What should be paid attention to in the calibration of CNC bending machine


At present, most of the bending machines are operated by CNC with high efficiency. Sometimes parts may affect the efficiency of the equipment(CNC bending machine). Therefore, when installing parts to equipment, it is important to pay attention to the bending radius of the parts.


When free bending is used, the bending radius is 0.156 times the opening distance of the die. During free bending, the gap between the die openings should be 8 times the thickness of the metal material. For example, when forming low carbon steel with a 1/2 inch opening distance, the bending radius of the bending machine parts is about 0.078 inches. If the bending radius is almost as small as the material thickness, a bottom die is formed. However, the pressure required to form a bottom die is about four times greater than that required for free bending.


If the bending radius is less than the material thickness, use a punch whose radius of the front corner is less than the material thickness and turn to the embossing bending method.10 times the free bending pressure is required. For free bending, the convex and concave dies are machined at or below 85 degrees. When using this set of dies, pay attention to the gap between the punch and the die at the bottom of the stroke and to the excessive bending of the material that is sufficient to compensate for the rebound.


The spring-back angle produced by the free bending die on the new CNC bending machine is less than 2 degrees and the bending radius is equal to 0.156 times the opening distance of the concave die. For bending of a bottom die, the angle of the die is generally 86-90 degrees. At the bottom of the stroke, there should be a slightly greater gap between the die and the lug than the material thickness. A large number of tons of bending with bottom concave dies reduces the stress which usually causes a rebound in the range of bending radius.


The stamp bending is the same as the bottom die bending except that the front end of the die is machined to the required bending radius and the gap between the die and the bottom end of the stroke is less than the material thickness. Due to adequate pressure. Force the front end of the punch to contact the material, basically avoiding rebound. In order to select lower tonnage specifications, it is better to plan a bending radius larger than the material thickness and adopt the free bending method as far as possible. When the bending radius is large, the quality of the part and its future use are not affected.


How to calibrate the bender

After calibration, the CNC bending machine has a better effect on bending sheets than the bending sheets of uncalibrated equipment. The bending shape basically meets the user’s requirements. It can be said that calibration is necessary to work before using the equipment. How do I calibrate it?


  1. The operation of laser calibration instruments requires professional metrologists. The cover of the bender saw needs to be opened so that the optical elements can be adjusted on the workbench, the spindle and on a separate tripod. The process of space calibration takes several days, depending on the size of the saw machine.
  2. The measured target does not move in a straight line but in a large lateral direction. A single-aperture laser stakeholder is like a laser Doppler displacement meter, which is unaffected by large lateral movements. Using a flat mirror as the target to be measured, the movement parallel to the mirror does not divert the laser travel or adjust the gap from the light source.
  3. Calibration and offsetting can affect cycles when there is a need to weigh quality carefully. A bender within the precision range works at high speed while maintaining polishing accuracy. Calibration parts are collected on-line, and on-time calibration can also be used to predict whether the saw machine is approaching the deviation accuracy index.
  4. When calibrating the bender, careful measurements are required to do a good job of calibration everywhere. Calibration plays an important role in the operation of bending plates of equipment. Calibration work needs to be taken seriously. Make bending of sheet metal.


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