Heijunka and Lean Pitch Chart
Load leveling to create a lean schedule for batch flow, lean pull, or one piece flow
The biggest benefit of Flow
What it it?
Why is it important?
When can it be used?
Where can it be used?
How to do it?
See our Lean Flow training page
Bookmark = LoadLeveling
What is Heijunka Load Leveling?
One of the primary purposes of value stream mapping is to create flow (ideally one piece flow).
In addition to being a root cause of so many quality problems, (learn more),
batches also cause all kinds of disruptions to continuous flow,
so Load Leveling is an important cornerstone upon which lean flow systems are built.
The idea of lean Load Leveling is to intercept batches of kanban orders or sales orders (or whatever is being processed), and then smooth out the volume of demand (and possibly the mix) by:
1) Releasing only enough orders at a time to meet takt time demand (thereby leveling demand spikes)
2) Spreading the types of orders throughout the shift as much as possible.
Load Leveling for One Piece Flow
The batch way to make 10 units of product X, 5 of product O, and 3 of product Z would be:
The Level Load way might be:
Bookmark = PitchBoard
Lean Pitch Chart
Also known as Pitch Board or Production Pitch Tracking Chart
Used to level the flow of work to an operation set up for lean flow
This lean tool is appropriate for operations that:
- expect a steady flow of production — based on takt time.
(you would use a Lean Pull Priority Queue for a process governed by lean pull rather than lean flow)
- produce a single product or product family
(you would use a Heijunka Load Leveling Box for a process that also needs to consider variety mix)
There are several ways to use your Systems2win Pitch Chart Excel template:
- If it is convenient for your workers to do data entry directly into the computer,
and the Pitch Chart will almost always be visibly displayed on a large monitor throughout the day — (so that it meets the criteria for an effective visual control), then you might enter your data directly into the Pitch Chart Excel document.
- More commonly... you will print the Excel template, and have your workers manually enter the data throughout the day. (Perhaps having a low-pay-scale person enter the data at the end of the day just to cross-check their math)
- You might personalize the Excel template for creative variations for unique situations.
Perhaps use it as a prototype to create a non-computer-based Pitch Board using moveable magnets, or an erasable white board, or a wall board with pocket folders, or any other creative way of accomplishing the same objective.
Monthly Pitch Log
The Monthly Pitch Log provides a color-coded summary for at-a-glance trend analysis,
so that your supervisors and managers can quickly see patterns that need attention.
(Does productivity often dip after break times? Are Wednesdays better than Fridays?)
Bookmark = Heijunka
What is a Heijunka Box?
to level the flow of both work volume and variety mix
Also known as a Heijunka Board, Lean Schedule Box, or a Post Office Box
A Heijunka Box is a physical device used to level the flow of work volume and variety mix.
(Contrast this with the Pitch Board or Priority Board, which level work volume only)
A Heijunka box is usually a mailbox-looking thing mounted on a wall — with cubby holes that each hold one kanban card or folder or other form of work authorization.
The labels at the top of the box are usually time periods
(in the time increment determined by the Pitch ).
If there are labels on the side of the box, they will indicate variety mix. More commonly, there are no side labels, and variety mix is determined by the contents of the kanban card or folder in each slot.
If the product family has products with varying takt times, (e.g. some products take 2 mins, some 4 mins, and some 8 mins), then some of the slots will be empty beneath a kanban card for a long-takt-time product. It is common to color-code the folders or kanban cards to make the length of takt time visually obvious.
If there is more than one worker, then either:
- The workers work as a team
- Each worker pulls work authorization from the Load Leveling box
- Each worker has his or her own Heijunka Box
Bookmark = SchedulingTimeIncrements
Heijunka Scheduling Time Increments
might be smaller than your Pitch Interval
To establish the smaller load leveling scheduling time increments within the Pitch interval,
If there is no common denominator, then your choices are:
Remember — every implementation of lean principles is an invention. Your ultimate goal is to use lean management and mentoring to instill a lean culture — where people truly understand the underlying principles — and can apply them creatively to unique situations.
Although some ERP applications do offer electronic heijunka load leveling options,
it is far more common (and usually much simpler) to use a physical heijunka box...
unless you only need to level the flow of work (without consideration for variety mix),
and then you can use the Systems2win Lean Pitch Chart template (described in the section above).
Late Load Log
A simple visual system to continuously improve your heijunka scheduling
You can always just glance at the heijunka box itself to see orders that are currently late,
but that just takes care of your immediate firefighting —
and doesn't provide the visibility of trends needed for more proactive continuous improvement.
That's why it is often worth the extra data entry to also maintain a Late Load Log
comparing estimated to actual completion time —
with clearly articulated comments explaining the reasons for each miss.
Make your own Late Load Log template
Try making your own Late Load Log Excel template — consisting of just 4 columns, with no math, no buttons, no dropdown lists, and no special formatting... it's as easy as a template gets.
And a half hour from now...
you will better appreciate just how much time your Systems2win templates save you,
You will better appreciate the "extra touches" that make Systems2win templates so much more useful than home-made templates.
