Quality Control DX - Introducing a new quality control method - Part 1
Recently, due to the influence of a series of quality fraud incidents both in Japan and internationally, the standards required for quality control in manufacturing are increasing. However, attempting to perform quality control that meets the required standards using conventional methods places a considerable burden on the manufacturing site. At our company, we are adopting SPC (Statistical Processing Control) as a new quality control method and the software called PiWeb as a tool to realise SPC. In this issue, we will introduce SPC, which is one of the quality control methods, and the software PiWeb.
About SPC
SPC (Statistical Processing Control) is a process management method used not only in the manufacturing industry but also in the service industry. The general contents are as follows.
- Step 1: Collect data obtained during the process.
- Step 2: From the collected data, determine indicators that will serve as standards for normal conditions.
- Step 3: Compare the indicators created in step 2 with the latest data and monitor for any abnormalities.
- Step 4: If an abnormality is found in the data, analyse to identify the cause and take countermeasures.
Continuously carrying out the above is a characteristic of the SPC.
In the MIM manufacturing process,
- Data on components such as dimensions and hardness
- Data related to production equipment such as injection molding machines and sintering temperatures
- Records data related to the environment at the manufacturing site, such as manufacturing date and time.
Collect these data to define the normal state of the component and visualise small changes. By comparing daily component data with normal conditions using the 7 QC tools that are already in widespread use, if an abnormality is detected, it is possible to quickly analyse the cause and take countermeasures.
About PiWeb
PiWeb is a software for quality data management provided by Zeiss. It achieves unified management of measurement data obtained from various measuring instruments. The data collected using this software is statistically processed to visualize changes in the manufacturing process, which is useful for process monitoring and abnormality detection.
For example, the X control chart shown above is a tool that graphs the quality of parts and makes it easier to notice changes. The design value is displayed as the center line, the upper control limit line (UCL) and lower control limit line (LCL) are displayed above and below the center line, and the trends in the acquired data are displayed in a line graph. Since the limit line is automatically calculated from the collected data, it is necessary to process the data so that the UCL and LCL are set to the predefined normal state (SPC Step 2). The graph is then updated each time the component is manufactured and measured, allowing you to monitor the latest status of the component and its manufacturing process.
Come and meet us at the Medical Device Development Expo in Tokyo, Japan!
We will be exhibiting between 19th and 21st June at Tokyo Big Site, Japan.
Hall: East 4, Stand #E31-37
Greetings from Osaka, Japan
Hi, I am Oh Chang Sun. I joined Taisei Kogyo (our sister company which specialises in manufacturing of Micro MIM parts) in June 2023, so I have been working here for a year now. My position is in the manufacturing department: to be more specific, in the sintering section. I am mainly responsible for the process control and debinding/sintering. My aim is to do my best and to make no mistake. In my free time, I rest at home, playing games and sometime I go to Karaoke or visit other cities. I recently visited Nara and the photo is of a deer in Nara park. They were sweet and there were lots to see in Nara!
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Conclusion
Cracking, slumping or blistering is commonly observed due to the binder swelling and/or residual stress difference between the surface and interior. It is possible to avoid these problems by selecting appropriate organic solvents and temperature control.
The catalytic deboning uses sublimation of binder, thus it is possible to decompose the binder in relatively short processing time with minimizing the deformation. However, with a strong acidic atmosphere, theapplicable metal material option is limited.
In the sintering process, the necking, which is bridging the metal powders by thermal diffusion, starts at the sintering temperature. Once the necking starts, the shrinking is observed and increases the density, thus before starting the necking reaction, all the organic components should be decomposed and gas between the powders should be removed. In the sintering process, the unwanted chemical reaction, such as oxidation or carbonization, leads to mechanical property loss, therefore a precise atmosphere control with low heating rate at the beginning of the process is required. Also, when it reaches the sintering temperature, some add it vegetal can be evaporated.