Many different components but only small batch sizes: Motorcycle accessories manufacturer SW-MOTECH was hunting for a suitable machining center to cope with the challenge of using automation to manufacture 400 reoccurring parts in batch sizes of 30 to 200 pieces. »After we'd ascertained that all well-known machining center manufacturers could mill well, it was the way the CHIRON Group took such great care to understand our problems that finally made the difference,« says Kai Jockel, Managing Director of SW-MOTECH GmbH & Co. KG and responsible for production there. Together, they found a solution with the FZ 15 S five axis machining center and designed a concept for the robots and clamping technology which was appropriate to the variety of parts. The system has now been running flawlessly in three-shift operation for a year. These are the most important points of the application, but there's plenty more interesting things about the project and customer.

First and foremost, SW-MOTECH has interesting beginnings, with its origin on a ferry ride between Italy and north Africa. In 1994, mechanical engineer Jürgen Swora developed a tail tank for his Honda Africa Twin for a motorcycle ride to Libya that he was taking with his friend Jörg Diehl. The bikers met on the ferry crossing to north Africa, where there were not only lots of riders, but also a motorcycle dealer who was interested in the tail tank.

Everything started with the invention of a tail tank
From there, grew a business idea which led to the founding of SW-MOTECH in 1999. The third member on board was Kai Jockel, who remembers the time well, »We started back then on a farm, in an old barn, with a drill and a welding device. Today, we have a headquarters in Rauschenberg, in Hesse, Germany, 180 employees, a second production location in Czechia and sales branches in Spain, France and now in the USA too.«

Right from the start, the company focused on the production of premium motorcycle accessories produced in-house. Our recipe for success was products that no-one else was offering,« the managing director explains. Thus, in 2000, the first removable luggage rack in the world, based on the Quick-Lock bayonet locking system, became their USP. This was followed, five years later, by the patented Quick-Lock mechanism tank ring for mounting a tank bag with just one click. »This pioneering product made sure even the OEM motorcycle manufacturers knew who we were, when before we had only supplied traders.«

The workload required a third machining center
And with that came new requirements for production. While at the beginning, the majority of orders were welded components, now increasing numbers of milled components were needed. And so, the first three-axis machining center found its home at SW-MOTECH. »With VCP 800 from Mikron, we very slowly started getting into milling, only to then discover, quite quickly, that the machine was at full capacity,« Jockel remembers. Then came the second three-axis milling machine and, when that too was running around the clock, the company went to the EMO 2019, in Hanover, in search of another machining center. The slogan »Tool change in 1.5 s« drew Jockel to the CHIRON Group stand at the exhibition.

»Although the speed, in this respect, is not remotely relevant to us,« the Head of Production says with a grin. »The part numbers in the motorcycle industry don't really compare to the automotive industry. 30 parts is a typical batch size for us, and we also wanted to mill prototypes or mechanisms on the new machine. However, we still wanted automated manufacture of a wide range of parts.«

The clamping concept played a decisive role
That's why the clamping concept, for the around 400 different components, played such a decisive role. »We needed to find the balance between the level of investment for the machine and for the mechanisms, because the workpiece side couldn't cost any more,« Roland Ranisch, CHIRON Group Sales Partner, describes the initial situation. »So, using a variety of mechanisms for each part, about half of which would only be used once a year, wasn't an option.«

Together, they developed a robot and clamping concept, which also required compromises on the part of SW-MOTECH. The unmachined parts, or blanks, for certain component groups were thus standardized, so that the same mechanism could be used more often. »Because it's quicker to mill off 5 mm excess material from a blank, for example, than to re-mount,« Ranisch explains. For Jockel, the be all and end all was to remain with the vice as the final clamping element. »This meant we only had to invest once in the base device with zero-point clamping system and only need to adjust the second clamp at the top with the vice.«

Rack with six device positions and a station for eight double-grippers
The final solution now comprises a Fanuc robot, a paternoster rack with drawers for the blank part pallets, a rack with six device positions and a gripper station for eight double grippers.

The pallets are 600 mm × 400 mm and have space for up to 52 parts. »The store is designed for a runtime of eight hours, with 24 pallets and, thanks to the six device positions, six different components can be machined per shift without operators needing to manually interfere. The average machining time is three to four minutes,« Ranisch describes normal operation. Bastian Feußner, who is responsible for machining, describes the process of changing products, »The robot takes the device out of the machining center, changes it for a new one and then takes the gripper with the correct clamps. The pallet with the new blanks is prepared from the paternoster rack and the robot places the part in the machine. The following step, thanks to the double-gripper, is when the robot takes the finished component and places the blank part in. The production order always specifies whether the necessary devices and gripper are in the racks. A complete switch over takes around five to six minutes.«

The number of clamping positions needed to be reduced
Choosing the machine itself was relatively simple, and they decided on the FZ 15 S five axis machining center because it was best suited to the range of components. There was, of course, a reason that it had to be five-axis this time. Managing Director Jockel explains, »We often needed up to four clamping positions for our three-axis machines. Five-axis machining allowed us to not just reduce the number of clamping positions, but also gave us more options for more expressive design parts on the motorcycle.«

The acceptance parts were milled in the required quality
The CHIRON 15 Series machining centers are fundamentally standard machines, but the options catalog includes around 300 positions for individualization. »For SW-MOTECH, because of the customer-specific design on the workpiece-side it was, again, a turnkey project, including acceptance and production monitoring,« says Ranisch. A forged part for a frame and an aluminum profile were milled to the required surface quality and precision, and after three weeks of support from a Chiron application engineer, SW-MOTECH was able to operate the system without aid.

Now, that really is the whole story and all that's left is to sum up. Here, the experts Kai Jockel and Bastian Feußner thoroughly agree, »The system makes what it's meant to make and has run without a hitch since installation. And that's just how we like it.«

For more information: https://www.SW-MOTECH.info/en/