For many large manufacturers, material conveyance has been the “last mile” for automation. That’s been the case for Denso, a Tier 1 automotive supplier that manufactures products ranging from spark plugs to fuel injectors in its 800,000-square-foot powertrain component production facility in Athens, Tenn. A renewed emphasis on improving manufacturing efficiencies and profitability, combined with a tight labor market, brought automated conveyance to the forefront.
Denso turned to Mobile Industrial Robots (MiR) to automate material conveyance and is now running six MiR250 autonomous mobile robots (AMRs) through two production areas, including transport to and from the warehouse, to support line-side manufacturing and facilities and spare parts transport. The company also has five MiR500s for anticipated new business.
Inefficiency drove the move to AMRs
Like most manufacturers, Denso is always looking for opportunities to boost productivity and efficiency. “We knew we had a lot of people that were getting paid to move parts all day long, walking carts from one place to the other,” said Travis Olinger, logistics and automation engineer in Denso’s Total Industrial Engineering (TIE) group. “But if we have people that are only conveying parts, then that’s a non-value-added activity, and we had plenty of open jobs for value-added activities within the production environment. We wanted to pay people to make parts for us that make us money, and not pay them to move parts that cost us money.”
Research showed that Denso associates were walking up to 12 miles per day, moving material between production and the warehouse, and spending about 60% of their time just pushing carts. As the team explored options for automated conveyance, it quickly became clear that automated guided vehicles (AGVs) and their infrastructure requirements and costs couldn’t meet Denso’s needs.
“We’re an extremely dynamic environment,” said Olinger. “We didn’t want to have to go through that entire infrastructure change every time we moved something. The autonomous mobile robot was key to us: to be able to navigate on its own, with quick mapping, quick changes.”
In-house testing on warehouse production conveyance
The team brought MiR and other AMRs in-house for testing, using the spark plug production lines as a pilot area. The processes included moving empty totes to production and fully finished kit totes back to the warehouse.
“We set up a test course and we ran [the robot] through the wringer,” said Robert Blackburn, project leader. “We were able to throw different things at it, different challenges, and get user feedback.”
The MiR250 had recently been introduced, and the team was attracted to its 2-mps speed, the payload of 250 kg to handle heavy metal parts, and the ability to navigate narrow spaces.
“Honestly, my initial concern was safety,” said Danny Thompson, logistics associate. “A lot of people were worried about them running into stuff or hitting something. I was very surprised at how well they responded to anything stopped — traffic or things that have blocked their pathway. The robot’s able to communicate and move out of the way or make adjustments — or even come to a complete stop and allow the other foot traffic to continue on.”
REST APIs integrated disparate systems
MiR partner Advanced Control Solutions (ACS) helped develop the third-party integration necessary to work with the REST API calls along with Denso’s internal software to integrate with production.
“We use Fleet for our maps for all of our mission creation and our locations,” said Olinger. “But we also wanted to be efficient with some proximity cueing and to allow the associates themselves to call for the robots and prioritize in FIFO [firstin, first-out] order. Also, the REST APIs enabled us to manage charging.”
Denso can prioritize robots based on charging status and use a decision tree when a mission is finished. The system looks for other missions available, checks for adequate charge percentage, and sends robots to missions or to charge as appropriate.
Denso has also been able to integrate the robot to automatically open the door in and out of a clean-room area, using the MiR I/O modules to send wireless signals to Wise Modules in the roll-up door controller. Fleet zones automatically send the appropriate signals via the I/O module when the robot approaches the door.
Associates were the key to success
To prepare for the MiR robot implementation, the TIE team studied the workers in the area to understand exactly what the job entailed, what aspects of the job could be carried out by a robot (conveyance), and what parts of the job would need to remain with the associate. From there, work elements were transferred until all conveyance could be handled by one associate. That person acted as the robot during the research period.
