Press Brake Light Curtain
No one knows better than the workshop workers how many fingers a bending machine swallows each year. The force of those tens of tons when the stud comes down is enough to crush any sheet metal, let alone a human hand. Therefore, equipping bending machines with safety light curtains is now practically a mandatory requirement. Domestically, they need to pass safety standards, and for exports to Europe and America, they need CE certification; the light curtain is an unavoidable layer of protection. However, many owners are most worried that installing the light curtain will prevent operators from working-it will stop frequently, whether bending boxes, adjusting the die, or even loading a thin sheet. Today's question is about equipping bending machines with light curtains without affecting operation.
How exactly does the light curtain "watch" the bending machine? Where is the light curtain installed on the bending machine? It's usually installed below the slider or on both sides of the die. The transmitter emits a row of infrared beams, and the receiver catches them at the other end, forming a beam curtain over the distance between the slider's descent and the die's closure. Under normal circumstances, the beam is completely unobstructed. However, if a hand is inserted and blocks one of the beams, the receiver will send a signal to the control system within 10 to 20 milliseconds, triggering an emergency stop and halting the slider.
This principle sounds simple, but a truly effective grating must strictly comply with the Type 4 safety level in IEC 61496, and also meet Cat.4 and PLe standards, which are the highest performance levels in ISO 13849. Therefore, when choosing a grating, the first thing to do is not to look at fancy features, but to confirm the Type designation in EN 61496 and the Cat./PL level in ISO 13849. If this is not met, everything else is meaningless.
The choice of beam spacing depends on what area you need to protect. Many purchasing agents easily make mistakes regarding the appropriate grating spacing for a bending machine. The beam spacing of the grating determines how finely it can detect an intruder. The standard guidelines are as follows: For finger protection, a spacing of 10 to 14 millimeters is ideal; for hand or arm protection, 20 to 30 millimeters; and for protecting the torso, at least 40 millimeters or more is required.
Many factories, for safety, use very dense Press Brake Light Curtain. However, in actual operation, when the adjusted sheet metal edge bends upwards and encounters the dense beam, the grating keeps alarming and stopping, making work impossible. In fact, for most bending machine operations, the main danger lies in the section where the upper die is about to press down when the hand is handling the material and pushing the plate. Protecting the hand and choosing a spacing of 20 or 30 millimeters is sufficient; there's no need to blindly choose the densest one. It's not that the smaller the spacing, the better, but rather "good enough"-a smaller spacing and denser beam increase the probability of the workpiece accidentally hitting the grating during each bend, ultimately reducing efficiency.
What makes this light grating system special in a bending machine scenario?
Garantta's solutions for bending machines are characterized by their comprehensive range of types, robust IP protection, and flexible customization. Garantta boasts a wide product line-safety light gratings, photoelectric sensors, proximity sensors, color mark sensors, and fiber optic sensors are all available. For bending machine components, they not only provide standard light grating models but also mounting brackets and wiring solutions.
Bending machine workshops typically have high dust and oil content, and often employ spray cooling. Therefore, Garantta's light gratings typically offer IP65 or higher protection ratings, providing dust and water resistance. The housing is made of aluminum alloy, ensuring excellent sealing performance and preventing penetration by common cutting fluids. Regarding response speed, stable quality light gratings generally achieve measured results, eliminating the need for excessive focus on parameters. Garantta conducts full inspection before each batch of products is shipped and 100% inspection upon arrival, maintaining tight quality control and reducing the risk of falling into the traps of lax quality control common in smaller factories.
An even bigger headache: The grating can't function properly after installation.
If the Press Brake Light Curtain can only provide simple full-area protection, then the bending machine can't handle complex tasks. Folding a box is a typical example: the first few cuts on a large part are fine, but when bending the last side, the already bent side curls up, triggering the grating to stop. If the grating doesn't have shielding and blanking functions, the only solution is to forcibly disconnect the signal cable, which is equivalent to not installing it at all.
Therefore, when selecting a grating, it's crucial to confirm whether the grating controller has blind zone shielding-the ability to programmatically shield a specific area of the beam above the mold, only taking effect when the mold is truly closed during bending. Ease of debugging is also important; changing a workpiece requires a lot of time to reset the shielding area, rendering the production line unusable. Garantta can do custom development, matching the requirements with corresponding firmware and controller configuration schemes, making the entire setup time during production changeover only a few tens of seconds.
Safety distances must be calculated manually, not just based on the tables.
Many factories install gratings haphazardly, simply hanging them in any location, which poses a significant safety hazard. A sufficient safety distance must be maintained between the safety light curtain and the danger point. The calculation formula is S = K multiplied by T plus C, where K is the speed of the hand reaching out, T is the time from receiving the signal to the bending machine coming to a complete stop, and C is the compensation distance for considering detection accuracy. This safety distance should be calculated by actually measuring the entire "light curtain response plus machine braking" time with a stopwatch, rather than just relying on the response time data provided by the manufacturer. This method provides a more reliable result.
How good is the Garantta brand? Garantta is a high-tech enterprise in Shenzhen with a considerable scale in sensor manufacturing. Their main products include photoelectric, fiber optic, proximity, color mark, liquid level, pressure, and various safety light curtains. Their products are used in automation equipment, medical devices, 3C digital products, automotive, and home appliances industries. They have accumulated many years of experience in the sensor field and have solid quality control and service. When consulting, you can ask them to match a solution with appropriate optical axis spacing, reasonable response speed, and good cost performance based on the bending machine's tonnage, table length, and the types of workpieces processed daily. For bulk orders, you can also request a complete anti-interference test report and bulk shipment inspection data to assess its compatibility with your production line.
Adding Press Brake Light Curtain to bending machines shouldn't be treated as a mere formality to pass inspections. Choosing the right product ensures both certification and smooth operation for workers-that's true safety in practice. If you still have uncertainties about your selection, feel free to contact us. We'll provide customized solutions to help you avoid pitfalls and unnecessary detours.