Plastic Rapid Prototyping

Casting Techniques for Plastic Prototype Manufacturing
Silicone casting is an excellent process for low-batch plastic prototype fabrication since it requires a master model (a sample) to create the molds. You usually suspend the master model over an empty tank. Then, you add some technological elements (usually plastic as well) to the model, such as the channel for pouring plastic and ventilation. After that, you pour liquid silicone into the tank, wait until it solidifies, and sometimes cure it in the oven. You split the mold in half, and it’s ready to produce up to 25 plastic parts. No capital investments are necessary.

How to Use 3D Printing for Plastic Prototyping
Additive manufacturing, often called 3D printing, is a comparatively innovative process for manufacturing different parts. What defines 3D printing is the change in mass; the initial material is usually larger than the final part. However, in additive manufacturing, the initial material can be either powder or a thin filament. It is applied to the printer's base plate layer by layer and is sintered or cured to replicate the current cross-section of the part. Since its invention in the 1980s, additive manufacturing has made significant strides in precision, surface finish, material choice, and lead time.

Selective Laser Sintering (SLS)
Selective laser sintering is one of the earliest processes among the various additive manufacturing techniques used for rapid plastic prototyping. It is the most versatile type of additive process that can be used for practically any material, including plastics. SLS does not require a lot of laser power to sinter materials together, and the main advantage of spreading powder over the base plate is that it serves as a support structure for overhanging elements to some degree.

Fused Deposition Modeling (FDM)
FDM is the cheapest and easiest additive process available for manufacturing plastic prototypes. Many hobbyists create FDM 3D printers at home. FDM uses raw material in the form of a plastic filament that is liquefied and deposited layer by layer on the plate, forming the current cross-section of the part. Overhanging structures are supported using another material—a more brittle type of plastic that can be easily removed. Overall, FDM is the most economical process but yields the poorest surface finish and quality, requiring more post-processing if aesthetics are important.

Stereolithography (SLA)
SLA is considered the "father" of all 3D printing processes and is known for producing the highest part quality. The surface finish is almost perfect, and precision is limited only by the diameter of the UV/laser light. This process is widely used to manufacture master models for future casting and prototypes where aesthetics are crucial. However, SLA is the most expensive process since the liquid polymer is costly, and a considerable amount is required. Another issue with SLA is that support structures can only be made using the model material and must be mechanically removed, which can leave blemishes on the surface that require post-processing.

MultiJet Printing (MJP)
MultiJet printing is a popular choice for prototypes made of plastic, as it combines many advantages of FDM while lacking some disadvantages of SLA. In MJP, raw plastic is melted into droplets and dispensed from the printer nozzle in the required contours. One of the main advantages of MJP is that the quality of the parts is similar to that of SLA, but it does not require filling a tank with liquid polymer. MJP is also the only multicolor process among those mentioned.

How to Create a Plastic Prototype with Rapid Injection Molding
Rapid plastic injection molding is a variation of conventional injection mold manufacturing technology. The main difference lies in the details; for example, rapid molds have more joints. The cavity of the mold is connected to the base, so if you need to modify the design, you can simply remove the cavity and change it without altering any other elements. This lowers accuracy but increases flexibility. Additionally, instead of hardened steel, which is suitable for millions of iterations, aluminum alloys are used. While they are less durable, their manufacturability is up to five times better. These modifications make it possible to use plastic injection molding even for prototypes. However, it is advisable to use this method for high-quality work, as the process is still relatively costly.

Using CNC Machining to Create Plastic Parts
When it comes to machined plastic and metal components, many plastic prototype manufacturers use CNC machining for form, fit, and functional testing of plastic parts due to its advantages in the prototyping realm. With the upgrade in production-grade material selection that machining provides, we use CNC prototyping to create plastic prototypes and metal parts. This allows your design team to closely simulate the final product's appearance and function, reflecting the validity of assembly work and providing the time and space needed to modify and optimize the design.