Things like pop-up help on every header, every cell correctly formatted for its intended purpose, consistent styles and formatting conventions used for all templates, a Sample of what a finished document might look like, a Help worksheet with step-by-step instructions, links to online training web pages, training videos, free technical support... and a whole lot of useful features that would take you a lot longer than a half an hour to do right... and then a lifetime to continuously improve each tool. Even simple ones like this one.
Bookmark = PullQ
Lean Pull Priority Queue (FIFO Lane)
Also known as Lean Priority Board
Used for load leveling production flow to an operation set up for "pull" (rather than "flow")
One lean principle is "Flow where you can, pull where you can't, only push with a FIFO Lane"
When a shared or constrained resource supplies a supermarket using a pull system kanban system, the visual system for production tracking is usually some form of a Pull Priority Queue.
When Production Kanbans (or similar production signal) return to the producing operation, they are typically put into the Pull Priority Queue in FIFO sequence. (first in first out)
Please keep in mind that every application of lean principles is an invention. Your "pull priority queue" could be a board, rack, track, wire, or a taped off lane leading to the work center with carts carrying the FIFO-sequenced incoming work. Also keep in mind that the FIFO lane might not use FIFO — but could use any sequence-scheduling algorithm — which is why the more correct term is sequenced pull lane.
The important thing is to incorporate some form of coding (usually green, yellow, red colors) onto the background of your lean Pull Priority Queue to indicate the likelihood that the orders in that portion of the queue will be completed on time.
Color codes for a Lean Pull Priority Queue:
- Green = Plenty of time to fill the orders in this portion of the queue.
- Yellow = Heavy load — but should be able to fill these orders without overtime — as long as nothing goes wrong.
- Red = Will require overtime or the last jobs will be late — unless preventative action is taken.
Think of the color codes this way...
You are standing in line with your kids queued up for a roller coaster ride. You look down at the color painted on the sidewalk below you. If you see green, then you are standing in the part of the queue with other happy visitors who will soon step onto this ride very soon. If you see yellow below your feet, then you are visiting on a day with heavy loads, but you will probably get on the ride within a reasonable amount of time as long as nothing goes wrong. If the sidewalk beneath your feet is red, then you are standing at the back of a very long line.
Now imagine that you are at the top of the ferris wheel looking down on the long lines of people waiting for each ride. With one glance, you can quickly see whether the last person standing in each line is standing on green, yellow, or red sidewalk.
That's how a Pull Priority Queue works.
Pull Priority Queue Hourly Status Report
With one glance at a Pull Priority Queue, you can tell whether that production center is on track
to meet its production requirements.
But in order to view trends over time, you will want to maintain a Pull Priority Queue
Hourly Status Report.
Every hour (or your chosen time increment), you color-code the cell for the color that you see
beneath the last order in the Pull Priority Queue.
Bookmark = JobLog
aka Job Tracking Log, or Job Estimate to Actual Tracking
One of the foundational principles of any lean management system is that every lean production system needs a corresponding lean management system — and one key element of each lean management system is to provide a way for the workers to record clear and articulate comments explaining the reason for every "miss" of expected vs. actual performance.
For this purpose, the best lean system for visual management for a pull operation is a simple Job Log — that compares estimated to actual set up times and run times per job — with space for the operator to explain the reasons for each miss.
In addition to the lean load leveling templates on this page,
When you own your Systems2win templates, you own them all.
Bookmark = Reading
Suggested Reading and Resources for Lean Flow
These books introduce even more approaches for Lean Load Leveling —
such as the Card Rack Scheduling Board, a Floating Pitch Board, Refinish Reorder Boards,
visual control boards for non-cyclical tasks, and more...
Acid test for Visibility of Lean Flow
(or you have invented your own creative tool to make flow visible)
ideally with no further instruction, but perhaps with a brief explanation for:
1) how to read your at-a-glance visual control chart that makes heijunka flow visible for this process
2) how often it is updated — which usually coincides with your Pitch Cycle
(which is measured in hours; not days)
and then ask...
Is this process flowing as expected?
The answer should be either yes or no... red or green... no yellow.
Learn more about why this is the ultimate acid test for your entire lean transformation
Do something about the problems you find
A primary purpose of any lean visual management system is to reveal problems.
No matter which heijunka tool you are using, if it shows (red) flow stoppages,
the assumption is that you will actually do something about the problems that get revealed.
Every lean tool needs
Lean Coaching System
- Perhaps the flow stoppage is urgent enough to trigger an immediate jidoka swarm.
- Perhaps your team might maintain a Pareto Chart of the top 3 priority problems you are currently working on — and publish it on your Team Accountability Board.
- Perhaps a team member might volunteer to lead an A3 problem solving exercise.
- Perhaps a problem might prove worthy of a Kaizen Event.
- Perhaps initiate a series of PDCA Kata Coaching Cycles.
- Perhaps a problem might need to be escalated
to a higher tier of your lean management structure.
- Perhaps a problem might affect and be of interest to the larger value stream.
If your lean leaders don't actually solve problems as they surface —
then people will quickly lose interest, and wonder why they're doing all this extra paperwork to identify even more problems that management ignores.