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BASF Engineering Plastics

Design Capabilities: Secondary Operations


Electroplating
BASF Engineering Plastics' mineral-reinforced nylon 6 material (Ultramid® 8260), which is designed to accept plating, results in excellent plating adhesion and appearance. Plating can be used to enhance conductivity, shielding and/or aesthetics. An electrolytic pre-plating process of copper or nickel prepares the surface for final electroplating of copper, nickel and chrome in that sequence. Other plating materials can also be used where desired. Good design practice for an effective end product includes:

1. Avoiding deep cavities or sharp corners.
2. Application of abundant radii to avoid plating buildup.

Deep pockets can be expected to be void of plating. Special surface preparation may be needed in some cases. The total thickness of plating is in the range of .001 in. to .005 in.

Painting
Most plastics accept paint systems well, especially the amorphous resins. With special preparation of the surface for better adhesion (cleaning is essential), even the more difficult plastics, such as PE, PP and Acetal that have more slippery surfaces and chemical resistance, can be painted.

BASF Engineering Plastics materials will accept paint systems well. Nylon or PET are excellent resins for paint applications, especially where high-temperature curing is required. Their ability to tolerate high temperatures for long periods of time without softening is a key advantage.

Printing/Hot Stamping
All known printing methods are effective when using BASF Engineering Plastics materials. Occasional surface preparation may be needed for improved adhesion quality. A well-cleaned surface is the most important preparation for quality adhesions.

Machining
Engineering resins are readily machinable using conventional metal-cutting equipment. Cutting techniques for plastics are different than those for metals and special preparations should be taken. When cutting, you should remember to:

Provide for cooling during the cutting process (especially for un-reinforced materials).
Maintain a sharp tool with relief after the cut, especially for reinforced resins.
Provide good support at the cutting area.
Apply low cutter forces.
Use carbide where possible.
Use cutting points with a radius.
Surface Treatment

A designer can choose from a variety of surface treatments and plastic colors. Both can be molded into the plastic part and require no further finishing operations. The injection molding process will accurately duplicate the mold surface. Part function and/or aesthetics usually dictate the surface requirements. A smooth, uniform surface is often preferred for plating and painting, and high gloss is popular on many consumer applications. However, matte or textured surfaces are also attractive, are less slippery, provide contrast, hide sink marks, and disguise wear and abuse.

Specifying mold finish has often been arbitrary or neglected completely. A practical guide to surface finish selection is the SPI Mold Finish Guide, which is available from the Society of the Plastics Industry. The finish should be specified by SPE/SPI number where possible.

Uniform matte and textured mold surfaces are usually less costly than a high polish and can be obtained by vapor blast or glass blast, while machining or chemical etching can produce a variety of patterns and textures. A wide selection of textures are available from companies that specialize in mold engraving.

 

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