Despite life’s many uncertainties, there are a few things we can be sure of – the sky is blue, water is wet and stamping presses are designed to work with flat, consistent material. When material is fed into a machine that hasn’t been straightened, the ensuing issues can be incredibly costly.
Anyone in the stamping business knows all too well that uneven material can cause a host of headaches, including misfeeds and poor positioning. These feeding and alignment issues force operators to stop what they’re doing to clear jams, readjust their setups and rerun parts. On top of that, the parts that make it through can be warped and distorted, which opens up an entirely new set of issues.
But that isn’t even taking into account the worst-case scenario: when dies crash. If misaligned material binds or buckles in the die, it can jam and cause catastrophic damage. Adding insult to injury, excessive forces caused by unstraightened material can affect ram alignment and overall press performance.
At the core of it all is a lot of downtime, unwanted scrap and unhappy customers. To avoid those outcomes, Dimeco, a French manufacturer of press feed lines, coil processing equipment and material handling systems, developed a software system to help customers consistently produce straight material to keep their operators on task, quality high and customers coming back.
A material shift
Twenty years ago, when Dimeco first embarked on the development of its software system, the industry was faced with a new reality – one with a larger range of material thicknesses and more advanced grades of steel. Its customers were also just beginning to feel the labor pains created in part by the retirement of the baby boomer generation that is still prevalent today.
Working closely with its customers, Dimeco realized that the growing material mix was creating a dual challenge for coil-fed operations: correcting strip defects related to coil winding without overly compromising formability, that is, controlling elastic springback without causing tearing during stamping. According to Sylvain Touboul, sales manager at Dimeco, this new challenge was put under a spotlight by a customer attempting to straighten thin high-tensile-strength steel.
“In 2005, we sold a machine to an integrator and long-time partner based on the historical models that we’d always used for mild steel in the past,” Touboul explains. “We were provided with the material thickness, width, yield and tensile strength and used a simple, straightforward calculation to straighten the material.
“The machine was shipped overseas, installed and running production work – until it got to the thinnest material,” he continues. “Back then, formulas were based on long-running experience, but materials were becoming more and more complex by the day. That’s when we knew we needed to develop a software system that could help.”
Knowing its own strengths and weaknesses, Dimeco, whose strengths lie in machine building, decided to reach out to a technological center in France for its software development expertise. “We’re a small company, so it would have taken us forever to develop it on our own.” Within three years, the desired software was ready for use – for the company’s internal sales team and for its customers.
The resulting software provides Dimeco and its customers with a comprehensive material database that considers yield strength, tensile strength and beyond for straightening a range of metals, which can be cross-referenced with Dimeco’s machine database. The software also generates straightening diagrams based on a material’s properties to provide operators with the optimal roll position settings to achieve flat material. It also offers dynamic roller adjustments to compensate for coil diameter changes during processing.
Internal use
Considering Dimeco has an extensive library of standard equipment and also produces custom solutions, there is a lot to choose from. The company’s software, however, can help its sales team narrow down machine options for customers. When a potential customer is vetting equipment, it can be as easy as providing a Dimeco sales rep with a list of material characteristics. These characteristics – thickness, coil width, tensile strength, etc. – are entered into the software’s material database, which then pairs it with a list of Dimeco machines that will work. Machines that are an acceptable match will be listed in green.
“And, when a potential customer processes a variety of materials – everything from thick aluminum with a narrow coil width to thin mild steel with a standard width – it’s just a matter of entering those properties into the software, as well,” Touboul says. “We can upload information for multiple materials into the software, which will prompt the software to further narrow down the list of machines that will fit their needs.”
When it comes to making a machine decision, customers can also provide Dimeco with the amount of plastic deformation they can tolerate. Plastic deformation is the permanent change in shape that occurs when a material is stressed beyond its elastic limit – with “permanent” being the key word.
on display, such as this straightener.
Compared to elastic deformation where the material returns to its original shape after stress is removed, plastic deformation leaves material permanently bent, stretched or compressed as found with coil material. Straighteners, therefore, rely on inducing controlled plastic deformation to remove residual stresses and ensure the strip stays flat and dimensionally stable – which stamping presses need to function properly.
When it comes to plastic deformation of the material, there is a rate given between 0 and 100 percent; the higher it is, the more stress the customer needs to remove from the material. With Dimeco’s software, customers are provided with a range of percentages each type of equipment can achieve. This, too, can be taken into account when making a purchase decision.
Customer benefits
While Dimeco’s software is incredibly helpful during the purchasing process, it is also helpful for pre-existing customers. Post-equipment purchase, it isn’t uncommon for customers to reach out to Dimeco when they’re presented with the opportunity to process a new material.
“Customers can call us at any time when they need to process a new material,” Touboul says. “We simply plug the material’s properties into the software to determine if it’s possible to process on their current equipment.”
But the software isn’t just helpful when it comes to choosing equipment or making sure that equipment already on the shop floor can handle new material. It’s also incredibly helpful when it comes to the actual straightening process that operators are responsible for every day.
Every time a coil is changed, adjustable rollers are used in coil straighteners and levelers to achieve the flat, uniform material needed for stamping operations and other downstream processes. But, if they aren’t set up correctly, strip defects, springback and issues related to plastic deformation will rear their ugly heads. With machine operators responsible for this task and with an ever-increasing skills gap, the team at Dimeco recognized a growing need for help.
“Some of the historical knowledge in the industry has disappeared,” Touboul says. “We have a lot of customers that have our machines, which are working perfectly, but they don’t know how to use them. Not only can we train these customers and provide them with the information they need to adjust the rollers in the straightening equipment, but we can also quickly upgrade a machine or propose another newer machine that can automatically make those adjustments.”
These roller adjustment guidelines are available on the machine’s control panel where operators only need to input the material’s basic parameters. The settings can then be saved as recipes for quick recall on repeat jobs.
Having the specific settings saved and easy to recall speeds up the process while also reducing the reliance on the operator’s skill level or experience.
“For manual adjustments, the software provides operators with a chart that identifies where to position the rolls for optimal straightening,” Touboul says. “The chart provides clear instructions for how to set the specific position for each roll. The goal is to make it incredibly easy for the operator to follow.”
Overall, everyone benefits. The easy-to-use instructions ensure that the material is properly straightened before entering tooling, which reduces the risk of material jamming or damaging expensive tooling. It improves part quality and consistency, dramatically reduces setup and changeover times, and extends tool life by ensuring proper material feeding.
As with any software, Dimeco is constantly making improvements and adding more materials as they are developed. And, as always, the company’s overriding goal is to ensure that its customers can be as productive and profitable as possible.
“Dimeco doesn’t just build machines for processing sheet metal from coils,” Touboul says. “We deliver complete solutions that guarantee perfectly flat material – and it stays that way – with optimal settings right from the very first part.
“Today, the real challenge in manufacturing isn’t just production,” he concludes. “It’s maintaining quality while skilled operators are becoming more rare and while materials are frequently changing. Every coil change can cost time, material – and profitability.”
