Process

Our Plastic Machining Process

We meet your plastic fabrication needs utilizing precision plastic machining and plastic polishing technology

Lathe:
As a premier plastics fabricator we pride ourselves on creating some of the finest turned components in plastic machining today. For precision machining requirements, we have developed lathe tooling technology capable of delivering superior surface finishes and optical clarity. Our continuous upgrades on equipment have allowed us to maintain the highest quality machined components in the industry.

Our CNC machining equipment can process a wide range of components from micro turning to 20 inches in diameter. Equipped with milling heads and subspindles, our lathes can produce many components complete with efficient cycle times. The best and most consistent components in plastic machining are produced without secondary operations such as deburring.

Milling:
At Connecticut Plastics, we have assembled a state of the art plastic milling department for plastic machining. We are proud to produce mill components with a high degree of consistency to close tolerances with no burrs. Surface finishes can be optical-quality grade as needed via plastic polishing. Complex components are easily manufactured through the direct import of files from most CAD systems for precision machining.

Micro Plastic Machining:
Connecticut Plastics has developed a unique high precision machining process of micro plastic machining.

Our capabilities far surpass the usual in standard CNC machining practice. In particular, for precision plastic fabrication of micro components, Connecticut Plastics tolerancing is +/-.0005 or better with exceptional surface finish. These requirements are met while producing complex configurations in runs from 100 - 100,000 pieces.

If required, similar accuracy can be maintained with plastic polishing.

Polishing:

The most common plastic polishing methods are vapor polishing, flame polishing, and mechanical buffing. Each process is best suited for particular configurations and materials.

Flame plastic polishing uses a hot flame to flow a surface. Operator skill is critical with this method. When done properly, flame plastic polishing produces the clearest finish, especially on acrylics. Flat external surfaces are the most applicable configuration for this method.
Vapor plastic polishing utilizes a chemical vapor which attacks the surface of the plastic, causing it to flow. The best plastics for this process are polycarbonate, Ultem ®, and polysulfone. Acrylics do respond to this method, though not quite as well. The most appropriate acrylic polishing technique depends on the configuration of the component. Vapor polishing is not for an inexperienced person as special equipment is needed to in order to avoid vapor contact with the operator. However, Wwhen done properly, it can provide absolute optical quality finishes. This method can be used for both internal and external features, including threads and drill holes.
Mechanical plastic polishing is the most common, easiest to do and is useful on any plastic. This method tends to leave very fine scratches on the surface and will usually look nice but is not acceptable for optical work. In addition, buffing would degrade the surfaces of the two other methods above.

Annealing of Plastics:
Annealing or stress relieving, of plastics is an important step in the plastic machining process.

While not all components require annealing, there can be important advantages for some materials and part configurations when plastic machining.

Many manufacturers believe that their own internal annealing process is sufficient. However, in practice, batch processing can yield inconsistent results.

Connecticut Plastics has multiple programmable ovens for precise control of the stress relieving process for plastic fabrication. Our own annealing process allows us to create highly consistent material qualities from one rod to the next for the highest precision machining possible.

In addition, post-machining annealing can improve the properties of some components, especially those in the harder materials. These materials are sensitive to stress cracking, accumulated from the rod stock or precision machining. To achieve the lowest possible stress and the most stable component, consider stress relieving after machining. This operation is a must post plastic polishing. Plastic components polished without annealing will likely crack in operation.