Two types of Kanban system
To separate Pick-up Kanban from Instruction Kanban
The Kanban itself is clearly divided into two categories: movement instructions for the pick-up Kanban and production instructions for the Instruction Kanban.
The e-Kanban sent by email from the customer with shipping instructions is placed in a box in the shipping area. Replace it with a take-back kanban that is inserted, ship it together with the box to the customer (in this case, one box), and The original goods are checked with the shipping slip and e-Kanban. The replaced Pick-up Kanban remains at the Kanban post.
When a predetermined number of take-back Pick-up kanban left at the kanban post in the shipping area are accumulated (in this case, 2 kanban), they are returned to the assembly yard and replaced with Instruction Kanban that is inserted in the box, and the Instruction kanban is returned to the kanban post to pick up the 2 boxes in the shipping area.
When a predetermined number of Instruction Kanban in the assembly area are accumulated (4 Kanban in this case), they are returned to the assembly area to start assembly work.
For processes with short tact time, such as the molding process in the previous process, the forming process starts when the minimum stock is exhausted, using a signal kanban.
When an Pick-up kanban and an Instruction kanban are combined into an In-process kanban
Kanban is treated as an In-process kanban that rotates in the same process.
When the number of In-process Kanban left in the shipping area is accumulated, the In-process Kanban are returned to the Kanban post in the assembly area (in this case, 2 boards) and the 2 boxes are collected in the shipping area.
When the In-process kanban left on the kanban post in the assembly area, the Kanban is returned to the assembly area when the required number of Kanban have been accumulated (in this case, 4 Kanban), and assembly work begins.
The number of Kanban sheets is the total number of Kanban sheets (Kanban to be picked up and Kanban in progress) or the number of Kanban sheets in process.
- Number of boxes required per day x (Kanban L/T + processing L/T + safety stock) = 1 x (2 + 4 + 0) = 6 boxes
Toyota needs to have a plan to put the product on a level playing field
The "pull-type" kanban system, which operates autonomously on the shop floor to take only the required quantity of items from the front-end process and produce only the quantity that is in short supply, is said to be in direct contrast to the MRP production plan created by the management organization using the "push-type" method.
In order to establish this input order schedule at the Toyota assembly plant, five or six deliveries are made every day. Theoretically, the subcontractor's plant is a subcontractor factory Even though it's not necessary for the company to create a production plan on the side, it still provides what you need, as much as you need, and when you need it Since the daily instructions require you to do the same variety in the same quantity, the daily instructions are leveled to produce the same variety in the same quantity. If the system is not standardized, it is difficult to prepare for production, such as arranging personnel and reconfiguring lines.
In every process, a system that allows us to manufacture the required amount of products at the required time is required. method, it is necessary to eliminate the variation in production volume and the variation in the type of goods, so that 100 units today, 100 units tomorrow, and It's a wasteful and costly way to keep the production system in place with a production that feels like one piece. Even if the Toyota assembly plant receives a large number of orders for the same vehicle model, it will still be able to meet the needs of its own line and those of its subcontractors. A schedule was set up to deliberately introduce vehicle models into the mixed flow line to avoid exceeding the production capacity of In other words, it is not necessary for the subcontractor plant to create a production plan because the Toyota assembly plant prepares a detailed production plan for leveling off.
In other words, it can be said that the reason why subcontractor plants do not need to create a production plan is that the Toyota assembly plants prepare a detailed production plan for leveling off.