyrene Impact Mod	1.04	0.96
Polysulfone	1.25	1.16
Polyurethane	1.20	1.13
PVC – Rigid	1.39	1.30
PVC – Pipe	1.44	1.32
PVC – Flexible	1.29	1.20
SAN	1.08	1.00
T/P Ruber (Santoprene)	1.08	1.00
T/P Elastomer (Urethane)	0.97	0.93
	0.83	0.82

Common Plastic Abbreviations

Common Abbreviations for Misc Resins
Resin Generic Name	Common ABBR
Acrylonitrile-Butadiene-Styrene	ABS
Cellulose Acetate	CA
Cellulose Acetate Butyrate	CAB
Cellulose Acetate Propionate	CAP
Chlorinated Polyethylene	CPE
Chlorinated Polyvinyl Chloride	CPVC
Ethylene-Propylene Diene Rubber	EPDM
Expandable Polystyrene	EPS
Ethylene Vinyl Acetate	EVA
Fiber Reinforced Plastic	FRP
High Density Polyethylene	HDPE
High Impact Polystyrene	HIPS
Low Density Polyethylene	LDPE
Linear Low Density Polyethylene	LLDPE
Maleic Anhydride	MA
Medium Density Polyethylene	MDPE
Polyamide (Nylon)	PA
Polyacrylonitrile	PAN
Polybutylene	PB
Polybutylene Terephalicate	PBT
Polycarbonate	PC
Polyethylene	PE
Polyetheretherketone	PEEK
Polyetherimide	PEI
Polyetherketone	PEK
Polyethylene Terephalicate	PET
Polyethylene Terephalic Clycol	PETG
Polyimide	PI
Polymethyl Methacrylate	PMMA
Polyoxymethylene	POM
Polypropylene	PP
Chlorinated Polypropylene	PPC
Polyphenylene Oxide	PPO
Polyphenylene Sulfide	PPS
Polyphenylene Sulfone	PPSU
Polystyrene	PS
Polysulfone	PSU
Polyurethane	PU
Polyurethane	PUR
Polyvinyl Chloride	PVC
Reinforce Polybutylene Terephthalateic	RPBT
Reinfor Polyethylene Terephalic	RPET
Reaction Injection Molding	RIM
Styrene Acrylonitrile	SAN
Styrene Butadiene Rubber	SBR
Styrene Maleic Anhydride	SMA
Sheet Molding Compound	SMC
Thermoplastic Elastomer	TPE

How much draft angle do you need in your plastic part?
Below are draft angles commonly used from 1/32″ to 1″ are noted in degrees in the table below.
Each block is the amount of draft with the corresponding angle and depth of the cavity.

DEPTH	1/2°	1°	2°	3°	4°	5°	DEPTH
1/32	.0003	.0005	.001	.0016	.002	.0027	1/32
1/16	.0005	.0011	.002	.0033	.004	.0055	1/16
3/32	.0008	.0017	.003	.0049	.006	.008	3/32
1/8	.0011	.0022	.004	.0066	.009	.0109	1/8
5/32	.0014	.0028	.005	.008	.011	.014	5/32
3/16	.0016	.0033	.006	.0098	.013	.016	3/16
7/32	.0019	.0039	.008	.011	.015	.019	7/32
1/4	.0022	.0043	.009	.013	.018	.022	1/4
9/32	.0025	.005	.010	.014	.020	.024	9/32
5/16	.0027	.0055	.011	.016	.022	.027	5/16
11/32	.003	.006	.012	.018	.024	.030	11/32
3/8	.0032	.0066	.013	.020	.026	.033	3/8
13/32	.0035	.007	.014	.021	.028	.035	13/32
7/16	.0038	.0077	.015	.023	.031	.038	7/16
15/32	.0041	.008	.016	.024	.033	.041	15/32
1/2	.0044	.0088	.018	.026	.035	.044	1/2
17/32	.0046	.009	.019	.028	.037	.046	17/32
9/16	.0049	.0099	.020	.03	.039	.049	9/16
19/32	.0052	.010	.021	.031	.042	.052	19/32
5/8	.0055	.011	.022	.033	.044	.055	5/8
21/32	.0057	.011	.023	.035	.046	.057	21/32
11/16	.006	.012	.024	.036	.048	.060	11/16
23/32	.0063	.013	.025	.038	.050	.063	23/32
3/4	.0065	.013	.027	.039	.053	.066	3/4
25/32	.0068	.014	.028	.040	.055	.068	25/32
13/16	.0071	.014	.029	.043	.057	.071	13/16
27/32	.0074	.015	.030	.045	.059	.074	27/32
7/8	.0076	.015	.031	.046	.061	.077	7/8
29/32	.0079	.016	.032	.048	.063	.079	29/32
15/16	.0082	.017	.033	.050	.066	.082	15/16
31/32	.0085	.017	.034	.051	.068	.084	31/32
1	.0087	.0175	.035	.052	.070	.087	1

Inches to Millimeters Conversion Chart

Inch Fraction	Inch Decimal	mm	mm	Inch Decimal
1/32	0.03125	0.794	1	0.0394
1/16	0.0625	1.588	2	0.0787
3/32	0.09375	2.381	3	0.1181
1/8	0.125	3.175	4	0.1575
5/32	0.15625	3.969	5	0.1969
3/16	0.1875	4.763	6	0.2362
7/32	0.21875	5.556	7	0.2756
1/4	0.25	6.350	8	0.3150
9/32	0.28125	7.144	9	0.3543
5/16	0.3125	7.938	10	0.3937
11/32	0.34375	8.731	11	0.4331
3/8	0.375	9.525	12	0.4724
13/32	0.40625	10.319	13	0.5118
7/16	0.4375	11.113	14	0.5512
15/32	0.46875	11.906	15	0.5906
1/2	0.5	12.700	16	0.6299
17/32	0.53125	13.494	17	0.6693
9/16	0.5625	14.288	18	0.7087
19/32	0.59375	15.081	19	0.7480
5/8	0.625	15.875	20	0.7874
21/32	0.65625	16.669	21	0.8268
11/16	0.6875	17.463	22	0.8661
23/32	0.71875	18.256	23	0.9055
3/4	0.75	19.050	24	0.9449
25/32	0.78125	19.844	25	0.9843
13/16	0.8125	20.638	26	1.0236
27/32	0.84375	21.431	27	1.0630
7/8	0.875	22.225	28	1.1024
29/32	0.90625	23.019	29	1.1417
15/16	0.9375	23.813	30	1.1811
31/32	0.96875	24.606	31	1.2205
1	1	25.400	32	1.2598

Screenshot 2023-02-24 150627

Density of Plastic, Shrinkage, Draft Angle, SPI Mold Class & Conversion Reference Charts

Request for Consultation Form

Stelray Blogs

Pages