If you can automate the loading of products onto machining equipment, that must also be possible for the welding production.
If you can automate the loading of products onto machining equipment, that must also be possible for the welding production. That was the underlying idea when Valk Welding, working in partnership with Marel Stork Poultry Processing, developed a production cell in which the handling and logistics surrounding the welding robot are automated. The result is a welding production cell that produces completely continuously, is entirely designed for one piece flow production and yields a substantial saving in manpower.
The smaller components (up to 500 x 500 mm) for the poultry processing machinery of Marel Stork Poultry Processing are manufactured at the production establishment of Marel Stork in Dongen, and since recently a number of components have also been assembled into sub-assemblies there. The products are fully developed and finished at the main establishment in Boxmeer. Industrial Engineer André Kouwenberg: "There has always been a lot of technical know-how in Dongen (Stork PMT), which is extremely valuable to us." The technical know-how is reflected in the drive to always be the first to adopt new production technology. Marel Stork Poultry processing became involved in welding robotisation at an early stage, and in 1996 was one of the first users of Panasonic's offline programming system DTPS. This was also Valk Welding's first customer for a welding robot with the Arc-Eye laser sensor.
Continuous workflow in new production concept
Marel Stork Poultry Processing, which builds their machines to order, plans to use the new cell to facilitate a continuous workflow in production. André Kouwenberg: "That means that we will produce as little as possible in batches, but will instead place the entire process from laser cutting, welding and milling in a single flow. If for example we need 20 components, we won't wait until all 20 are ready but will send each completed product straight to the milling department. That actually amounts to working according to the Quick Response Manufacturing principle, which we have 'borrowed' from car manufacturers. Each part has to be processed directly without creating any dead time and the delivery times are kept as short as possible."
Handling robot operates welding robot with 2 workstations
In the new production cell parts are clamped onto pallet carriers and stored in one of the 58 pallet positions in the warehouse. When a part is to be welded a handling robot (Panasonic HS-165) collects the pallet in question from the warehouse and mounts it on one of the two workstations of the welding robot (Panasonic TA 1600). While the welding robot is welding the component, the next pallet is changed on the other workstation. As soon as a pallet has been welded with one or more components, the handling robot places it back in the warehouse. "The cell contains 58 jig carriers with a total of 240 different jigs. By creating the right combinations between fast and slow movers you achieve the right production balance to maintain a continuous workflow, explains André Kouwenberg.
Complete cell instead of 2 standard cells
Valk Welding was also able to meet Marel Stork Poultry Processing's requirement for 2 standard cells. Valk Weldings sales manager Cees Wierenga: "But that still calls for extra manpower to convert the clamps and place the products in the two cells. The fully automated cell is 'operated' by a single operator who takes the parts to be welded in and out of the pallet carriers outside of the cell in an input/output location. André Kouwenberg: "For that reason we used a simulation process to compare the yields of both processes. This showed that the process in one complete cell could be operated by just one person per shift. This gave us the green light to go for our aim of achieving a continuous workflow.
Software determines production
The software determines which part is to be welded first. The software advises the operator rather than the other way around. The operator can however interrupt the system if the workflow for a simple part has to be stopped. Cees Wieringa: "For that purpose there is a third workstation at the front of the cell where the operator can insert and take out a component himself. Without that option the system would be too rigid and you would run the risk of the assembly having to wait needlessly for a single part." The software was written entirely by Valk Welding’s software engineers.
Automatic torch change
To ensure that the welding robot can be used with the MIG and TIG welding and TIG with wire feed, Valk Welding has developed a torch change system that is integrated in the cell. In this system the swan neck of the Valk Welding robot torch can be automatically changed without any manual intervention in the production process being required. The pallet carriers manufactured by Marel Stork Poultry Processing are divided into whole, half and quarter measurements. The carriers are equipped with a Schunk clamping connector and are picked up in mirror-image form by the handling robot with the same type of connector.
Full confidence in the supplier
André Kouwenberg: "As early adopters we are usually closely involved in the development of new technology. When it comes to welding Valk Welding and Panasonic incorporate a lot of our feedback in later versions. That open approach and the short lines of communication have resulted in our gaining a lot of confidence in Valk Welding's people over the past 25 years, which is why we were willing to take on the development of the new production cell. There are probably other system integrators that are able to do this, but Valk Welding is increasingly raising its profile in this market with its specific knowledge of welding matters."Request for information