Every year, KTM Sportmotorcycle of Austria produces 110,000 high performance ready-to-race motorcycles. However, motorsport is one of the toughest environments, and a part-failure due to a material or design defect can have serious implications.
Helmut Gröbner, who is KTM group leader for plastic components and heads-up a team of ten designers, explains that the pressure on the product development team is enormous – a plastic part approved for production needs to be 100% right.
A new part is initially developed as a 3D CAD model in ProEngineer Wildfire and then immediately subjected to extensive static and dynamic finite element stress analysis. When the CAD design is finalised, the company uses Moldflow to simulate the injection-moulding process. Only then can a prototype part be made for physical ‘real-world’ testing – KTM shorthand for conditions most people and motorcycles would never encounter.
The only way to test the part is to make it and subject it to extremes of stress, temperature, load, etc., and the prototype should be as close to the final production version as possible, both in terms of mechanical qualities and also material.
“Our first project with Proto Labs’ rapid injection moulding service Protomold was a cover for a silencer on the exhaust,” said Gröbner. “Our budget for tooling was only €25-30,000 and we couldn’t risk going straight to production with a new design.
“Time was also short, but a colleague remembered seeing an advertisement for Proto Labs. So, we gave it a go, took delivery of the prototype, and in testing quickly discovered that the part we had designed in plastic wasn’t durable enough. Eventually, we decided to make the part from metal, but had we not made the prototype with the help of Proto Labs, we would have wasted a great deal of time and money and we may well have ended up with a sub-standard part on the bike.”
KTM’s second opportunity to work with Proto Labs came soon after this, when the company was optimising the design of a filter compartment cover, which had previously been made of metal. The cover needed to open quickly without the need for a tool, but would also be secure enough that strong vibrations couldn’t loosen it.
Gröbner said: “Proto Labs’ Protomold service came to our rescue again. We made our first part, which immediately showed up problems with the fit and the securing mechanism. We made some design revisions and with the second part everything was perfect. In just five weeks we had tried two versions, finalised the design and taken delivery of 5,000 finished parts of production quality. Proto Labs even had sufficient material in stock, so there was no delay. Our production launch was flawless and the solution to the filter box cover was found to be perfect.”
Most of the motorcycles, however, have to be road ready, which means parts must meet high standards for TÜV certification. “We designed a new grab handle for pillion passengers. The fundamental question was whether to use plastic or metal, and if we did use plastic, would the part achieve the required strength. Of course TÜV tests only finished, production parts, which we were able to submit by making them with Protomold. The parts passed the rigorous tests and are now in full production.”
The next challenge came just three months ahead of the INTERMOT trade show when the company decided to create a new rear-view mirror for the KTM 1190 Adventure, a year ahead of schedule.
“Usually, you need a full year for a design process from concept to production, including technical inspection,” commented Gröbner. “In this case, our tight deadline was only met because of Protomold. We designed and took delivery of parts that were inspected and passed by TÜV before being fitted to the bike at INTERMOT.”