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Warped Parts Cause Rework And Scrap

March 2013

Mayville Engineering Co. (MEC) calls itself the go to company and the one stop shop for cost effective fabrication, quality manufacturing and complex assembly.

With capabilities that include metal cutting and forming, stamping, machining, tube forming, welding, painting and assembly, there’s no manufacturing process it seems it can’t do.

But being able to do all types of manufacturing also brings problems: parts that can be challenging to build. And some of these types of parts were ones that needed flattening. This challenge, however, brought a unique solution.

Deeming itself a contract manufacturer, Mayville Engineering Company, Inc. is 100 percent employee owned and has 16 facilities. It’s the parent company to six divisions: MEC Shotshell Reloaders, MEC Contract, MEC Prototype/Service, Phoenix Coaters, Fabricating Specialists and Center Manufacturing. MEC Shotshell Reloaders is the company’s own product line for reloading shotgun shells.

MEC provides a broad range of prototyping, product manufacturing, production fabricating, coating and assembly services to companies that include: commercial vehicle, agricultural, construction, military, recreational, power sports, medical and industrial. Along with process engineering and development services, MEC offers conventional and CNC stamping, shearing, sawing, laser, plasma, forming, drilling, tapping, grinding, tube bending, machining, welding, assembly and logistic services. MEC also offers finishing capabilities including shot blasting, e-coating, powder coating, wet spray and military grade chemical agent resistant coating painting.

“We do tiny stampings that are smaller than a dime up to 24-ft.-long frame weldments used as a base for diesel engines that run power plants. So we have a very wide gamut of parts that we produce,” says Kevin Smith, manufacturing engineering manager.

Smith manages MEC’s manufacturing engineering group. “We are responsible for launching and sustaining all the company’s products throughout their lifecycle.”

Although MEC is primarily a contract manufacturer using its customers designs, engineers at the company usually develop a design for manufacturing process with their customer’s product to optimize the production of the part while looking to reduce costs.

“We want to give them a good, robust product, and make sure that the product that’s designed will work for them while meeting the customers cost goals,” notes Smith.

Flat parts

Smith says that the company was experiencing problems with parts that weren’t flat that could often cause downstream problems for welding or bending.

“We’ve had a straightener here for over 20 years, but could only handle up to 0.25-in.-thick material by 24 in. wide. For a lot of our small stampings, which was part of our core business 10 years ago, that capability was fine. We could stamp out all types of parts in the flat and run them through the straightener and meet our customer’s requirements for the most part.

“However, in the last five to 10 years we’ve been growing the size of our products. We process a lot more material now that’s over 0.25 in. thick and with a larger overall part size. If these parts didn’t meet our flatness requirements, we were having to use more labor intensive processes to straighten them. This included either setting up a punch press and flattening them, or bumping them in a brake press. Or in certain cases, just living with the out of flatness,” remarks Smith.

With MEC’s lasers, plasma and punch presses there are certain things that could be happening to get an uneven part, says Smith. The raw-sheet material can have some variance in it. It might have a small crown, or it could be rolled on the edges. Also when parts are cut using heat, the sheet might buckle or warp.

“You can start out with a flat sheet and then end up with a portion of your parts with some bow in them. All of which needs to be corrected,” says Smith.

Smith decided that it was finally time to find another piece of equipment to solve MEC’s problem.

Looking for a solution

“As a company we typically do our due diligence to look at various manufacturers’ equipment before we purchase anything,” he says.

“We look at the various technologies because it’s always changing. You ask questions and search the Internet. ARKU’s Flatmaster seemed to be at the top of the list as far as anything that we could find for a straightener/leveler. We started with them. But we really couldn’t even find any other competitive companies that were producing this type of equipment that was specific to the application we wanted. It was usually modifying some other equipment to do what we needed. So they were really one of the only ones that offered a product line that met our needs,” he adds.

Smith says that they saw the machine in operation through a video and talked to several of ARKU’s customers, but didn’t make any trips to see the equipment actually operating.

“ARKU does contract manufacturing for flattening parts and we had been sending them different parts to see the capabilities of the Flatmaster. So we knew what the parts were before they would straighten them for us. This allowed us to validate the performance of the equipment. We did this on a wide cross-section of parts,” he adds.

Although Smith says that they had an immediate need for the equipment, they still had to justify it. They did an analysis that reviewed how many of their customers’ parts needed flattening, and how much money it would save them to get a ROI.

Greater capabilities

With the purchase and use of the ARKU Flatmaster, Smith says that they have gained the capability to flatten thicker parts along with larger parts, as their old straightener was limited in both areas. They can also flatten materials like high-strength steels that they couldn’t before.

“Now we flatten parts to meet our customers’ specifications and help current processes that can’t keep a part as flat as what is specified (such as laser or plasma cutting that might warp the flat part). This also helps us with other downstream processes.

“We have more automated processes than we used to, such as robotic welding machines, programmable press brakes and robot tended press brakes. The key to robot handled parts is having good, consistent parts. When we have varying part flatness, we have to accommodate this with other things such as vision systems and touch sensing for our robots, which all add significant time and higher dollar equipment for this gear,” Smith mentions.

By having parts come flat to the post process operations, Smith gets much better repeatability along with a lot less rework while gaining more capacity especially on the higher dollar, higher value equipment.

“This inconsistency factor is what really kills us when we’re trying to process parts downstream. Getting them all back to flat is why we bought the ARKU flat master,” he says.

Parts that MEC is now robotically welding are in the 0.375 in. to 0.5 in. thickness range. The ARKU Flatmaster that MEC purchased is capable of handling up to about 0.5 in. thick material.

“The time savings of just running the material through the straightener and getting the proper consistency is where the payback is for us,” concludes Smith.

ARKU’s Flatmaster

ARKU
Mayville Engineering Co. Inc.

ARKU Coil Systems is the US subsidiary of ARKU Maschinenbau GmbH in Baden-Baden, Germany. ARKU has been in business since 1928 and is a leader in leveling technology. The company offers the widest range of precision and high capacity levelers. In addition to its headquarters located in Baden-Baden, Germany, ARKU has subsidiaries in Cincinnati, OH and in Kunshan, China and a comprehensive network of worldwide distributors.

The company manufactures levelers for flatening sheet metal parts and coil strips. All manufacturing is done in Germany, but it sells and services its levelers worldwide. ARKU has over 140 highly skilled employees. Albert Reiss owns and manages the traditional family enterprise in third generation.