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Troubleshooting

Chip Welding & Built-Up Edge: How to Stop It

Material welding to the flutes ruins finish and breaks tools. The fix is coolant, the right coating, and giving chips room to escape. Here's the full checklist.

Chip welding — built-up edge — is when the chip sticks to the cutting edge instead of leaving with the swarf. It welds, breaks off taking a piece of coating or carbide with it, and welds again, destroying finish and eventually the tool. It thrives in gummy materials, packed flutes, and dry cuts. Break any one of those conditions and it usually stops.

Chip welding — causes & fixes

Cause
Fix
Insufficient coolant
Add coolant or increase pressure to flush and cool the chip
Wrong cutting direction
Climb mill so the chip thins as it exits and releases cleanly
Gummy / sticky material
Use coated tools — the right coating keeps material from adhering
Flutes packing with chips
Use fewer flutes to open up chip room
Chip load per tooth too low
Increase the feed rate so chips form and eject

Give the chip somewhere to go

In sticky materials like aluminum, low-carbon steel, and some stainless, flute room matters more than flute count. A high-flute-count tool simply doesn't have the gullet to clear a big chip, so material packs, recuts, and welds. Dropping to a 2- or 3-flute tool — and feeding hard enough to form a real chip — gives the swarf room to leave the cut before it can adhere.

The right coating for the material

Coatings are the chemical half of the fix. A slick, non-reactive surface keeps gummy material from bonding to the edge: DLC (Black Mamba) and uncoated-polished tools excel in aluminum, while AlTiN handles the heat that drives welding in steels. RobbJack matches the coating to the work material and can coat or re-coat tools to suit.

Flood the cut, climb mill, run fewer flutes with a real chip load, and put the right coating on the tool — built-up edge can't survive all four.

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