Thanks to its compact and lightweight format, the sensor can be easily integrated into various machine structures.
Why Do Angle Deviations Occur During Bending?
During bending, the bending angle is crucial for the quality and fit accuracy of a workpiece. Even the smallest deviations from the desired angle can lead to components not fitting correctly or needing to be reworked. In the industrial environment, numerous factors affect the bending process. The most common are the following.
Material variations: Differences in sheet thickness, alloy, tensile strength, rolling direction or coating can lead to varying springback.
Machine deformation: Under high pressing force, the upper and lower beams bend slightly. Without targeted cambering of the press, an uneven angle over the length of the sheet is created. The camber compensates for these deflections and ensures an even distribution of angles. Temperature fluctuations, for example due to different seasons, can additionally influence the machine geometry and thus further change the angular accuracy.
Increasing quality requirements: Tight tolerances, full traceability and 100% control require stable processes and precise compensation for all variations, including material variations and machine deformations.
Manual vs. Automatic Angle Control
Manual Angle Control
| Interruption of the production process: Every test takes time and reduces throughput. |
| Limited significance: Individual samples only cover a fraction of production, so errors can go unnoticed. |
| Operator influence: Different employees measure with different accuracy, which reduces process reliability. |
| Rework and rejection: If a deviation is only detected late, several parts have often already been produced incorrectly. |
Inline Measurement with 2D/3D Profile Sensors
| Real-time results: Deviations from the target angle are detected immediately and the machine can readjust in real time. |
| Ongoing monitoring: Every bending process is monitored automatically. |
| Consistent results: The accuracy of the bending angles always remains the same, regardless of material batches, component length or operating personnel. |
| Automatic correction: Angle corrections are automatically transferred to the press control and the press parameters are adjusted accordingly. |
How Does Inline Angle Measurement Work with a 2D/3D Profile Sensor?
In order to ensure constant and precise bending angles during the bending process with press brakes, the optical inline angle measurement method is used. A 2D/3D profile sensor is positioned below the sheet and measures the bending angle from below at a defined position. The measurement is based on the laser triangulation principle: The sensor sends a laser line to the sheet. The reflected line is recorded and evaluated at a fixed angle on the camera chip. The measurement data is transferred to the machine control system in real time, angle deviations are detected immediately and the bending process is adjusted accordingly.
Benefits of Automatic Angle Measurement
Exact Angle Measurement from 10 Millimeters Leg Length
Angle measurement is already possible for workpieces whose sheet metal legs protrude at least 10 mm beyond the outer edge of the lower tool. Even compact components can be reliably monitored and integrated into the production process. Users benefit from high flexibility and precise angle control, regardless of workpiece size.
Stable Profile Generation over the Entire Bending Range
The 2D/3D profile sensors deliver stable and evaluable profiles across the entire bending range – from flat angles to the extreme range of up to 85 degrees. The sensors also ensure reliable measurement data at angles close to 0 degrees, where reflections between the sheet metal and the die could make measurement difficult.
Excellent Repetition Accuracy
Automatic angle measurement ensures reproducible measurement results and consistently precise bending angles for every workpiece.
Angle Monitoring over the Entire Component Length
To precisely monitor the bending angle over the entire length of the component, the sensor can be moved along the press. This makes it possible to check the angle at different positions of the component. This is particularly advantageous for long components. The parallel use of multiple sensors also enables seamless process monitoring, which contributes to higher productivity.
Springback Compensation
The automatic angle measurement measures the actual springback directly during the bending process. This allows the required overbending to be precisely determined so that the desired target angle can be reliably achieved even with changing materials and material batches.
Large Measuring Range for Maximum Flexibility
The sensors have a large measuring range and are suitable for a wide range of tools and sheet thicknesses – from very narrow and low to larger and higher tools, from V4 to V80 and beyond. This enables versatile and flexible use without sensor replacement or additional systems. The active area of the sheet observation is adjusted automatically.
