Why Rubberwood Wears Your Polishing Wheels So Fast

A furniture factory in Muar, Malaysia runs panel lines on rubberwood, and rubberwood is hard on tooling. The wood carries silica in the fibre, and silica takes the edge off a cutting tool and loads up a buffing face faster than most species the machinery was designed around.

The plant was replacing polishing wheels on a short cycle and redressing them mid-shift to keep the gloss acceptable.

Wheels were bought on price and stored open on a shelf next to the line, which is convenient and quietly expensive. Operators dressed the face with a rasp when the gloss dropped, ran the wheel until the cotton was too thin to dress, then fitted a new one.

Two things were being treated as normal that were not: the loading rate, and the gloss step whenever a fresh wheel went on.

Three separate causes sat behind one symptom.

The first was the loading itself. Rubberwood dust is fine and slightly resinous, and a soft face holds it. Once the face is loaded, the cotton is no longer polishing, it is burnishing with a mat of compacted dust, and the gloss falls away gradually instead of failing outright, which is why it gets tolerated.

The second was face pressure. The polishing station had been set up by eye, and the wheel was pressed harder than the station needed, which generated heat and accelerated loading.

The third was storage. Wheels kept open on a bench pick up swarf and grit, and a contaminated face scratches an edge instead of polishing it. Some of what the plant had recorded as "worn out" was simply dirty.

The wheel grade was changed to a structure that clears dust rather than holding it, with the same 150 mm diameter and 20 mm face so nothing else on the station had to change.

The station was reset with the wheel just kissing the edge line rather than pressing into it. Spares were kept in their cardboard boxes instead of on the shelf, and the operators were asked to change a boxed wheel rather than dress a loaded one.

Dressing dropped from a mid-shift routine to an occasional correction, and the gloss no longer steps when a wheel is replaced. The plant now measures life by panels run rather than by shifts, which is the only number that compares across a shift pattern.

None of this came from a harder cotton. Loading, pressure and storage were each contributing, and fixing only one of them would have moved the number by a little and the conclusion by nothing.