Understanding Molding Shrinkage
Molding Shrinkage refers to the percentage reduction in the dimensions of a plastic part after it is removed from the mold and cooled to room temperature.
Because shrinkage is not only caused by the thermal expansion and contraction of the resin itself but is also related to various molding factors (such as pressure, temperature, and wall thickness), the shrinkage rate of a molded part is technically referred to as the Molding Shrinkage Rate.
Note for Engineers: Accurate shrinkage data is critical for mold design to ensure the final part meets dimensional tolerances.
PA6 Series Shrinkage Rates (Nylon 6)
Polyamide 6 is known for its high mechanical strength and toughness. Below are the shrinkage rates for various modifications.
| Beschrijving | Shrinkage Rate (%) | Grade Code |
|---|---|---|
| Glass Fiber Reinforced | ||
| 15% Glass Fiber Reinforced PA6 | 0.5 - 0.8 | PA6G15 |
| 20% Glass Fiber Reinforced PA6 | 0.4 - 0.6 | PA6G20 |
| 30% Glass Fiber Reinforced PA6 | 0.3 - 0.5 | PA6G30 |
| 40% Glass Fiber Reinforced PA6 | 0.1 - 0.3 | PA6G40 |
| 50% Glass Fiber Reinforced PA6 | 0.1 - 0.3 | PA6G50 |
| Flame Retardant (FR) | ||
| 25% GF Flame Retardant PA6 | 0.2 - 0.4 | Z-PA6G25 |
| 30% GF Flame Retardant PA6 | 0.2 - 0.4 | Z-PA6G30 |
| 30% GF Halogen-Free FR PA6 | 0.2 - 0.4 | Z-PA6G30 |
| Halogen-Free FR PA6 | 0.8 - 1.2 | Z-PA6 |
| Mineral & Filled | ||
| 30% Mineral Filled Halogen-Free FR | 0.5 - 0.8 | Z-PA6M30 |
| 30% Glass Bead Filled PA6 | 0.8 - 1.2 | PA6M30 |
| 30% GF + Mineral Composite | 0.3 - 0.5 | PA6M30 |
| 40% GF + Mineral Composite | 0.2 - 0.5 | PA6M40 |
| 30% Mineral Filled PA6 | 0.6 - 0.9 | PA6M30 |
| 40% Mineral Filled PA6 | 0.4 - 0.7 | PA6M40 |
| General & Toughened | ||
| General Injection Grade PA6 | 1.4 - 1.8 | PA6 |
| Rapid Prototyping PA6 | 1.2 - 1.6 | PA6 |
| General Toughened PA6 | 1.0 - 1.5 | PA6 |
| Medium Toughened PA6 | 0.9 - 1.3 | PA6 |
| Super Toughened PA6 | 0.9 - 1.3 | PA6 |
| MoS2 Filled Wear-Resistant PA6 | 1.0 - 1.4 | PA6 |
PA66 Series Shrinkage Rates (Nylon 66)
PA66 offers higher temperature resistance and stiffness compared to PA6.
| Beschrijving | Shrinkage Rate (%) | Grade Code |
|---|---|---|
| Glass Fiber Reinforced | ||
| 15% Glass Fiber Reinforced PA66 | 0.6 - 0.9 | PA66G15 |
| 20% Glass Fiber Reinforced PA66 | 0.5 - 0.8 | PA66G20 |
| 25% GF Heat/Oil Resistant PA66 | 0.4 - 0.7 | PA66G25 |
| 30% Glass Fiber Reinforced PA66 | 0.4 - 0.7 | PA66G30 |
| 30% GF Hydrolysis Resistant PA66 | 0.3 - 0.6 | PA66G30 |
| 40% Glass Fiber Reinforced PA66 | 0.2 - 0.5 | PA66G40 |
| 50% Glass Fiber Reinforced PA66 | 0.1 - 0.3 | PA66G50 |
| Flame Retardant & Filled | ||
| 25% GF Flame Retardant PA66 | 0.2 - 0.4 | Z-PA66G25 |
| 30% GF Flame Retardant PA66 | 0.2 - 0.4 | Z-PA66G30 |
| 30% Mineral Filled Halogen-Free FR | 0.2 - 0.4 | PA66M30 |
| Halogen-Free FR PA66 | 0.8 - 1.2 | Z-PA66 |
| 30% Mineral Filled Halogen-Free FR | 0.4 - 0.7 | Z-PA66M30 |
| 30% Glass Bead Filled PA66 | 0.8 - 1.2 | PA66M30 |
| 30% GF + Mineral Composite | 0.2 - 0.5 | PA66M30 |
| 30% Mineral Filled PA66 | 0.6 - 0.9 | PA66M30 |
| 40% Mineral Filled PA66 | 0.4 - 0.7 | PA66M40 |
| General Grades | ||
| General Injection Grade PA66 | 1.5 - 1.8 | PA66 |
| Rapid Prototyping PA66 | 1.5 - 1.8 | PA66 |
| General Toughened PA66 | 1.2 - 1.7 | PA66 |
| Medium Toughened PA66 | 1.2 - 1.6 | PA66 |
| Super Toughened PA66 | 1.2 - 1.6 | PA66 |
| MoS2 Filled Wear-Resistant PA66 | 1.2 - 1.6 | PA66 |
PP Series Shrinkage Rates (Polypropylene)
PP is a semi-crystalline material with relatively high shrinkage, which can be reduced with fillers like talc or glass fiber.
