Cutter guide bushes:

Support the product as it is cut

Cutting plastic, rubber or any other material with a flying knife type cutter such as the Servo-Torq® requires a device to support the material while the cut is in progress.

The cutter guide bushes are cylindrical metal devices which have been bored, or otherwise machined, to match the outer diameter or cross-sectional profile of the material to be cut.

They serve the following functions:

  1. Guide the product to the cut point.
  2. Provide support for the material as it is cut.
  3. Guide and support the knife blade.

Although frequently overlooked, cutter guide bushes are extremely important in obtaining a clean cut on extruded tubes, hoses, pipes and profile.

Material to make the guide bushes from:

We recommend stainless steel. This is long lasting & won’t rust. Mild steel is adequate, but ideally the bushes should be plated to avoid rusting.

Aluminium can be used, but does wear fast, so is not recommended for 24/7 applications.

Avoid plastic (however hard it might appear). The knife blade can potentially cut into the bush face, causing serious damage to the blade & a potentially harmful jam-up to the cutting machine.

Boring the guide bushes:

Have the cutter guide bushes machined or bored to suit the product outer diameter or cross-sectional profile.  Clearance must be provided to permit the material to freely slide through the opening.  However, the clearance must not be great enough to permit excessive movement of the product material.  This may cause irregular or angular cuts.

Excessive clearance will allow the material to move laterally and may cause irregular or angular cuts.

The opening in the pair of guide bushes should be continuous.  Any misalignment will cause feeding problems.

Do not radius or enlarge the entrance of the outlet guide bush unless the product is being held-up on the edge at each cut.  The more square the entrance, the better the cut quality.

Positioning the guide bushes:

The inlet cutter guide bush should be as close as practicable to the discharge point of the caterpillar infeeder/puller which precedes the cutter.

For the optimum results the inlet end of the inlet cutter bush should be coned so that it can fit in between the upper and lower belts of the caterpillar.  This ensures that it reaches right into the exit of the belt nip, giving the product no opportunity to snag or jam.

Generally speaking, the more flexible the extrudate the nearer the inlet cutter guide bush has to be to the caterpillar belt.

Please download an article on improving your cutting process here: Cutting Hints (PDF file).

For more information please email our Technical Team: