Create a Pull System with FIFO, Kanban Triggers and Visual Management
‘By making our process visible, including visual triggers and a small standard inventory where necessary, we can create our product or service as our customer orders it, instead of working to create something that no one wants.’
We know that our customer can be our end customer or anyone who is next in the process (downstream) from our department or process. In this part of our Lean journey we will start doing things to get rid of work piling up and being forced on us or our downstream customers.
At the Lean Enterprise Institute, this fourth step is simply called “Pull”, and the idea is to create a Pull system as opposed to a Push system. What this means is that you or your department creates a product or service only as your customer (or downstream process) requests, or “Pulls” it. We don’t “Push” our product to our downstream process or customer, or we don’t create product unless it is asked for.
This has the effect of reducing large inventory of unnecessary items, reducing “work in process” or a build-up of unfinished work, streamlining the process and promoting one piece flow (3.5). This in turn improves upon our customer driven metrics of Quality, Delivery and Cost.
Many of the tools below will assist in promoting a Pull system, and fit nicely with the methods we’ve already learned.
FIFO Lane
FIFO stands for First in First out, and it is an outstanding way to make sure that stock doesn’t go out of date, or that work is distributed fairly. It is most commonly used in a “FIFO Lane” where items in a lane are taken at one end and supplied from the other.
Figure 19: An example of First In First Out – a small amount of inventory that takes the oldest first.
You will have seen this in the bread aisle in your local supermarket – you take, or “Pull” bread from the bottom as you need it, and they restock it from the top. Of course, this is the best way to avoid stale old bread! But it might also be how you delegate work. It might be how you replenish perishable medicines. It might be the order in which you prepare food in after taking a customer’s request in a drive-through. The main idea is that the item is pulled only as it is needed, and an empty space in the FIFO lane triggers the need for the item to be replaced.
Not every job will be able to create their product or process from scratch as quickly as a customer orders it. A bakery still has to bake their goods, and a hotel still has to prepare their rooms, for example. This is why keeping a small amount of “inventory” handy in any process via a FIFO Lane or Supermarket (below) can assist you in delivering quickly, without overproducing.
Supermarket
Another similar theme to FIFO is the Lean “Supermarket”. A Supermarket is a predetermined standard inventory that is kept to supply the downstream process in exact amounts.
For example, if a doctor used 10 vials of medicine at a time in one operation, we might keep 10 of that particular medicine in one place so the doctor could take that exact amount for each operation. When that box is taken it will leave an empty space, triggering us to replace it with another pre-made box of 10.
Figure 20: A basic Pull system, where the customer pulls (orders) the product, and the empty squares prompt our team-mates to pull ingredients from their upstream supplier and create another product for the customer.
Kanban Trigger
Kanban is a Japanese term for “sign” or “signboard” and is basically a signalling system to trigger action. In other words, we ask ourselves:
- How do we know when we need to begin work on an item?
And:
- How do we let our supplier know we are pulling work (or product) so they can replenish or create their product as necessary?
What is the trigger that tells us these things? This is where a Kanban comes in.
Traditionally Kanban was associated with a “Kanban card”, which was a card (or small “sign”) holding details such as the product and quantity required of a product, handed to the upstream supplier to trigger production.
In a company using Agile techniques (5.3) it might be items in a Kanban “To Do” lane waiting on their wall. Ask yourself what the trigger is, or if you don’t have one, what trigger would work best for you? In other industries, a Kanban can simply be any trigger to begin working on an item. It might be a green light telling us “ready to go!”, it might be an “ORDER MORE” or “REPLACE” card placed where there are two left of something in stock, it might be an empty slot in a FIFO lane or an empty space (specially allocated by Five S in 4.4) for our Supermarket.
Figure 21: A simple Kanban card, with standard instructions and quantities included.
Visual Management
Visual management is another Lean method that can be applied to industries of all types. The idea is to increase transparency by making your process “visible”. Things that are visible tend to get noticed, and things that are visible tend to get done. This can include detail of work queues, anything blocking the flow of the process, who is doing what or sizes of jobs; the list goes on and really depends on your industry or workplace.
For this step we ask ourselves:
- What information would be really useful to see at a glance, so we can know if things are working as they should?
Then we can go about putting this on one board, signal or sheet of paper for all to see. A Layered Check Act board (5.2) that shows process metrics is a good example of visual management. It could also be instructions for a process step made clearly visible at the work station with Five S (4.4). The Kanban board or Kanban card we mentioned earlier is also an example of visual management.
Visual Management is something that Lisa might use, if she wanted to make her sales calls visible. It is not uncommon for a call centre to have a large electronic board with the amount of people waiting, or the amount of people available to take calls.
If you come up with any ideas for visual management during your Kaizen meeting, add them to your current Value Stream Map as a Kaizen burst (2.5) so you can remember them for later.
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