Plastic machining is both an art and a science. Plastics can change dimensionally due to humidity, temperature and machining process and there is an “art” to keeping machined components within stated tolerances. All polymers and copolymers react differently to coolant and machining technique- the science required to properly machine plastic.
Plastic can be machined or molded to create plastic components. Plastic machining is typically used for low volume components or components that may have a short life span. While creating a mold is costly up front, each individual component created from the mold is a cost effective way to produce high volume, long life span components.
Machining a plastic component can allow an OEM to test certain materials for reactivity as well as tolerance to stresses. Parts can be turned or milled or both turned and milled. In selecting a shop for plastic machining, it is important that the shop have experience in both the science and art of plastic machining. Plastic only shops in particular will help to avoid contamination with coolants and metal fragments usually found in a metal shop. They are also familiar with both annealing and polishing of your plastic component.
In selecting a shop for your plastic machining, three criteria are important:
Does the shop have the expertise and experience to produce your component within your stated tolerances?
Does the shop use up-to-date equipment and machining techniques?
Does the shop care about quality and producing quality parts 100% of the time?
In order to find the answers to these questions, review the company’s web site and talk to their salesperson.
Additionally, ask for a sample lot before full production in order to review your component.
Take a look at an example of some PTFE (teflon) turning we do at East Coast Precision Manufacturing. The part you see here is thin walled. It features a OD grooving with a notched feature on one end.
PTFE is often used in the electrical and chemical industries. It is very chemical resitant, stable, and a good insulator.
Teflon machining is one of our core competencies here at East Coast Precision. We have been working with it for a long time and look foward to quoting on your teflon work today!
This part is made out of Polysulfone. Polysulfone is known for being tough, wear resiting, and high temperature stability. It is also a dielectric material that can be used in capacitors. Dielectric means that it will not transmit electricity.
This part is milled in the milling department here at East Coast Precision. It is approximately 1.5 inches square. It features a milled out body, some threaded holes and a polished top. Due to the geometry, the part is actually able to spring a little bit.
This a sample of some turned Ultem we have been working on at East Coast Precision Manufacturing. Ultem is known for its resistance to chemicals, solvents, and heat. It is often used for instrumentation and reusable medical components. More information about Ultem.
On this part, each end is bored to a very tightly toleranced TIR (total indicated runout). The outside diameter is nicely contoured as well.
East Coast’s machining processes allow for thin walled parts like this to be manufactured very little stress. This makes for a more durable and longer lasting part.
This is the machining of the part we first featured on the blog a week or so ago. The process for other materials is very similar. We chose acrylic because the chip we produced was easy to blow off with a blast of air. Other materials would require cutting fluids and would have made it difficult to record and see clearly. Hope you enjoy.
UPDATE: It has come to my attention that the sound track to the video was quite obnoxious. Problem fixed. Apparently, youtube offers stock music for videos you upload. Pretty Cool.
Sometimes it is necessary to utilize multiple machines to effectively produce a part for our customers. This is an example of that. This manifold is machined from acrylic. A turning center (lathe) is used to turn the outside diameter and round features that are concentric to the center of the part. A vertical machining center (mill) is used to complete the rest of the features. On this part, we can see some port work, deep hole milling, and thread milling.
The manifold is also vapor polished for a nice finish. Acrylic vapor polishes quite well but if you need “optical” clarity, polycarbonate would be the way to go.
Take a look at this acrylic manifold we made for one of our customers. It features four ports connected to a main track. Each port features thread-milled threads.
This part also showcases our vapor polishing process. Not only can we polish the exterior of a part, we can polish interior features that would not normally be able to be polished otherwise.
This part is made out a Delrin-AF, a blend of delrin and teflon. The most striking feature is the helical slot that is machined on the OD. The slot width is tightly toleranced at ±.00025. It also features an OD groove and counterbores on each end. Our machining process allows us to produce these parts with minimal to no burrs so secondary operations are not needed in most cases.
This is an example of some of the Acrylic work we can do in our lathe department.
This part has a few different features. The front face has a knife edge where it blends with the inside diameter. It also has a 3 barbs machined on the outside diameter. There is also a groove and contouring on the rest of the OD.
The inside diameter is drilled thru and features a counterbore on the knife edge (end facing up)
East Coast Precision Manufacturing provides customers with precision machined plastic parts. We also offer many services including polishing, vapor polishing, annealing, assembly and packaging. Let us know how we can team with your company to produce the best plastic parts possible.
