The way in which the tube is formed is called bending, and the way in which the square tube is formed is called bending. There are two basic methods of bending forming: solid bending and empty bending by the China Forming Pipe Machine.
1, the real bend
As a Forming Pipe Machine Supplier, we know that the solid bend, as the name implies, is compacted and bent, and the inner and outer rolls and the inner and outer walls of the tube blank are biaxially compacted during solid bending.
1) The advantage of solid bending is that the rebound is small, the forming is accurate, and as long as the roll type is accurate, the R formed at the inner corner is more accurate.
2) The disadvantage of solid bending is the stretching/thinning effect. First, the solid bend causes the bend to be stretched, and the stretch effect shortens the longitudinal length of the bend line. Second, the metal at the bend bend becomes thinner due to stretching.
2, empty bend
The hollow bend is formed by the unidirectional contact between the outer roller and the outer wall of the tube blank to form a bending moment to bend the strip. The hollow bend causes the bending line to compress, and the compression effect causes the bending line to longitudinally elongate, and the metal at the bend is thickened. This is the compression/thickening effect of the empty bend.
1) The advantage of the empty bend is that the side length can be bent when the solid bend cannot be performed, for example, the upper side/side side of the square tube is synchronously bent and finished. The hollow bend can also bend the internal angle of R < 0.2t without causing the tube wall to break.
2) The disadvantage of the empty bend is that when the square tube is synchronized with the upper side/side side, the forming force easily exceeds the critical point due to the simultaneous pressure generated by the upper and lower rolls, causing the edge to be unstable and concave, and also affecting The unit is stable in operation and molding quality. This is also a different feature of the rectangular tube and the tube when it is formed by air bending.
In practical applications, the two basic methods should be configured in a reasonable process position according to the product requirements in the square tube forming. We are China Forming Pipe Machine Manufacturer. If you have demand, welcome to contact us.