Dorel Juvenile Group in Columbus, Indiana, is the largest child car seat manufacturer in the world. The company’s 700 employees manufacture products sold under the Safety First, Costco and Eddie Bauer brands, and all molding is performed in the Columbus assembly plant on 68 injection molding machines.
“Three years ago, we had 89 injection molding machines,” said Gabe Revell, operations manager and continuous improvement manager. “A few years before that, we had 100 molding machines. Capacity wasn’t an issue, and our utilization numbers were less than 50 percent on every press category, so we didn’t worry about changeover.”
Over time, however, older equipment was phased out, and the facility began operating with fewer machines. Utilization climbed into the 80s and, rather than letting a mold sit in a press until it was needed again, changeovers happened with greater frequency – but, not much efficiency.
“Changeovers were taking us four to six hours,” explained Revell. “To do that changeover, we would schedule a machine for a full eight-hour shift. We realized we were doing about 130 mold changes a month, and that was leading to a lot of lost time. We set a goal to accomplish mold changeovers in one hour, part to part.”
QMC Consortium shares information, processes
At that same time, Troy Nix, executive director of Manufacturers Association of Plastics Processors (MAPP), called to see if Dorel Juvenile Group would be interested in taking part in a mold change consortium. “We said not only would we be interested in participating in it, we’d like to host it,” Revell explained.
The QMC Consortium consisted of 18 Indiana companies that were performing anywhere from five to 150 mold changes per week. The consortium defined a complete mold change as the amount of time consumed from the last good part of the old job to the first good part of the new job. The consortium members’ mold change times ranged from 30 minutes to six hours or longer, although the most common responses were in the range of 60 to 90 minutes.
The majority of companies participating in the consortium had timed the mold change process manually, half had value stream-mapped their processes to make improvements and nearly a third had videotaped their processes to identify opportunities for change.
That’s where Dorel Juvenile Group decided to start.
Dorel digs deep to find bottlenecks
“Once we agreed to host the consortium, we had a deadline to meet,” said Revell. “We felt one-hour mold changes were achievable without major investment, so the first thing we did was film a mold change.”
“It was terrible,” he admitted. “Watching a six-hour mold change is rough. We had to plug the camera in because a camera battery won’t last six hours, and at one point, the technician doing the change went to break. For 30 minutes, the press just sat there. It was excruciating.”
However, the exercise provided a place to start. A team from Dorel watched the film and listed the steps involved in the mold change. At the time, Dorel was using one technician per mold change, so as each step was done on one side of the injection molding machine, the technician then had to walk around to the other side of the press to perform the same operation. “It was grueling to watch,” Revell said, “but it was necessary for us to understand where the waste was happening.”
Uncovering the opportunities for improvement
During the QMC Consortium event, Dorel staff presented all the activities that happened during mold changes – the order of the steps, the time each step took, the personnel involved – and the consortium attendees critiqued the process. “We took that input,” said Revell, “and looked at how we could implement those ideas, but we also wanted to involve our mold change technicians in making changes to the process.”
Staff from Purdue University’s Manufacturing Extension Program (MEP) were present at the QMC Consortium, and, after talking with them, Dorel Juvenile Group contracted with the MEP to assist with training. “We went through an initial session that was a lean overview as it relates to changeover,” he said. “It was very focused on what has value and what’s non-value-added. Value is only found when the machine is running and making parts, so we made a list of changeover steps that could done outside of the machine stopping.”
The Purdue MEP consultants worked with the Dorel team to find solutions to objections and initial resistance. With input from those in the tool shop and maintenance shop, the changeover process was dissected step by step. Each time objections or concerns were raised by Dorel team members, those concerns were challenged until a resolution was achieved, and each person had direct input in finding ways to reduce mold changeover time. “The improvement team then trained their peers on the shift,” Revell explained.
“Bringing someone in from the outside to work with our team added credibility to what we were trying to achieve,” he said. “And, it was critical that this wasn’t an order that came down from the management staff. Our team came up with the solutions – the guys who were doing the work needed to understand where the problems were and then come up with the best ways to fix them. We wanted them to believe in what they were doing and understand how it adds value to them and their jobs. Not doing that is probably why weve had less success with similar efforts in the past.”
60-minute changeovers are in reach
The solutions were simple, but the impact has been immense. The mold changeover process at Dorel Juvenile Products was recently filmed again – in one hour and 20 minutes.
“First, we made some process improvements,” said Revell. “There were issues with scheduling, planning and sequencing, so we spent time really thinking about how we were doing things.”
Solutions included taking the mold to the press and having the crane ready before stopping the machine and having the tools press-side before beginning work. “These were simple things that the technicians didn’t really think about until they watched themselves do the changeover,” he added.
Another simple solution was implementing a two-person change. “We started understanding that two technicians are more than twice as fast as one technician once you remove the travel time around a machine,” he said.
From the mold improvement standpoint, Dorel Juvenile Group standardized the hookups for water and hydraulics. “We also bought eyebolts for every mold,” Revell explained. “It seems silly, but the amount of time people spent looking for an eyebolt for a mold was ridiculous. That was an idea that came out of the consortium, so we spent a few hundred dollars to make sure one was located with each mold.”
Revell acknowledged the company is still working on its one-hour goal, but he’s proud that Dorel Juvenile Group has made no major investments or equipment purchases to accomplish the improvements.
“Focusing on the process owners and engaging them in the solutions were the keys,” he said. “We could’ve gone out and bought tons of equipment and made huge investments, but if we didn’t change the technicians’ approach to the problem, it wouldn’t have changed anything.”
Additional Improvement Ideas Offered by QMC Consortium Participants
- Use two cameras to film a mold change, with one mounted above the press for additional visibility into the process.
- Dedicate tool carts specifically for mold changes.
- Bring mold and tools to the press prior to machine stoppage.
- Pre-dry material prior to changeover.
- Plumb all water-to-water manifolds on mold with only one direct water line to each manifold.
- Standardize clamps for all molds.
- Invest in technology such as magnetic platens, shuttles, hydraulic clamping systems and master unit die bases.