Indiana Rubber & Plastics: Lathe-cut rubber washers and sleeves

The most popular method for sleeves and washers
Rubber lathe-cutting is a method to produce a rubber washer or sleeve with good precision, at high speed and efficiency.

The method described
A sleeve is produced by extruding or mandrel-building, which is then cured. The cured sleeve is then optionally O.D. ground to the finished O.D. The sleeve is then transferred to a cutting mandrel which is mounted to a lathe specially designed to cut the rubber to the desired washer thickness or sleeve length.

Cost reductions
One cost-reducing options include elimination of the grinding step when an extruded sleeve is used and when extrusion tolerances are sufficient.

A second cost-cutting option allows for inline cutting of the sleeve, eliminating the separate lathe-cuting step.

Both options may be combined for maimum cost savings; however, utilization of normal methods yield a part of excellent precision at very economical cost and with minimal part-to-part variation.

Limitations
Most compounds can be lathe-cut; however, there are limitations on the use of very soft and very hard rubber compounds and some compounds do not lend themselves to grinding, including natural rubber and urethane.

Infinite possibilities
Uses include seals, gaskets, spacers, shims, belts (unsupported), vibration dampeners, and air and liquid filter gaskets.

Lathe-cut sleeves make excellent roll and roller coverings.

METHODS
Extrude and lathe-cut
Mandrel build and lathe-cut
Extrude and throp cut
Bevel cut

COMMON COMPOUNDS
Butyl
Carboxylated nitrile
EPDM (a/k/a EPR, EP rubber)
Fluoroelastomer (a/k/a Viton)
Hydrogenated nitrile
Hypalon
Natural rubber (a/k/a isoprene, polyisoprene, gum)
Neoprene
Nitrile (a/k/a Buna-N)
Polyacrylic
SBR (a/k/a GRS, G-RS, Buna-S)
Silicone
FDA-compliant, UL, military, NSF

ALTERNATE METHODS FOR WASHERS AND SLEEVES
Die cutting
Molding (including Tool$aver)