The mainstream plastic prototype services include four processing methods, CNC machining, vacuum casting, 3D printing, and reaction injection molding (RIM). Each of them has its unique characteristics.
1. CNC machining
CNC (Computer Numerical Control) Machining is the primary digital manufacturing technology to produce rapid prototypes.
Materials for plastic prototypes
ABS, PC, PC+ABS, PMMA, PA, POM, PP, etc.
ABS is the most commonly used plastic material for plastic prototype services. The colors of the raw materials are beige, black, and white. It is easy to be post-treated. However, ABS used for prototyping is less vulnerable than that of mass production. So ABS prototypes usually cannot be sold as end-use products.
PC and PMMA are for semi-transparent and transparent parts, such as auto lamps and lenses. PMMA’s transparency is higher than PC’s. PC is half clear. You can increase the transparency by fumigating.
Materials with excellent mechanical properties like PA, POM, and PP are typically applied to make structural parts.
The choice of plastic materials depends on the detailed requirements. In other words, if prototyping aims to test its appearance, structure, or function.
Molds
Not needed.
Applications
CNC-machined plastic parts are for prototyping purposes only in most cases. The highest tolerance can be +/- 0.01mm.
2. Vacuum casting
Based on the silicone mold made from a product prototype, vacuum casting produces the same parts in the vacuum environment.
Materials for plastic prototypes
Liquid PU or polyurethane resin.
There are many series of PU raw materials. After being injected into the silicone mold and drying down, the properties of the solid part can be similar to those of ABS, PC, PMMA, etc.
Molds
Silicone molds are made based on a CNC-machined or 3D-printed model.
Applications
As each silicone mold lasts for 10~25 shots, that vacuum casting is an efficient low-volume production process for the quantity of 10~100 sets of plastic prototypes and products. It takes a shorter time and less cost than CNC machining. But The tolerance is also lower.
3. 3D printing
3D printing is an additive manufacturing process that can print parts with small features.
Materials for plastic prototypes
ABS, PLA, PC, PA, PMMA, PEEK, PPEK+GF, photopolymer, etc.
As 3D technology develops rapidly, it is possible to print a wide range of powder-shaped materials.
Molds
Not needed.
Applications
Because 3D printing manufactures parts layer by layer, it can produce plastic prototypes with complex structures. The tolerance is about +/- 0.1mm. So the surface of the parts is slightly rough. It finds applications in toys, handicrafts, jewelry and construction industries, etc.
4. Reaction injection molding (RIM)
Reaction injection molding (RIM) is a rapid molding process for making unreinforced thermoset parts rapidly in an environment of low pressure and room temperature.
Materials for plastic prototypes
Liquid PU or polyurethane resin.
The material is different from vacuum casting. RIM mixes two kinds of PU, namely material A and material B, into two pressurized chambers while machining.
Molds
ABS, resin, aluminum, or steel molds.
Applications
RIM is a cost-effective way of producing large plastic parts for the automotive and medical device fields. For plastic prototype service, it fits situations where you need to make large-sized parts in one piece with different wall thicknesses.
X Rapid Technologies provides rapid prototyping and low-volume manufacturing services such as CNC machining, vacuum casting, 3D printing, sheet metal fabrication, rapid tooling, reaction injection molding, and surface finishing. We are always ready to offer you the best plastic prototype services. Don’t hesitate to get in touch!
