## 4 Improvement Proposals
### Improvement Opportunities
#### 4.4.1 5s  
IO 1.1 (as well as IO 27.1) concerns the displacement that exists when the worker who is disassembling/assembling the seat needs a tool that is not next to them but on their workstation. As it will be explained in Section 4.4.2, this is proposed as a work instruction, so that the worker takes the mobile toolbox (which each worker has) with them to the vehicle when disassembling/assembling the seat. For this to be possible, the storage and organization of the shelves (behind every workstation) and the mobile toolbox is proposed according to the 5S philosophy: the individual shelves should be arranged so that the tools are arranged according to their use in each phase of the process and it is also proposed to mark on the shelves the areas referring to each phase. IO 14.1 (as well as IO 15.1, IO 18.1, and IO 19.1) refers to the displacements when looking for a suitable foam to repair the original upholstery. For this situation, as will be explained in Section 4.4.2, a work instruction is proposed. Associated with this instruction, several 5S measures should be considered: the creation of individual storage boxes for leftovers, exchanging the leftover box into a leftover shelf, and tidying and organizing the foam shelves. First, it is proposed to place individual leftover boxes on each workstation, where the leftovers are placed directly after using the foam boards. In this space, it is also proposed to place the cans of glue in use as well as boxes of staples that each bench must have (also solving IO 23). In Gemba, next to the workstations, there is a wooden box where the leftover foam is currently placed and, later, where the workers search for leftovers that can still be used. However, this method does not allow visualization of the leftovers at the bottom of the box, representing a waste of material. Therefore, it is proposed to replace this box with a shelf, which will also function as a shelf for stocks of staples and glue cans, to also provide a solution to IO 24 and IO 17. Finally, workers must move to the foam shelves. For these shelves an organization scheme is proposed that follows the fundamentals of the 5S methodology, where the foam boards are arranged and placed on the shelves according to their density and applications (the areas should be properly identified). These shelves should also be used to store vehicle seat molds (as will be explained in Section 4.4.3). Regarding IO 22.1, as will be explained in Section 4.4.3, it is proposed to create a shelf where the stocks related to the Sewing stage are arranged and organized by a 5S methodology, for example, the ordination of needles and lines from thinnest to thickest. To ensure that these practices are maintained they should be audited, according to the checklists (an example of the checklists created, namely, for the 5S concerning the workstation shelves, is presented in Appendix B). The frequency of these audits should be established, ideally, weekly. With periodic audits, it is possible to track and monitor the status of each 5S practice, through the \"Total Rating\" value. The \"Total Rating\" should be assigned according to the scale adapted from [44]: \begin{table}
\begin{tabular}{c c c} \hline
**IO** & **Description** & **Lean Tool** \\ \hline
27 & The displacement between the workstation and the vehicle to fetch tools needed to assemble the seat & Standardized Work \\ \hline
27.1 & The displacement between the workstation and the vehicle to fetch tools needed to assemble the seat & 5S \\ \hline
28 & The waiting time for a worker to assist in assembling the seat due to the complexity of the model & Kaizen \\ \hline
29 & The displacement between the workstation and the vehicle to fetch the cleaning & Kaizen \\ \hline
30 & Specific waste situation—Defects & Poka-Yoke \\ \hline
31 & Specific waste situation—Movements & Kanban \\ \hline \end{tabular}
\end{table}