Press Brake Depth Calculation for Deflection-Compensated Bending
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Solution Overview
Problem
Existing press brake systems face challenges in achieving accurate bending of sheet metal due to deflections in side frames, upper and lower tables, which affect the desired bending angle, despite corrections using the D value.
Innovation Solution
A press brake control device and method that incorporates a NC device with units for calculating spring back, stroke, and deflection amounts, using material and tool conditions to adjust the bending load and deflection coefficients for precise control of the punch and die holders, thereby improving bending accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the punch is lowered by a calculated stroke to achieve desired bending angle, then the bending operation is completed, but the bending accuracy deteriorates due to deflection of side frames, upper table, and lower table
Solution Approach 1:
The system performs preliminary actions by calculating deflection amounts of side frames, upper table, and lower table before the bending operation, and pre-adjusts the punch stroke accordingly. The control device computes the required stroke correction based on predicted deflections and sets the corrected stroke value in advance, ensuring accurate bending angle is achieved despite anticipated deflections during operation.
Solution Approach 2:
The system implements feedback by measuring actual bending angles after trial bending operations, comparing them with desired bending angles, and using this information to calculate and apply corrections to the punch stroke. The control device continuously refines the stroke value based on measured results, progressively improving bending angle accuracy through iterative correction.
2Manufacturing precision
If the D value is corrected in consideration of deflection of punch to improve bending accuracy, then the bending operation is refined, but it is still not possible to bend the sheet metal at the desired bending angle
Solution Approach 1:
The system segments the total deflection compensation into distinct components: deflection of side frames, deflection of upper table, deflection of lower table, and deflection of punch. Each component is calculated separately using specific formulas and parameters, and then summed to determine the total stroke correction. This segmented approach allows comprehensive compensation while maintaining clear calculation methodology.
Solution Approach 2:
The system applies parameter changes by modifying the punch stroke parameter based on calculated deflection amounts. The control device adjusts the stroke value from the initially calculated value to a corrected value that compensates for all identified deflections. This parameter adjustment transforms the bending process to achieve the desired bending angle despite structural deflections.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances bending accuracy by accurately calculating and compensating for deflections in the press brake system, ensuring the sheet metal is bent at the desired angle by adjusting the punch stroke based on detailed calculations of spring back and deflection amounts.
Implementation Method 1
due to the existence of deflection of side frames of the press brake as well as deflection of the upper table and the lower table
Implementation Method 2
The press brake bends the sheet metal by lowering the upper table toward the lower table and then sandwiching the sheet metal disposed on the die between the punch and the die
Implementation Method 3
A distance (stroke) by which the punch is lowered toward the die from a state in which the tip of the punch is in contact with the sheet metal is determined by a desired bending angle
Data Source
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AI summary
When a sheet metal is sandwiched between a punch held by a punch holder and a die held by a die holder to bend the sheet metal at a set bending angle by moving the punch toward the die, a stroke calculation unit (202) calculates a stroke (St) of the punch for bending the sheet metal at the bending angle in consideration of a spring back amount of the bent sheet metal. A bending load calculation unit (203) calculates a bending load (BF) required to bend the sheet metal at the bending angle. A punch deflection amount calculation unit (206) calculates a punch deflection amount (d206) according to the bending load (BF). A punch holder deflection amount calculation unit (207) calculates a punch holder deflection amount (d207) according to the bending load (BF). A depth value calculation unit (210) calculates a depth value (D210) by adding at least the punch deflection amount (d206) and the punch holder deflection amount (d207) to the stroke (St).