Polyester (Hard PE)

The sample appears to be very brittle. All sample has been fed within 20 seconds. Afterwards, only a small amount of residues use to remain loose inside of the grinding chamber.

A bit of fine ground sample use to stick by electrostatic charge below the sieve cassette. We found an output of ~ 93g in the collecting vessel.

Cleaning can be done rapidly by vacuuming with a soft brush.

In this trial, we used a 0,25 mm perforated sieve cassette instead of 0,75 mm (as shown in result 1).

A bit of fine ground sample dust use to escape by the standard funnel.

We placed the tube of the vacuum cleaner next to the funnels opening to avoid dust exploration. Exploration can be reduced by using the protected funnel with sample pusher, or by using the optional sample exhauster system with cyclone separator.

The complete sample has been fed within 90 seconds.

After 2 minutes of grinding, the typical grinding sound has stopped. Rotor seems to spin without a grinding of further sample. After the first 2 minutes, already 80 g of ground sample have been found inside the collecting pan. After a total of 4 minutes, already 107 g have been found in the collecting pan. And after a total grinding time of 6 minutes, the airflow has blown 115 g of sample into the collecting pan.

After 6 minutes, only a small quantity of residue use to remain inside of the grinding chamber. Bit of electrostatic charged sample use to stick below the used sieve cassette. Almost all openings use to free of sticking sample, even higher amounts can be ground without problems.

Usually, for plastics we recommend a pre grinding step with e.g. 2 mm sieve ring as we performed in this trial.

During the 35 seconds of feeding, no grinding sound appears.

This sample use to be so brittle, that even with 2 mm sieve ring, most of sample use to be comminuted to fine powder. Only a few particles appears to show a length > 0,5 mm.

Ground sample use to be small enough for a further grinding with 0,2 mm sieve cassette (see result 4).

After 1 minute of grinding and a fed sample amount of 20 g, change in grinding sound indicates that sample started to melt in front of the sieve ring. Most of sample got ground successfully; a small amount of sample started sticking in the upper part of the sieve ring and melted to sieve ring and lid.

Sieve ring and rotor needs to be cleaned with a wired brush afterwards.

Possibly electrostatic charged particles have been connected to the inside of sieve ring and build up until the layer reached the outline of the rotor and started to melt.

Because the sample is brittle enough, a pre grinding is not necessary for the usage of a 0,25 mm sieve ring.

The complete amount of sample has been ground within 140 seconds. Electrostatic charged sample use to stick to the collecting pan, lid and outside of the used sieve ring.

We are guessing that a grinding of a batch of 100 g of sample as desired should be ground without problems by using the accessories for grinding large quantities. Also an optimized airflow will be beneficial to chill the sample. (see following trial).

The desired amount of 100 g of sample has been used for a direct grinding with 0,25 mm sieve ring.

The complete sample got ground within 210 seconds. Sieve ring and rotor are mainly free of residues; even higher amounts can be ground this way.

Because of the optimized airflow with the accessories, even a grinding with 0,2 mm sieve ring might be possible (see result 7).

The desired amount of 100 g of sample has been used for a direct grinding with 0,20 mm sieve ring.

The complete sample got ground within 230 seconds.

Sieve ring and rotor are mainly free of residue; even higher amounts can be ground this way.