Vehicle color glossiness study using SPC in an automotive manufacturing company

High quality glossiness color for exterior body panel is critical to the success of automobile sales because of the impact on the purchasing decision is relying on the coating. Based on this statement, a visit to Malaysian Truck and Bus Sdn. Bhd. (MTB) has been conducted. This visit regarding many reworks is produced in coating process on the metallic color Mitsubishi Storm model vehicle. The reworks occurred when the process failed to meet designated specification limit. As calculated, there is about RM1 100 a month or RM13200 annum is spent for bad quality coating. Therefore, this project has undertaken analysis and report on the statistical process control (SPC) in the company to address this issue. SPC is invented as a prevention tool to monitor manufacturing processes and becoming framework for preventive action. By using SPC tools specifically the x and R chart and capability study which is the C. and indices in this particular study, variation due to assignable causes in the process has been identified where the 4M; Men, Machines, Methods and Materials, causes become the main sources of variation. The C index shows how well the process spread is compared to the specification spread and the Cpk index shows whether the process is producing reject or not. Analysis has showed that the painting process is in out-of-control situation. Even the C, index is 1.22 which is more than 1.00, the pattern on the control chart showing the unnatural ran process where many points in a row fell below the centerline and some points located beyond the control limits. The index value is 0.94 and showing that rejects are produced in the process. The variations cause the C and the Ck indices value are lessef than expected value which are C = 1.33, and Ck Ck = 1.00. Prevention action and countermeasures are proposed in order to get the process back on its target based on the effect of the 4M. Cp