In fact, this piece does not seem to be made of sheet metal at all. Some profiles have a series of notches or grooves. These shapes make the part look like a hot forged or extruded part, but it is not. It is a profile created by a cold forming process on a roll forming machine, and the European business of Welser Profile has perfected and protected the technology through patents in the United States and other regions. It applied for its first patent in 2007.
Johnson said: “Welser has patents for thickening, thinning and slotting profiles through cold forming.” “This is not machining, nor is it thermoforming. In the United States, even if there are any attempts or attempts, there are very few.”
Since roll forming is a very mature technology, it is not an unexpected area that many people want to see. On FABTECH®, people smile and shake their heads when they watch an incredibly fast cutting super-powered fiber laser or an automatic bending system that corrects material inconsistencies. Considering all the advancements made in these manufacturing technologies in recent years, they hope to be surprised. They don’t want to be surprised by roll forming. But as the “show me flowers” statement made by the engineer shows, roll forming still cannot meet people’s expectations.
In 2018, Welser acquired Superior Roll Forming in Valley City, Ohio, to enter the US market. Johnson said that this move is of strategic significance, not only to increase Welser’s business in North America, but also because Superior Roll Forming has many of Welser’s cultural and strategic views.
Both companies are committed to solving areas of expertise in the molding market that are not crowded with competitors. These two organizations are also committed to addressing the industry’s lightweight needs. The parts need to be made more, stronger, and lighter.
Superior focuses on the automotive sector; although both companies provide services to many customers, Welser has always focused on other industrial applications, such as construction, agriculture, solar energy and shelving. Lightweight in the automotive field has always been focused on high-strength materials, which has always been the best choice for Superior. It was not until engineers saw the strength of the rolled material that the relatively simple geometric shape of the rolled profile attracted attention. It is not uncommon for Superior engineers to develop part programs involving materials with tensile strengths of 1,400 or even 1,700 MPa. It’s almost 250 KSI. In Europe, Welser Profile engineers are also facing the challenge of lightweight, but in addition to using high-strength materials, they also solved this problem through complex molding.
Welser Profile’s patented cold forming process can be processed with lower-strength materials, but the geometry of the rolling mill helps reduce the weight of the entire assembly. Geometry allows the contour to have multiple functions, thereby reducing the number of parts (not to mention the dollars spent on production). For example, roller grooves may form interlocking joints, eliminating welding or hardware. Otherwise, the shape of the contour may make the overall structure hard. Perhaps the most important point is that Welser can create thicker contours in certain areas and thinner contours in other areas to provide strength where needed while reducing overall weight.
Those who engineer and design for conventional roll forming abide by decades of manufacturability rules: avoid tight radii, short legs, 90 degree bends, deep internal geometries, etc. Johnson said: “Of course, we will always form the 90s.”
The profile looks like an extruded part, but it is actually rolled by the cold forming process of Welser Profile.
Engineers of course require rolling mill manufacturers to break these manufacturability rules, and this is where the tools and engineering capabilities of the roll forming shop come into play. Engineers can push farther processes (to form tighter 90 degrees, deeper internal geometries) while minimizing tool costs and process variability, making the calender more competitive.
But as Johnson explained, the significance of cold forming on a roll mill is much more than that. Most engineers don’t even think of the contours of the parts produced by this process to be shaped at all. “Imagine a metal plate with a thickness of about 0.100 inches, which has undergone a roll forming process. We can create a T-slot at the bottom center of the profile. Most people would say that it can only be extruded. And, If you need to make it into carbon steel, it must be hot rolled or machined according to tolerances and other parts requirements. But we can easily roll it into this geometry.”
The details behind this process are proprietary and Welser will not release flower patterns. But Johnson did describe several process foundations extensively.
First, consider the stamping operation on the press. “As you compress, you are also stretching or shrinking. Therefore, you need to pull the material out and move it to different areas of the tool [surface], just like filling in the radius on the tool. But [this kind of on the roll The cold forming process in compression molding] is like filling a radius on steroids.”
Cold working does harden the material in certain areas, which can be engineered to benefit the designer. In other words, roll forming settings must also consider the changes in these material properties. Johnson said: “You will see a lot of work hardening, sometimes an increase of 30%,” he adds that this increase needs to be designed into the application from the beginning.
Even so, the roll forming application of Welser Profile in cold working can incorporate auxiliary operations such as perforation and welding. Like in traditional roll forming, perforation can occur before, during or after the roll forming itself, but the tools used do need to adapt to the cold working effect throughout the process.
