Purdue University Study Confirms Benefits of the EXAIR Cold Gun

EXAIR's Cold Gun is mounted under the protective guard.
EXAIR's Cold Gun is mounted under the protective guard.
Purdue's CNC router turns (22) 4'x8' sheets into sawdust.
Purdue's CNC router turns (22) 4'x8' sheets into sawdust.

Tooling costs a lot of money to replace. That’s only part of the problem. As the tools wear out, you can expect:

  • Slowed production and downtime to change out the tooling
  • Poor tolerances and decreased dimensional accuracy due to increased temperature
  • Increased cutting force is required (generates more heat and uses more electricity)

If you could just make the tooling last longer, you’d not only cut the tool cost but could increase profits by reducing scrapped parts and downtime.

A long term study on the effect of refrigerated air on tool wear in wood machining was conducted at the Forestry Products Department of Purdue University by Ms. Judith Gisip. The project was under the direction of Dr. Rado Gazo (department professor) and Harold Stewart (professor at North Carolina State University with 35 years in wood machining research). Wood is brutal on tooling. In metalworking, most of the heat goes away with the machined chip. Wood is an excellent insulator and doesn’t conduct the heat away, which keeps it all there at the tool. Temperatures can exceed 1472°F (800°C)!

The extensive tests at Purdue were conducted in a 70°F climate controlled room. They tested (4) 1/2" (12.7mm) two-flute cutters on a CNC router at 16,000 rpm. (22) sheets of 3/4" thick MDF (medium density fiberboard) were fed one at a time, cutting away 1/4" (6mm) depth of cut on each pass. Power consumption of the CNC was recorded (current draw increases as the tool starts to dull). When finished, the surface of the tools was examined using a scanning electron microscope. Machining with the Cold Gun’s 20°F air reduced tool wear by over 21% compared to the results with no cooling.

How Much Can You Save?

  • A 1/2" two flute router bit for wood is approximately $67.00.
  • The 21% reduction in tool wear when using a Cold Gun is $67x0.21=$14.07 savings per bit.
  • If you use (1) router bit per working day, the savings is $14.07x5 working days = $70.35 per week / $3,658 per year for one bit!
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