Separation drums for reliable separation of parts

Rectangular drums have a rectangular drum cage with four outlet openings. The height of the outlet opening can be adjusted continuously between 0 mm and 58 mm. This creates channels consisting of parallel surfaces. This parallelism ensures that "S-shaped" sprues, for example, cannot wind their way through the gap, as can sometimes be the case with roller separation drums or perforated drums.

In addition, the rectangular separation drums feature a mechanism patented by MTF Technik which ensures that the separation gap is opened slightly in the upper area with each rotation of the drum cage. This is achieved by means of a toggle lever mechanism integrated into the drum cage. This special technology efficiently ensures that parts cannot become jammed in the separation gaps. Even wedge-shaped, rubber or silicone-like components always fall back into the separation process, leaving the gaps free for optimum separation results.

The separation gaps can be adjusted very precisely using a scale attached to the drum cage. This ensures reproducible results at the highest level.

MTF Technik uses rotating rollers in the separation drums with individual adjustment and those with planetary central adjustment. These rollers are driven by a rubber belt fixed to the base frame as soon as the drum cage rotates. This ensures that all rollers rotate in the same direction. Where two rollers run parallel and form a separation gap, this results in a counter-rotating movement of the roller shells.

This effectively prevents parts from getting stuck in the separating gap and jamming. The separating gaps remain free and the throughput remains at a maximum.

Yes. Many customers of MTF Technik also use the separation drums in clean room environments. If required, the parts that come into contact with the product can be made of stainless steel.

Depending on the geometry of the parts, large-looking parts may "make themselves small", i.e. they may partially twist through existing separation gaps. An S-shaped part may look large in terms of surface area, but for a roller or hole separation drum, it is only as thick as the material thickness. This allows the "S" to pass through a small hole along its lines.

However, if the hole is turned into a tube by applying the sleeves, the "S" can only dip into the tube but cannot wriggle through because it is blocked by the walls. The sleeve drums can thus ensure very good separation results for complex parts.

Perforated drums are primarily used where components of the same height but different surface areas need to be separated from one another. This applies, for example, to discs of the same thickness but different diameters.

A clear "YES and NO". It depends on customer requirements and the hardness of the components. For surface-sensitive parts, MTF Technik offers rubber or silicone perforated drum cages, for example. These protect the parts and ensure "gentle" separation.

No. The chain is just there to adjust the central adjustment. It doesn't transfer any drive forces. Since the drum cage just sits loosely on the drive wheel and the support wheels, it's easy to stop. The chain isn't dangerous.

When converting from one product to the next, the separating gap must be adjusted accordingly. To do this, first switch off and stop the separating drum. Then loosen the long green belt that surrounds the drum cage so that it is only loosely guided in its holder.

In the next step, the clamping lever on the drum cage is released and the separation gap is opened as far as possible. The drum cage can now be rotated manually on the base frame. During this rotation, check whether there are any parts between the separation rollers and the inlet ring. These must be removed if necessary. After checking, the separating gap should be closed completely. If this is not possible, the last check step must be repeated.

Finally, the separator gap must be adjusted so that the larger component just does not fit through the separator gap. Always aim to set the separator gap as large as possible – the larger the gap, the better the separation result.

That always depends a little on the definition. As a general rule, in a separation drum, the small parts first fall out of the drum cage at the bottom and then the larger parts run to the end of the drum and are discharged there.

If the size differences are sufficient, it can be absolutely guaranteed that none of the larger parts will "squeeze" through the separation gap. In this case, it can be guaranteed that only the smaller parts are present under the drum cage. However, it cannot be completely ruled out that in individual cases one of the smaller parts may reach the outlet and cause "contamination" of the larger parts. This can happen, for example, if parts become entangled with each other.

MTF Technik is happy to carry out separation tests in its technical centre and document them on video so that you can see the separation results for yourself – and any risks to the separation rate. For many applications, MTF Technik also offers test equipment so that tests can be carried out directly on site in your production facility. This is particularly useful if conditions prevail that cannot be simulated at MTF Technik – e.g. parts that are still soft during demoulding and only solidify and become dimensionally stable later.

Yes. There are various options here. First of all, the drum inlet is available as an additional separation zone for all separation drums. This area is often used to sort out small parts. In the die casting sector, these could be beans, for example.

The same applies to the discharge ring. Here too, holes can be made to create an additional separation stage.

With perforated drums and specially designed rectangular drums, it is also possible to subdivide the actual separation zone.

No. The holes in a perforated drum can have virtually any geometry. In some cases, it is necessary to incorporate rectangular, star-shaped or other holes into the drum cage in order to achieve the best possible separation results.

In a knock-off drum, the drum performs two functions. In the first step – knock-off – the connection between the good part and the sprue must be "broken". The actual separation, i.e. sorting by size, then takes place in the second process.

Depending on the part geometry and material, it may be necessary to place an additional stripping medium loosely in the drum cage, which falls onto the parts at regular intervals. This can be a wooden strip, a plastic rod, a roller or a brush roller, for example. To ensure that this knock-off medium always falls onto the parts to break the connection between the component and the sprue, the cage must reverse. Otherwise, there is a possibility that the parts will simply lie in front of the knock-off medium but will not be impacted by it.

The roller separation drum with individual adjustment is suitable for applications where the separation task remains unchanged for long periods of time, i.e. where few changeovers are necessary. In this case, individual adjustment offers a price advantage.