Press Brake Optical Beam Detection for Thin Workpiece Bending
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Solution Overview
Problem
Thin workpieces with large lower tool widths cause leakage of scattered beams, making it difficult to detect beam shielding and thus the presence or absence of the workpiece, leading to inefficiencies in the bending operation due to the need for attaching magnet sheets for reliable detection.
Innovation Solution
An optical safety device with a beam projector and receiver that switches detection sensitivity from normal to high sensitivity mode when the press brake is performing initial processing, allowing reliable workpiece detection without a magnet sheet by adjusting the beam receiver's height position relative to the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a monitoring beam is used to detect workpiece presence, then automation and productivity are improved, but for thin workpieces with large lower tool widths, scattered beam leakage causes unreliable detection
Solution Approach 1:
A magnet sheet is introduced as an intermediary object attached to the lower tool to enhance the workpiece's magnetic properties. This mediator enables reliable detection by creating a detectable magnetic signal difference between the presence and absence of the workpiece, solving the unreliability caused by beam leakage in thin workpiece scenarios
Solution Approach 2:
The detection method changes from optical beam detection to magnetic field detection by utilizing the magnet sheet. This parameter change allows the system to detect workpiece presence through magnetic flux changes rather than relying on optical beam shielding, which was unreliable for thin workpieces
2Reliability
If a magnet sheet is attached to the lower tool to enable reliable detection, then detection reliability is improved, but the complexity of the bending operation increases due to additional attachment steps
Solution Approach 1:
The magnet sheet is designed to be automatically attached to the lower tool through magnetic attraction when the tool is inserted into the holder, eliminating the need for manual attachment operations. The system serves itself by utilizing the inherent magnetic properties to perform the attachment function automatically
Solution Approach 2:
The magnet sheet is pre-positioned on the lower tool before the bending operation begins. This preliminary action ensures that the detection system is already prepared and configured correctly, eliminating the need for setup steps during the actual bending operation
3Reliability
If a magnet sheet is attached to the lower tool, then workpiece detection reliability is improved, but the time required for bending operations increases due to additional setup steps
Solution Approach 1:
The magnet sheet attaches automatically through magnetic attraction when the lower tool is inserted into the holder, eliminating manual attachment time. The system performs the attachment function itself without requiring operator intervention, thus avoiding time loss
Solution Approach 2:
The magnet sheet remains attached to the lower tool throughout multiple bending operations without requiring reattachment. This continuous state maintains detection reliability across all operations while eliminating repetitive attachment and detachment time losses
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
Enables reliable detection of workpiece presence and correctness of height position without a magnet sheet, simplifying the bending process and improving operational efficiency by eliminating the need for magnet sheet attachment.
Implementation Method 1
a beam projector (46) provided on one side in a length direction of an upper table (26) and configured to project a monitoring beam (B) passing through an area and surroundings immediately below an upper tool (12) toward another side in the length direction of the upper table (26)
Implementation Method 2
a beam receiver (52) provided on the other side in the length direction of the upper table (26) and configured to receive the monitoring beam (B)... a beam receiver for receiving the monitoring beam is provided on the other side in the length direction of the upper table, and the beam receiver has a beam receiving element that outputs a beam receiving voltage (a voltage signal) corresponding to a received beam amount of the monitoring beam
Data Source
AI summary
A received beam amount acquisition section 60 acquires a received beam amount per unit time of a beam receiver 52 at certain sampling time intervals. A beam shielding detection section 66 detects presence or absence of beam shielding of a monitoring beam B by determining whether or not the acquired received beam amount per unit time of the beam receiver is lower than a determination threshold Th for detecting the presence of beam shielding of the monitoring beam B. A detection sensitivity of the beam shielding detection section 66 is configured to be switched from a normal sensitivity mode to a high sensitivity mode when bending is initial processing based on a predetermined processing program, and an acquired height position of the beam receiver 52 is lower than a predetermined second height position LP2.