## 5 Implementation
### Phase 1--Process Selection for Improvement
#### 5.1.2 Measure and Data Understanding  
In this phase, the current operations involved in manufacturing a medical implant were mapped and measured to detect potential areas for improvement. Figure 6 illustrates the process map for the manufacturing operation. Scrap history over 9 months was collected for targeting the operation with the lowest performance for improvement. The source of this scrap data were available in manual scrap records. The operation with the highest scrap rate from the Pareto chart in Figure 7 was then selected for further analysis. Milling operation 2, which involved the CNC-CMM pair, had the highest percentage of scrap (36.96%). The total cycle time for this operation was 314 min/batch. The daily target output from this operation was 67 parts/day. \begin{table}
\begin{tabular}{l l} \hline \hline
**Charter Element** & **Focus** \\ \hline \multirow{2}{*}{Current situation} & Process is operating with manual non-standardized decision-making based on static dataset. \\ \multirow{2}{*}{Purpose} & Optimize production process using digitized data: \\  & Standardize manual steps and automate when possible. \\  & Reduce process variation. \\ \multirow{2}{*}{Scope} & Use best operating conditions. \\  & Reduce non-value-added work. \\  & Reduce cycle time \\ \multirow{2}{*}{Approaches} & Brainstorming, process-mapping, Pareto chart, Ishikawa diagram, \\  & capability analysis, histogram, Poka-yoke, cycle-time analysis. \\ \multirow{2}{*}{Constraints} & Mitigation of random tool fail was out of scope for this study. \\ \multirow{2}{*}{Risks} & Poor quality of data. \\ \multirow{2}{*}{Key team members} & Operator, quality engineer, automation engineer, Process engineer, \\  & machining engineer. \\ \multirow{2}{*}{Success criteria} & Eliminate non-value added manual steps. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Project charter. Figure 6: Process flowchart. A focus group with engineers and operators was organized to discuss the causes of scrap, which is primarily tool variation. Key factors that contributed towards scrap were identified from scrap history for milling operation 2 and illustrated in the Ishikawa diagram in Figure 8, which presents the relationship between the causes of scrap and the effect. A Pareto chart of the causes of scrap in milling operation 2 was plotted to identify the most significant factor that was responsible for the highest number of scraps (Figure 9). Figure 8: Ishikawa diagram of scrap causes. Figure 7: Pareto chart of operational scrap. It was observed that the highest percentage of scrap detected was due to process parameter #1 (26.31%), and scraps resulting from the failed dimensional profile of the machined part can be caused by misaligned or damaged CNC tools. Therefore, it was critical to check which tools had significant contribution to the scrap rate. An observational study was conducted for one shift to monitor the milling operation 2 process. The CNC tools were then mapped to the related dimensions of the part measured on the CMM, shown in Table 4. The dimensions on the medical implants were referred to as DIM. From the observational study, an Ishikawa diagram was used to highlight all the manual actions in milling operation 2, as shown in Figure 10. Reducing manual operations will reduce scrap that results from product mishandling while making the process more automated. It was noticed that first-off inspection included all the major manual steps, i.e., visual inspection, product movement, documentation, and system setup. First-off inspection is required in industries to ensure that the process setup is in order for production operations. \begin{table}
\begin{tabular}{c c} \hline
**Tool Number** & **Dimensions Affected on CMM** \\ \hline
25 & DIM 7, DIM 8 \\
11 & DIM 1, DIM 6, DIM 7, DIM 8, DIM 9, DIM A \\
7 & DIM 33 \\
3 & DIM 13, DIM 14, DIM 15, DIM A \\
9 & DIM 2, DIM 3, DIM 4, DIM 5 \\
15 & DIM 10, DIM 11, DIM 12, DIM C \\
19 & DIM 16, DIM 17 \\ \hline \end{tabular}
\end{table} 
Table 4: Tool map.