How to avoid PTFE bands falling off the grooves of sinter piston?

Cause A: The roughness of inner tube Ra is too high, or there are tiny welding slag and scratches on the inner wall, which wear down the PTFE layer like a "file".

Solution: If the cylinder wall roughness Ra is too high or contains weld spatters, it acts like a file. Ensure Ra ≤0.2 and implement strict cleaning protocols.

Cause B: Insufficient banding strength. It is a hot-press banding process, the cleanliness of the sinter piston surface or the failure of embedded PTFE material will cause the bands to separate from the powder metallurgy substrate.

Solution: Optimize parameter of heating temperature and time, clean the surface of sinter piston, redesign the grooves on the sinter piston.

Cause C: High-frequency operation raises oil temperature, causing PTFE bands fall down if the gap design between piston and working tube is not reasonable.

Solution: Verify the linear expansion coefficient and adjust tolerance fits to ensure clearance at 150℃.

Cause D: Additives in the shock oil may react with the band material, causing swelling or softening.

Solution: Conduct soaking tests to ensure full compatibility.