| Beschrijving | Shrinkage Rate (%) | Grade Code |
|---|---|---|
| Talc Filled | ||
| 20% Talc Filled PP | 1.0 - 1.5 | PPM20 |
| 30% Talc Filled PP | 0.8 - 1.2 | PPM30 |
| 40% Talc Filled PP | 0.8 - 1.0 | PPM40 |
| 20% Talc Filled Toughened PP | 1.0 - 1.2 | PPM20 |
| Glass Fiber & Beads | ||
| 10% Glass Fiber Reinforced PP | 0.7 - 1.0 | PPG10 |
| 20% Glass Fiber Reinforced PP | 0.5 - 0.8 | PPG20 |
| 30% Glass Fiber Reinforced PP | 0.4 - 0.7 | PPG30 |
| 20% Glass Bead Filled PP | 1.2 - 1.6 | PPM20 |
| 30% Glass Bead Filled PP | 1.0 - 1.2 | PPM20 |
| General & Flame Retardant | ||
| Brominated Flame Retardant PP | 1.5 - 1.8 | PP |
| Halogen-Free Flame Retardant PP | 1.3 - 1.6 | PP |
| High Flow High Rigidity PP | 1.5 - 2.0 | PP |
| General Toughened PP | 1.5 - 2.0 | PP |
| Medium Toughened PP | 1.4 - 1.9 | PP |
| Super Toughened PP | 1.3 - 1.8 | PP |
| Weather Resistant | ||
| Heat Aging Resistant PP (1/2/3) | 1.5 - 2.0 | PP1/2/3 |
| Impact Resistant Weatherable PP4 | 1.5 - 2.0 | PP4 |
| High Impact Weatherable PP5 | 1.5 - 1.8 | PP5 |
PC Series Shrinkage Rates (Polycarbonate)
Polycarbonate has low shrinkage and high dimensional stability.
| Beschrijving | Shrinkage Rate (%) | Grade Code |
|---|---|---|
| Glass Fiber Reinforced | ||
| 10% Glass Fiber Reinforced PC | 0.3 - 0.5 | PCG10 |
| 20% Glass Fiber Reinforced PC | 0.3 - 0.5 | PCG20 |
| 25% Glass Fiber Reinforced PC | 0.2 - 0.4 | PCG25 |
| 30% Glass Fiber Reinforced PC | 0.2 - 0.4 | PCG30 |
| Flame Retardant | ||
| 20% GF Flame Retardant PC | 0.2 - 0.4 | Z-PCG20 |
| 25% GF Flame Retardant PC | 0.2 - 0.4 | Z-PCG25 |
| 30% GF Flame Retardant PC | 0.2 - 0.4 | Z-PCG30 |
| 20% GF Halogen-Free FR PC | 0.2 - 0.4 | Z-PCG20 |
| 30% GF Halogen-Free FR PC | 0.1 - 0.3 | Z-PCG30 |
| Mineral Filled | ||
| 20% Glass Bead Filled PC | 0.3 - 0.6 | PCM20 |
PC/ABS & PC/PBT Series Shrinkage Rates
These alloys combine the properties of Polycarbonate and ABS or PBT.
| Beschrijving | Shrinkage Rate (%) | Grade Code |
|---|---|---|
| PC/ABS Alloys | ||
| 20% Glass Fiber Reinforced PC/ABS | 0.2 - 0.4 | PC/ABSG20 |
| Brominated Flame Retardant PC/ABS | 0.3 - 0.6 | Z-PC/ABS |
| Halogen-Free Flame Retardant PC/ABS | 0.4 - 0.7 | Z-PC/ABS |
| Weatherable PC/ABS | 0.4 - 0.7 | PC/ABS |
| PC/ABS (35% PC Content) | 0.4 - 0.6 | PC/ABS |
| PC/ABS (65% PC Content) | 0.4 - 0.7 | PC/ABS |
| PC/ABS (85% PC Content) | 0.4 - 0.7 | PC/ABS |
| PC/PBT Alloys | ||
| 10% Glass Fiber Reinforced PC/PBT | 0.5 - 0.8 | PC/PBTG10 |
| 20% Glass Fiber Reinforced PC/PBT | 0.4 - 0.6 | PC/PBTG20 |
| 30% Glass Fiber Reinforced PC/PBT | 0.3 - 0.5 | PC/PBTG30 |
| 30% GF FR High Heat PC/PBT | 0.3 - 0.5 | Z-PC/PBTG30 |
| High Impact High Heat PC/PBT | 0.6 - 1.0 | PC/PBT |
ABS Series Shrinkage Rates
ABS is widely used for its impact resistance and surface finish.
| Beschrijving | Shrinkage Rate (%) | Grade Code |
|---|---|---|
| Glass Fiber Reinforced | ||
| 20% Glass Fiber Reinforced ABS | 0.2 - 0.4 | ABSG20 |
| 25% Glass Fiber Reinforced ABS | 0.2 - 0.4 | ABSG25 |
| 30% Glass Fiber Reinforced ABS | 0.1 - 0.3 | ABSG30 |
| 20% GF Flame Retardant ABS | 0.1 - 0.3 | Z-ABSG20 |
| General Grades | ||
| General Flame Retardant ABS | 0.4 - 0.7 | Z-ABS |
| General Injection Grade ABS | 0.4 - 0.7 | ABS |
| Weatherable ABS | 0.4 - 0.7 | ABS |
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