Granulator Cutting Chambers

There are three basic cutting-chamber designs: conventional offset, tangential, and straight-drop.

There are pros and cons to each of these designs, so here are some considerations when selection cutting chamber geometry:
 

 Straight Drop Chamber

Plastic granulator drop chamber

 

A straight-drop design feeds material from the top of the rotor and is recommended for large and thick-walled parts. There is also a hybrid model designed to process both thick- and thin-walled materials in the same machine.

Advantages:

  • Well suited to heavier parts with thick cross sections.
  • Minimizes the size of the “bites”

Disadvantages:

  • Light or bulky parts can bounce on the rotor

 

 Tangential Chamber

Plastics tangencial cutting chamber

The popular tangential design positions the rotor at an offset from the feed opening to provide a larger "bite" radius, which is the most efficient way to achieve high throughput and clean regrind with bulky, thin-walled parts.

Advantages:

  • Allows parts to drop into the cutting area before knife intersection to create a self-feeding action.
  • Can process larger volumes of less dense parts with a smaller machine.

Disadvantages

  • Heavier cross section parts can stall the rotor

 

 Offset Chamber

The offset chamber directs material to the cutting area at an angle perpendicular to the rotor, which is good for general purpose applications.

Advantages:

  • Limits the bite which is necessary for thicker walled, high density parts

Disadvantages:

  • Not as efficient as tangential for processing less dense parts

 

 Combination Chamber

plastics granulator combo cutting chamber

The combination chamber mixes the benefits of the gravity fed straight drop chamber with the efficiency of the larger bite tangential chamber.

Advantages:

  • General purpose allows for better ingestion without biting too much
  • Raised Bed Knife version processes heavy parts and purgings

Disadvantages

  • Light or bulky parts can bounce on the rotor