What is ABS injection moulding? Acrylonitrile Butadiene Styrene, more commonly known as ABS is a widely used thermoplastic polymer in injection moulding, due to the ease in which it is moulded and its relatively low cost, making it suitable for mass production.
ABS is known for its strength and durability, as well as its glossy, smooth surface finish, which makes it aesthetically pleasing. For this reason, ABS is commonly used in a lot of industries where parts will be on display, such as electronics, automotive parts, toys and home appliances. One place you will recognise ABS from is Lego bricks.
What are the applications of ABS?
So, let’s look in a little more depth at the kinds of items ABS is commonly used for/ is suitable for.
- Consumer Electronics – Its impact resistance, versatility and electrical insulation properties make it suitable for a wide range of consumer electronics components such as, keyboards, computer mice, remote controls, and phone cases.
- Automotive Parts – Its strength, impact resistance and surface finish make it a great material for parts such as, dashboards, door panels, trims, grilles, mirror housings, and interior console parts.
- Toys and Games – Think Lego! It’s popular for parts from toys and games due to its durability, impact resistance and ability to be moulded into intricate shapes.
- Household Appliances – Strength, chemical resistance and ease of processing make it good for use in vacuum cleaners, blenders, coffee makers, toasters, and kitchen utensils.
- Medical Devices and Equipment – Durability, chemical resistance, and ease of sterilisation mean that ABS is suitable for components such as, medical instrument housings, equipment casings, laboratory equipment, disposable syringes, and medical device components.
- Sports and Recreation Equipment – For helmets, protective gear, athletic equipment, skateboards, and bicycles. ABS’ impact resistance and ability to withstand outdoor conditions make it suitable in these applications.
What are the advantages of injection moulded ABS?
- Impact Resistance – ABS’ excellent impact resistance makes it suitable for applications that require durability and toughness.
- Strength and Stiffness – It has good mechanical properties, including high strength and stiffness. Its ability to withstand stress makes it suitable for structural components.
- Versatility – ABS can easily be moulded and shape
- Chemical Resistance – It displays a wide range of chemical resistance, including acids, alkalis and various solvents.
- Electrical Insulation – The material’s good insulation properties make it good for electrical components, housings and enclosures.
- Surface Finish – It can easily be finished and post-processed for a smooth and aesthetically pleasing surface.
What are the disadvantages of injection moulded ABS?
- Poor Weather Resistance – ABS tends to degrade when exposed to sunlight and UV radiation. It can become brittle and discoloured over time. Meaning its outdoor applications are limited.
- Flammability – It is classified as combustible and has relatively low resistance to fire. It tends to soften and burn, releasing potentially toxic fumes. Although flame-retardant additives can be used to improve its resistance.
- Limited Heat Resistance – The material is an amorphous thermoplastic with a moderate glass transition temperature of 105 °C. It may deform or lose its mechanical properties at higher temperatures. This also restricts applications.
- Dimensional Instability – ABS has a higher coefficient of thermal expansion compared to other engineering plastics. This can lead to dimensional changes with temperature variations. Consequently, tolerances can be difficult to maintain.
Design Considerations for injection moulded ABS
When designing parts that will be injection moulded using ABS, there are several things to consider to ensure a functioning, manufacturable, part.
To learn more about considerations for injection moulding in general, visit our injection moulding toolkit.
- Material Flow – ABS has good material flow, but even ABS may struggle with long, thin sections or complex geometries and parts like this will likely require additional flow analysis.
- Material Drying – ABS is hygroscopic (absorbs moisture) meaning if not dried properly moisture can turn into steam during the moulding process leading to splay marks or weak parts.
- Wall Thickness – should be consistent across the part and at Protolabs we advise should be between 1.143mm – 3.556mm. If variation is necessary, transition should be gradual.
- ABS can be moulded with additives such as flame retardants and fillers, however, these can affect things such as flow and shrink. Special considerations may need to be considered, depending on which additive is being used. For example, for glass-filled ABS, higher mould temperatures and pressures may be needed.
Common Pitfalls when injection moulding ABS
Many of the considerations mentioned above can turn into pitfalls if not thought about and properly before the part goes to print.
- Shrinkage – ABS typically has a shrink rate of 0.4% - 0.8% and this should be considered when designing parts with tight tolerances.
- Improper Cooling Time – Not allowing enough time for parts to cool properly can lead to warpage and deformation after ejection. On the opposite side of the spectrum overly long cooling times reduce production efficiency.
- Material Degradation – As mentioned in the disadvantages ABS can degrade when exposed to excessive heating. This includes during the moulding process. This can result in weakened material properties or discolouration.
To learn more about injection moulding defects in general, read our blog on injection moulding defects and how to prevent them.
Design Parameters for injection moulded ABS at Protolabs
At Protolabs design parameters for injection moulded ABS are the same for any moulded plastic material. To learn about our capabilities in detail, visit our injection moulding webpage.
- Size - Our innovative operating model enables us to handle a wide range of variables, meaning we can quote in a number of ways. Plus, with our Digital Network, we’re equipped to take on more projects than ever. Simply upload your CAD file for a rapid assessment and let us take care of the rest.
- Tolerances - Protolabs can maintain a machining tolerance of +/- 0.076mm. Depending on the material selected the resin tolerance can be as accurate as 0.002mm/mm. The resin tolerances of all thermoplastic materials are now visible on your quotes.
