Questions and answers referring to
cutting and treating of tubes/pipes
1. Which advantages offers chipless cutting of tubes
-> No chips when cutting tubes and pipes
Up to 30.000 to 80.000 cuts with one knife.
Chipless cutting of tubes and pipes means the deletion of washing procedures. Thereby tremendous cost savings can be realized, e. g. reduction of working time during transportation, placing the tube cuts into the washing plant, unloading and renewed storage.
But also the washing plant as such can be expensive: Service, washing medium, ecological duties, and more are costly.
In addition chipless cutting saves raw material. A sawing blade (1-2 mm) produces chips, which are lost as raw material. (With in average 1,5 mm and only 30.000 cuts you safe 45 Meters of material = MORE PROFIT FOR YOU!)
The knife rotating around the tube is the pre-condition for tearing and breaking whereas the tube is not cut through totally. Using the tear/break-procedure there is, contrary to sawing, no inner burr. Due to that in many cases it is not necessary to de-burr.
With an adittionally rotating pressure roll the tube end may be chamfered.
2. Which advantages offers a processsing of coil-ware compared to rods?
There results a major material saving due to the elimination of starting and end pieces. In addition material supplied in coils is in most cases less expensive. For copper tubes e. g. the price may be lower by up to 20%.
Reloading of rods is avoided, thus reducing the circle time by about 10 %.
In a single shift operation based on copper tubes up to 3.000.000 tube cuts may be produced (depending on tube size and wall thickness).
A further advantage is the less expensive storage of coils, its compact dimensions and no cases.
3. Which raw materials can be processed from coils?
For copper tube diameters of up to 35 mm with a wall thickness of 1,5 mm are possible.
Furthermore tubes from AL-alloys can be processed from coils.
Steel tubes, especially high grade, can be processed from coils if the diameters are small.
4. How is uncoiling done?
The coils are placed on a driven uncoiling unit. The uncoiling speed is stepplessly adjustable. For shorter set-up times in some applications a double uncoiler may be advisable. The tube is not directly supplied to the tube cutting machine but is placed onto an air-suspended balancing roll. This balancing roll guarantees a smooth, secure uncoiling in interaction with the servo drive of the tube cutting machines’ feeder.
5. What about the straightness and diameter tolerances of the tube cuts?
The tube coming from the coil is calibrated and straightened by 18 straightening rolls. The diameter tolerances after straightening will be at + 0,05mm, the straightness of tubes at 1 mm per meter.
6. Can soft copper tubes be hardened?
Soft copper tubes are very well processed with regard to uncoiling, in addition it has an interesting pricing. However, often a certain hardness of the material is requested. Soft copper tubes can be hardened by straightening to a yielding point of R0 = 180 N/mm². Due to the exact stepless adjustable straightening rolls this hardening procedure can be executed.
7. How are the set-up times when changing the coils?
When using the same diameter of tubes between the used coil and the new one, the coil end and coil start can be connected using a crimper. This work including placing the new coil to the uncoiler needs about 5 – 7 minutes. The connection between the coils is recognized by the tube cutting device and can be cut off there.
When using different coil diameters in addition 3 chucks have to be exchanged and the cutting diameter has to be adjusted as well as the straightening rolls be exchanged. The adjustment of the straightening device to different diameters is done very easily. Without loosenig any screws the straightening rolls can be
drawn off and the new rolls placed. The adjustable straightening rolls are provided with an absolute scale so that registered adjustment values can be regulated without locking device pretty easily. The whole set-up time will reach about 10 – 12 mins.