The material cold formed at the Welser Profile plant in Europe is not as strong as the high-strength material rolled at the Superior plant in Ohio. The company cold-forms the material to approximately 450 MPa depending on the application. However, it is not only necessary to select materials with certain tensile strength.
Johnson said: “You can’t do this on high-strength, low-alloy materials,” he added, “We often like to use microalloy materials, which help prevent cracking. Obviously, material selection is an important part of the process. .”
To illustrate the basics of the process, Johnson describes a telescopic tube project. One tube is nested in another tube and cannot be rotated, so each tube has a ridge groove at a specific location on the circumference. These are more than simply reinforcing ribs with radius. After one tube is nested in another tube, some rotational movement is caused. These tight tolerance pipes need to be accurately nested and stretched smoothly, with almost no rotation gap. In addition, the OD of the outer tube must be exactly the same, and the shape of the ID must not have protrusions. For this reason, these tubes have actual grooves that appear to be squeezable at first glance, but they are not. They are cold formed on a roll forming machine.
To create grooves, the rolling tool thins the material at specific points along the circumference of the tube. Engineers design the process in such a way that they can accurately predict the material flow, away from those “tapered” grooves and toward the rest of the pipe. The material flow must be precisely controlled to form a consistent wall thickness between these grooves. If the tube wall thickness is not consistent, the components will not be nested together as designed.
The cold forming process in Welser Profile’s European roll forming operation can thin some parts, thicken others and place grooves in other locations.
Once again, taking a glance at the part, the engineer might think that it is extrusion or hot forging, which poses a challenge for any manufacturing technology that violates conventional wisdom. Many engineers will not consider designing such a part, but think it is too expensive or impossible to manufacture. As a result, Johnson and his team are spreading the word, which is not only about the capabilities of the process, but also about the benefits of involving the roll forming engineers of Welser Profile in the early design phase of the project.
Design and rolling engineers work together to strategically select thickness and refined grain structure in material selection, which is driven to a certain extent by the tool part, and when the flower is formed, cold forming is exactly performed ( (Ie thickening and thinning) complete personal data. This is more than just piecing together the modular parts of the scrolling tool (and Welser Profile almost exclusively uses modular tools), it is much more complicated than the puzzle.
Welser has more than 2500 employees and more than 90 roll forming lines. It is one of the largest family-type roll forming machines in the world. It employs a large part of the labor force in mold production. Only the engineer works with the mold library. Over the years, the roll has formed more than 22,500 different profiles.
Johnson said: “Currently, we have more than 700,000 (modular) roll molds in our inventory.”
Johnson said: “The roll forming machine manufacturers don’t know why they require certain specifications, but they must comply with our requirements.” He added that the “abnormal adjustments” in the rolling mill helped Welser improve its cold roll forming process.
So, how long has Welser worked in the metal industry? Johnson smiled. “Oh, almost the entire time.” He was just joking. The establishment of the company can be traced back to 1664. It started in a foundry and rolled sheet products in the late 1950s and has been developing ever since. ”
The Welser family has owned the business for 11 generations. Johnson said: “The chief executive officer is Thomas Welser.” “His grandfather began to work in roll forming at the company. His father was indeed an entrepreneur. He expanded the scale and scope of his business.” Today, the world. Annual revenue exceeds 700 million US dollars.
Johnson continued: “When Thomas’ father established the company in Europe, Thomas was truly involved in international sales and business development. He felt that this was his generation and when he made the company global.”
The acquisition of Superior is part of this strategy. The introduction of cold-formed roll forming technology to the United States is another part. At the time of writing, the cold forming process takes place in the European operations of Welser Profile, exporting from the company to the world market. No plans have been announced to bring the technology to the US market, at least not yet. Johnson said that, like anything else, the roll forming machine plans to expand production capacity based on demand.
The flower pattern of the conventional roller profile shows the forming stage of the material as it passes through the roller station. Since the details behind the cold forming process of Welser Profile are proprietary, it will not release flower patterns.
Both Welser Profile and its Superior subsidiary provide conventional roll forming, but both tend to focus on areas that do not require regulation. For Superior, it is a high-strength material; on the Welser Profile, the forming process is very complicated. In many cases, they do not compete with other rolling mills, but with extruders and other manufacturing specialties.
In fact, Johnson said that his team is paying attention to the manual for the aluminum extrusion press. “In the early 1980s, aluminum companies entered the market and said:’If you can dream, we can squeeze it out.’ They are very good at providing engineers with options. If you just dream of it, then we will do it for you Pay a small fee for tools. It gets rid of the shackles of engineers because they can indeed draw almost anything. Now, we are doing something similar-only now, in roll forming.”
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Post time: Sep-25-2020