Understanding Carbide Dimensional Tolerances

Introduction

Dimensional tolerance is a key specification when ordering carbide components. Understanding what is achievable helps specify parts correctly and control costs.

As-Sintered Tolerances

As-sintered carbide parts have looser tolerances due to shrinkage variation. They typically require grinding allowance of 0.3 to 0.5 millimeters per side.

Ground Tolerances

Surface grinding achieves tolerances of plus or minus 0.005 to 0.01 millimeters. Cylindrical grinding holds round and diameter tolerances to plus or minus 0.005 millimeters.

EDM Tolerances

Wire EDM holds tolerances of plus or minus 0.005 millimeters for complex shapes. Sinker EDM achieves similar precision for internal features.

Lapped Surfaces

Lapping achieves the tightest flatness and surface finish. Flatness of 0.002 millimeters and surface finish of Ra 0.02 are achievable on seal faces and precision components.

Cost Considerations

Tighter tolerances increase cost. Specify only the tolerance needed for function. Critical dimensions should be identified on drawings; non-critical dimensions can be looser.

Conclusion

Carbide can be manufactured to very tight tolerances through grinding, EDM, and lapping. Understanding achievable precision helps specify cost-effective carbide components.

References

GB/T 7714: GUPTA R, SONG J. Powder metallurgy processing and mechanical properties of cemented tungsten carbide composites[J]. International Journal of Refractory Metals and Hard Materials, 2020, 91: 105246.

APA 7th: Gupta, R., & Song, J. (2020). Powder metallurgy processing and mechanical properties of cemented tungsten carbide composites.

MLA 9th: Gupta, R., and J. Song. "Powder Metallurgy Processing and Mechanical Properties of Cemented Tungsten Carbide Composites."