Integrated with Many Control Systems
Thanks to the open, Ethernet-based interface, the MLSL1xxS50 sensors can be quickly and easily integrated into existing control systems or virtually any other control environment. After activating the “Angle measurement” option in the relevant control system, the sensor is seamlessly integrated and is immediately ready for use after the IP address has been matched. Pre-configured function blocks are available for Beckhoff, Siemens and Rockwell to facilitate initial startup.
Our Control System Manufacturer Partners for Brake Presses
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Easy Initial Startup and Diagnostics
After mechanical and electrical integration, only the IP addresses of the sensor and the machine control need to be matched. The IP address of the sensor can be set directly via the integrated OLED display. The setup is then complete and the angle measurement can be started.
(1) Arrow up button
(2) Enter key
(3) Arrow down button
(4) Display
- The integrated web interface can be accessed directly for initial startup, parameterization and troubleshooting.
- The web interface provides a quick overview of all relevant instrument and measurement data.
- The profile recording can be visualized in real time.
Highest Precision in Sheet Metal Processing with the Smart Profile Sensor
Thanks to the plug-and-play function as well as the preset mode of operation “Smart profile sensor” and the uniVision software, including pre-configured modules for angle measurement, the MLSL1xxS50 sensors are immediately ready for use without the need for complex programming or parameterization. The evaluation takes place in the uniVision software directly on the sensor – an external industrial PC is not required.
- Profile detection:
The profiles are detected by the sensor. - Data analysis and calculation by uniVision:
The data is analyzed by the uniVision software on the sensor and the angle is calculated precisely. - Data transfer and adjustment:
The angle is transferred directly to the machine control so that the press can automatically adjust and adapt the bending process. This enables angle deviations to be detected early and ensures reproducible results even under changing production conditions.
Two Options for Angle Calculation
The angle calculation can be performed with different reference systems. The angle can be calculated either directly on the sheet with reference to a known sensor position or between the sheet and the lower tool.
Measurement on Sheet Metal
The mounting position of the sensor is taken into account for angle measurement only on the sheet metal leg. This means that the entire measuring range of the sensor can be used to record the sheet metal profile. The status of the dies have no influence on measurement result.
Measurement Between Sheet and Die
The die is included in the angle calculation as an additional reference. This allows the angle to be calculated regardless of the mounting position of the sensor.
Which Materials Is Optical Angle Measurement Suitable For?
The wide range of sheet metal materials and surfaces requires robust surface detection. The 2D/3D profile sensors for bending angle monitoring are specially designed for these requirements and enable precise angle measurements on typical sheet metal surfaces – including foiled, high-gloss or brushed aluminum sheets as well as perforated sheets, corrugated or rusty steel sheets. The recorded angle information is transmitted directly to the integrated control system for fine control of the bending press in accordance with the process.
Gloss
Rusty
Brass
Brushed
Brushed, twisted 90 degrees
Film-coated
Perforated plate
Knurled plate
Practical Example: Comparison of Stainless Steel and Sheet Iron
The following example shows that the MLSL123S50 2D/3D profile sensor delivers reliable measurement results with the same sensor settings on different materials and surfaces.
Stainless Steel with Protective Film
Profile detection is not affected by varying brightness levels or surface structures.
Corroded Iron Plate
Even dark or rusty surfaces are reliably detected with the same sensor settings.
Precise Angle Measurement on Demanding Surfaces
Automatic Adaptation to Dies and Sheet Geometries
With each tool change, the tool geometry and the position of the measuring ranges change. To ensure that the bending angle is still accurately recorded, the control system automatically adapts the application on the sensor to the selected die-tool combination. The job and tool selection made by the operator determines the position of the active measuring ranges through which the sheet moves during bending.
Thanks to the measuring principle from below, laser-assisted bending angle measurement can be used flexibly for different die and tool combinations. After entering the mounting position of the sensor (height, distance and angle to the y-axis of the press brake), the measuring ranges are precisely positioned. This allows the desired angles to be determined precisely regardless of the condition and degree of contamination of the dies.
