A fast space saver
Goma lacked the space for endless stacks of sheet metal. It needed an automation concept that was fast, without taking up too much space.
The little robot is extremely busy. Located between two press brakes, it first inserts a strip of sheet metal roughly two meters long into one machine, swings the bent sheet over its head, and then positions it in the second press brake. The robot then moves the panel into several different positions and, with as many strokes of the press brake, a complex profile is created. It will later be used to reliably seal a refrigerator door. Weights are attached to the ends of the gripping device to deaden vibrations caused by those quick movements. It looks a bit improvised, but it works. And this is typical for Goma. The company’s expert workforce builds its own manufacturing equipment if necessary. They draw suitable components from various suppliers and combine them to create a system that meets their exact requirements.
From prototype to mass production
Jan Oortgiesen, one of the two proprietors of the company located in the Dutch town of Hengelo, aligns the automation at his production facilities with current trends. “Batch sizes are getting smaller and smaller. For us, a typical order would be for between 25 and 300 parts.” However, many jobs are repeat orders and that makes automation worthwhile. Goma operates a total of eight robots. “As far back as 1998, we purchased our first pick & place robot combined with a press brake,” says Oortgiesen. Their production work is also supported by automated CNC laser cutting and punching machines. In 1982, the first TRUMPF punching machine was delivered to Goma, followed five years later by a TRUMATIC 180 LW combination punching and laser cutting machine.
High-quality sheet metal components
If larger series are involved, these experts in metal processing make their own tooling for their punching machines. The simple reason is that Goma started out as toolmakers in 1962. “When developing new products for a customer, we can start off by submitting prototypes and short production runs. When batch sizes increase, we switch over to manufacturing from coils,” states Goma’s general manager Foppe Atema. Over the years, he has expanded the company and transformed it into a supplier of high-quality sheet metal components. They focus on manufacturing enclosures and cladding for a whole range of markets — starting with minute housings only a few centimeters long for the medical trade — and continuing to meter-high cladding for electrical switching panels used in buildings.
Not much room for a lot of metal
The linchpin in production operations is the fully automatic Stopa storage system. Installed in 1996, it was the first of its kind in the Netherlands. It provides storage space for some 400 mild steel, aluminum and stainless steel sheets. Attached to it at twelve locations are laser cutting machines, press brakes, punching machines, and guillotine shears — some with manual part removal and some fully automatic. An independent administration system controls the storage and the machines integrated into the system.
Originally, the Goma professionals built their own handling unit to feed the first TruLaser 3030. “Components were still being removed by hand, though,” says Oortgiesen. This all changed when the unit was replaced by a new TruLaser 3030 ten years later. “The laser cutting machine makes us very flexible. We can process any kind of sheet metal immediately, without having to build a tool.”
The most important reason for this investment, however, was the automated unit for loading and unloading the sheet metal components — the LiftMaster Compact: “We don’t have a lot of space in the factory, and that is precisely why its compact dimensions appealed to us. No other supplier was in a position to offer us such a compact solution,” says Oortgiesen. The laser cutting machine’s air exhaust, control and cooling equipment has been grouped on a pedestal above the TruLaser 3030, which saves even more space. “The current solution requires only half of the floor space when compared with the previous unit.”
But it’s not only the compact dimensions that speak in favor of the new LiftMaster Compact. Its speed is no less impressive, because it can load and retrieve simultaneously: A tined frame removes the cut parts while a vacuum frame equipped with suction cups picks up a new sheet from the storage systems’ exit point and transports it to the pallet changer. While the new sheet is being positioned, the tined frame places the finished blank on the top of the vacuum frame, which then returns the blank to the storage system.
Rapid sheet turnaround
Some ninety percent of the components processed on the punching machines and on the laser cutting machines are held in the Stopa storage system prior to further processing. The time needed to load and retrieve blanks is of particular significance. “The LiftMaster Compact has let us reduce this to 65 seconds — with our ‘home-grown’ solution we needed more than two minutes just to load a machine,” emphasizes Oortgiesen. “Rapid blank turnaround is important as otherwise the TruLaser 3030 would have to wait until the loading and retrieving process is completed.”
“Lights out” manufacturing
Installing the equipment initially gave their techies a headache, because the LiftMaster Compact was the first to be linked with a Stopa universal storage system. It soon became clear that the LiftMaster Compact’s table was not going to fit between the storage system’s rack support struts. Their technicians’ solution was to install a crossbar above the LiftMaster’s frame — on two new struts that were further apart. They then attached supports to the bar at the distance required to make the storage racks fit again normally.
With the new TruLaser 3030 and its fully automatic loading and unloading unit, a third station is now directly connected with the storage system. And this setup can operate unsupervised — which was ultimately Jan Oortgiesen’s goal: “Machines are expensive and ought to run 168 hours a week.” Since they only work two shifts at Goma, the machines would have to operate without staff during the third shift. “But that doesn’t always work,” admits Oortgiesen. Before running an unmanned shift, every machine setting has to be perfect before the last operator goes home. “If they don’t get it right, unmanned operations just won’t work.”
But there’s progress at Goma — mass production of relatively simple parts has already commenced in a third shift with no operators present. In line with this philosophy, Goma will only commission a new machine if it is fully automatic and will operate around the clock. Oortgiesen is already considering expanding his production facilities. The shop floor space is to be extended by a further 1,500 square meters, the automated storage system is to be enlarged, and new punching and laser machines are to be integrated. “You never finish automating — it’s an ongoing process,” he says.
Contact us: MastersofSheetMetal@trumpf.com
This article was first published in autumn 2011.