Plastic Injection Moulding
Our plastic injection moulding process produces custom - rapid prototypes and end-use production parts in 15 days or less. We use aluminium moulds that offer cost-efficient tooling and accelerated manufacturing cycles, and stock more than 100 different thermoplastic resins.
Plastic Injection Moulding Design Guidelines will help you understand capabilities and limitations.
Why Choose Plastic Injection Moulding For Your Project?
Protolabs utilise a rapid injection moulding a technology-driven process that leverages manufacturing automation. CAD models are sent directly to the production floor where mould milling begins, but in most cases, moulds are fabricated from aluminium, not steel. This allows for faster and most cost-effective tooling when compared to traditional steel moulds. We offer a number of additional secondary services to support your project.
What is Injection Moulding?
Plastic injection moulding is the process of melting plastic pellets (thermosetting/ thermoplastic polymers) that once malleable enough, are injected at pressure into a mould cavity, which fills and solidifies to produce the final product.
How Does Plastic Injection Moulding Work?
The thermoplastic injection moulding process at Protolabs is a standard process involving an aluminium mould. Aluminium transfers heat much more efficiently than steel, so does not require cooling channels - which means the time we save on cooling can be applied to monitoring fill pressure, cosmetic concerns and producing a quality part.
Resin pellets are loaded into a barrel where they will eventually be melted, compressed, and injected into the mould’s runner system. Hot resin is shot into the mould cavity through the gates and the part is moulded. Ejector pins facilitate removal of the part from the mould where it falls into a loading bin. When the run is complete, parts (or the initial sample run) are boxed and shipped shortly thereafter. Request your Free Design Cube which shows surface finishes and thick and thin finishes.
- 25 to 10,000+
- Shipped in 15 working days or less
Rapid injection moulding works best for on-demand production, bridge tooling, pilot runs, and functional prototyping. Our affordable aluminium moulds and quick turnaround times help reduce design risks and limit overall production costs.
Manufacturing has experienced radical change over the years, but one of the few constants has been the prevalence of injection moulding as the most common process within the sector. But what makes injection moulding so compelling to design engineers around the world?
Design Guidelines: Plastic Injection Moulding
480mm x 770mm
101mm from parting line with 3° of draft
|Up to 202mm if the parting line can pass through the middle of the part|
|Projected Mould Area||
Typically, Protolabs can maintain a machining tolerance of +/- 0.08mm with an included resin tolerance that can be greater than but no less than +/- 0.005mm/mm
If your part is outside of these listed tolerances, please contact us direct to discuss how we can help [email protected]
- Acetal Copolymer
- Acetal Homopolymer
- Nylon 6
- Nylon 5/12
|low-cosmetic, most toolmarks removed|
|SPI-C1||600 grit stone, 10-12 Ra|
|PM-T1||SPI-C1 + light bead blast|
|PM-T2||SPI-C1 + medium bead blast|
|SPI-B1||600 grit paper, 2-3 Ra|
|SPI-A2||grade #2 diamond buff, 1-2 Ra|
Read our design tip on surface finishes
|MINIMUM FOR SHUT OFF||3°|
|MINIMUM FOR LIGHT TEXTURE (PM-T1)||3°|
|MINIMUM FOR LIGHT TEXTURE (PM-T2)||5°+|
Read our design tip on Draft
Maximum Side Core Dimensions
Read our design tip on Undercuts
RECOMMENDED WALL THICKNESS
1.143mm - 3.556mm
0.762mm - 3.048mm
|Acrylic||0.635mm - 12.7mm|
|Liquid Crystal Polymer||0.762mm - 3.048mm|
|Long-Fiber Reinforced Plastics||1.905m - 25.4mm|
|Nylon||0.762mm - 2.921mm|
|Polycarbonate||1.016mm - 3.81mm|
|Polyester||0.635mm - 3.175mm|
|Polyethylene||0.762mm - 5.08mm|
|Polyphenylene Sulfide||0.508mm - 4.572mm|
|Polypropylene||0.635mm - 3.81mm|
|Polystynene||0.889mm - 3.81mm|
|Polyurethane||2.032mm - 19.05mm|
* The table is adapted from manufacturingcenter.com.
Some part corners will have a radius rather than a sharp edge since we use an automated CNC milling process to make the mould for your parts. This typically does not require a change to your model, but resulting radii are identified before the mould is milled.
Read our design tip on Radii
How can I reduce mould costs?
|1. Eliminate undercuts|
|2. Get rid of unnecessary features|
|3. Use a core cavity approach|
|4. Reduce cosmetic finishes and appearances|
|5. Design self-mating parts|
|6. Modify and reuse moulds|
|7. Pay attention to DFM analysis|
|8. Use a multi-cavity or family mould|
|9. Consider part size|
Learn More about Reducing Mould Costs
What can Injection Moulding be used for?
Injection Moulding is used to make a variety of widely used products. If you look around your desk/ home you will find a multitude of injection moulded products, from bottle tops, remote control casing, console covers, syringes and most plastic made products.
To see an example of an injection moulded part worked on by Protolabs, please view our Hager case study here.
To show off some of the features our injection moulding service can offer, please click to register for your free design cube
Product designers and engineers can upload a 3D CAD model online at any time to receive an interactive ProtoQuote® with free design for manufacturability (DFM) analysis and real-time pricing information within hours. The DFM analysis helps eliminate potential problems like sink, challenging undercuts or walls that are too thin or thick. Once a part design is ready and a quote approved, production begins almost immediately. Upload a part today for a ProtoQuote with design analysis.
Needing to solve difficult tooling and design issues? Shut-offs are a design element that help engineers solve this. Read more about incorporating shut-offs into your mould design.
For more information on injection moulding, please check out our White Papers and comprehensive library of design tips
Need support in choosing materials for your project? See our whitepaper on thermoplastics Materials Matter
and for further support with cosmetic appearance of moulded parts. See our whitepaper on Cosmetics