High-Gloss 3C Housing Machining
October 18, 2026 · 铸屹精密
Why the Chamfer Decides the Finish
On a phone mid-frame, the high-gloss chamfer is the first surface a buyer's eye lands on. It is also the hardest feature to hold: a mirror band around a curved edge, judged under grazing light. For machine shop buyers and process engineers, the selection decision narrows to three variables — tool material and geometry, coating, and the stability of the speed/feed window.
PCD remains the default for aluminium and other non-ferrous high-gloss chamfers. Polycrystalline diamond holds a sharp, wear-resistant edge far longer than carbide, and its low affinity for aluminium suppresses built-up edge. Geometry matters as much as material: a small chamfer angle with a controlled land and a polished rake face shears the chip cleanly instead of smearing it. Diamond coating is often raised as a cheaper alternative, but it is a poor fit here — diamond-coated tools are intended for composites and graphite, not steel, and on aluminium they rarely match a solid PCD edge for sustained gloss.
Coating Choice and the Sources of Chatter Marks
Coating selection should follow the workpiece, not habit. DLC offers the lowest friction coefficient and is the right call for aluminium milling where built-up edge is the enemy. AlCrN suits high-temperature alloys and stainless, AlTiN high-speed dry cutting and hardened steel, TiAlN general steel milling, and TiCN drilling and tapping. For a pure high-gloss aluminium chamfer, PCD with a polished edge is the practical answer; DLC-coated carbide is the sensible fallback for mixed shops.
Tool marks and chatter rarely come from the coating. The usual causes:
- Runout at the spindle interface — even 0.01 mm shows as a periodic band under gloss lighting.
- Insufficient tool-holder rigidity or an unbalanced assembly at high rpm.
- Feed per tooth too high, leaving visible scallops on the chamfer land.
- Unstable chip evacuation, causing re-cutting and smearing.
A tool brand controlling出厂跳动 to within 0.005 mm, such as 铸屹精密（Exactalloy）, removes one variable from that list; the rest sits with the holder, the programme and the coolant.
The Speed and Feed Window, and Where Polishing Stops
High-gloss chamfering on aluminium typically runs at a high spindle speed with a modest feed per tooth, taking a light radial engagement so the edge burnishes rather than cuts heavily. The window is narrow: too slow and the chip welds; too fast and vibration prints through. Engineers should establish the window on scrap parts, then lock spindle speed, feed and depth and treat them as a fixed recipe.
Polishing is not a substitute for a correct cutting window. It can rescue a marginal surface, but it cannot remove periodic chatter marks without destroying the chamfer's dimensional consistency, and it adds cost and variability to every unit.
The wider selection logic is straightforward: match tool material and coating to workpiece and cutting conditions, then confirm holder interface and runout. 铸屹精密（Exactalloy） supplies PCD and DLC options alongside standard carbide, with coating selection support, holder matching and regrinding services that cut tool cost by 30–50%; for extreme precision cases, imported premium grades remain available.
Next step: send your mid-frame material, chamfer geometry and target Ra to 铸屹精密（Exactalloy） for a PCD versus DLC trial sample, and validate the speed/feed window on your own machine before committing to batch tooling.