1. Classification of pipe bending machines:
According to whether the pipe is heated or not, it is divided into a cold pipe bending machine and a hot push pipe bending machine
The transmission mode is divided into 4 types: pneumatic, manual, mechanical transmission, and hydraulic transmission
Divided into 4 types according to the control mode: manual control, semi-automatic, automatic, and numerical control
2. Scope of application of pipe bending machine:
Pipe bending machines are generally classified according to the control method, and they are introduced one by one as follows:
Manually controlled pipe bending machine: Manually controlled pipe bending machine: Manual pipe bending is the use of simple pipe bending devices to bend pipes. It does not require special pipe bending equipment, the pipe bending device has low manufacturing cost, convenient adjustment, and use, but high labor intensity and low productivity, and is mainly used in single-piece and small batch production.
Semi-automatic control pipe bending machine: generally only automatically control the bending angle, mainly used for medium and small batch production.
Automatic control of pipe bending machine: The whole process of pipe bending (feeding, pipe bending, and space angle) is automatically controlled through the size pre-selection mechanism, feeding trolley, and program control system. This kind of pipe dazzling machine generally adopts hydraulic transmission and servo motor control. The production efficiency is high, but the initial investment is large, and it is not suitable for occasions where the pipe size parameters are changeable, and it is suitable for mass production.
CNC pipe bending machine: It can realize the automatic control of the pipe bending process by inputting data according to the size specified in the part drawing. It is suitable for mass production, especially when the pipe size parameters are changeable.
Countermeasures for analysis of common problems when using pipe bending machines to bend pipes:
From the process analysis, it can be seen that the common elbow defects are wrinkles, bulging, tool indentation, fracture, insufficient wall thickness, and bending spring back. The existence of elbow defects will have a great negative impact on the quality of the bent pipe. . Therefore, corresponding measures should be taken to prevent the above-mentioned defects before bending, so as to obtain the ideal pipe and ensure the various performance indicators and appearance quality of the product. The following is an analysis of common elbow defects in production, and corresponding solutions are proposed:
Metal accumulation:
Possible reasons: The tip of the anti-wrinkle die is thick and positioned at the front, and a step is formed after the cut point of the wheel die. When bending, the metal inside the tube is compressed. When the hardness of the tube material is low, accumulation is formed here.
Solution: repair the root of the anti-wrinkle die and reduce the thickness of the tip of the anti-wrinkle die; grind the tip of the anti-wrinkle die to make it smoothly transition to the surface of the wheel die; in the case of no wrinkle, the anti-wrinkle die is withdrawn until the accumulation disappear.
Metal split layer:
Possible reasons: The tip of the anti-wrinkle die is thick and positioned in the front, forming a step after the cutting point of the wheel die, and the metal inside the tube is compressed during bending, and the layers are staggered here.
Solution: Refer to the solution for metal buildup.
Bend pits:
Possible reasons: The size of the mandrel is small or the boosting speed is too much greater than the rotation speed during mold adjustment, and the die pressure and boosting pressure are large.
Solution: Select the correct mandrel size and reduce the boost speed, die pressure, and boost pressure.
Cracks appear on the outside of the bent tail:
Possible reasons: The surface of the mandrel is rough or there are metal shavings between the core ball and the shaft; the surface of the die cavity is irregular, with undulations or metal shavings; the die is too tight against the pipe, causing excessive frictional resistance, resulting in rupture.
Solution: Check the surface of the mandrel or the mold cavity for defects, and repair the mold if necessary; reduce the boost and mold pressure, increase the gap between the mold and the anti-wrinkle mold; eliminate metal chips and metal slag on the mold surface.
Bending fracture:
Possible reasons: There are obvious transverse pits on the surface of the pipe, and the die is too tight against the pipe, causing excessive frictional resistance and rupture; the size of the mandrel is large, and the pipe is too tight after being inserted; the position of the mandrel exceeds the cutting point of the wheel die too much; The pressure of the die is large, the booster and clamping pressure are not enough, causing slipping and breaking; the surface of the die, the clamping die or the pipe is oily, causing the surface to slip and break; the surface of the die is smooth, causing the pipe to slip and break; the boosting speed is less than the rotation speed, The tube wall is thinned and broken; the mandrel is not properly lubricated or the surface is rough, resulting in large resistance and rupture.
Solution: Strictly control the surface quality of the pipe; adjust the boosting speed or rotation speed; check whether the size or position of the mandrel is appropriate; check whether there is oil on the surface of the clamping die and the die, and clean the surface; check the die, anti-wrinkle die, wheel die to Check whether the gap is suitable, adjust it properly; check whether the pressure of the die and the clamping die is suitable, and adjust it appropriately; if the clamping dies still cannot be clamped after adjusting the pressure and gap, an auxiliary mandrel can be added, or the surface of the clamping die cavity can be roughened; Lubricate the mandrel or polish with emery while checking that the mandrel material and lubricant are compatible with the pipe material.
Curved end section convex hull:
Possible reasons: The mandrel exceeds the cutting point of the die too much during adjustment.
Solution: withdraw the mandrel until the bulge disappears. If there are wrinkles, the number of heart balls can be increased.
The axial double convex hull of the curved segment:
Possible reasons: The size of the mold cavity is too small or the diameter of the pipe is large, and the metal is extruded into an ear shape under high pressure.
Solution: Use a bending die with the correct cavity size; reduce the die pressure/assist pressure, increase the clearance between the die and the anti-wrinkle die/wheel die, or reduce the boost stroke; properly lubricate the edges and corners of the die cavity, strictly Control tube size.
Bending segment mandrel spherical mound convex:
Possible reasons: The compression molding is too tight, and the boost force is less than the bending tension; the mandrel ball pitch is large.
Solution: reduce the die pressure, increase the boost force; reduce the mandrel ball pitch.
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