All entries for November 2012
November 30, 2012
In this post I will describe some of the fascinating and enchanting things that I have learned during a module that I just finished. The module subject was about Quality, Reliability and Maintenance. I would love to share what I think I have gained after the course of this module which will be divided in three parts
QFD is useful tool which can help manufacturer to follow the true voice of customer from design stage to delivery stage. The example of sport cars from Mazda was surprising me when they failed in the market because they didn’t make noisy engine which is required at that time for sport cars. So this indicates the importance to focus on customer requirements which can be achieved by QFD. I thought before attending this module that QFD is quality tool while it is obviously a planning tool.
Also I have learned many tools which have the ability to measure the quality such as scrap rate, SPC (I will mention it later in detail) and process capability, and the difference between Cp and Cpk. Cp refers to how much variability so it will be misleading if one depends on Cp only. Therefore, Cpk is important to know how close process centre to nearest specification limit. Cp and Cpk should be used together to know the capability of the process.
My awareness of important of quality has been increased by COQ definition in sense that reduction cost is one of vital goals for most organisations; specifically by knowing that reducing overall costs can be achieved by spending on prevention.
Bathtub curve (human being example was good) in reliability session and learning characteristics for each period of time can lead to know which action one can apply and what kind of maintenance one can use. Weibull distribution can be used to know where product is located in Bathtub curve through shape parameter. One of the tools of reliability that I have learned is FMEA which can be used to estimate the potential failure of process and the consequences of this failure.
In seminar, I have learned how to draw SPC chart either by X bar chart or R chart. Both of them indicate if the process out of control or not. However, R chart can lead one to know where to look specifically when the process out of control while X bar chart cannot. Usually one can use about five samples to measure for X bar chart in sense that large number of sample size could be misleading. Before, I thought whenever the sample size is larger this would provide accurate result. Also I have learned that SPC chart is not enough in sense that SPC focus only on consistency (reduce process variability) not to the desired target (example of the student who blamed SPC was useful). Moreover, one of the information I have gained that how to analyse the SPC chart and when do you have to take action before the process crossing control limitation.
Also, in Rainbow Textiles case study, I have learned to define the problem and measure it by flow chart. And we analysed the problem by using fishbone diagram to try to find out the problem which caused the light marks.
EFQM and Six Sigma are option to implement TQM and they share many elements which come from TQM. The significant difference between EFQM and Six Sigma is Six Sigma has deeper implementation on process management than EFQM. However, EFQM and Six Sigma is similar to each other and they can be integrated.