Know-how and craftsmanship
Our top priority was, of course, high product quality. And we can only achieve this with a good tool. That’s why our toolmaking experts defined all the necessary parameters such as draft angles, ribs, wall thickness ratios and injection point. We incorporated all of this into our tool design – at that time still on the drawing board – and implemented it by hand. Without the CNC or CAD support that is common today.
In order to develop the most economical solution for John Deere, we also had to build a very durable tool with a high level of wear protection. Of course, we didn’t have the options available to us back then that we have today. Nevertheless, we succeeded: By hardening the tool, it became durable for decades even without a wear-resistant coating. That was state of the art at the time. But only a few managed to achieve the right balance between a hard surface and a tough tool core during hardening. But that is precisely what is important. Because a hard surface is not everything. Only if a mold is not rigid on the inside, but tough, can stresses or fractures be prevented during injection molding.
For hardening, we first heated the tool to a high temperature and then quenched it in an oil bath. To toughen the core, we also tempered the tool in our tempering furnace – in other words, we heated it again in a targeted manner. The big challenge here is that the mold contour can easily be destroyed by heat distortion. However, we mastered this challenge perfectly with the necessary sensitivity in the hardening and tempering furnace. And we achieved the ideal ratio of hard surface and tough core without damaging the shape contour.
