Press Brake Crowning for Variable Workpiece Length Accuracy
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Solution Overview
Problem
Existing crowning methods in press brakes struggle to ensure accurate bending of workpieces of varying lengths and positions, particularly when the workpiece is longer than the slit interval or shorter than the slit spacing, leading to inconsistent bending angles and reduced throughput accuracy.
Innovation Solution
The proposed solution involves independently or simultaneously adjusting the crowning of both the right and left sides of the upper and lower tables in a press brake, allowing for precise regulation of the table curvature to match the specific dimensions and position of the workpiece, regardless of its length or position relative to the slits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lower table is provided with slits at both right and left end sides to enable crowning, then the through-out accuracy is improved for standard workpiece lengths, but the bending accuracy deteriorates when the workpiece is longer than the slit interval or shorter than the slit spacing
Solution Approach 1:
The lower table is divided into multiple crownable regions by providing slits at both right and left end sides, allowing independent curvature adjustment of each segment. This segmentation enables the system to adapt to different workpiece lengths by selectively activating appropriate crownable regions, resolving the contradiction between maintaining bending accuracy and adapting to workpiece length variation.
Solution Approach 2:
The crownable regions are made dynamically adjustable through deformation means that can change the curvature of each region independently. This dynamic capability allows the press brake to adapt its table configuration to match various workpiece lengths and bending requirements, overcoming the limitation of fixed slit positions while maintaining bending accuracy.
2Adaptability or versatility
If dies are mounted on multiple sites on the upper and lower tables for step-bending, then different bending operations can be performed, but the bending accuracy deteriorates due to difference in warping deformation in the upper and lower tables
Solution Approach 1:
Different regions of the upper and lower tables are given different crownable characteristics through localized slits and deformation means. This allows each die mounting position to have tailored table curvature that compensates for local warping deformation, ensuring high bending accuracy across multiple die positions while maintaining the versatility of step-bending operations.
Solution Approach 2:
The system incorporates measurement means to detect actual table warping deformation at each die position, and control means that use this feedback information to adjust the curvature of crownable regions accordingly. This closed-loop control ensures that bending accuracy is maintained across multiple die positions despite variations in table deformation, enabling precise step-bending operations.
3Stability of the object's composition
If the upper and lower tables are supported at both ends, then structural stability is provided, but the central portions of the tables curve apart causing looser bending angles
Solution Approach 1:
The table curvature is adjusted in advance before bending operations by deforming the crownable regions to create a pre-curved configuration that counteracts the natural sagging of the centrally supported tables. This preliminary action compensates for the structural deformation caused by end support, ensuring that the tables maintain the correct geometry for accurate bending angles throughout the workpiece length.
Data Source
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AI summary
A crowning method applied to a press brake comprising an upper table and a lower table as being vertically opposed to each other and comprising first slits opened in right and left directions on both right and left sides of the upper table or the lower table, is by deforming end sides of upper portions or lower portions of the first slits of the upper table or the lower table upward or downward to carry out a crowning regulation.