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Many fabricators have a problem with galling when the sheetmetal adheres to the punch tip. Galling is more prevalent when punching aluminum or other ductile materials. Caused by pressure and heat, galling occurs when you combine the plasticity (softness) of the materials with the heat generated by the punching process (friction). Within a relatively short period, a galled punch starts producing inferior parts. Before you can resume punching, you need to stop the press and remove the punch to clean it with a fine stone. This costs maintenance time and material waste due to the poorly made parts.

There are a few things you can do to minimize galling. If you order punches with a 2° total back taper to facilitate stripping, the material is less likely to adhere to the punch. You can also request a 2° total back taper (1° per side) on the punch and 20% to 30% clearance for the die. Mate’s SuperMax™ or Maxima® coatings are other options. The best way to prevent galling is to apply lubrication to the punch tip consistently.

Mate’s Eliminator™ (patents pending) punch tip lubrication pads assist in keeping the punch tip lubricated during the punching process. As a result, they help eliminate unwanted galling during the punching process and help extend tool life and keep the punch from overheating.

Mate Eliminator lubrication pads are made from polyether foam and are easy to install. In many cases, you can “punch” the hole into the foam using the punch and stripper. Then, after saturating the pad with 46-68 ISO viscosity hydraulic oil, place the punch into the holder, and you’re ready for gall-free punching. After thousands of hits during Mate’s extensive product testing, there was no evidence of any galling.

If you download the Solution Bulletin, you will learn about a customer punching stainless just beyond the breaking point to increase speed and reduce contact with the material. Initially skeptical, they were amazed after they produced 200 parts with 11,600 holes without galling. However, the punch still looked new and was used to make other orders.

Mate Eliminator punch tip lubrication pads are available in most tooling styles and station sizes. They are a very affordable way to keep your punches gall free and in tip-top condition.