In our previous posting, we introduced “The Framework for Smoothing” by Yasuhiro Monden (1983). Starting from the bottom up, you are led through the Production (Process) Smoothing actions required from: Flexible Machinery and Reduction of Production Leadtime to Just-In-Time Production leading to Enabling Production that is Promptly Adaptable to Demand Changes.
The Production Smoothing actions within the dashed line box in the graphic are fundamental to attainment of customer demand and building/completing products/services as required by customers. Additionally, the highlighted section shows the areas of focus for product/service sequencing. The basics of the functions contained in this graphic can and should extend beyond the production/service processes, to include the entire supply chain, and the practice of “Inter-Number Sequencing.”
The reason “why” Inter-Number controls are needed, regardless if you have a single model type or a mixed model offering:
- A method to assign raw material
- A method to assign work sequence
- Used to report incomplete component/missing part identification
- Used extensively for shop floor control (lot size of 1)
- Used as key to daily result reporting
- Is primary control link between component scheduling and final assembly
The “requirements” for using Inter-Number control:
- Timely issuance of schedule and manufacturing/service instruction sheets by Material Control Department
- Accurate and timely feedback of results (daily)
- Timely completion of components/activity according to schedule and manufacturing/service instruction sheets
- Any changing of manufacturing/servicing instruction sheets or inter-number swapping must be by Material Control Depart
A basic process flow example (see below) entitled “Normal Process Flow” shows how Inter-Numbers are used to establish connectivity between components, sub-assemblies, and final assemblies. In the example, if you start by looking at the Main Assembly Line, you will see numbers (1-18) that are circled. These indicate the current day build activity. Also on the Main Assembly Line, you will see numbers (19-39) that have dashed squares around them. These represent the build activity for the next day.
Sub-assemblies, on the example, are indicated by associated numbers that feed into the main line in time for assembly on Main Assembly Line. The same is true for main components that feed into the sub-assembly lines.
The model (assembly) type and associated unique components for each assembly or sub-assembly are indicated on Manufacturing/Processing Instruction Sheets. These sheets coordinate the sequence and configuration throughout the build/service processes.
A recent article written by John Shook does a good job of describing why Lean methods used for timely movement of materials (often referred to as JIT), should in fact be referred to as “In Time” movement of materials. When discussing supply chain in an “In Time” environment, it makes sense to look forward in your scheduling and try to anticipate the needs for “unique” materials, both domestic and imported. Calculate each step in the supply chain and even assign order numbers to each unique component if necessary. Build in the capability to move product/service with the right quality, right quantity, right place, at the right time! It would help you to look back at Blog vol. 27 entitled “Early Local Parts Ordering Flow”, prior to considering the import component flow below that illustrates the level of detail considered in the initial stages of our Toyota plant. It would also help you to look back at Blog vol. 19 entitled “The Importance of Parts Consolidation as Related to Just-in-Time”. In the beginning of our operation, we had to import approximately 70% of our components, while domestically resourcing approximately 30% which tended to be bulkier and heavy materials. Our objective was to change that resourcing so that at least 70% of our components were resourced domestically. As we moved toward that objective, we also tried to be sure to pick a supply base, for each item, where we could establish supplier relationships such that we could order approximately 80% from one supplier, and 20% from a second supplier. This provided us with flexibility to cover unanticipated issues. As I think back, these lessons were not new to manufacturing! Some ten years prior to our establishing Toyota Industrial Equipment (TIEM) in 1987, I spent a lot of time studying Eliyahu Goldratt and his book entitled The Goal, as well as his Optimized Production Technology (OPT) System. It was the first software providing finite capacity scheduling that I used to successfully build “In Time” ordering, delivering, and building quality products in a large air conditioning compressor facility, and in a domestic leader in the material handling equipment industry. Ironically, the work in this ladder operation led to my working to establish the Toyota Industrial Equipment operation in 1987.
Shifting to imported materials, the graphic here is an early, and perhaps crude, example of the detailed planning we did when establishing the flow of materials from suppliers in Japan, through the supply transportation chain to the plant in Indiana. Keep in mind that this graphic was done prior to everything being created using a computer.
To recap the end-to-end supply chain management:
- Determine customer demand (Forecast and actual) (3 mos.)
- Place up dated forecast with suppliers (domestic and imported) (1 month)
- Confirm actual supply demand (domestic 10 days) (imported 35-45 days)
- Adjust customer Supply demand (1 day)
- Receive domestic and imported goods either direct into plant (large and non-common goods), or (common goods into near-by interim holding cross-dock location to be transported to line side on an as needed basis – same day)
- All goods have clearly identified locations within the plant for staging and line side
The ideas contained within this volume of “From the Archives of a Common Sensei” are intended only to provide you with ideas regarding interrelated (Systems Thinking) actions to be considered in your supply chain.