In fact, this part does not at all look like it is made of sheet metal. Some profiles have a series of notches or grooves that make the part look like it was hot forged or extruded, but this is not the case. This is a profile made using a cold forming process on a roll forming machine, a technology that Welser Profile’s European enterprises have perfected and patented in the US and other countries. He applied for his first patent in 2007.
“Welser holds patents for thickening, thinning and cold forming grooves in profiles,” Johnson said. “It’s not machining, it’s not thermoforming. Very few people in the US do it, or even try.”
Since profiling is a very mature technology, many do not expect to see surprises in this area. At FABTECH®, people smile and shake their heads when they see extremely powerful fiber lasers cutting at breakneck speed or automated bending systems correcting material mismatches. With all the advances in these manufacturing technologies in recent years, they were expecting a pleasant surprise. They didn’t expect roll forming to surprise them. But, as the engineers’ “show me flowers” statement suggests, profiling still exceeds expectations.
In 2018, Welser entered the US market with the acquisition of Superior Roll Forming in Valley City, Ohio. Johnson said the move is strategic, not only to expand Welser’s presence in North America, but also because Superior Roll Forming shares many of Welser’s cultural and strategic visions.
Both companies aim to conquer specialized areas of the cold rolling market with few competitors. Both organizations are also working to meet the industry’s need for lighter weight. Parts need to do more, be stronger and weigh less.
Superior focuses on the automotive sector; while both companies serve a wide range of customers, Welser focuses on other industries such as construction, agriculture, solar and shelving. Light weight in the automotive industry has always focused on high-strength materials, which is also an advantage of Superior. The relatively simple geometry of a bent profile goes unnoticed until engineers see the strength of the bent material. Superior engineers often develop part programs using materials with a tensile strength of 1400 or even 1700 MPa. That’s almost 250 KSI. In Europe, Welser Profile engineers also addressed the issue of lightness, but in addition to using high-strength materials, they also addressed it with complex moulding.
Welser Profile’s patented cold forming process is suitable for low strength materials, but the geometry created by the roll forming machine helps to reduce the weight of the entire assembly. The geometry can allow the profile to perform multiple functions while reducing the number of parts (not to mention the money spent on production). For example, profiled grooves can create interlocking connections that eliminate welding or fasteners. Or the shape of the profile can make the whole structure more rigid. Perhaps most importantly, Welser can create profiles that are thicker in some places and thinner in others, providing strength where needed while reducing overall weight.
Traditional shaping engineers and designers follow a decade-long processability rule: avoid small radii, short branches, 90-degree bends, deep internal geometries, etc. “Of course, we always had a tough 90s,” Johnson said.
The profile looks like an extrusion, but it is actually cold-formed by Welser Profile.
Of course, engineers demand that roll forming machines break these rules of manufacturability, and this is where the tooling and engineering capabilities of the roll shop come into play. The further engineers can advance the process (forming denser 90-degree, deeper internal geometries) while minimizing tool costs and process variability, the more competitive a roll forming machine will be.
But as Johnson explains, cold forming in a rolling mill is much more than that. This process allows you to get part profiles that most engineers would not even consider using profiling. “Imagine a strip of sheet metal that has gone through the rolling process, maybe 0.100 inches thick. We can make a T-slot in the bottom center of this profile. must be hot rolled or machined depending on tolerances and other part requirements, but we can easily roll this geometry.”
The details behind the process are the property of the company and Welser does not disclose the flower pattern. But Johnson outlines the rationale for several processes.
Let us first consider the embossing operation on a stamping press. “When you compress, you also stretch or compress. So you stretch the material and move it to different areas of the tool [surface], just like you fill in radii on a tool. But [in profiling] This cold forming process] is like for filling radii on steroids.”
Cold working does strengthen the material in certain areas, this can be engineered to the advantage of the designer. However, the profiling machine must also take into account these changes in material properties. “You can see a significant increase in performance, sometimes up to 30 percent,” says Johnson, adding that this increase should be built into the application from the very beginning.
However, the cold forming of Welser Profile may involve additional operations such as stitching and welding. As with conventional profiling, piercing can be done before, during, or after profiling, but the tools used must take into account the effects of cold working throughout the process.
The cold-formed material at Welser Profile’s European facility is nowhere near as strong as the rolled high-strength material at its Superior, Ohio facility. Depending on the application, the company can produce cold forming material at pressures up to 450 MPa. But it’s not just about choosing a material with a certain tensile strength.
”You can’t do that with high-strength, low-alloy materials,” Johnson said, adding, “We often like to use micro-alloyed materials, which help prevent breakage. Obviously, material selection is an important part.”
