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RSA has announced the launch of the Rasacut XS, a high-performance circular saw for small diameters.

The minimisation of variants in the automotive industry is leading to larger batches for the production of semi-finished products made from tubes, hollow sections and solid bars.

However, quality demands are also increasing.

A machine concept aiming at a wide spectrum of workpieces mostly can cope only to some extent with demands made by highly specific parts, for example line systems, in the automotive sector where strict requirements are applied concerning the degree of purity and precision of the tubes.

However, the large quantities just allow comparatively low piece costs.

This is the background for the development of the new high-precision Rasacut XS that achieves a high total output.

Generally multicut or bundle cut saws are used for the production of large batches in the diameter range up to 25mm.

However, aiming at an improvement in quality and lowering of piece costs, the new RSA development counts on the single cut.

The fully automatic processing cycle – even for large fixed lengths up to 2000mm or longer – presents an essential advantage.

When working with bundle cut saws, tubes are manually bundled.

The workpieces are counted, fixed with an adhesive tape and inserted into a prismatic guide that feeds the tube bundle to the saw.

In case of the Rasacut XS, tubes are automatically singled and fed.

In this way, personnel costs are lowered because one person can operate several saws.

In case of bundle cut saws the fixed lengths are falling uncontrollably apart after cutting.

This is the so-called ‘mikado effect’.

The feeding of the tubular sections to another processing step, for example deburring, requires further logistics – either an automatic singling machine or the manual feeding of a magazine.

The Rasacut XS can be modularly expanded to a processing centre.

In this way the processes of sawing, deburring or facing and chamfering, checking of lengths, roundness or chamfer as well as cleaning and stacking are united in one line.

Another argument for the single cut concerns the quality of the parts.

Apparent motions in the tube bundle or in the layer are leading to scratches on the tube surface.

Due to minimal misalignments within the tube bundle, parts are outside of determined tolerance.

The fact that the Rasacut XS achieves in a single cut output values that are as high as those of multicut or bundle cut saws – depending on the dimensional range even more – is due to the rigorous reduction of ancillary times.

The random material is fed by means of a gripper with an acceleration of up to 40m/s2.

The next tube is still fed during the current sawing process so that a loss of time during the change-over to the next stock length is avoided.

On the basis of the Rasacut XS output values, round about 150 change-overs to the next stock length are required per hour for a tube with 8mm diameter and a fixed length of 250mm for a stock length of the random material of 6000mm.

This example shows clearly the importance of the ancillary times with regard to the total output.

Take the example of a round tube with a diameter of 12mm and a wall thickness of 1mm, material E235.

For a fixed length of 150mm the output of the saw adds up to 4,014 pieces per hour.

Forward feed and drive of the saw is accomplished through servomotors.

The saw blade diameters are between 175 and 200mm.

Depending on the material, HSS, carbide or solid-carbide saw blades can be used.

The specific tuning of the teeth profiles with the material and workpiece characteristics of the parts to be cut is done by RSA.

The use of saw blades with small diameter and high speed reduces cutting times.

To cover the whole spectrum of workpieces with saw blades of this diameter range, tubes are centrally clamped and not on a support.

For the various requirements of pre-productions with a wide spectrum of workpieces and pre-productions of special workpieces in large batches, RSA signals further saw developments for the near future putting the main emphasis on a reduction of piece costs.

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