Industry Applications
Application
Case Details
Tungsten Carbide Drilling of Fuel Injection System Components
1. Processing Requirements
For this engine fuel-injection-system component, electrical-discharge machining was validated at the customer’s site; however, the hole surface finish did not meet expectations, and the customer now requires the surface-quality achieved with CNC machining.
Incoming raw material: bar stock materials such as GU20UF/ZK30UF, with Co content of 10% and a Rockwell hardness of 91.4–92.3.
Test item: Through-holes with apertures of φ0.48 mm and φ0.8 mm are used to evaluate drilling efficiency and hole-quality performance.
Raw material Finished product
2. Processing Results
(1). Surface finish of machined holes
Observation under a Zeiss 50x microscope
(2) Surface Roughness of Machined Holes
Testing instrument: White-light interferometer (Zygo NewView 8300)
| Sampling Location | Sa/μm | Size/μm | Sp/μm | Sv/μm | Image | |
| Small hole | 1 | 0.155 | 1.719 | 0.997 | -0.721 |  |
| 2 | 0.191 | 1.530 | 0.768 | -0.762 | ||
| Large pore | 1 | 0.186 | 1.780 | 0.861 | -0.919 |  |
| 2 | 0.220 | 2.248 | 1.178 | -1.070 | ||
(3). Drilling Machining Efficiency
Machining of fuel-injection system components requires a surface roughness of Sa 0.15–0.22 μm. For a φ0.48 mm hole with a depth of 1.9 mm, the machining time is 4 minutes and 26 seconds; for a φ0.8 mm hole with a depth of 6.95 mm, the drilling time is 16 minutes.
| Serial Number | Drilling | Time | Remarks |
| 1 | Φ0.48 | 4min26s | Procured equipment can once again provide cutting tools for efficiency optimization. |
| 2 | Φ0.8 | 16min |
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