How Is Measuring Accuracy Ensured During Angle Measurement?
To ensure maximum process reliability, the MLSL1xxS50 has a “Calibration” application. Together with the defined calibration object, it determines the three relevant parameters. The recorded values can be read directly on the sensor via the uniVision software or displayed in a web visualization. They can be permanently stored in the control system and used to correct the measured angles if necessary. This allows the measurement system to be checked at any time and the correct sensor position to be validated quickly and reliably.
Enhanced Application Options Thanks to Additional Accessories
Protective Screen Retainers and Protective Screens
With a protective screen retainer and replaceable protective screens, the sensors on bending presses are optimally protected against contamination, scale, chips or unsuitable cleaning agents. This keeps the windows for laser and measurement free of damage.
Cables
In addition, wenglor offers an extensive portfolio of cables in straight or angled versions. These include drag chain cables that are designed for a particularly long service life and allow flexible installations.
Applications for Precise Angle Measurement in Sheet Metal Processing
Inline angle measurement is used wherever there are high requirements for angle accuracy, process reliability and component quality. In sheet metal and metal processing as well as in mechanical engineering, automatic bending angle measurement enables reliable quality monitoring directly in the production process. Continuous angle control enables material fluctuations, springback effects and angle deviations to be detected early and automatically compensated for.
Application Examples
In sheet metal and metal processing, components must be manufactured with high angular accuracy. The automatic bending angle measurement ensures continuous quality control during the bending process.
Related Applications
Frequently Asked Questions
Angle measurement is based on the optical laser triangulation principle: A laser line is projected onto a bent sheet. A 2D/3D profile sensor records the profile of the workpiece and uses it to calculate the current bending angle. The sensor enables continuous monitoring of the bending process and delivers measured values in real time. Automatic angle detection can compensate for material fluctuations, springback and tool tolerances. The determined angle values can be transferred directly to the press control so that it can automatically readjust the bending process.
Springback refers to the effect of a sheet partially returning to its original shape after the bending process. During bending, the material is subjected to both plastic and elastic stress. If the pressing force is removed, the elastic part is reduced again and the bending angle opens slightly. To achieve the desired target angle reliably, the springback must be compensated. The level is determined by numerous influencing factors, including material (e.g. aluminum, steel, copper or titanium), alloy, rolling direction, sheet thickness, bending radius and the condition of the tools used. Inline measurement makes bending quick and easy, as the required overbending can be precisely determined by the specified angle and the springback.
wenglor’s 2D/3D profile sensors enable precise angle measurement on a variety of different sheet materials and surfaces. These include foiled, high-gloss and brushed aluminum sheets, perforated sheets, corrugated sheets and rusty steel sheets. A sensor variant with blue laser is available for particularly demanding, highly reflective surfaces.
Yes, provided that the sensor has the current systems of the control providers of Delem, Esa and Cybelec. Retrofitting is only possible after consultation with the bending press and control manufacturers.
Product Overview
| MLSL123S50 | MLSL133S50 | |
|---|---|---|
| Working range Z | 90…280 mm | 90…280 mm |
| Measuring range Z | 190 mm | 190 mm |
| Measuring range X | 62…145 mm | 62…145 mm |
| Resolution Z | 9.4…49 µm | 9.4…49 µm |
| Resolution X | 54…123 µm | 54…123 µm |
| Laser class/light source | 2M/laser, red | 2/laser, blue |
| MLSL123S50 | ||||||
|---|---|---|---|---|---|---|
|
Working range Z
90…280 mm
|
Measuring range Z
190 mm
|
Measuring range X
62…145 mm
|
Resolution Z
9.4…49 µm
|
Resolution X
54…123 µm
|
Laser class/light source
2M/laser, red
|
|
| MLSL133S50 | ||||||
|
Working range Z
90…280 mm
|
Measuring range Z
190 mm
|
Measuring range X
62…145 mm
|
Resolution Z
9.4…49 µm
|
Resolution X
54…123 µm
|
Laser class/light source
2/laser, blue
|
|
