09.12.2019
Manufacturing engines requires the highest level of precision. In order to ensure the best-possible engine properties, the corresponding surfaces in the engine block must be machined with the utmost accuracy. They have a complex geometry and numerous key characteristics (KC) for which the highest tolerance classes must be reliably observed. Depending on the engine type, these include multiple H7 fits, various areas with accuracy specifications less than 15 μm as well as chamfers with tight tolerances, including a 20° chamfer with an outlet, for which an angle tolerance of just ± 0.025° (1' 30") must be observed while meeting the high requirements in terms of surface quality at the same time. Aside from all the accuracy, the focus is also on cost-effective manufacturing.
Only manageable with actuating tools
A first line for machining these engine blocks was commissioned in 2011. When planning a second line, the persons responsible drew on their experience with the first line. They identified the machining of the bores for the cylinder liner adapters as particularly challenging. The machining was divided into two stations: one for pre-machining and one for fine machining.
Closed quality control loop
The measurement results determined on the setting fixtures are transmitted directly to an RFID data medium on the tool. The controller of the machining system reads it out when the tools are inserted. This way, the machine can readjust some of the important measurements using the actuating slides during machining. As from the second workpiece, the results of the routine QA measurement are taken into account. This closed quality control loop for the tools was a high priority for Mercedes-Benz.
