Automated Brush Deburring Results in Productivity, Safety Benefits
HHI Forging uses automated deburring process with Weiler brushes for high-volume production of transmission parts
|An example of a Weiler brush being used to deburr a transmission component in an automated setup. In recent years, HHI has seen productivity and quality gains by implementing deburring automation processes.|
As the largest supplier of forged and forged/machined steel components in North America, HHI Forging produces wheel-end, transmission, drivetrain, and steering and suspension components for customers such as General Motors, Ford, Chrysler, Toyota, Honda and Harley-Davidson.
HHI has the capacity to do high-, mid- and low-volume production at its nine forging locations, two machining plants and the two other production divisions that fall under the umbrella of HHI Group Holdings, a company with nearly 3,000 employees.
“We’re 80 percent automotive. We have some of the higher volume forging capabilities, so we have very competitive pricing,” says Christopher Bass, an application engineer who has been with HHI eight years and worked in CNC machining for 35 years. “People do business with us because of the quality of the tooling we build, our quality systems and our capabilities.”
With annual production volume of 500 to 600 million pieces, HHI needs reliable processes and equipment to help meet the output and quality demands of its customers. That customer-driven demand for quality includes the necessity to deburr the parts HHI produces, and the company in recent years has seen productivity and quality gains from the addition of automated deburring processes in some facilities.
The CNC turning process HHI uses in production generates small burrs — raised edges or pieces of material often as small as two-thousandth to five-thousandth of an inch thick — inside many of the parts. The process of deburring removes these pieces and smooths out rough edges or ridges.
Customers provide specific instructions to HHI on the deburring of their parts. A contract may require no sharp edges larger than a specific size or no burrs at all, for example.
“We have to get in there and ensure with our process that we remove every burr we generate. You look at the quality, and that’s the critical part,” Bass says. “The parts we’re generating are inside the transmission housing, so if burrs are breaking off, they can be a catastrophic failure for that transmission. You cannot have any burrs in a transmission.”
A look at automated deburring
During a visit to the HHI Cloyes division in Arkansas in 2011, Bass noticed that facility had a piece of equipment that was automatically filing the burrs off parts. Cloyes had previously used a manual deburring process before switching to automated deburring.
The automated deburring offered such consistency, speed and improvements in employee safety through reduced fatigue and repetitive motion that Bass knew it was the best solution for HHI to use in the manufacture of a new product. Bass saw an opportunity to implement automated deburring when HHI began production of multispeed transmission parts for a large transmission customer.
“When you automate and put it in a production line, you’re pretty much guaranteed it’s going to get deburred, so it’s a more controlled process,” he says. “We looked at the process; we’ve never made this type of part before. We realized an automated system would ensure a more robust process and the quality of deburring would be better. We never even considered manual for this product.”
The automated deburring system used at the Cloyes production facility came from Cleveland Deburring Machine Company (CDMC), so Bass approached that company about designing and creating deburring equipment for the two HHI machining facilities in Bolingbrook, Illinois, and Fraser, Michigan, that would be making the transmission parts.
Those type of parts, asymmetrical with teeth and castellations on them, are harder to deburr by hand, especially in a high-volume production situation. The ability to automate the process reduces fatigue and wear and tear on employees, so it benefits safety along with productivity.
“When you’re doing the high volume we have, you have to have a consistent system that you can rely on,” Bass says.
The automated brush deburring solution
CDMC designs and manufactures automated deburring equipment for many big players in the industry, typically creating 25 to 35 custom deburring systems each year for customers. The company frequently uses Weiler brushes in its equipment and deburring applications, including the equipment it created for HHI.
For HHI’s needs in this case, CDMC determined a brush made from ceramic material would provide the lowest cycle time. Weiler offers both high quality and a wide range of brush types, styles and materials, including many brushes with ceramic materials, so Weiler brushes were a natural choice for this system.
“A lot of other companies aren’t using the ceramic materials yet. Weiler is progressive in making more brushes available in that aggressive cutting media,” says Eric Mutschler, vice president of sales for CDMC. “They provide a nice variety of brushes, so we are better able to apply their products to meet our customers’ specific needs.”
CDMC and Weiler also worked in tandem to make any adjustments to the brushes used in the deburring system, to make sure the machine was exactly what HHI needed for this process.
“Weiler is very willing to work with us and design brushes to optimize our system performance,” Mutschler says. “They’re very responsive and supportive of our requirements.”
At HHI, about 10 to 15 percent of the products machined in-house require automated deburring. Of those, the majority are using a deburring process with brushes — mostly Weiler brushes, Bass says.
“The Weiler technical support has been wonderful. They spend time on our production floor, watch the process and give us feedback on enhancements to improve productivity,” Bass says. “They listen to our concerns and respond.”
The two lines that use the automated brush deburring process — in place for about two years now — at HHI’s facilities in Bolingbrook and Fraser each produce about 700,000 units annually. That’s full production of three shifts a day, five days a week.
“We do know if you considered doing it manually, that wouldn’t be successful. This type of product — when you have irregular surfaces or shapes — to consider doing it manually would be ludicrous,” Bass says.
The automated deburring equipment used by HHI has multiple stations and tools that run simultaneously, so three or four brushes hit different parts of the burr at the same time. The parts are put into one end, and they come out the other end complete and deburred.
“So every 10 seconds you index a complete part,” Bass says. “The operator never has to intervene. We want the workers to worry about the process as a whole, not to worry specifically about deburring.”
The brush life is metered based on amperage draw from the motors. When the machine starts to draw more current because the brush is wearing and it takes more effort to remove the burr, it’s time to change out the brush.
“The wheels are quick changeovers typically, in and out in a matter of minutes,” Bass says. “The Weiler group went to our facilities, worked with our engineers to make sure we got the best wheel for performance and tool life.”
It’s also key to monitor tool life upstream in the process, otherwise when tooling is allowed to wear too long upstream, the burrs can get too large to be removed under the parameters set for the automated brush deburring process. The expected size of the burrs to be removed is what determines the type and size of brush used in deburring.
“You’re metering tool life, metering brush life,” Bass says. “It’s a living cell, things are always happening, and it’s up to the operator to be aware of it all.”
Quality and safety benefits
Anytime that rotating tools are used in production, safety issues can be a concern. The self-contained automated deburring units used by HHI remove that issue from the equation, with the operator safely standing away from the process.
“When you look at it from an ergonomics standpoint and an operator safety standpoint, it’s just tenfold the savings,” Bass says. “You take all of that out of the equation.”
The quality control of the deburring, the productivity and throughput gains that result from the automation, and the increased safety and reduced fatigue for employees, make the system an investment that has paid off for HHI.
“To me, the difficulty of the part you’re deburring and the volume of parts you’re going to handle are the big issues to consider,” Bass says. “Then look at man versus machine, the wear and tear.”
An automated deburring process will always be the first option for consideration in future production opportunities for HHI.
“We see transmission components as being a big part of our opportunities going forward,” Bass says. “If we are awarded more components that require deburring, then we will stay with automating.”