Lean Standard Work: How to Build to Flow
In this series, we’ll be talking about standard work. And in this article, I’ll describe lean standard work.
What is Lean Standard Work? Lean standard work is used to clearly define the exact way of working, the exact number of operators needed and the ideal balance of work-in-progress in order to work to the required pace to satisfy customer demand. At the heart of lean standard work are several tools that are used to improve productivity and to enable the team make when the customer wants product and only what they want it.
The rest of the guide will break down exactly what lean standard work is and how to use it in your facility, to improve productivity.
Table of Contents
For ease, here are quick links to the rest of the main topics within this article:
What takt means and why is it so important to flow? We’ll answer both…
We’ll revisit why we need lean standard work in the first place and how it can take you further than creating a simple standard operating procedure.
We’ll define the 4 main tools used in creating flow and when using lean standard work
Lean standard work starts with observing timings and how things are done. Here’s an overview.
We’ll walk through the 4 main templates and phases that create lean standard work, and which allow you to drive single-piece-flow in your work cells.
All About Takt
Before we get embroiled in the components of lean standard work, we must begin with Takt.
Takt is a German term, meaning drumbeat.
In lean, we refer to Takt as the customer drumbeat. It’s what sets the pace of production and allows us to align all our processes and systems to support this takt rate.
TAKT and Pull
In a pull production facility, takt is the rhythm of production in harmony with the pulse rate of our customers. In other words, we build our processes to suit the rate our customers consume our orders.
It’s like the conductor to the orchestra.
Takt sets the pace for our systems to follow.
Using lean standard work, we can quickly define the exact resources needed in the best possible sequence of work, to ensure Takt time is met, and without the added cost of too much resource (space, operators, equipment, materials, etc).
It’s like Goldilocks – everything is just right.
Remember, Takt is not a measure of how many you can produce, but how many you must produce, according to your customer pace of demand.
Takt will change on two accounts:
- When the number of hours available changes
- When the customer demand changes
Takt Time Formula
The way to measure your takt time is:
Available time / The number of units required over that same time period
For instance, if you needed to produce 1000 luxury grip pens per day (on average), and your business works 8 hours (28800 seconds), Takt would be:
28,800 seconds / 1000 pens needed = 29 seconds
What Does This Mean?
Well, it means that we need to be producing one pen on average, every 29 seconds.
We can create lean standard work to ensure that one pen is produced every 29 seconds, and using just the right resource to do it.
We use facts and data to define this optimum way – meaning we can increase our productivity and profitability.
Why Lean Standard Work Helps Us
Lean standard work allows us to:
- Analyse and observe current cycle times of processes
- Think in one piece flow (and move away from the slow batch and queue methods)
- Create the best way of working to suit takt, based on fact and data
- Standardise it and make it the way things are done
Why Batch & Queue is Not the Way
On the other end of the spectrum to lean production (and pull production) is mass production. Often referred to as batch and queue, it involves making products in batches. This typically means that products are produced and then moved on in large quantities at a time.
The problem is that there are many inefficiencies to this type of work, including:
- Products that have been made, wait until the entire batch has been completed. This slows the entire production machine down
- Often, the batch doesn’t reflect what the customer actually wants – just what the business believes is efficient to run
- There’s no real thought in terms of scientific analysis to streamline processes – people are allocated work, but not in an optimised fashion
- Making in batches slows the production system down – fact. It harbours the 8 wastes.
One-Piece Flow Utopia
One-piece-flow is the optimum of lean. It involves making one product at a time, and then moving it on. This is repeated until all demand is completed for that period of time (often the day).
This style is reflective of a lean production business, and pull production.
In theory, by reducing batch sizes to one, your production is drastically sped up. Your productivity increases and so does profitability – think reduced work-in-process, less people needed in the process and less space needed too.
Reducing batch sizes to the goal of one is the utopia of lean… and something you should be working towards.
You may not achieve it today, but over time, you should definitely aim for it.
Lean Standard Work Examples
Here are some real-life experiences I’ve had by implementing lean standard work and creating one-piece-flow:
- A Door Manufacturer –
In another lean standard work programme, we managed to double productivity, increase sales capability by around £3 million per year, and converged two factories into one, without adding any additional headcount.
- An Aerospace Manufacturer –
An assembly team in a large aerospace company, assembled fuel pumps. They had to produce 40 ship-sets per week. The team of 4 people worked excessive over time, but couldn’t get anywhere near 100% on time delivery each week. After implementing their standard work project, they managed 100% on time every week and with only 2 people in the assembly process.
- Valves Assembly –
In another assembly cell, one person spent all week assembling valves. Typically, 5 out of 10 would come back for rework after testing. Once we had completed our lean standard work project, we improved productivity by 3 times and improved right-first-time into testing to over 90%.
- A Medium Sized Manufacturing Business –
We turned a work cell that was working in large batches, but always missing delivery, from 4 people…. down to 2 people, working to one-piece-flow.
Building Work Cells
Where lean standard work is at its best, is when you bring multiple processes together and build a small team or cell around them.
This often results in creating multi-skilled teams, working in dedicated work cells, where they effectively managing themselves.
It’s good for both morale and productivity. And in this scenario, everyone knows exactly how to work and what to do in this cell, every day.
Tools for Lean Standard Work
So, we know that by using lean standard work, we can systematise exactly how things are done to takt.
We can do this using matter of fact thinking.
This creates repeatability and consistency.
We can know with certainty how much work-in-progress we need, how many operators are needed, how their work content is divided, and consistently know how long it will take to make the products.
We do this by using lean standard work tools.
Each one builds up our analysis and facts, until we’re clear as to how to work optimally to takt.
