For rotary draw bending without mandrel the tool is equipped with a catch. By rotating the tool round the bending axis the tube is inclined in the radius of the bending tool. A slide rail or counter rollers (counter bearings) serve for absorbing transverse forces during the forming process and support the straight tube end from outside. For bending thick-walled solid tubes the counter roller is used. Thin-walled tubes like, for example, stainless steel, copper, AL, etc. are bent with a slide shoe. By guiding the material from outside and by pressing the slide shoe and thus the workpiece into the bending tool, possibly occurring wrinkle formation as well as expected oval distortions can be counteracted.
For extremely thick-walled tubes or solid material we replace the catch by two welded fish-plates where a solid stud is plugged in.
We gladly supply specially designed tools for the requirements as listed below:
- Larger radii (type 3000 max. 125mm – type 6000 max. 500mm with extended upper plate)
- smaller radii
- Bending of isosceles profiles (resistance should be distributed equal-sided)
- Bending of square and rectangular tubes in standard or as an “American arc” (the inner flank is pressed in a controlled manner)
Besides observing the bending capacity of the material, the selection of the radius is decisive in order to achieve good results with this bending process. Depending on material properties we supply standard bending tools of 2.5 - 4 x diameter (D).
Clear advantages of these bending systems are:
- quick and easy handling
- larger bending radii and higher wall thickness
- simple programming (Model 3000 + 6000)
- small, compact and maintenance-free units
- special constructions can be realised at low cost
- extremely mobile machines and precise bending results