If your part is outside of these listed tolerances, please contact us direct to discuss how we can help. - Draft – We also have a design tip available that covers the topic of draft in detail.
| Vertical Faces |
0.5° |
|---|---|
| Most Situations |
2° |
| Minimum for Shut Off | 3° |
| Minimum for Light Texture (PM-T1) | 3° |
| Minimum for Medium Texture (PM-T2) | 5°+ |
- Undercuts – we also have a design tip that covers the topic of undercuts in detail.
| Width | Height | Pull |
|---|---|---|
| 450mm | < 150mm | < 200mm |
- Surface Finishes – we also have a design tip that covers the topic of surface finishes in detail.
| Finish | Description |
|---|---|
| PM-F0 | non-cosmetic, default |
|
PM-F1 |
low-cosmetic, most toolmarks removed |
| SPI-C1 | 600 grit stone, |
| PM-T1 | SPI-C1 + light bead blast |
| PM-T2 | SPI-C1 + medium bead blast |
| SPI-B1 | 600 grit paper |
| SPI-A2 | grade #2 diamond buff |
For further consideration we have available our Design for Mouldability Toolkit, which looks at moulding at Protolabs in detail including some of the advisories that may appear in your quote and how to navigate them.
ABS Material Grades available for moulding at Protolabs Factory - Compared
| Tensile Strength ASTM D638/ ISO 527 | Elongation ASTM D638/ ISO 527 | Hardness (R-Scale) ASTM D785 | Heat Deflection ISO 75-2/A | Benefits | |
|---|---|---|---|---|---|
| Polylac PA-717C
|
42.1 MPa
|
30%
|
115
|
82°C
|
Medium Impact Resistance RoHS Compliant Good Mechanical Properties and Dimensional Stability |
| Polylac PA-727
|
45.06 MPa
|
40%
|
113
|
87°C
|
Medium Impact Resistance Solvent Resistance Good Mechanical Properties and Dimensional Stability |
| Polylac PA-758
|
39.7 MPa
|
40%
|
107
|
77°C
|
Clear / Transparent Good Flow RoHS Compliant |
| Polylac PA-765
|
38.1 MPa
|
15%
|
100
|
74°C
|
Flame Retardant RoHS Compliant Good Flow High Strength Versatile |
| Novodur HD 15 ABS (Natural)
|
48 MPa
|
10%
|
105
|
99°C
|
Sterilisable Well-Balanced Mechanical Properties Excellent Chemical and Stress Cracking Resistance |
Plastics that are similar to ABS
First of all, we should mention ABS/PC, which is a blend of both ABS and PC. Combining the benefits of both materials to create a more versatile, durable option.
| Tensile Strength ASTM D638/ ISO 527 | Elongation ASTM D638/ ISO 527 | Hardness (R-Scale) ASTM D785 | Heat Deflection ISO 75-2/A | Benefits | |
|---|---|---|---|---|---|
| Bayblend FR3010 Black/ Natural
|
60 MPa
|
50%
|
122
|
100°C
|
Flame Retardant Improved Chemical Resistance and Stress Cracking Increased Heat Resistance |
| Bayblend T65 XF Black / Natural
|
54 MPa
|
50%
|
115
|
122°C
|
Good Flow Increased Heat Resistance High Impact Strength |
| Gebablend 85 (Repro) > 90% Recycled Content Black (rPC/rABS)
|
50 MPa | 128°C |
High Impact Resistance Recycled Content Good Flow |
In terms of properties and applications there are several materials, similar to ABS
- Polystyrene (PS) – Its similarities to ABS are its transparency, ease of processing and affordability. Although it has lower impact resistance and mechanical strength. Common uses include packaging materials, disposable cutlery, and insulation.
- Polypropylene (PP) – Has good chemical resistance, high heat resistance and low density, but has lower impact strength and stiffness than ABS. Common usage includes automotive parts, packaging, containers, and household products
- Polycarbonate (PC) – With similar impact resistance to ABS, but generally a higher price point. PC is known for its high impact resistance and excellent clarity. Common uses include applications that require optical clarity, such as, automotive lighting, safety goggles, and electronic display screens.
- Polyethylene (PE) – Known for its excellent chemical resistance and low friction properties, but PE does have a lower impact strength and stiffness than ABS. Common uses include, packaging, pipes, containers, and various household products.
- Polyamide (Nylon) – Strong and durable, with good mechanical properties. It has a higher impact strength than ABS but is also more expensive. Commonly used for parts that require high strength and wear resistance, such as gears bearings, and automotive parts.
Alternatives for ABS
- PSU – An alternative to ABS when higher temperature resistance, chemical resistance, and mechanical properties are required.
- ASA – Similar to ABS, but with improved weather resistance. Making it an excellent choice for outdoor applications.
- COC – generally considered when transparency, chemical resistance and performance at low temperatures are required.
- PPO – An option when higher temperature resistance, chemical resistance, and mechanical properties are needed.
- ABS-Like for Stereolithography – A good alternative when complex geometries and high precision are required. Also, time saving when it comes to prototyping and iteration due to the lack of requirement of a moulding tool.
- ABS for CNC Machining – Is highly machinable and good for creating complex shapes and intricate details and allowing for modifications and customisations.
ABS is a versatile and reliable material for injection moulding parts. Utilised in numerous applications across various industries, its impact resistance, dimensional stability, chemical resistance, and cost effectiveness make it a popular choice for a range of products and parts. If you have further questions about ABS or injection moulding, please contact one of our sales team or application engineers on +44(0) 1952 683047 or email [email protected]