Strip edge processing

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The strip edge trimming is a metal-cutting process for machining the edges of metallic strips. Similar to turning (see manufacturing process according to DIN 8580), the workpiece is moved in the strip edge processing system along the stationary tool or along the stationary tools. The infeed movement for the individual tools is usually carried out using precision spindles that are equipped with a fine display.

Tools

The tools are indexable inserts like those used for turning tools or milling cutters . The tools are usually arranged on a machine base frame and can all be opened and closed together with a combination of fine spindle and servo drive. This means that each individual tool can be fed to a specific cutting depth and all tools can be fed together.

Operation

The linear movement of the workpiece takes place in such a way that the strip to be processed is applied to a decoiler in the form of a coil . The decoiler is equipped with a reel mandrel, the diameter of which can be changed by mechanical or manual expansion. This makes it possible to clamp the inside diameter of the collar on the decoiler. With the help of various transfer and driving devices, the beginning of the strip is threaded through the actual machine, in order to be clamped on a reel mandrel at the other end of the machine. This is usually done with a so-called clamping slot, which can also be operated mechanically or hydraulically. As soon as the beginning of the tape is clamped on the mandrel of this reel, both reels can be accelerated to the desired feed speed by means of electrical servo drives. Usual feed speeds are between 50 and 250 m / min, depending on the material.

The cutting force or tape tension required for machining is generated by a torque difference between the decoiler and the decoiler. With a high chip volume, an S-roller set is used in front of the reel to increase the cutting force. The tape runs over several driven rollers, the speed of which is slightly higher than that of the reel. This lead and the friction between the tape and the roller can significantly increase the tape tension and thus the cutting force.

For the processing of very thin strips, especially for the transformer industry , the strip and the strip edge must be stabilized and fixed horizontally and vertically during the cutting process.

Cutting contours

The cutting contour, i.e. the edge to be attached to the tape, can have very different shapes. Right-angled contours, bevels, rounds or combinations can be produced. The more complex the contour to be cut, the more tools are required.

application

The method is used when large quantities of strips have to have a specific contour. Typical applications are blades (razor blades, knife blades, scalpels etc.) as well as folding bars for press brakes.

Another large area of ​​application is the production of all kinds of saw blades. For the production of saw blades, 2 steel strips are welded together lengthways. Before welding, the longitudinal edge of both strips must have a certain contour with a correspondingly high level of accuracy. The finished saw blade must also be rounded on its rear edge. These contours are usually produced on strip edge processing machines.

The transformer industry is a special field of application. The transformer cores usually consist of stacked metal sheets, the edges of which must be rounded and completely free of burrs.

Band dimensions

Strip edge processing systems are built today for strips from 0.03 mm up to 6 (8) mm thick. The bandwidths vary between 2 mm (flat wire) and around 1000 mm.

Cutting tolerances

By delivering all tools at the same time and continuously measuring the bandwidth, which works in a closed control loop, a bandwidth tolerance of +/- 0.01 mm can be achieved.

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  • Stahlmarkt European Edition 01/2012, page 50, publisher: Montan- und Wirtschaftsverlag GmbH, Düsseldorf
  • Focus Rostfrei 07/2012, publisher: Verlag Focus Rostfrei GmbH, Xanten
  • Stainless Steel Focus 04/2012, publisher: S…