From automotive panels to aerospace components, leveling and deburring processes can help increase quality and productivity. Leveling converts warped and stressed sheet metal and cut parts into truly flat surfaces. Removing burrs and slag to provide smooth edges results in parts ready for downstream fabrication processes, such as bending and welding, that ensure consistent high-quality outputs and less scrap.
“Leveling and deburring are important process steps that typically occur directly after cutting,” says Denis Weinfurtner, North American marketing manager, Arku Inc. “A lot of shops still do these processes manually, and the problem with that is it produces inconsistent results. It’s very time-consuming, and it can also be dangerous.”
When sheet metal and plate arrive from suppliers, they often have various surface irregularities, such as waviness or scratches. These materials typically also have high internal stresses and unevenness. This can hamper subsequent processing operations. Further, when a shop exposes the material to a thermal cutting process, such as laser or plasma cutting, while it might appear flat, cutting the parts releases internal stresses that may distort the part. In addition to issues with part tip-ups, which can lead to laser head damage, these imperfections can lead to poor part fit-up, increased scrap rates and quality issues.
Leveling up
The leveling process addresses the imperfections that occur during production and handling of the material to transform coiled metal, cut-to-length sheet and parts themselves into products suitable for further processes. Precision levelers from Arku not only achieve flatness, but they also remove up to 99 percent of internal stresses, thus allowing for optimal downstream processing conditions thanks to flat and stress-relieved sheet metal and parts.
The levelers are available for soft materials such as copper all the way up to hard plate used for armored tanks (for example, AHSS). Material thickness ranges from 0.005 in. to 2.4 in., which is covered by nine machine models, from small to large, for a range of industries from shipbuilding to medical devices.
A majority of fab shops will cut parts first and then run them through the leveler, but some industries, like aerospace or medical, require tighter tolerances.
“Leveling is kind of unique because it can be used for the sheet metal prior to cutting, but then also for the final parts after cutting, depending on how tight the final tolerance needs to be,” Weinfurtner says. “For example, some of our medical customers level the sheet prior to cutting to make sure it’s dead flat and has up to 99 percent of residual stresses removed. When they cut it, because of the immense heat, it adds some stresses back into the sheet and maybe also distorts it a bit so they might level the actual parts again after cutting to really be sure that they meet the required tolerances.”
The process described
Today’s precision leveling machines combine basic mechanical principles with cutting-edge technology. An immense amount of engineering and knowledge go into a precision leveler, but the principle itself can be explained rather quickly, according to Weinfurtner.
“Our levelers are all built the same, from the smallest to the biggest,” he says. “Each has a series of rollers, with the number of rollers depending on the size of the machine. As an example, let’s use our FlatMaster 55 that’s popular for job shops. This is a medium-size machine that processes material up to about 0.5 in. thick. If the material is 0.25 in. thick, you would set the machine up to have the gap of the first set of rollers be approximately 50 to 90 percent of the original material thickness. So, if it’s 0.25 in., you would set the inlet gap to about 0.20 in. The gap between the last set of rollers is set right at the material thickness.
“As the material goes in the machine,” he continues, “it gets bent strongly up and down because the rollers are nested tightly together due to a lower material thickness being entered. Then as it travels throughout, it gets bent less and less, and by the time it reaches the last set of rollers, it comes out right at its material thickness and dead flat. Bending the material past its yield point is the only way to remove up to 99 percent of the internal stresses in the material.”
The result is level and stress-relieved parts that are going to reduce downstream inaccuracies and inconsistency, whether it is during bending, punching or welding.
“The part might appear flat, but the minute you add heat, all those trapped stresses on the inside of the part want to become external and then the part starts bowing,” Weinfurtner says. “Shops are moving more and more toward robotic welding, but guess what? If there’s deformation that occurs during the welding process because of the heat, the robot will just keep welding and then you have a bad part. With a leveler, all your parts remain flat thanks to also removing the internal stresses. Then, everything down the line goes smooth the first time around, and you don’t have to touch that part again.”
In theory, leveling is a simple and easy process to perform, but the reality is that it requires some knowledge and experience.
“I’ve said it many times – an operator is never going to get the full potential out of the machine if they’re scared of it,” Weinfurtner says. “They have to be confident.”
To help with this, Arku levelers feature a part calculator tool to help operators get started.
“With the part calculator, you can enter the material type and thickness, and then it provides a suggested inlet and outlet value,” Weinfurtner says. “It tells you what a good starting point is and, depending on the cutouts, you might need to make an adjustment.”
Finishing touch
There are many reasons sheet metal and cut parts might have formed burrs. Perhaps the focal point for the laser beam is not set precisely. Maybe the material is too thick for the laser cutter. Often, the cutting gas is the culprit. Some materials, such as aluminum, tend to from more burrs than other materials during laser cutting. With plasma cutting (often used for thicker materials), some of the molten metal is not fully expelled from the cut path, causing it to stick to the material, forming slag.
Whatever the cause, Arku has several deburring machines dedicated to laser cutting and flame cutting applications. In addition to deburring and deslagging, some machines also feature edge rounding and surface finishing.
To make them easy to operate, the Arku Wizard is a standard feature on all the deburring machines. The operator answers a series of questions about the material and desired edge result, and the user interface automatically tells them what the right settings are and the right consumables to use to be successful.
One of the biggest differentiators with Arku deburring machines is that some work single sided while others are double sided. This allows the parts to be processed from the top and bottom side in a single pass.
Edge rounding offers many benefits. Deburring creates sharp edges, and if the parts will be welded together, it is much more advantageous if the edges have a little bit of a roundness. Also, operators appreciate handling parts with rounded edges for safer handling.
“For painted surfaces, it’s especially important to have a slightly rounded edge because you need to allow the paint surface area to adhere to the edge,” Weinfurtner says. “If the edge is too sharp, the paint can’t stick to it and will flake, thus causing rust.”
Surface finishing of laser cut parts can also be integrated into some deburring machine models. This gives the parts the desired appearance after deburring. This is especially useful for parts that will stay as is and will not be painted or coated, such as architectural panels or medical components.
A complete system
If parts are going to be leveled, it can be beneficial to remove the burrs first.
“We always recommend making sure that all burrs that actually stick out from the edge are gone before you level,” Weinfurtner says. “If you put that material straight into the leveler, it’ll just roll over those burrs and potentially push them into the material. Then, you’re stuck having to grind those out, which is even more labor-intensive. You’re also safeguarding the leveling machine. Even though leveling rollers are extremely durable, putting material with burrs through them just isn’t good for the machine in the long run.”
As for automation, Arku does offer a vision-based robot, which has been available for about three years. For loading and unloading, the robot can be connected to a deburring machine, leveler or both. Thanks to the state-of-the-art vision technology, the robot does not require any programming.
“We do sell complete lines and, sometimes, if a customer wants to save money and space,” Weinfurtner says, “we’ll take a machine and put a conveyor at the inlet and a conveyor at the outlet and then maybe a 180-degree conveyor coming back to the inlet – and then the customer can use one robot for loading and unloading. More and more customers are purchasing the robot afterward to then make their machines completely autonomous.”
Precision levelers and deburring machines alleviate a shop’s workload and increase its efficiency and speed, increasing output and productivity. Investing in this type of equipment can deliver consistent high-quality parts for downstream fabricating processes. This not only saves a shop money by reducing costs, it also provides a competitive advantage by providing higher initial material quality.
Arku Inc.
