"DELMIA’s IGRIP Paves The Way For Welding Robot"

Delmia

AN OFF-LINE programming system supplied by Delfoi made it possible for Zetterbergs to invest in a robot system.

Zetterbergs Product AB in Östervåla markets, produces, and assembles additions for trucks in the construction, facility, and waste management industries. The company is a market leader in Sweden and Norway in dumper truck bodies and additions.

Every order the company receives is unique to that particular customer, so constant re-programming is a requirement. “With IGRIP, production is never interrupted,” said Thomas Lindgren, production engineer at Zetterbergs. As a result of implementing the new system, turnaround time is estimated to be an impressive six times shorter than was previously the case.

Last year, Zetterbergs bought a welding robot from Motoman. “It was an enormous step for the company,” said Thomas Lindgren. Between 1923 and 2001, almost all welding had been carried out manually. Six months before the robot system was installed, the company acquired the DELMIA IGRIP off-line programming system which was supplied by Delfoi. While waiting for the robot – which was later named Evelina – the technicians had plenty of time to dicover the program’s functionality and also learn the practicalities during the several Delfoi arranged training sessions.

Customer-unique Products

“The off-line programming system was absolutely necessary for us if the welding robot was to fulfill its purpose,” said Martin Öhman, production engineer at Zetterbergs. The reason for this is that Zetterbergs’ line of products consists of several different types with countless variations. “Each construction project is customer-unique,” explained Thomas Lindgren. “Some modification is always made from one product to the next.”

“It isn’t just varying the length, width, and height that we have to take into consideration,” said Martin Öhman, “but also varying lengths of the beams because of the chassis, and other modifications.”

Since all the products are different, the robot must be reprogrammed for each product. If this is done on-line, it means programming must take place at the robot and production must be stopped, requiring one to two weeks per product. Using the off-line program, programming can take place while the robot is working, and downtime can be reduced to thirty minutes.

“The biggest gain is that the DELMIA’s IGRIP made the robot investment possible,” said Martin Öhman. “The welding robot has also improved the quality of our products.”

Successful Fast Conversion

The conversion to the robot system and the off-line program went faster than anyone could have predicted. The goal for Zetterbergs was to weld flat bottoms and dumper sides initially, since the company wanted to introduce the system cautiously at first. However, a major order from China came in only four months after IGRIP had been first introduced.

“We decided to run the complete construction project using IGRIP,” says Thomas Lindgren. “We contacted Delfoi, and soon we were up and running. We were tremendously successful!”

The technicians programmed the off-line program, and then the files were placed on the network. The robot operator was able to download the file and upload it to the robot’s control system, after which the robot was ready to get started. In the first step, it checked all welding starting points in the assembled dumper basket. Any mistakes were automatically corrected. The second step was the welding itself.

“The operators have a very important function in the whole picture,” said Thomas Lindgren. “They are experts on both the robot and the welding part, and can give us vital feedback.” Zetterbergs products make up the foundation of the IGRIP program. The technicians feed in specific values for each product. At most, fifteen basic parameters are reset. “What we are doing now is eliminating minor problems, making changes in production, and continuing to work on improving the welding speed and optimization. Currently, we can handle about 98% of the total welding length for a dumpcart.”