LongXi Machinery Works
LongXi is geared to increase its market share for small multi-cylinder diesel engines but the growing quality concern over production of critical parts is jeopardizing LongXi’s growth in the agricultural sector market. Continued quality issues with our DGS, a critical part within LongXi’s Small Multi-Cylinder Diesel Engine has resulted in breakdown, engine failure and loss production at several customers. Customer complaints are increasing and we need to react to and eliminate our quality concerns. We must develop ways to improve quality in house. Our QC group is well established therefore we are recommending that we collect and analyze data relative to why the DGS is failing and…show more content… Workers were then expected to judge this process based on visual cues and overall time. Since this is the initial phase of the heat treatment process, it is important that the part is preheated to the correct temperature to maintain consistency throughout the remaining processes. Perhaps an automatic temperature sensor and timer can be added to the preheat furnace to indicate when the part is within the temperature range for the allotted time. This would eliminate the inconsistency of the workers judgment.
Processing the DGS through the main furnace is set up to have the furnace monitor the heat cycle and times and then records them on a chart recorder. While this is good, the operator is once again asked to manually hold the parts until the cycle is complete. This again can introduce inconsistency into the process. The tempering process is a very important step in the overall heat treatment process. This step is automated and electrically controlled. There is a ten minute wait time for each basket of parts between the quenching process and the tempering process.
The DGS is then returned to the machining department a second time for grinding. This operation is a two shift operation utilizing one operator per shift.
The attached Fishbone chart outlines possible problems causes we are