Machine Portfolio – WEIMA Shredders
Single-Shaft and Horizontal Shredders
WEIMA offers a variety of size reduction equipment including single-shaft shredders, horizontal shredders, four-shaft shredders and granulators. Single-shaft shredders incorporate a rotor (cutting system) which is equipped with special rotor knives. These knives cut the material that is pushed horizontally towards the rotor by a hydraulic ram. WEIMA’s innovative V-rotor has the capability to handle many different applications. The fraction size, meaning the size of the output material, is determined by a screen that is mounted underneath the rotor. The screen size can vary depending on the goals of the application.
WEIMA’s four-shaft shredders (ZM and ZMK series) are hopper-fed. In contrast to twin-shaft shredders, four-shaft shredders can be equipped with a screen. This leads to consistent output size. The material is powerfully torn and shredded by the cuttings discs, then pressed through the cut grooves of the clearing discs and finally discharged through a screen.
WSM granulators can be used either as a stand-alone solution or as a second-stage in a two-stage process. The large hopper allows for both manual or convey feeding. The highly effective V-rotor cutting technology, with it double diagonal cut, generates a consistent granulate size with little dust.
Rotor and Cutting Technology
WEIMA shredders can be equipped with different rotors and knives. The rotor selection is based on the application and the desired use of the shredded materials.
WEIMA’s innovative V-rotor with “SuperCut” knives is able to shred the largest variety of material with optimum efficiency. The effect: Consistent output size, high throughput, low energy consumption and low knife wear.
A rotor with special knives and cutting technology has been designed for difficult-to-shred textile filaments, ribbons and films. The F-rotor (the F stands for “filaments”) is an evolution of the proven WEIMA WLK series, used for shredding multi-filaments, Big Bags and film. The rotor can be provided with bolted or welded knife holders.
A wide range of knife choices
for general use
for better cutting action
for better cutting action without self-feeding
for greater wearability
for extremely harsh applications
for optimum cutting gap adjustment
The innovative ‘CrossCut’ rotor knives are now available for all WEIMA single-shaft shredders. The square rotor knife has a saw-tooth shaped grooved profile around the edges that enables enhanced grind quality along with significantly reduced energy consumption and increased knife longevity.
These new rotor knives can be rotated a number of times and are suitable for shredding plastics, wood, paper, cardboard and industrial waste. CrossCut knives are offered in different levels of hardness and toughness so that the proper knife can be selected for the variety of applications.
Rotor knives are available with edge lengths of 40, 50, 60 and 80 mm.
Knives are mounted with hexagonal bolts. These bolts are recessed into the knife carrier. By recessing them, the heads of the bolts are not exposed to the material and therefore do not wear. This offers lasting bolt durability and makes for easy removal when it comes time to rotate or replace these knives. Knife bolts of other manufacturers are often exposed, causing excessive wear and making knife rotation or replacement difficult and time consuming.
WEIMA’s broaching knives are located at the ends of the rotor. The combination of the end deflector bolted into the frame of the shredder and the broaching knife prevent thin gage material from wrapping on the rotor. This combination and prevents material from escaping through the shaft and accessing the bearing.
The drive makes the difference!
The conventional drive is used for single-shaft shredders incorporating a standard motor and an in-house developed gearbox to regulate the rotational speed.
The electrical motor of a compact drive is directly connected to the shredder. The rotational speed can be adjusted by a frequency converter, making a gearbox obsolete. Machines with compact drives are characterized by compact dimensions, high performance, quiet running and high system rigidity.
The hydraulic drive works in the harshest of applications. Speed and torque can be adapted to the application without undesirable current peaks. The available drive power can be optimally applied, potentially reducing energy consumption.
WEIMA shredders are equipped with a newly developed gearbox – the WAP gearbox. Manufactured by WEIMA, this gearbox is specifically designed for the abusive application of a single shaft shredder. The shoebox shape of the new gearbox makes it very maintenance-friendly. By removing a single cover it is fully exposed. Moreover, the gearbox needs only four mounting bolts – competitors often need more than seven.
The main advantage of the gearbox is that is has been set up specifically for the purpose of shredding (e.g. heavy-duty designed gears and shafts.) Standard gearboxes are designed for constant loading which is not applicable for industrial shredders. Gearboxes for size-reduction equipment are required to withstand fluctuating loads and shocks. The WEIMA WAP gearbox is designed for these environments, which reduces wear and increases longevity.
Why a WEIMA shredder?
The cylinder driving the hydraulic ram is mounted in a universal joint. Lateral forces on the cylinder are buffered by allowing movement vertically as well. This leads to a longer life of the cylinder and the suspension. Others who don’t provide this feature are not able to absorb these shocks. The result is repetitive high wear characteristics.
The safety limit switch used for WEIMA shredders prevents damage of the rotor by foreign objects or malicious damage. If for example a hammer head is unintentionally introduced into the shredder, the switch is automatically triggered. Damage to rotor knives and counter knives can be avoided by the machine stopping automatically. Competitors often do not provide this protection. This can lead to catastrophic rotor, knife, counter knife or gearbox damage.
The advantage of a bolted shaft stud is its hardened design which leads to minimized wear caused by abrasion of bearings. The shaft studs don’t need to be replaced. Moreover, there’s no need to change the entire rotor when it has been damaged by foreign objects. It is only necessary to replace the stud, which is a much less expensive option.
The advantage of a hydrodynamic clutch is that the machine will start smoothly, even when the hopper is fully loaded. This prevents extreme power demand spikes, which in turn avoid excessive energy costs. Furthermore, the clutch prevents damage of the gearbox when the rotor reverses.
The closed, offset and maintenance-friendly spherical roller bearings are specially designed for plastic shredding applications and processing very dusty material. Shredded plastics can create excessive heat transfer into the rotor bearing. This effect is prevented by an offset bearing. In this case, bearings are not mounted on the machine frame directly and therefore no material reaches the bearings. This results in higher durability and lower maintenance costs. Exchanging out K bearings is much easier than with other bearings, which are harder to reach and take longer to replace.
Instead of plastic guides, WEIMA use guides made of brass – the increased durability is most relevant especially when very abrasive materials (e.g. pallets) are to be shredded. The ram can also be mounted on rollers. Others don’t offer this feature and opt to exchange their guides more frequently. This increases maintenance costs and production downtime.