Proven by our customers:
- up to 50 % lower drive power is required
- up to 70 % less dust
- complete cleaning in 5-15 min
- safety while and after the size reduction process
Hellweg-rotors are fitted out with the double angled scissors cut technology. Produced from a single solid block of metal, the rotor has highest possible own weight, stability and torque - no welding! Suited for a save size reduction of all kinds of technical plastics.
- Half the drive power rating: up to 50 % lower drive power is required, due to the Hellweg shearing slanted cut geometry* - without a reduction of the throughput quantity - An advantage that pays back every hour.
- Minimal dust level: produced from a single solid block of metal, the rotor has highest possible own weight and torque and therefore brings very quiet running. The gentle slanted cut and quiet running make the main contribution to a low level of dust also for rough materials like PC, PA (with fibre glass) or POM.
- No adjustment of the rotor: in general, only the stator blades of Hellweg granulators are adjusted. This is an important advantage, as a significant amount of personnel costs can be saved. A direct example: changing and setting of an entire blade set of a Hellweg machine-side mill takes max. 10-15 minutes! Not to forget that rotor and stator blades can be re-sharpened at low cost up to 50 times without special equipment (simple flat grinding).
- No bridging or formation of long spike-shaped material: Hellweg slanted cut granulators produce sharp-edged, low dust ground material with high homogeneity and without thermal degradation. Special screens prevent formation of spike-shaped particles in ground material and ensure high process security.
- Fast and safe handling: safe and fast handling are always in the foreground during design of a Hellweg granulator. By this is understood, e. g. fast cleaning, fast changing of screens and blades as well as design to avoid or reduce points of potential hazard.
Find out even more advantages:
The Hellweg-angled-scissors cut
The Hellweg angled cut offers decisive advantages compared with the straight cut, the V-cut and the so-called segment cut.
V-cut involves cutting at two points, however this method tends to result in transport of some of the uncut material to the centre of the grinding area, due to the lack of even cutting force. Disadvantage: the material output takes place very much in the centre, which in turn results in uneven wear on the sieve and blades, as well as lower throughput.
Segment-cut is performed in rows by blades offset to each other. This results however in many straight and therefore rather hard cuts, which inevitably leads to a high degree of dust formation. Furthermore, much time tends to be needed for the downtime due to the large amount of blade setting and cleaning work required.
Hellweg angled scissors cut makes a very gentle cut and only at one point. The stator blades, that are also arranged at an angle, take up the cutting force that is anyway light and directed sideways. This guarantees that the material is delivered evenly and over the entire width of the blades and sieve. The decisive advantage for the operator consists of the self-dosing behaviour that is achieved by granulate with an angled cut. This means in practice that the granulators do not become overfull and that they always work in a range close to the maximum throughput of the machine.
The Hellweg enclosure technology
Hellweg granulators are characterised by stable and quite operation. The housings of the central mills are welded, those of the machine-side mills assembled with screws and dowel pins.
The machines guarantee fast material intake as well as fast delivery of ground material. Special attention is paid in the design of the grinding enclosure to avoidance of so-called “dead corners“. This enables complete cleaning within a short time, particularly important with frequent colour changes.
Rotor and bearings
The rotor and bearings are understood by Hellweg as being one unit, of which the proportions have to be exactly adapted to each other. Only this way is so-called “calm running“ possible, resulting in sharp edged regrind with a low level of dust.
The stability provided by the machines has furthermore direct influence on the blades’ lifetimes: the less vibration of the cutters arises, the longer the lifetime of the blades. The solid rotor furthermore offers its own high momentum of gyration, whereby it is also possible to use just a low level of drive power.
Construction of the cutting mills
The construction of the Hellweg cutting mills is sturdy and compact. The generously dimensioned outer bearing recesses are fixed by flanges directly to the grinding enclosure and therefore guarantee highest stability and support for the heavy rotors.
The grinding chamber is opened for example with the aid of a hydraulic pump device or electrically driven hydraulics. The ground material can be alternatively delivered with a standard extendable container or evacuated with the aid of an evacuation device fitting to standard extraction supports.
All central mills are fitted with so-called “shoes“ above the machines’ feet. This way the machines can be quickly picked up and transported by a fork lift truck.
Additional momentum discs for increased momentum
Additional momentum discs produce higher torque and thereby increase the tractive power of the rotors.
Optimum shredding of large and heavy parts is made possible this way, as well as handling of large quantities.
Connection to injection moulding machines
Hellweg machine-side mills can be easily connected to injection moulding machines.
The example on the left shows the 150 series machine attached by flange to an Arburg injection moulding machine. The 80 series cutting mills can be installed directly within an injection moulding machine.
This way, no additional area is needed at the production location.
Design of the intake
The design of the intake is made according to specific customer wishes, for example, with material input by sprue picker or via a conveyor belt.
Other possibilities in the design of the intake:
- Intake connection at the injection moulding machine
- Via an additional input shaft
- Sorted and thrown through a rotary valve
- Via a venturi system connection
Best regrind quality
Hellweg cutting mills produce sharp-edged regrind with low levels of dust that is highly homogenous and without thermal degradation.
This best quality level is an important prerequisite for further processing in high quality.
Finally straight to the point:
Characteristics influencing regrind quality
Gentle angled cutting avoids burden at peak loads, guarantees a high value regrind that is not thermally degraded and that is distinguished by sharp edges, high homogeneity and low level of dust.
Optimum speed range of the machines according to the size and purpose, thereby optimum speed range for low energy consumption, low level of dust and quiet operation.
Sieves with sieve hole diameters from 5-30 mm, designed to prevent formation of long, thin regrind, large sieve area enables high throughput and low level of dust as a result of fast material delivery, special sieves.
High throughput at low drive power
Engineering, design characteristics
- Stiff, non-twisting rotors produced from one solid piece of metal, no imbalance.
- Double-sided exterior rotor bearings, no penetration of dust and therefore longer bearing life, no contamination of the ground material by lubricant.
- Knives in high quality knife-grade steel, high durability.
- Constant cutting gap over the entire knife width, so optimum specific energy consumption.
- Noise absorbent hoppers, off-centre insertion guarantees self-dosing feeding behaviour, no dancing and hurling out of material.
- Compact design, less need for space.
- Wear resistant versions for reinforced plastics.
- Extensive consideration of safety measures regarding risks according to the equipment safety law
Operation, maintenance, cleaning
- Opening of the granulators without tools, enabling fast cleaning with changes of colour and material, faster sieve and knife replacement.
- Structural design for easy, complete cleaning through absence of dead corners.
- Direct mounting of the knives on solid rotors, eliminating need for rotor knife adjustment.
- Both rotor and stator knives can be re-sharpened many times due to their structural design.
- Start-up of the machines with filled grinding chambers ensured under normal operation conditions