To recycle sprues and rejected parts beside the press, there are two technologies: the conventional high-speed granulator, whose rotor turns at several hundred rpm above a screen, and the low-speed granulator, which turns at 25–30 rpm with high torque. Here is what sets them apart.
The principle: torque rather than speed
A high-speed granulator works on speed and inertia. The screen sets a maximum size: material keeps circulating in the chamber until it can pass through. That is what causes heat, dust and fines.
A low-speed granulator works on torque, delivered by a geared motor. There is no screen: the material is cut in a single pass, and the tooth geometry of the roller sets the regrind size (from about 5 to 10 mm depending on the tooth profile).
What it changes on the shop floor
- Better regrind: consistent granule size, no long granules, very few fines, little heating. The regrind goes back into production more easily.
- Less wear: at low speed, cutting parts wear slowly. Fewer interventions and fewer parts to replace.
- Less energy: the torque comes from the gearbox, not from motor speed. At MO-DI-TEC, installed power ranges from 0.55 kW to 2 × 4 kW.
- Less noise: under 70 dB(A) depending on the material, so the granulator can sit beside the press without an enclosure.
- Restart under load: with no inertia to rebuild, the granulator restarts with a full chamber. No hopper to empty after a stop.
Which materials?
Low speed makes the most sense on hard, brittle or filled engineering materials: PEEK, ABS, glass-filled PA, PC, PBT, POM, glass- or carbon-filled polymers. The harder the material, the wider the gap with a high-speed granulator.
Three common misconceptions
- “A high-speed granulator has more throughput.” Beside the press, the useful throughput is the press’s own. Our low-speed granulators cover roughly 2 to 200 kg/h depending on model and material.
- “My parts are too big for a slow granulator.” The Titan ranges handle bumpers, housings and massive parts.
- “It costs more.” Think total cost: lower installed power, slow wear, regrind returned to production.
What about high-speed granulators?
They remain the right choice for some applications. MO-DI-TEC also offers conventional-speed granulators, the Mini BM and BM ranges. What matters is to start from your material, your part size and your throughput.
Not sure? We can run a grinding test on your material. Contact: commercial@mo-di-tec.fr