Restoring Precision and Extending The Service Life of Your Barrel
Barrel refurbishment and relining offer practical, cost-efficient ways to restore performance for plastics processing equipment while preserving existing machine features. For large or elaborately equipped extrusion and injection barrels, refurbishment often accounts for a substantial fraction of the cost of new equipment. Repair can reduce expenditure by roughly 25 to 50 percent compared with purchasing a replacement, and savings grow with barrel complexity and size.
Injection molding barrels often present the strongest case for repair because wear is frequently concentrated in a relatively short region near the discharge or stroke end. A short sleeve can be installed at the check-ring end to restore bore geometry and sealing, correcting leakage that undermines shot-size control and part consistency. As a general rule, when bore wear reaches about 0.020″, it is prudent to consider repair or replacement; for high-precision molding applications, the service limit may be as low as 0.003″. Extrusion barrels tolerate higher wear in some applications, sometimes up to 0.250″, so the decision window differs by process and tolerance requirements.
Reliable barrel repair depends on restoring an exact metal-to-metal fit between the new liner and the original barrel shell. The repair process reproduces most of the steps used to manufacture a new barrel: the barrel is rigidly fixtured in a heavy-duty boring machine, and the inner wall is bored out, typically to about 1″ larger than the original bore. This operation must remove hard bimetallic inlay and backing steel while maintaining straightness within roughly 0.005″ TIR, which is critical for screw alignment and melt quality. A replacement liner is produced with tightly controlled wall thickness and an OD tolerance of 0.001″, combining a wear-resistant bimetallic inlay with backing steel.
Securing the liner requires an interference fit achieved through controlled heat-shrinking, which produces the necessary contact pressure and concentricity without weld buildup or uneven stresses. Final machining and polishing restore the finished bore geometry and surface finish required for consistent melt behavior, followed by thorough inspection. When performed to these standards, relining preserves original barrel features (jackets, ports, and mounting interfaces) while restoring dimensional accuracy and surface hardness, enabling stable process control and extending service life at a fraction of the cost of replacement.
How can we help you?
The doors have been open at Santa Fe Machine Works, Inc. since 1923. We are dedicated solely to manufacturing and supplying new & rebuilt injection & extrusion screws, barrels & valves to the plastics industry. We also offer custom-tailored screw, barrel, and valve combinations, allowing our customer’s production goals to be met in the best, fastest, and most cost-effective ways possible. Our employees have over 200 years of combined experience in the plastics industry and are eager to support your specific extrusion or injection needs. Have a question, need assistance, or looking for a quote? Contact us today!
