Sheet in POM Ast 1000x610 mm white

A sheet in POM Ast is acetal with antistatic properties. The additive lowers the surface resistivity so static charge is led away instead of building up on the part. The result is a material that behaves like ordinary POM mechanically but that does not cause electrostatic discharges against sensitive electronic components, powder or film.

The base is POM C, a copolymer acetal. The density is 1.41 g/cm³, which gives a heavy and compact material that feels solid in the hand. The long term temperature is 105 degrees and the material keeps its properties down to minus 40 degrees. The flammability rating is HB according to UL 94. Water absorption is low, around 0.8 percent at saturation, which means the dimensions hold even in damp environments.

Mechanically POM Ast is stiff, tough and has low creep under load. Wear resistance is good against both metal and other plastics, and the coefficient of friction is low in the dry state. The material machines cleanly and has good spring properties, which makes it useful for snap fit parts and holders.

Antistatic additives work best when the part is clean and there is a little normal humidity in the surroundings. In an extremely dry environment the effect is lower, and cleaning with alcohol can affect the surface temporarily. This is not a conductive material in the same sense as ESD plastic with carbon filler, but an antistatic material that prevents static charge building up on the surface.

The sheet format is used where machined parts are to be cut or milled out of flat stock: assembly fixtures in electronics production, slide rails and guides in powder handling, sleeves and holders in printing machinery and parts in the textile industry where fiber dust would otherwise pick up a charge and stick. On assembly lines for semiconductors and circuit boards POM Ast is used in jigs and positioning blocks where an ordinary acetal would risk ESD events.

Machining is done with the same tools and parameters as ordinary POM. Milling gives clean chip formation with sharp tools and enough rake angle, and the chip is dry and runs off. Drilling works with standard points in HSS or carbide. Turning gives a shiny surface straight away without polishing, and thread cutting is forgiving in POM. Sawing with a fine toothed band saw or circular saw gives clean edges without large burrs.

POM cannot be bonded the way styrene plastics can. Mechanical fastening, snap fitting or ultrasonic welding are more common. If needed, the surface can be flame treated or plasma treated to improve adhesion, but the antistatic effect is then reduced locally. Bolted joints work well with self tapping screws or brass inserts.

The sheet is handled dry and is best stored in its original packaging until it is to be machined. Direct sunlight in storage does not affect the material noticeably over reasonable storage times, but a dusty environment can bind particles to the surface. The natural color is beige to light yellow-white, and the shade can vary somewhat between batches since the additives affect the base color.

Do you need help choosing the right thickness or comparing against the ESD grades filled with carbon? Get in touch.

The 1000x610 mm size gives a narrower white sheet for smaller guides and machine parts, where the material not picking up a charge helps in places where dust would otherwise stick.