Do-it-yourself collaborative robotic project
Case study: Collaborative robots at a thermal wrap manufacturing company deliver a zero-defect rate while doubling production output. Installation, integration and use has been a do-it-yourself (DIY) project.
Without robotics experience, the family-owned Zippertubing company integrated collaborative robots in vision-guided applications tending snap fastening machines for wrap-around cable jacketing.
The collaborative robots deliver zero defect rate while doubling production output. Zippertubing savings included 32% of labor in the applications now automated.
“What integrator are you using?” was a question Tim Mead, operations manager with Zippertubing in Arizona, kept hearing as he visited robot manufacturers at trade shows.
“But we wanted something that we could integrate ourselves. Something that would save us a lot of money and bring the installation down to a price point that made sense for us,” said Mead. His company was facing a very large increase in demand for its thermal wraps used by automotive and aerospace industries to protect hoses, pipes and cables. On Zippertubing’s production line, workers had a hard time keeping up with the fast-paced, precise, and repetitive task of correctly inserting the cable jacketing into snap machines. The company looked into user-friendly collaborative robots to help.
A 5-kg load collaborative robot was selected “for a few reasons. After a quick demo we realized this was a collaborative robot we could integrate on our own. We were also looking at the versatility,” said Matt Hesselbacher, engineering manager at Zippertubing, as he explained how Zippertubing’s products can change from month to month. Safety was another concern as operators would be working around the robot, feeding it raw parts and take away the finished pieces.
“The biggest benefit we’ve found,” Mead said, “is that our product quality really has improved; the robot has been running for eight months now, and we have gone from having some product returns to now zero defects on parts produced. With the robot itself, we can specify 300% more tolerance on our parts than with manual operation.”
Mead added Zippertubing’s customers are noticing this improvement as well.
The Arizona company programmed its first collaborative robot to pick up pre-cut fabric material that the robot moves through a snap-set machine where five male snaps are inserted, then it moves over to a second machine where five female snaps are added. The 25-second cycle concludes as the collaborative robot presents the piece to a vision camera that inspects if the snaps are added correctly. Depending on the outcome, the collaborative robot is directed to place the finished piece in either the “good” or the “scrap” pile.
Enabling more manufacturing
Zippertubing is working on a more compact, second collaborative robot installation that reduces cycle time while increasing the quantity of parts to run after-hours by integrating a turntable for delivery of the fabric.
“We can have the robot run all night and double our production output. We also can have it handle two or three additional parts and cover even more of our production,” Mead said, detailing how the collaborative robots enabled the company to reduce its labor force by 32% in those applications. “We can now take that freed up labor and move them to other more customized high-skilled, high-demand sections of our production line, where our operators can use their skills in a more beneficial way.”
Overcoming integration fears
Mead’s background is in chemical engineering, not robotics programming, so he was initially hesitant to build a robotics cell from scratch.
The collaborative robot distributor created a demonstration that “looked very straightforward, and there’s also a lot of cool training stuff on the manufacturer’s website,” Mead said, who used free online training to get up to speed after purchasing the robot. The distributor’s “training guy came out and taught us some programming, but then we were off to the races and on our own,” he said.
Zippertubing’s first challenge was to figure out how to have the robot pick up the fabric, which was solved using the built-in de-stack wizard in the collaborative robots’ programming interface.
“Second step was snapping, that was very simplistic, it’s a simple latch lever that we wired up to a relay. Instead of having a foot pedal, we just have a digital I/O from the robot,” Mead said, whose team iterated through the correct positioning of the snaps.
Robot is brain of the cell
The quality inspection with the vision camera was next. The challenge was “How do I get the robot to talk to the camera, and who’s in charge?” Mead said.
In working through the application, those involved realized the collaborative robot brain (controller) could serve as the programmable logic controller (PLC).
“It sends out all the commands, and it takes in all the feedback,” Mead said. The robot looks for feedback from the camera. If it doesn’t find it, it says it’s a bad part; if it finds it, that means the part was good, and it sorts it accordingly.
Cross-discipline risk assessment
Final step after the cell is fully developed is the risk assessment. Robots used are classified as “collaborative” because of the built-in safety system that makes the robot arm stop operating if it encounters objects or people within its route. Zippertubing had a multi-functional team representing the accounting, production, and engineering departments. The team identified two areas with safety concerns.
Neither area was part of the collaborative robotic system.
“We’ve tested the robot. We did the hard stops,” Mead said. The concern was the ancillary systems; the snap machine and the part hopper that automatically trigger the robot. A light curtain prevents people from reaching a hand into the hopper while an area scanner makes the robot drop into reduced mode once a person enters the work envelope. When the person leaves, the robot resumes normal speed.
Quick change-overs, tool changer
Programming the entire cell took Zippertubing less than a week. Hesselbacher said the robot allows for a more flexible production flow.
“Rather than being under the gun to produce a bunch of parts all at once, we’re now able to run a more consistent production level,” he said. For change-overs requiring different tools, the company went to the collaborative robot manufacturer website, which has an online platform with certified plug-and-play products, and found the Milibar tool changer.
“The benefits of using this is quick changeability, adding a new tool to the end of the robot arm is not an issue now,” Mead said.
Next challenge: sewing
The Arizona company is now looking at other tasks to automate. Sewing is one of them.
“It will be a unique challenge as we want the robot to do snaps and sewing with the same tool. We’re going to put snaps in the part, then fold it in half and present it to a sewing machine. Getting the sewing machine to trigger with the robot should be simplistic. The really difficult part is going to be the mechanical tool head and how to make that work,” Mead said, adding he is optimistic his team will figure out the sewing project soon.
Sharing automation help
Zippertubing estimates about a two-year ROI on collaborative robot purchases.
“The return on investment is not just a return on the money we spent on the robot and the system; it’s also a matter of quality for us and for our customers,” Hesselbacher said, who stressed that robots continuing to work after hours will decrease time to ROI.
Zippertubing’s China facility noticed the Arizona plant’s success.
“Our Asia facility is totally manual at the moment, and they’ve reached out to us to see if we could build them some of these robotic cells,” Mead said, who will refine the next collaborative robot application and provide it to his Chinese colleagues.
DIY is not unusual
Seth Garrison, sales engineer with collaborative robot distributor In-Position Technologies, said it’s not unusual to see companies without robotics programming hit the ground running using collaborative robots.
“Most of our installations are pretty much handled by the customers. We usually spend about a day with them, teaching them the robot, and from there they’re able to integrate and design the cell,” Garrison said, adding a distributor expert occasionally stops by to provide more in-depth services. “Had this been a traditional industrial robot, customers would have a much harder time doing this by themselves.”
KEYWORDS Collaborative robotics, robot case study
Collaborative robots can be used in do-it-yourself applications.
Robot controller can perform programmable logic controller functions in a workcell.
Robot manufacturer website and distributor can provide training and services.
Would working on a collaborative robot application excite people you work with?