Secondary Operations: Deflashing, Machining, Decorating

Usually engineering thermosets are not only molded but undergo further processing to be fit for application. Here are some tips on how ETS parts can be handled in secondary operations.

Deflashing

Use of automatic deflashing machines is the state of the art. Small engineering thermoset parts can be deflashed in a tumble process using soft media, such as polyamide or polycarbonate pellets, filled polyamide, crushed nut shells, or thermoset materials. Larger parts can be deflashed using the same media in closed loop media blast machines. Parts can also be manually deflashed using hand tools and fixtures.

Machining

Engineering thermosets can be machined using standard machine tools but unlike metals, they are hard, brittle and often contain abrasive materials. This is especially true for grades that have high levels of glass fiber or sphere reinforcement.

Machining should be done with carbide tipped or diamond coated bits instead of high speed tool steel or nitrited bits. Production cutting tools should be fitted with replaceable carbide inserts to allow for frequent replacement of the cutting edges.

Material can be machined with high cutting speeds and feed rates but care must be taken not to chip or break off corners. Cutting fluid is not recommended because of the thick dust created during machining. The preferred method is to machine the material dry, using a dust collector for the cuttings and compressed air to cool the tool.

Decorating

Engineering thermosets may be painted. They are compatible with a wide array of commercially available paint systems both liquid and powder. Surface preparation before painting is critical to achieve proper adhesion of the paint to the surface.

Contact a Bakelite® technical representative for specific recommendations on grades and for technical assistance with your application.

Bakelite® Molding Compounds are shipped ready for use. Any material with visible moisture or other contamination should not be used.