To illustrate the basics of the process, Johnson describes the design of the telescoping tube. One tube is inserted inside the other and cannot rotate, so each tube has a ribbed groove at a specific location around the circumference. These are not just stiffeners with radii, they cause some rotational play when one tube enters another. These tight tolerance tubes must be accurately inserted and retracted smoothly with little rotational play. In addition, the outer diameter of the outer pipe must be exactly the same, without formwork protrusions on the inner diameter. To this end, these tubes have real grooves that at first glance appear to be extruded, but they are not. They are produced by cold forming on roll forming machines.
To form grooves, the rolling tool thins the material at specific points along the circumference of the pipe. The engineers designed the process so that they could accurately predict the flow of material from these “thin” grooves to the rest of the pipe’s circumference. The material flow must be precisely controlled to ensure a constant pipe wall thickness between these grooves. If the pipe wall thickness is not constant, the components will not nest properly.
The cold forming process at Welser Profile’s European rollforming plants allows some parts to be made thinner, others thicker, and the grooves to be placed in other places.
Again, an engineer looks at a part and might think it’s extrusion or hot forging, and that’s a problem with any manufacturing technology that defies conventional wisdom. Many engineers did not consider developing such a part, believing it would be too expensive or impossible to manufacture. In this way, Johnson and his team are spreading the word not only about the capabilities of the process, but also about the benefits of getting Welser Profile engineers involved in profiling early in the design process.
Design and roll engineers work together on material selection, strategically selecting thickness and improving grain structure, partly driven by tooling, and exactly where cold forming (i.e. thickening and thinning) occurs in flower formation. complete profile. This is a much more complex task than simply connecting the modular parts of a rolling tool (the Welser profile uses almost exclusively modular tools).
With over 2,500 employees and over 90 roll forming lines, Welser is one of the largest family owned roll forming companies in the world, with a large workforce dedicated to tools and engineers using the same tools that have been used so far. for many years Die library. Profiling over 22,500 different profiles.
“We currently have over 700,000 [modular] roller tools in stock,” Johnson said.
“The plant builders didn’t know why we were asking for certain specifications, but they met our requirements,” Johnson said, adding that these “unusual adjustments” at the plant helped Welser improve its cold forming process.
So, how long has Welzer been in the steel business? Johnson smiled. “Oh, almost always.” He was only half joking. The foundation of the company dates back to 1664. “Honestly, the company is in the steel business. It started as a foundry and started rolling and forming in the late 1950s and has been growing ever since.”
The Welser family has run the business for 11 generations. “The chief executive officer is Thomas Welser,” Johnson said. “His grandfather started a profiling company and his father was actually an entrepreneur who expanded the size and scope of the business.” Today, the annual income worldwide exceeds $700 million.
Johnson continued, “While Thomas’ father was building the company in Europe, Thomas was really into international sales and business development. He feels like this is his generation and it’s time for him to take the company global.”
The acquisition of Superior was part of this strategy, the other part was the introduction of cold rolling technology to the US. At the time of writing, the cold forming process takes place at Welser Profile’s European facilities, from where the company exports products to global markets. No plans to bring the technology to the US have been announced, at least not yet. Johnson said that, like everything else, the rolling mill plans to expand capacity based on demand.
The floral pattern of the traditional roll profile shows the stages of material formation as it passes through the rolling station. Because the details behind Welser Profile’s cold forming process are proprietary, it does not produce floral designs.
Welser Profile and its subsidiary Superior offer traditional profiling, but both specialize in areas where specification is not required. For Superior, this is a high-strength material, for Welser Profile, the molding is a complex shape that in many cases competes not with other rolling machines, but with extruders and other special production equipment.
In fact, Johnson said his team is pursuing an aluminum extruder strategy. “In the early 1980s, the aluminum companies came into the market and said, ‘If you can dream it, we can squeeze it out.’ They were very good at giving the engineers options. If you can just dream about it, you pay a small fee for the tooling. We can produce it for a fee. This frees up engineers because they can literally draw anything. Now we are doing something similar – only now with profiling.
Tim Heston is Senior Editor of FABRICATOR Magazine and has been in the metal fabrication industry since 1998, starting his career with the American Welding Society’s Welding Magazine. Since then, he has handled the entire process of metal fabrication, from stamping, bending and cutting to grinding and polishing. Joined The FABRICATOR in October 2007.
FABRICATOR is the leading stamping and metal fabrication magazine in North America. The magazine publishes news, technical articles and success stories that enable manufacturers to do their job more efficiently. FABRICATOR has been in the industry since 1970.
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Post time: Aug-22-2023