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Bale Cutter – A Rubber Machinery with a Monstrous Synonym

Bale Cutter is a common rubber machinery, also known with its monstrous synonym – Guillotine. Rubber needs to be cut into small pieces before they are fed into the batch mixer. The rubber bale cutter (aka guillotine) does this job to the satisfaction of most users.

In the past, there has been guillotine machines with a fixed knife and a table moving upwards. In its current form, hydraulic bale cutters are popular.

Rubber Bale Cutter

Image Courtesy: Bainite Machines

The standard bale cutter is designed for 33.3 kg bales. They handle all Natural Rubber (NR) and Synthetic Rubber (SR) bales in the range 25-35 kg. This is because, NR usually comes in rectangular shape with a weight 33.3 kg or 35 kg (± 5%) and dimensions 670 mm x 330 mm x 170 mm. Bulk SR such as unvulcanized elastomer is normally supplied in a dense rubber bale or slab wrapped in a thin protective plastic film. Its size is around 600 mm x 450 mm × 200 mm and weighs 24 kg.

While a bale of this size can be fed directly into batch mixers, the bale cutter is required to get the correct weight for the compound recipe being mixed in a batch. Hence, most standard bale cutters has a cutting section varying between 600-750 mm and a cutting height of 300 mm.

Each machine consist of a cutter or a precision blade, hydraulic cylinder, frame structure and hydraulic power pack unit. The hydraulic oil supplied by the hydraulic power pack unit operates the blade or cutter through hydraulic cylinder to cut the rubber bale.Most manufacturers incorporate roller conveyor or conveyor belts in their bale cutters for carrying the rubber bale to the blade and similarly discharge conveyors to transport the cut slices further away from the blade.

Advanced rubber bale cutters does not require operator attention other than during loading. They have a continuous blade cycle with conveyor advancing in a pre-determined speed. Such machines have an in-built cutting control and display unit operated by PLC controlling various guillotine functions. This includes pre-programming the required cutting information such as nominal slice thickness, total number of cuts required or dwell time between cuts. In some bale cutters, a pneumatically actuated plate keeps steady the bale during the cut operation.

Bale cutters can be dangerous for an operator if not securely fenced with interlocking access gates and interlocking guards to prevent access to the cutting area. So it is crucial that rubber bale cutters are comprehensively guarded for safe operations.

With user-friendly features, safety and automation incorporated, manufacturers compete to position their bale cutter as high technology rubber machinery for better quality cutting and higher productivity.

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