2.7.4a Waste: DefectsDefects result from products that are not fit for use. This results in the product either gettingreworked or dumped, which is costly as this adds additional costs to production without addingany value (Soliman, 2017). LM aims to prevent defects from occurring rather than correctingthem. 2.7.4b Tool: Poka YokePoka Yoke can be used to eliminate defects. Sable and Dakhore (2017) identify Poka Yoke asmistake proofing using any automatic device or method that prevents an error from occurringor makes the error immediately identifiable once it has occurred. As shown in Figure: 10, aprevention-based Poka yoke system detects the defect before it occurs and a detection-basedPoka yoke signals when a mistake has been made. Once the detection has been made, thesystem does not allow continuation of the process until the problem has been solved. Thiseliminates the waste of defects.Figure 10: Poka Yoke (Source: RNA Automation, 2019)However, the challenge with Poka Yoke has been the difficulty in convincing all stakeholders toimplement poka-yoke devices. Some of the devices are expensive and some businesses mightnot be keen on making the investment. 13Prevention-based Poka YokeDefectsMistakesProcessDetection-based Poka YokeMOD005581SID Number:
2.7.5a Waste: WaitingThe waste of waiting includes delays for example process delays, idle equipment, people delays,instruction delays etc. This is costly as it ties up capital and also not adding any value to theproduct (Soliman, 2017). Waiting can also trigger the waste of defects if the processes gethurried in order to catch up, shop floor workers have been noted to take shortcuts and bypasssystems when they fall behind in production. 2.7.5b Tool: Takt timeSoliman (2017) recommends Takt time to eliminate the waste of waiting through ensuring thatprocesses are better matched with regards to cycle times. Takt time is the rate and speedneeded to complete a product so as to meet customers demand (Sundara, Balajib andSatheeshKumar, 2014). These rates and speeds are measured through determining the averagetime that is taken from the start of production of a unit and the start of production of thefollowing unit (Sundara, Balajib and SatheeshKumar, 2014), as shown in Figure 11.However, takt time has been known to create boredom in employees because of repetitivetasks.14Figure 11: Takt time (Source: Wedgwood, 2006, p.138) MOD005581SID Number:
2.7.5c Tool: Total Productive Maintenance (TPM)Wilson (2010, p.63) recommends using TPM to Improve machine reliability. TPM is amanagement approach to maintenance focusing on the involvement of all the business’employees in equipment improvement. As shown in Figure 12, TPM involves a range ofmethods which leads to in improved reliability, quality, and production (Das, Venkatadri andPandey, 2013).