One of the central questions, people do when start to develop a lean strategy is:
How do I start?
Because we have so many thinks to do as
it seems a mess.
So, how do I start?
Lean Strategy in Toyota
To answer the question,
we need to check what Toyota do to deploy the Lean Strategy and follow their lead.
The first question in TPS (Toyota Production System) is always the same:
What does customer want?
Then we can start defining value:
- What customer want
- How does he want
- When does he want
- How many units does he want
If we know that,
then we can check any process and
define which steps add value (according to customer needs)
and which not.
Any activity must be verified answering this question:
Does this activity add value to the customer?
In other words,
will the customer pay more for the product after doing this activity?
But maybe we have many clients,
so how can we know, what do they value?
If this is the case, check the top ones, those that give us the best benefit.
How many customers do generate 50% of sales?
I bet not many.
Then, what do they need?
Talk directly with them,
ask sales people if you can join them to visit these customers.
if you get the top 10 and you talk directly with them
(don´t speak with sales, speak with customers directly),
you will know where is the value.
The seven wastes
Now with this information, let´s remove muda.
anything that adds time or cost with no value for the customer.
how can I identify muda?
take note of all errors in production, in picking, in packing, and identify the root causes.
Check all the processes and define the steps that don´t add value for customers, to eliminate them.
For instance, classify each step as:
1º Generate value (normally 5%)
2º Don´t generate value but is necessary to permit the company work (normally 35%)
3º Waste (normally 60%)
Concentrate all your efforts to eliminate type 3 and errors in production and logistics;
then you will see great success.
Maybe you think, this is a time-consuming process and is true,
but lean is similar to search gold, is bored, is tired, and we need to have a lot of discipline to find it, however, when you find gold, you don´t care about the effort.
Lean, means to do more with less,
and this is everything except smooth and comfortable,
but it permits companies to survive by implementing the Lean Strategy.
To better understand here there are 4 very explaining pictures:
In the previous section,
we spoke about value and muda,
when we have identified them,
the next step is to start working with a continuous flow.
How can we do that?
Toyota’s Lean Strategy is explained in the next points:
1º Re-design the working processes to achieve a continuous flow that creates value added.
2º Make any effort necessary to reduce to zero the time waiting for somebody to continue the next step of the process.
3º Create a continuous flow to move quickly the parts and information to link all processes and people showing clearly wich problems block the flow.
how can we create a continuous flow and eliminate wasting time?
How can we move parts and information, linking the processes?
There are 3 lean production tools you can use.
Lean Production Tool #1 – 5S
Five Japanese words that mean:
1 – Seiri = Sort
2- Seiton = Set in order
3- Seiso = Shine
4- Seiketsu = Standardize
5- Shitsuke = Sustain.
Clean, sort and standardize processes to get
each piece in the right place, and the right place for each piece.
Lean Production Tool #2 – Value Stream Mapping
Create the value stream map,
showing the actual value stream map and creating the future value stream map.
You can see additional information in other posts.
Lean Production Tool #3 – U-Cell
Move parts quickly from one process to next one,
reducing the time, creating U shape cells.
This U shape permits operators to attend different workstations,
as they are close to machines and have all parts and tools close to their hands.
When we achieve these steps, you can start to continue the Lean Strategy development
working to create a Pull System.
How do we work in a pull system?
What does Toyota say?
Supply to your customers downstream in the production process,
what they want,
where they want,
and in the quantity they want.
The material replenishment based on consumption
is the fundamental principle of just in time.
Reduce as much as possible the work in process and the inventory,
replenishing very frequently according to customer consumption.
Be proactive to daily changes in customer demand
instead than trusting in planning and the computer systems
which follow the inventory evolution.
Here it starts the funny lean;
we need to produce or ship what is needed in the next process immediately,
no more no less, and with the minimum possible inventory.
And how can we do that?
First, checking the stock level, we do have.
Remember that stock is excellent to hide inefficiencies or waste,
and therefore cost increases, longer delivery times, and quality problems.
But hiding inefficiencies doesn´t mean, that doesn´t exist.
A pull process means that material movements
are flowing according to customer demand at any time.
It means that the demand defines what should we deliver,
not what planning says based on the forecast.
Every process is demanding to the previous one,
what customer need, and this is the concept of pull,
as the last process, demand to previous what customer need,
this process, demand to previous, and so and so till the first process.
However is not possible to work in flow with no interruptions,
there will be areas where we will need some stock
to prevent stops in the production process.
Remember that theory and reality are completely different,
there are different cycle times,
in each process, also long distances between processes,
different change over times per machine,
and maintenance or quality issues.
So, how can we proceed?
Pull explained by supermarket
A very clear example, we know is a supermarket.
When you do shopping, how many units are on the shelves?
All the supermarket stock
Only a few units, and what is happening when there is some consumption?
The part is replenished to the top.
In a Lean manufacturing plant works in the same way.
Process 1 won´t produce anymore till process 2 start consuming units.
It´s also similar to your car dashboard.
When do you replenish petrol for your car?
When the petrol light shine, right?
It would be stupid to replenish every X kilometers, just in case.
We have a light or a petrol indicator that gives the warning
to remind we need to replenish.
The supermarket, permits you working in flow with no interruptions,
keeping just a small stock with a warning indicator (kanban) between processes.
you only need to determine how much stock do you need,
to reduce as much as possible, the stock level in the plant,
but with no risk to stop production.
if the flow of a product can be interrupted for a maximum of 30 minutes,
and the next process works in a cycle time of a unit per minute,
the stock of 30 units, will permit work during 30 minutes, no stopping.
pay attention to the daily demand,
and if possible few times per day to determine how many times
do you need to replenish the supermarket.
how do we ensure that we replenish supermarkets properly?
Kanban System to replenish
that is just a card that controls the internal demand in the production system.
Here are the kanban rules.
1º Next process withdraws material from the previous process.
2º Previous process produces only the quantity withdrawn.
3º You can´t withdraw without kanban card
4º You can´t have parts with no kanban cards.
5º No defects in the parts withdrawn
6º Reduce as much as possible the number of kanbans.
Here there is a video with the 8 rules of a Kanban System.
But for some people is tough to define the quantity to produce per day,
To create a continuous flow we need to keep in mind the 3S, Standardize, Stabilize, Simplify.
Standardize processes, to be sure we always work as scheduled.
Stabilize the process, with no interruptions, as explained before
Simplify the process via kanban, to reduce lead time and keep it simple.
To stabilize may help you the 4M,
Conclusion – Lean Strategy in 6 Points.
Before to start with a Lean Strategy you have to understand what is lean.
Once you did it, you can follow this six steps.
1º – Resolve as much as possible the quality issues, as well as wasted time and other problems that produce instability in the flow.
2º – Make possible that parts flow as fast as possible with U shape cells, avoiding process variations.
3º – Process must be standardized as much as possible and stabilized along the different processes.
4º – Start using pull, don´t withdraw material till you get a demand from next process.
5º – Try to reduce production batches, increasing the deliveries and leveling the internal demand.
6º – Do Kaizen every day to improve the process.
Is not easy and need a lot of work,
but is possible.
I did many times with fantastic results.
I will be happy to understand your point of view.
Leave a comment below!