Jul 30, 2023

Taking tube bending to the next level

BLM’s ELECT is an all-electric tube bender configured for left- or right-hand bending of tubes up to 150 mm dia. BLM GROUP USA

Today’s tube benders are designed to meet the varying requirements of the many industries that use them. These machines are common across the aerospace, automotive, oil and gas, heating and air conditioning, refrigeration, and furniture manufacturing sectors.

“Most sectors are relatively strong right now, particularly oil and gas, but that may fade as the prices of oil and gas drop,” said Stuart Singleton, vice-president, Unison Tube LLC, Danville, Va. “Aerospace is still in recovery mode post-pandemic. We are seeing lower capital investment in automotive due to the transition to electric vehicles and uncertainty around whether hydrogen vehicles will take off.”

There is a push to make things faster and better. With tube bending, like with many other processes, manufacturers are turning to automation. The latest technology is helping fabricators take the human element and variability out of the process.

One way this is being done is through simple automation—particularly for loading/unloading. The loading process can be time consuming and requires an operator to orient the tube properly for the bend to be done correctly.

“There is a huge push towards automating various parts of the tube bending process,” said Robert Bowden, North American product manager - bender systems, BLM GROUP USA, Novi, Mich. “An operator responsible for loading a tube into a machine and taking a finished part out may not always work at a constant pace. By automating that process, it becomes more consistent, resulting in higher throughput, which is a huge advantage.”

During the loading processes, if an operator is working with a welded tube, the orientation of the tube becomes important. The latest loading/unloading automation automatically detects where the seam is and orients the part for proper bending. This is also true for tube with precut features that need to be placed accurately. Automatically loading tube with these features means that an operator doesn’t need to think about orientation and can focus attention on more important aspects.

“Automation can be as simple as just having a robot that loads and unloads apart,” said Bowden. “Or it could be integrating multiple machines into a common cell. For example, a tube bending machine can be integrated into a larger process, where tubes are loaded into the machine with a robot. After they are bent, the tubes are taken to an inspection station, where the bend angles and lengths are checked for accuracy. From there, the robot offloads the tube to a rack—one rack for good parts and another for bad parts.”

Not all fabricators will have the need or capacity for a larger system. Automation can be used simply to process the tube after it’s bent. Some parts may require end finishing or trimming, which can easily be automated.

“It’s important to think it through, though,” said Singleton. “Fabricators should consider if having a cell produce everything is likely to cost significantly more than focusing on the processes responsible for producing 80 per cent of parts. The 80-20 rule is a good starting point. The biggest error people make is usually around production volumes and the number of variants they want to automate.”

Getting more done with less is a common trend in today’s manufacturing environment, which is why incorporating multiple processes into a single machine can be quite attractive. With standard-style tube benders, there generally isn’t too much that can be added to make these machines more efficient.

A bending machine is an expensive tool, and fabricators need to make sure they aren’t holding it up for menial tasks. Unison Tube LLC

“However, a shear cutoff type system with a shear blade can be added to a tube bender,” said Bowden. “Tubes can often need trimming, and this is a good way to do it. This type of system is popular in the automotive sector with exhaust components.”

Integrating this system into a tube bender will save time, especially in components where there are only a few small bends. For example, an operator can load a standard 20-ft. length of material into the machine and have the machine bend the tube and then cut it off as it’s finished. A shear cutoff system eliminates the need to load and unload the parts.

Another way to incorporate additional features onto a machine is through specialized tooling. For example, with furniture applications, adding a punching process can be extremely helpful. Specialized tooling can apply holes for bolts and screws needed to attach seat, arm, and leg components of a chair.

“A bending machine is an expensive tool, and fabricators need to make sure they aren’t holding it up for menial tasks,” said Singleton. “If a shop has capacity in the machine, is making a limited set of parts, and the operator has other things to do whilst a part is being produced, then there is scope to incorporate multiple processes into a single workflow. But be careful not to tie yourself in knots. Generally, it is much better to complete multiple processes in a cell, with automation taking the parts through the cell, so that every process is done in parallel rather than in sequence.”

Some tube bending machines are designed to perform in a done-in-one fashion. For the most part, these systems can take material from a coil, straighten it, bend it, and perform trimming and end forming.

“These types of machines are typically used in the heating and air conditioning and refrigeration manufacturing industries,” said Bowden. “They are designed for bending copper or stainless steel tubing, where one or both ends require processing. We also can incorporate drilling, or a flow drill, as an option.”

Having a system with flow drilling is helpful because it basically extrudes the material inward, allowing for threads to be added and screws to be inserted.

“With these types of machines, fabricators are getting close to a completely finished part right off the machine,” said Bowden. “There generally isn’t a lot of secondary operations needed. All that is needed is an operator to manage the machine, with little interact needed. They even allow for one operator to manage multiple machines. It takes the labor required out as well, and with all process rolled into one, it increases your productivity.”

Beyond the machine itself, there are many opportunities for improving tube bending operations.

“True automatic setup for those companies wanting right-first-time bending to reduce scrap—especially those bending high-value materials—is something that still hasn’t been appreciated by everyone,” said Singleton. “People still focus on speed rather than the quality of the product—cutting 10 tubes, bending 10 tubes, selling 10 tubes. Imagine the noise that goes on within a business because it has to cut 11 or 12 tubes and it takes one or two tubes to set up. Then, if magically, it can be done in 10 tubes, what do you do with the other two? Or what if it takes 13 tubes in total and you need to issue a request for another tube? Consider how many people are involved in that type of process alone.”

While the bending process itself doesn’t change all that much, software can make the entire process more user friendly and ensure it functions properly. BLM GROUP USA

While the bending process itself doesn’t change all that much, software can make the entire process more user friendly and ensure it functions properly. The right software will provide the necessary functions to make an operator’s job that much easier.

“A lot of people think tube bending is like magic,” said Bowden. “But with the advances in software technology, you don’t have to know magic to be able to do it. Also, it does require skill and some background knowledge to get the most out of the process. Today’s machines are a lot more automated. With good software, fabricators can import a 3D file and within a few minutes, the machine will be bending a part. It takes a lot of those steps, like trying to figure out what pressure to use and where to set up the clamp die, out of the equation.”

Associate Editor Lindsay Luminoso can be reached at [email protected].


Unison Tube LLC,

Unison’s Opt2Sim tube bending simulation software uses machine and component data to provide a precise, virtual insight into the bending process before a single part is bent. Unison Tube LLC