Preparation before processing
According to the bending machine production task, be familiar with the part drawing, understand the bending angle, bending height, and bending length of the part, and analyze the bending method and sequence of the part.
Adjust the bending machine
Adjust the bending angle of bending machine
Using the downward stroke adjustment device, rotate the scale sleeve clockwise (or counterclockwise), the stop position of the slider downward stroke will rise (or decrease), and the bending angle will increase (or decrease).
Adjustment of the upper stroke length
Use the stroke switch to adjust the stroke length. When increasing the stroke, loosen the handle at the right end of the slider to lower the striker for a certain distance, and then lock the handle. When reducing the stroke, Loosen the handle to raise the striker a certain distance, and then lock the handle.
Adjustment of the pressure of the bending machine
The pressure of the bending machine can steplessly adjust with the required bending pressure of the workpiece. After the upper and lower molds are in contact, turn the handle of the relief valve to change the bending pressure.
When reaching the required value, lock the handle. The pressure of the bending machine can indicate on the pressure gauge. Generally, the working pressure of the relief valve set to 250Kg/cm2.
Select the upper punch edge and adjust the lower die slot
a) According to the part drawing, mark the radius and length of the fillet, and the bending shape to select the upper die edge and fix it on the upper tool holder.
b) Choose the lower die slot according to the material thickness of the part (generally the width of the lower die die is 8 times the material thickness). Turn over the lower die slot, the applicable slot face up, put the lower die knife edge on the lower die pad iron, start the bending machine to slowly lower the upper die knife edge into the lower die slot, adjust the front and back position of the lower die, Use the adjusting screw to adjust the position of the lower die slot on the lower die pad iron until it is suitable.
Adjust positioning size
Adjusting the positioning size means adjusting the position of the rear stopper. The method is as follows: Turn the handle to make the support plate move back and forth, and at the same time, adjust the extension length of the stop bar appropriately to make the size of the part bend meet the requirements of the drawing.
Perform trial bending with a piece of material to check whether the shape, straightness, and bending angle of the formed part meet the requirements of the drawing. Otherwise, the positioning size and the gap between the upper and lower blades should re-adjust until it meets the requirements.
The bending sequence determines according to the shape of the part. There are generally four typical bending sequences as follows:
Matters needing attention
a) When the part needs to bend, its bending height is less than 80mm. If it exceeds 80mm, you need to change the knife edge, or adjust the bending sequence, and increase the shaping process.
b) After bending, the parts stack neatly to prevent deformation caused by improper stacking.
c) The formed parts should mark with the product part name and drawing number so that the next process can be checked and accepted according to the drawing.
1. The dimensions of the short side without tolerance after bending divides into three levels: A, B, and C.
2.The angle granularity grades after bending divides into three grades: A, B, and C.
3.The straightness of the bending line after bending and the flatness of the two sides that make up the angle are divided into A and B levels.
4.The unmarked tolerance of the short side after bending
5.The angle tolerance after bending
6.The straightness and tolerance of the bending angle and the flatness tolerance of both sides of the bending angle
4.1 The surface of the parts should be smooth, free of rust and defects, and no cracks at the bending corners.
4.2 The size of the short side of the part after bending should meet the requirements of the drawing, and there is no special requirement, and it shall inspect according to the 1 B accuracy of this code.
4.3 The tolerances of the edges and corners of the parts after bending should meet the requirements of the drawings, and there is no special requirement, and they should test according to the 2 B accuracy of this code.
4.4 The straightness tolerance of the bending line of the bending angle of the part shall meet the requirements of the drawing. If there is no special requirement, it shall test according to the B-level accuracy of the table of this code.
4.5 The flatness tolerances on both sides of the bending angle should meet the requirements of the drawings, and there is no special requirement. It tests in accordance with the 3 B accuracy of this code.
The surface condition of the parts is visually inspected.
The linear dimension of the short side of the part after bending measures the parallel distance from side to side. As shown in Figure 3a, the measuring points shall not be less than 2 points.
4.6.3 The edges and corners of the parts after bending should be measured with a universal angle ruler. The measuring points shall not be less than three points, and the largest error shall take as the angle error of the tested part.
4.6.4 Measurement of the straightness of the bending line of the part Place the part on the inspection platform and measure it with a thickness gauge. As shown in Figure 4, the measurement points shall not be less than two points, and the maximum error value is the straight line of the bending line of the part.
4.6.5 Flatness measurement on both sides of the bending angle Support the part vertically on the flat plate, with one side of the flat surface facing upward, and adjust the measured surface to make it the same height as the flat plate.
Use a measuring stand with an indicator to measure points at different positions in this plane and record the readings.
Use the difference between the maximum and minimum readings of the indicator to approximate the flatness error of the bending corner, as shown in Figure 5.
Safety protection and precautions
5.1 Before bending, ensure that the sheet is flat.
5.2 Operating the bending machine by a dedicated person, and it strictly prohibits for non-operators.
5.3 Forbidding to operate when changing the knife edge of upper and lower molds (foot on the switch strictly prohibited).
5.4 Check the wear of the main components of the hydraulic press brake every three months. When finding to be abnormal, it need to shut shut down immediately for inspection and reported to the relevant department for handling.
5.5 The equipment need to scrubbed clean and lubricating oil should be added every day.
5.6 The shell of hydraulic bending machine need to be reliably grounded.