Bosch seals striking mechanism of hammer drill with TPE

The TPE sealing lip is injected directly onto the body instead of being inserted afterwards. It protects the striking mechanism against penetrating dirt and is intended to prevent the exit of grease and replaces a rubber sealing.

For this new application Kraiburg TPE had to optimise the compressive deformation properties of the Thermolast K compounds; compounds of this series have also been used for the grip zones of Bosch power tools for some time now.

What is special about the production process of the hammer drill body is that first of all, a turntable mould injects the 4mm high sealing lip, then surrounds it with the PA hard component and finally the grip zones and the Bosch logo are fixed. The sealing directly adheres to the PA and is therefore an inherent part of the body. This reduces the number of parts and makes one complete work step unnecessary. Additionally, less quality controls are necessary as the sealing cannot get lost unnoticed in the further assembly process. Through the multi-component injection moulding process for the body including the sealing, Bosch reduces the assembly time and assembly costs whereas the quality even increases.