Lean companies from every industry and market typically use Day-by-the-Hour (DBTH) charts in production cells and other processes. The DBTH shows what work must be completed each hour of the workday on a visual board which is located within the cell or process. In a factory DBTH represents the products to be made each hour and how many. At the end of each hour the lead person in the cell writes up the quantity actually made, shows the reasons for any problems that occurred, and any quality issues.
This DBTH board gets used throughout the production day to control the process and to make short-term adjustments to offset immediate problems. DBTH data is also used to drive longer-term improvement projects and solve problems permanently. DBTH is a vital part of Lean Continuous Improvement.
BUT WHAT DO I DO IF MY PROCESSES TAKE MANY HOURS OR DAYS TO COMPLETE?
In this blog I will tell a tale of two companies that have found excellent answers to this question.
COMPANY # 1
The first company – a large chemical multi-national – has a DBTH board for each production cell, and the boards show the specific machines or equipment used within that location. There are typically 3 or 4 machines per production cell. The boards are reviewed and updated every 4 hours – six times per day.
The boards list all the process steps and the production coordinator puts a green indicator to show the step that should be completed each 4 hours throughout the day and night.
Every 4 hours the cell team meets around the “4 hour board”. If the required production steps are completed and quality is good, they discuss plans for the next 4 hours and get back to work. If production is behind time, the causes are documented and the team makes decisions about how they can get back on track and resolve the short-term issues. This way the process is controlled, issues are quickly identified, and production is restarted. At the change of shift, the shift teams share the current progress and issues.
In order to solve the problems permanently, the issues/problems are added to Pareto charts (or similar documents) and reviewed weekly by the value stream leadership team. Kaizen events are planned and initiated each week so as get to the root causes, and to change the processes so problems are eliminated. Week-by-week and step-by-step the process is improved and improved again to eliminate waste, perfect the flow, and build in reliability.
HERE’S THE THEORY:
- Plan production using standardized work and establish detailed short-term expectations.
- Frequently review the progress.
- When the process goes “out of control” impacting quality, completion, or safety problems; stop the process and use team-based problem solving.
- When the issues are more complex or have a broader reach, instigate a kind of kaizen event to permanently solve the problem.
- There can be myriad issues, problems, and defects. This 4-hour review with short & long-term problem solving continues every day and every shift so the process is continuously improved.
(For more information about this plan-do-check-act process https://vimeo.com/80386001 The video will be available for 1 month from the posting date.)
THE RESULTS FOR COMPANY #1
The company’s production has been quite volatile for several years. Their average output has been 16 batches per week but some weeks were much higher and others much lower. The process has been out-of-control. As a result of using the Day-by-the-Hour approach to track, control, and improve the process, their output has reached a consistent 22 batches per week for over one year now. There is no magic here!! They achieved this by close attention to the process, and taking action to fix short-term issues, and solve the longer term issues. This is Continuous Improvement or Kaizen.
Our second example involves a medium-sized, privately held company making a range of products including a value stream that produces very large steel vessels. These are cut and welded from sheet steel. A number of fittings, valves, and connectors are welded in, and they are cleaned and coated inside and out.
The manufacturing process takes a similar route for most of the vessels but there are a lot of differences from one customer to another. The company has a pull-system “supermarket” of finished vessels based on customer forecasts of requirements. There is a visual planning board that includes heijunka (level scheduling) to provide an appropriate sequence of production for long and short lead times, and to maximize the flow through the final coating process that also is the value stream bottleneck. The production time averages 20 hours but can vary considerably.
Each time they begin to manufacture a vessel, the supervisors set the times required at each of the major steps in the process. These are posted by hand at the appropriate steps showing the start & stop times. At the beginning of the process the fabrication is done at stationary fixtures; later in the process the vessels are placed on large, wheeled carts that are moved through the process using tuggers.
The start and stop times are posted on boards for the stationary fixtures, and placed in the carts using magnetic signs.
As production proceeds the operators monitor the times taken and report the actual against the planned start and stop times. They also record reasons for delays or other problems. This is the equivalent of the “normal” DBTH, and is recorded on a daily “slope chart” for that day’s production. These charts are updated at the time the task is complete – not at a regular cadence because of the variability of the times taken.
The supervisors use the DBTH as input to their Week-by-the-Day slope chart monitoring the weekly output. The production engineers create similar slope charts that document the issues and problems that occur throughout each day and each week.
WHAT DOES ALL THIS DO FOR THEM?
These visual plans and DBTH charts:
- Control the process through the day and night shifts.
- Identify the causes of production problems when they occur.
- Trigger short-term action to immediately address the problems.
- The cumulative monthly charts enable the supervisors to schedule better and to level production, by showing real-time process information.
- The documented problems are analyzed by the production engineers and supervisors, and instigate many improvements small and large.
… AND THE RESULTS FOR COMPANY # 2?
Over the last 3 or 4 years the production capacity of the value stream has DOUBLED from 20 per week to 40 per week without significant investment or restructuring. The bottleneck now has become the shortage of qualified and experienced welders and operators.
A LAST WORD
DBTH is a simple but vital tool to control lean flow through production and other regular business processes. It also provides the data required to make real continuous improvement to the process.
DBTH works very well with long and variable production processes. You just have to tailor your DBTH to address your company’s unique issues. DBTH applies to all companies making Lean happen successfully.