“The associate level was very much involved throughout the implementation of the MiR robots,” said Blackburn. “Once we knew that they could handle all the robot elements, we knew that the robot could then take its place and become that associate. That’s how the transition took place.”
During that time, associates provided invaluable input and feedback to optimize the approach for better efficiencies. Associates are also very involved in the design of top modules for the robots.
“As we have designed those cart tops for different areas and different applications, the associates have been instrumental in those design processes because they’re handling those carts every day,” said Olinger. “From an ergonomic standpoint, we don’t just want to replace the conveyance and then shift that work onto someone else. They’re the experts. They’re the people handling the carts, they’re the people handling the parts. They are extremely helpful in those cart designs and making it a more efficient process.”
Standardizing on the MiR250 shelf lift and ROEQ carts allows Denso to expand quickly into other areas using the same cart base and customizing it for each use. As associates approach the engineering team with requests for automated conveyance, they can easily design racks around the carts, helping to free up space, increase flexibility, and gain the advantages of automated conveyance more quickly.
Those efficiencies now extend to other areas as well. The facilities maintenance crew purchased carts and now gets supplies delivered automatically from receiving.
AMRs created unexpected benefits
After the initial success of the warehouse and spark plug area, Olinger and Blackburn turned to work-in-process (WIP) conveyance and quickly expanded into the gasoline plant. An unexpected benefit was the alleviation of tensions around whether workers had delivered parts correctly, on time, and to the right place.
“Now, on both sides, everyone has accountability,” said Olinger. “We know what time parts were ordered, how many were ordered. We know what time it was completed, and when the robot picked it up. It took a lot of that tension away, and allowed departments to work together better, because all the information’s available.”
Results were immediate and ongoing with fast ROI
Denso’s ROI plans for projects are typically less than two years, but the indirect cost reduction specific to the MiR robots replacing conveyance achieved an ROI in a year or less. Within six months of the project launch, Denso was able to cover all finished kit lines in the ignition plant with AMR conveyance and achieve a six-head-count reduction in workers manually moving parts. Those workers have moved to inspection processes or other roles that allow them to challenge themselves professionally and add greater value to the company.
Overall, employee morale has also improved, with employees recognizing Denso as an innovative company that wants to make employees’ jobs easier and that the company cares about the ergonomic aspect of the job.
“The thing I would say for anyone else that’s looking at potentially rolling out AMRs for conveyance is that the benefits you’re not thinking of now are almost going to outweigh what you are considering,” said Olinger. “As you start to see the efficiency gains, and how it improves your overall culture, and then how departments will come up with their own ways to use them to save money, there is a broader benefit to be attained than just that initial indirect cost reduction. It’s well worth that initial investment and well worth that initial period of change.”
Support and training guide fast implementation and ongoing success
Denso received extensive support from both MiR and ACS to ensure a smooth rollout and ongoing success. ACS delivered the robots and walked the Denso team through the initial setup and mission-creation and mapping process. From there, the robots’ ease of use allowed the TIE team to move into new areas very quickly.
“Probably a day of setting everything up, and then another week of testing and working out all the little wrinkles,” said Blackburn. “After we learned that first area, we were able to do it independently.”
MiR provided a week of onsite MiR Academy training, including for Denso employees who could be groomed into super-user roles to support the project long-term. MiR has also assigned a Denso North America-specific contact, has created a group for Denso on the MiR community site, and conducts monthly meetings with Denso.
AMRs created a shift in planning and design
Denso has also purchased five MiR500s for anticipated new business. With automated conveyance and logistics now at the forefront of production decisions, the TIE team can better plan for things such as aisle widths, streamlined processes, and where to focus headcount with MiR conveyance systems in place out of the gate.
“Technology and innovation are very much a part of what we need to focus on going forward,” said Blackburn. “Basically, if you’re not going to focus on that, then you’re doing your company or your plant a disservice by not coming out with the best ways to improve on existing manufacturing environments.”
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