When the tube bending, the center line inside the material is compressed, when bending to a certain point of view, because the material compression force, will make the material being pushed back, and exceeded the cut-off point, if the area of wall is not supported by the bending die, will the formation of wrinkles. Wrinkles can not be removed even if they are flattened between the mandrel and the die. And when the end of the bend, the pipe will form a large wrinkles.
The use of Anti Wrinkle mold can increase the region's support, so that the wall of the tube after compression uniform thickening, no wrinkles. However, due to improper adjustment, wrinkles have been generated, then the wrinkle die can not eliminate wrinkles.
The shape of the anti crease die is very important. The groove through which the pipe slides should be slightly larger than the outer diameter of the pipe, and its value can be 10% of the wall thickness. It should also be carefully polished to prevent the pipe from scratching.
The front end of the die should be made thin and thin, extending to the point of the bending die, supported by bending die and fixed to form a closed cavity. In order to reduce the resistance to bending, the anti wrinkle die should have a small taper when it is installed. The die pressure should be adjusted properly. When installing and adjusting the anti wrinkle die, it is better to use the "adjusting mandrel" to carry out the clamping of the clamping die.
In the bending process, the anti wrinkle die should be coated with a suitable amount of oil. But too much or too much oil will cause wrinkles in this area.
In the use of Anti Wrinkle die at the same time often use ball mandrel. The anti wrinkle die is used to prevent the pipe from wrinkling while the ball mandrel keeps the tube from leaving the mandrel after it supports the tube without collapsing.
When bending thin wall, large diameter and small bending radius of the pipe, in order to avoid wrinkles, we should pay attention to the following points:
Reduce the resistance between the mandrel and the inner wall of the tube when it is bent. Before the tube is bent, the inner cavity must pass through the wet blown sand.
Machine tools and spindles should be rigid enough.
The rod should be rigid enough to eliminate the tremor and tension generated by the rod.
The radial clearance between the mandrel and the inner diameter of the pipe shall not be greater than 10% of the wall thickness.
Clamping, die, mandrel and anti crease die should be adjusted properly, especially the die pressure should be carefully chosen and adjusted.
Clamping large diameter tubes is a prominent problem in clamping. This requires a straight line between the two bends of the tube, a little longer and a wider clamping die to increase the clamping force and ensure the smooth progress of the bending. If the die is too narrow and there is not enough clamping force in the bending, the pipe slips and does not advance so that the bending cannot be carried out.
The selection of suitable lubricating oil.
The material supply status is also important. For stainless steel pipe, the hardness is HB=180 ~ 220, and HB=180 is the most suitable.
This article provided by Zhuo's brilliance Machinery Co Ltd finishing