Tube bending trends

Tube bending machine CNC 100 E TB MR in action: Schwarze-Robitec incorporating loading, bending and cutting in an automated process. Schwarze-Robitec

Canadian Fabricating & Welding sat down with Philipp Knobloch, global sales director, Schwarze-Robitec, to discuss the latest trends and advancements in tube bending.

CFW: How are fabricators able to gain a technical edge with feature-rich tube bending?

Philipp Knobloch: In the last few years, we’ve seen big development in ways of tube cutting, which is a mechanical process that can be added to tube bending machines. In combination with a bending machine, the most common cutting technologies are chopping and roll cutting. Chopping, which is also well-known as nick and shear cutting, is a very fast and effective way of cutting. As a main advantage, it allows very good cycle times in relation to the bending process. With this process, fabricators can work with minimum tube lengths so that the material use is optimized and less material is wasted. Those characteristics turn chopping into an optimal process for automotive manufacturing.

Chips can be an equally important factor when cutting on a tube bending machine. If chips from cutting get into the bearings or guide chains of the machine, it can be very problematic and cause the machine to wear prematurely. Tube bending machine manufacturers offer good solutions for this challenge. Where chips are produced, they can be safely guided out of the machine by vacuum extraction and by intelligent solutions for chip disposal within the tools. For example, pneumatic air nozzles transport the chips away from the critical areas within the machines.

However, when cycle times are not the most important factor, but manufacturers are instead looking for an especially clean cutting process, chopping might not be their first choice. A good alternative is the chipless cutting type roll cutting, where roller blades are running around the tube within the machine. This type of cutting brings the bonus of a very clean and chipless cut quality with it. As a result, the surface quality is so high that no further machining step is required for finishing tube ends. This is commonly added to applications where delicate cuts are needed.

Beyond these two options, a simple saw can be added on the tube bending machine. This method is especially suitable for tubes with large diameters or thick walls. The benefit of it is that it is wall thickness independent, so even heavy materials can be cut with a saw. This is commonly seen in heavy-duty applications like shipyards or the power generation industry.

The general advantage of combining a tube cutting process onto a CNC bending machine is that the tube is in control and can be positioned very precisely at the point where it should be cut. There is no additional handling or positioning. By integrating cutting into the bending process, the number of handovers is reduced. With each handover between two processes, handover tolerances occur. If the integrated cutting can take place directly in the same clamping, the precision of the process increases and with it, the general repeatability.

CFW: What are other features that fabricators can and should take advantage of?

Philipp Knobloch:Optimized axis control allows the tube bending machine to be operated with optimized cycle times. For example, Schwarze-Robitec’s NxG control system monitors the interaction between axes at all times. While one bend is being performed, the axes simultaneously prepare for the next step in the process. Depending on the component and tube geometry, the NxG control system can slash production times by 20 to 40 per cent. Additionally, springback of the tube can be more easily controlled. We also have a feature that allows for freely programmable axis movement on the machine. This way, the tube can be positioned for pre- and post-process steps, e.g. cutting on the bending machine independently of the bending levels.

There is a tendency towards developing a more detailed integration of the CNC control of the machines into shop systems. This allows for data from the machine to be collected into a user system that could potentially have specialized interfaces, depending on the information needed to examine, or even a calculating system.

Beyond that, there is also simulation and collision analysis to consider. It’s important to know early in the process if there is the potential for a collision problem or visibility issues. With special software integrated into tube bending machine, this can be checked and prevented.

One last feature that we are seeing more of is the addition of marking systems. Fabricators who need to add information to the tube before or after bending can use an inject or needle marking system. A tendency is the scanning of information directly from the tube, e.g. in the form of a barcode. These can contain details about the bending process, such as the bending angle, or enable subsequent tracking for traceability after tube processing.

CFW: With the latest tube benders, how can fabricators do more with less?

Knobloch: Technically, a lot is possible, but it’s important to know the technical limitations and whether a feature makes sense from a productivity or efficiency standpoint.

For example, if a customer is asking for a high level of automation with a system, where everything is running automatically and is robot-controlled, it’s important to look at the customer’s production volumes. We analyze the customer's prerequisite goals and quantities precisely in order to decide what level of automation is beneficial. Based on the customer's requirements, we develop a solution exactly tailored to the customer's needs. This might be an automated feature in one case and a whole bending cell in another.

Does it really make sense to do a certain process on the bending machine or can that be done before or after getting to the bending process?

For example, weld seam detection can be integrated into a tube bending machine, but it takes a minimum of 15 seconds. Does this 15 seconds of added non-tube-bending production time change cycle time values? Can it be moved to a pre- or post-production process to maintain bending cycle times? These are important questions to ask.

CFW: What are the latest trends and innovations in tube bending?

Knobloch: There is a tendency to automate the whole process and to combine and incorporate multiple processes into tube bending. In the end, it can make production a lot faster, more efficient, and resource-friendly on many levels. It also includes the benefit of repeatability. Start with pipe or tube handling, stocking, and storage, which can be done by adding an automated system. With a tube magazine, for example, shops can reduce the required space by preloading the pipes and tubes directly into the magazine, which is connected to the automated bending cell.

An automated system tends to be more reliable in terms of accuracy and can reduce error sources, but on the other hand, it might not always be as flexible as a customers’ production requires.

We are also noticing an increasing demand for more flexible automation solutions for smaller batch sizes. Due to an ever-increasing variety of parts and variants, companies are looking to produce many different parts within very small production quantities while still being able to produce cost-effectively. In such cases, too, automation can be worthwhile. But the production of small batches involves different requirements than automation for large-scale manufacturing. In such cases, the focus is often on fast and automated tool change and tailor-made software solutions, for example.

The latest in interfaces, monitoring, and controls along with data collection is a big asset. There is great cost savings related to cycle time, material, and wages when automation and technical features are incorporated.

CFW: How are tube benders being used in modern-day shops?

Knobloch: We are seeing a couple of different configurations. For large projects, an automated cell is common. For this, there could be multiple robots and processes integrated into one cell. But there tends to be only fewer applications with the required production volume where such a high grade of automation really makes sense.

This type of system requires significant effort and production volume to get the return on investment.

However, we are seeing more systems that are partly automated. For example, loading and unloading from a magazine into a bending machine is one common way fabricators can automate. Taking smaller steps towards automating still offers cost savings and cycle time benefits without such a high level of commitment needed.

Schwarze-Robitec, schwarze-robitec.com

For more on this topic, check out our feature on how to take tube bending to the next level!