What is Injection Molding Finishes?
What is injection molding finishes?
Injection molding is a manufacturing process to produce plastic parts. Injection molding process is cheap and fast. It allows to produce identical parts in high volume. The main benefit that injection molding process is the natural surface finish of injection molding parts. Injection molding process does not require any surface or additional processing treatment, parts have injection molding finishes for many final uses.
With Simple pre-coloration of plastic pellets, the injection molded parts do not need any painting or tinting sometimes after fabrication. A wide range of injection molded applications mean that some form of injection molding finishes are needed. It could be a fast polish or something comprehensive.
At TEAM Rapid, some customers need very smooth injection molding finishes for aesthetic purpose. And some customers like a high level of rough injection molding finishes to extend parts’ lifespan. The article describes some of the available injection molding finishes options at TEAM Rapid.
What are the injection molding finishes options available at TEAM Rapid?
At TEAM Rapid, we offer many injection molding finishes options for injection molded parts. Surface finishing process for injection molding help to increase or decrease the roughness of the injection molded parts. Glossy texture is attractive for aesthetic parts like toys. Rough injection molding finishes is widely used for some mechanical parts or to lower the overall product costs.
Industry standards for injection molding finishes and features are established by The Society of Plastic Industry. This standard relates to the aesthetic qualities of injection molded parts. There are 12 types of standard injection molding finishes which are divided into four categories, including smooth to rough injection molding finishes. At TEAM Rapid, our customers can leave their parts as molded which are the acceptable injection molding finishes options for non-aesthetic parts. They are also good for parts made from steel tooling.
1. Glossy injection molding finishes
Min roughness for glassy injection molding finishes is 0.012 μm. Injection molded parts can be made with rough finish by a diamond buff polishing. During this surface finishes process, manufacturer use a loose abrasive material to a wheel. And apply the wheel to the part’s surface to contribute the glossiest injection molding finishes. Not all materials can be made with glossy injection molding finishes, for example, TPU. Because of TPU has high abrasion resistant and is resistant to buffing process.
2. Semi-glossy injection molding finishes
Min roughness for Semi-glossy injection molding finishes is 0.05μm. When the injection molded parts need glossiness, using a grit sandpaper to make a B-grade is ideal. This process can be used in a wide range of injection molding parts. It allows to produce parts with highly aesthetic. It is widely used in producing consumer products.
3. Matte injection molding finishes
Min roughness for matte injection molding finishes is 0.35μm. Machining marks can be removed form the injection molded parts by grit sanding stones to make a glossy injection molding finish. This process if good suitable for parts which do not need consistent injection molding finishes and do not have aesthetic value. This process is suitable for most of injection molding parts.
4. Textured injection molding finishes
Min roughness for textured injection molding finishes is 0.80μm. Some injection molded parts need very rough or textured injection molding finishes to increase friction for mechanical purposes. Sandblasting process can be used to make this rough injection molding finishes. During the sandblasting process, sandblasting uses compressed air to direct abrasive material against the part with force to rough the part surface.
What factors affect injection molding finishes?
Making injection molding finishes is a good way to achieve maximum control over the texture of the injection molded parts. Below are the factors affect injection molding finishes.
a) Tooling
The mold is one of the main factors that affect the injection molding finishes. Steel and aluminum are the most common material to make molds. Steel and aluminum have different effect on the molded injection molded parts. Very smoothest injection molding finishes can be achieved by molds made from steel. If parts need very low level of rough injection molding finishes, steel molds is the best way.
b) Materials
There are a wide range of injection molding materials, but not all injection molding material can have the same injection molding finishes. Some materials are easy to have smooth injection molding finishes and some are easy to have rough or textured injection molding finish. Some material additives such as filler and colors will affect the injection molding finishes of the injection molded parts. Additive compounds which are mixed into the plastic material is also a factor affect injection molding finishes. For example, fiberglass results in lower gloss. Carbon black or mica will reduce surface roughness. So, manufacturers will avoid using these additives if surface roughness has to be maintained for function or appearance. Adding filler will increase surface roughness. Manufacturers can mix and resins and additives to create proper injection molding finishes.
c) Process
Injection speed and temperature will affect the injection molding finishes. Glossier injection molding finishes with fewer weld lines can be achieved by fast injection speed and high melt temperature. Weld line visibility can be reduced by a fast filling through mold cavities which will improve the overall appearance of plastic finishes. A smoother injection molding finishes can be achieved by high mold and melt temperature combined with high injection speed.
d) Function
Except for aesthetic reasons affect injection molding finishes, some functional reasons also impact injection molding finishes. Textured injection molding finishes can ensure the paint adheres to the parts better. So, smooth injection molding finishes can cause the paint to peel off. Some parts need solid gripping for better performance. Textured injection molding finishes enhances the quality of the grip. Injection molding finishes have better slip resistance. Textured injection molding finishes will add strength to the parts and enhance safety levels.
Injection molding finishes for functionality
There are may reasons to choose injection molding finishes types. Injection molding defects like weld lines, sinks, blush marks, flow line can be hidden by injection molding finishes. Parts with injection molding especially textured injection molding finishes can withstand damages during shipping or use. The paint adhesion can be improved by textured injection molding finishes. Aesthetics of the injection molded parts can also be improved by injection molding finishes. Injection molding finishes prevent the parts being scratched and scuffed and improve durability.
TEAM Rapid’s injection molding services
TEAM Rapid, as a professional injection molding and rapid manufacturing company, we offer high quality plastic injection molding services at the reasonable prices. We have more than 100 plastic materials available. Our engineers ensure that each injection molded part goes through top-class manufacturing. We are able to combine our expertise and experience to offer high quality injection molding services. Our rich knowledges of different injection molding finishes options ensure customers to get the best finishes. If you need help on your injection molding projects, just upload your 3D file, we will offer instant free quote.
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