Errors that result in the failure of press brake bending accuracy can arise from various factors, including mechanical issues with the machine, as well as external factors like bending tools, material thickness, and human operational errors.
In this article, we will examine the various factors that impact bending accuracy and provide solutions for some of the common scenarios encountered.
Machine Factors
There are several factors that can impact the bending accuracy of a press brake machine. These include:
- Straightness of the clamping opening of the ram in both Y and X directions.
- Repositioning accuracy and arbitrary positioning accuracy of the left and right ram.
- Reasonableness of the clearance between the press brake ram and the linear guide of the frame.
- Perpendicularity and inclination of the frame.
- The connection between the oil cylinder and the ram.
- Strength and accuracy of the frame and ram.
- Repositioning accuracy of the back gauge system in both X and R directions.
- Proper adjustment of the computer system.
- Adjustment of the hydraulic system.
- Matching between the hydraulic system and computer adjustment.
Tooling Factors
The accuracy of the upper and lower dies is critical.
Deformation, damage, wear, and other issues with the dies can impact all aspects of metal bending. If discovered, it should be promptly reported and corrected.
Misalignment between the upper and lower dies can result in deviation in the bending size. Ensure that the toolings are properly aligned during tool setting.
After the left and right positions of the back gauge move, the distance between the lower die and the back gauge changes. This can be measured using a vernier caliper and adjusted using the back gauge screw.
The accuracy and compatibility of the lower die compensation device should be verified, matching the design of the frame.
The upper die fixture should be highly precise.
The opening size of the V-shape die and the bending pressure are inversely proportional. When the plate length and thickness are fixed, the larger the opening, the lower the pressure required.
Therefore, when working with different thicknesses, the appropriate V-shape die opening size should be used.
When processing with a unilateral load, such as at one end of the press brake, the bending pressure may be impacted and it can cause harm to the machine. This is strictly prohibited.
The middle part of the machine should always be stressed when assembling the toolings.
Sheet Metal Factors
The straightness of the reference plane of the sheet metal must be checked.
Ensure that the stress on the metal plate is uniform.
Verify that the thickness of the sheet metal is consistent.
Inadequate parallelism between the workpiece and the lower die during bending can cause the workpiece to spring back after the upper die is pressed, affecting the bend size.
Material properties and thickness can impact the bending angle, so proper inspection and spot checking must be performed on each workpiece before bending.
Operation Factors
Check that the left and right forces are consistent when the operator pushes the material to bend.
Ensure that the system data error is properly adjusted when using the system.
An insufficient primary bending angle can affect the secondary bend dimension.
Accumulated bending error will increase the error in the workpiece's outline dimension.
The pressure required for bending varies with the length and thickness of the workpiece, and the length and thickness of the plate are proportional to the required pressure.
It is important to adjust the bending capacity accordingly when the length and thickness of the workpiece change.
Conclusion
To improve the bending accuracy of the press brake, various aspects need to be considered.
Aside from adjusting the machine's components, ensuring the accuracy of the tooling, and implementing correct bending compensation, attention should also be given to the daily maintenance and upkeep of the press brake.
This will help to extend its lifespan and maintain efficient bending.
Investing in a high-quality press brake is another effective way to guarantee productive operations.
ADH is a trusted manufacturer of press brakes, with two decades of expertise in the sheet metal industry.
Visit our press brake product page for more information, or go to our contact us page for detailed product and pricing details.