It’s like building a house. There are certain things we need to do in sequence to build it. In our lean standard work project, we need to analyse, observe, and then design how things should be, before ever thinking about building the new process.
These 4 tools are:
- Production Capacity Chart – Understand how many times each process can be repeated, to ensure you have enough capacity to meet regular demand
- Work Combination Chart – Define the best utilisation of each operator’s time in tandem with TAKT
- Work Methods Chart – Define how each operator will process the work as standard
- Standard Operations Chart – Bring it all together as a visual document, for operators to follow in the cell
Time Observation is the Way
Lean standard work starts with analysis. Much like an Architect would measure, check, measure some more and create mock-ups before finalising any detailed drawing, we need to do the same.
Our improved way of working is built on science and fact. Not opinions and gut feel.
We need to observe processes and timings.
- How long does it take to process the entire product from the minute the raw material arrives to delivery to customer?
- How long does it take to process the required daily demand?
- How long does each piece of work content take in their own right?
These are all answered through observation, using a Time Observation Sheet.
The objective here, is to observe how long every activity takes. Get a good average across the team.
Once you have these timings, it’s then about using this information to delve deeper in your analysis.
The next part in our process is to know exactly how many operators we need on each line and in each cell, to be able to build products to takt.
Line Balancing is an additional part of this. It shows us how to distribute work content across the cell or lines, so everyone is utilised.
This helps ensure that there’s little waiting time, and that some operators are not doing too much.
It’s called line balancing because the aim here is to balance work across the team and evenly distribute it based on the time it takes to process each work element.
4 Steps to Cell Staffing & Balancing
Step 1: Create a process map of the operations in sequence. At each stage, add the process time from your time observation sheets
Step 2: Create the current state operator balance chart to show how work is utilised right now.
Notice the gaps between the takt line and operator 2, 3 and 4’s total activity timings? These are nothing but pure waste and inefficiency and should be closed up.
Step 3: Identified the number of operators needed using the following formula:
Total Cycle Time / Takt Time
For example, 1351 seconds total cycle time against a 450 seconds takt time = 3 people needed
Any more operators than this, and you’d be adding waste and additional unneeded cost to the business.
Step 4: Now re-design the activities in a future state balance chart. Allocate different work content until each operator shares roughly the same load, within takt. (ideally each operator should have work balanced up to the takt line)
In our example, there are 3 operators needed. In some instances, a round number is never the case. It often falls at something like 3.3 operators needed.
In this instance, it means that there’s too much work for 3 operators and not enough for 4 to keep that person busy.
When this happens, look to reduce cycle times further by stripping waste out of processes, until you can comfortably run the area with 3 people.
4 Phases to Lean Standard Work
Once you’ve got the data, analysed it and balanced operations, it’s now time to use the 4 common tools to bring your lean standard work project to life.
The first of which is…
Phase 1: Understand Capacity
Using the process capacity chart, you can identify how many parts can be produced for each operation. It’s important to do this as there’s no point going any further if you’re going to be working over capacity.
Here’s an example of a Process Capacity Chart:
It’s simple to see.
- Enter each step and the associated timings.
- You’ll then get a total cycle time and total units that can be produced in the given period of time
- If the number of units in Column G is less than the daily requirement, then you’re over capacity.
- If you’re under, then, all is good!
Phase 2: Work Combinations
A work combination chart allows us to take the data from the process capacity chart and visually demonstrates all the work activities combined together, in relation to takt.
The work combination chart also shows the manual and machine times, walking times and set-up, too… all in one linked sequence of activities.
It’s created by:
- Drawing a red line to represent takt
- Including all the activity from walking, setting, machine time and manual on each line
Once you have this stage confirmed, you can use the agreed sequence of work to define the layout of the cell for optimum flow.
Note: Ensure that all the activities combined, do not exceed the takt line. If they do, then it’s time to return to the operator balance charts and re-evaluate, to ensure work content is aligned and fits within takt.
If the total time falls short from takt, then perhaps you can add more work content to ensure the operator and process is fully utilised.
Also, if a machine’s time exceeds manual time, then operators will be waiting for the machine. Can you get them to process more manual work whilst waiting?
Phase 3: Create Work Instructions at each Station
To do this, we need a Work Methods Chart. This document demonstrates the exact process steps at each workstation.
It details the specific process steps and work instructions to enable new workers to pick up the methods quickly and effectively.
Notice it has everything you need to show the sequence of work and other standards, like:
- The time it takes to do the task
- Reference to critical process steps (critical to quality, safety, etc)
- Any specific measurements or checks needed at each stage
- Clarity in terms of what to do and how to do it
This form allows the operators to follow the exact sequence of steps you’ve already defined in the earlier phases of the lean standard work project.
Now you have this standard, you can track it to see how it’s actually working. You can use it to quickly train others and to make additional improvements, as you go.
Phase 4: Define the Cell Standard
You’ve defined the work at each station.
You now need to create standard work for the work-cell. This involves all operations, and all employees and shows how work flows through each station as an entire process.
It typically demonstrates:
- The standard flow of all operations to takt
- The standard work in progress
- How product flows through the cell in sequence
- Any areas that are critical to quality and of health and safety importance.
This is often called a Standard Operations Chart and looks something like the following:
Notice that it’s clear to see the sequence of work in the cell and how each process repeats with every new part.
It’s also clear to see special pointers, like critical to quality, health and safety and where standard work in progress should be.
To ensure adherence to standards, operators should check this regularly. Management should, too, to ensure the standards are working.
With these documents in place, you’ll be well on the road to developing flow by using lean standard work for your business.
Want to know more about lean standard work? Check out my recommended book.