INJECTION & EXTRUDER SCREW WEAR & CLEARANCE GUIDELINES

Quick Reference for Injection & Extruder Screw Replacement

This quick reference guide outlines recommended screw and barrel clearance and wear tolerances for injection molding and extrusion applications. 

Understanding the proper clearance between screw and barrel helps maintain performance, reduce wear, and prevent processing issues. Use the chart below to evaluate barrel wear measurement and determine when replacement is needed [LINK to Repair page].

Technical diagram of an injection molding screw, illustrating its key components and design parameters used in plastic manufacturing.

Injection Molding & Extruder Screw Barrel Wear Chart

Screw Size New Screw Clearance Worn Screw Clearance Max Wear Clearance
½” 0.003 – 0.004” 0.008 – 009” 0.012 – 0.015”
1” 0.003 – 0.004” 0.018” 0.020”
1 – 1/2” 0.005 – 0.008” 0.020” 0.025”
2 – 1/2” 0.007 – 0.010” 0.021” 0.030”
3 – 1/2” 0.010 – 0.012” 0.030” 0.036”
4 – 1/2” 0.010 – 0.013” 0.030” 0.039”
6” 0.013 – 0.016” 0.039” 0.048”
8” 0.016 – 0.019” 0.048” 0.057”
10” 0.020 – 0.025” 0.060” 0.075”
25mm 0.003 – 0.005 0.013 – 0.014 0.019 – 0.020
30mm 0.003 – 0.005 0.014 – 0.015 0.021 – 0.022
40mm 0.004 – 0.005 0.014 – 0.015 0.022 – 0.023
60mm 0.005 – 0.006 0.016 – 0.017 0.028 – 0.029
80mm 0.006 – 0.007 0.019 – 0.020 0.034 – 0.035
90mm 0.009 – 0.010 0.021 – 0.022 0.036 – 0.037
100mm 0.009 – 0.010 0.024 – 0.025 0.041 – 0.042
120mm 0.012 – 0.013 0.030 – 0.031 0.049 – 0.050
140mm 0.014 – 0.015 0.034 – 0.035 0.055 – 0.056

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