We visited a production facility of ZF in Lommel, Belgium. At this enormous facility, the company produces gearboxes for wind turbines. Man-sized wheels, gears, planetary gears, all components for a very high demanding application. The quality of these components is vital, more so here than in many other industries. Recall operations or failure are unthinkable. Senior Engineer Danny Looijmans is willing to show us around and explain some of the challenges he faces every day. Looijmans uses low- and mid-frequency heaters from TM Induction Heating and along the way, he explains why.
The production facility in Lommel has developed special gearboxes dedicated for the use in wind turbines. This was a necessity because producers of wind turbines found the gearbox could be a technical bottleneck. Looijmans “The gearboxes used to have low revs, but modern ones have to be able to deal with very high revs. Gearboxes in general were starting to get a bad reputation because they could not cope. So we set to work to optimize the design, the materials and the production process. In our factory, we start from the raw material and produce highly precise gears and shafts and cure them. 
They are assembled with components from other manufacturers, but we have a very tight quality control, all along the way.” Everything is done according to PIM, Production Integrity Management. Right down to in-house metallurgical specialists.
The assembling of the very large and very precise parts of the wind turbines requires careful handling and heavy machinery that can do just that. In order to mount the bearing and gears, they need to be heated. The size of the parts mean a lot of material has to be heated in the shortest possible time. Because this production facility is no exception to the rule: time is money. “The heating process needs to be done quick, but very controlled,” Looijmans explains. “TM offers us very robust and reliable technology that does the job for a very good price. But they are also very experienced in the matter, so whenever we come up with a challenge, we can call on them.”
“At one point we started using new equipment, that allowed us to heat a part in a very short time. So we did. But we soon found out that we had compromised the integrity of the material, in doing that. And if there is one thing, we cannot afford, it is just that. 
So we spoke with the engineers of TM and we came up with a more controlled way of heating. Being the type of company that we are, we want to modify the heaters to set them up to our own standard, and we get every cooperation we need. TM now supplies us with a two-sensor heating, but we even modify some of the heaters to allow for a four-sensor heating process. We have a very good relationship with them, where we can exchange our experiences and knowhow and they will use it to get us to the next level. We get customized circuit boards to modify equipment to our specific needs.”
Looijmans is somewhat of a control freak, he admits. “I can look very deep into the parameterizability of equipment, and I do. I have a very critical mind and want to know all the ins and outs of every process. And that is exactly what my job requires of me. But I have to admit that I sometimes want things to be way more perfect than needed. And TM is very realistic about that, they understand our challenges and help us onwards. We have built up a relationship of trust and we know what to expect of each other.”
Looijmans is proud of the quality standard his company achieves and would like to spread the word to every other manufacturer of wind turbine gearboxes. “To let the world know that wind turbine gearboxes offer state of the art technology. If produced with the right methods, and at that, controlled induction heating makes a big difference.”
Of course guarding his advantage, but pleased if the industry follows his lead.
