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SFPM

Bandsaw machines are used in woodworking, machine shops, and to form cut. Bandsaw operation can also differ depending on the model used. Most applications associated with speed and blade control are relatively similar, though, and based primarily on the materials being cut.

The speed of the blade is expressed in surface feet per minute (SFPM).

The tooth pattern and blade speed required are determined by the texture, density, hardness, and porosity of the material being cut.

There are a variety of speeds available for bandsaw machines. They include fixed, variable pulley, infinite variable, and electronic drive.

The speed of the band is something that can be controlled and should be optimized for the material being cut in order to maximize cutting performance and blade life.

If the band speed is not right or too high, or when cutting hard metals, excessive heat is being produced and will result in shortened blade life.

Operators should make sure that the SFPM is optimum for the application to help avoid stripping of blade teeth.

The cutting edge of the blade (the blade face) governs blade speed.

For flexback saw blades, use the slowest cutting speed. For carbide saw blades, use the fastest cutting speed.

Calculating speed to SFPM is another of the processes a bandsaw operator needs to master, and here are two way in which to do that.

  • Mark the band with a stripe or use the weld as a point guide
  • Count the number of times that mark comes around in one minute
  • Multiply that number by the length of the band in feet and inches

Example: using a 12′ 6″ saw blade length, the weld came around 14 times in a minute, so 12.5 x 14 = 175 SFPM

  • Mark the idler wheel in the same manner

Example: if the mark came around 34 times, then multiply 3.1416 x 20” wheel and then divide by 12 = 178 SFPM.

Noise or vibration are the two leading causes of inaccurate cut and unsatisfactory output. If either present themselves during the cutting process, it is imperative that band speed be decreased.

Using coolant or cutting fluid during the cutting of extra hard materials is adequate. Be sure to adhere to the standard cutting chart band speeds provided by the bandsaw manufacturer.

If the cut is to be made dry, it is important to reduce the speed by 40-50 %.

  • Hard Materials — set the blade for 100 SFPM to start (30 M / Min)
  • Medium Materials — 200 SFPM to start (60 M / Min)
  • Soft Materials — 300 SFPM to start (100 M / Min)

Then adjust the band speed as needed to obtain the desired results.

How to know if the right band speed is in use: look at the chips being produced from the cut material. Check their shape and color. The goal is to have thin, tightly curled chips that are warm to the touch. If they change from silver to golden brown, it means a forced cut is generating too much heat. Blue chips are an indication of extreme heat that will definitely minimize saw blade life.

 

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