Recognizing Lean Opportunities
With the introduction of each new part into production, someone must establish new setup procedures, tools and fixtures. In many cases, when a new process or part is first set up, the most efficient and effective steps are not immediately apparent. After running the new part for a period, opportunities for improvement, such as setup time reduction, become more evident. In a Lean Manufacturing environment, line workers and supervisors are trained to recognize opportunities for improving workflow. Because setup time reduction produces big benefits, the workers in a Lean Enterprise are always striving to streamline setup procedures. Setup time reduction is an essential Lean practice for improving workflow.
Long Setup Times
Most production machines require setup before processing each new batch of parts. I have seen instances where it has taken as long as 8 hours to set up a machine for the next job. Unless the engineering design for the machine changeover is specific for speed, setting up is rarely quick. To minimize lost production time, most companies compensate for long setup times by running big batches. Big batches cause long lead times, necessitating a make-to-stock (MTS) manufacturing model. This is truly one of those tail-wagging-the-dog situations. Clearly, keeping an eye out for setup time reduction opportunities is a very worthwhile and valuable Lean practice.
Big Batches Waste Time
Reducing setup time is essential to running a Lean operation. Minimizing wasted chronological time is a fundamental Lean Concept, enabling the company to achieve their Lean Goals. Big batches waste chronological time! On the other hand, setting up the machine, which can take minutes to hours for every part, makes no sense when the operation takes only seconds to perform. We have a conundrum. How do we reconcile setup time and batch size? Bigger batches are not the solution. In a Lean workflow, we want “smaller quantities more often” often described as “One-Piece Flow.” We need to solve the real problem of lengthy setup times preventing one-piece flow. Setup time reduction requires using a practice called “Single-Minute Exchange of Die” or SMED.
The Old Process Needs an Update
Once again, the workers used the shadow board technique described in our previous article on Lean Empowerment. In this scenario, the production process required many different “standard” lengths of bar stock, each cut to a different standard dimension. Because this factory practiced one-piece flow, each order following the one before required a number of different standard-length bar stock pieces. The bar stock cutoff saw had to be reset on every order for each next standard length. Typically, there were two pieces of each standard length cut for every job. This required the cutoff saw to be set up after every two cuts. The workers recognized set up was taking much too long. Up to this point, the standard setup practice was to use a tape measure to set the stop distance from the saw blade and then make the two cuts. After the cuts, workers used a tape measure to reset the stop distance. Machine setup time was longer than the actual process time!
Workers Design a Better Method
The workers in the cut-stamp work cell recognized the need for setup time reduction and decided to come up with a more efficient process. They constructed a set of simple jigs representing the standard cut dimensions. In addition, the workers designed and built a shadow board to store the jigs, shown below in Figure 1.
The shadow board contains shadows representing each jig tool. Drilled holes in the jigs and pegs enable quick and easy parking of the jigs on the shadow board. If a jig is missing from the board, the workers know they need to find the jig and take it back to the board where the jig lives, unless it’s being used for setup. The shadow board, mounted in very close proximity to the cut-off saw, eliminates additional travel time for the worker to access the jig each time he needs to set up the saw.
Management Embraces Initiative
As in Part 1, the workers brought forward an idea, this time for improving productivity. Once again, management embraced the workers’ suggestion and supported the initiative with resources, mainly in the form of allocating worker time to fabricate and install the shadow board. By reducing setup time, productivity improvements paid for the project within a week.
The initiative also improved quality by ensuring uniform length for standard components every time. This, in turn, decreased pressure on the assembly workers who initially required additional time to compensate for minor variations in part length during the assembly process.
Motivated To Improve
So, what motivated the workers to take action? The recent Lean Training and exposure to tools in the Lean Toolbox inspired the workers to think about solving problems, which include things like setup time reduction. The workers learned about shadow boards, which have many possible applications for solving a wide range of problems.
After Lean Training, the workers started noticing many areas to implement shadow boards to resolve issues and increase efficiency. For example, In Part 1, workers created a shadow board to establish a two-bin system for maintaining their inventory of sharp saw blades. In Part 2, the workers created a shadow board to store the setup tools, which, in turn, reduced setup time.
The workers were also motivated because lighting was not sufficient in the corner of the plant where the cutoff saw was located. The workers had a hard time reading the fine graduation marks on the tape measure. For example, setting up the saw to make a cut length of 28 13/16” was very challenging due to the dimly lit corner. For every setup, the workers were straining to see the marks on the measuring tape, diminishing accuracy and repeatability. With the new process, the worker only needed to chuck in the setup tool, push the stop up against one end of the tool while the other end of the tool rested against the side of the saw blade, tighten down the stop, pull out the setup tool and the machine is ready to make the cut. Easy, simple motions. No need to think, no need to strain the eyes. The workers loved this.
Setup Time Reduction Achieved – Worker Stress Reduced
The new setup method took stress out of the job. The tools were set up with a color and numerical key. The shadow board was set up to make it easy to find the right spot for each setup tool. Once again, a minimal investment in time and money created tools and procedures, which improved productivity in concurrence with improving quality. This was an all-around win-win situation. While this may seem like a trivial project, once again, both workers and plant management took an important step toward building and reaffirming the newly emerging Lean culture at the company. A small victory but a victory nonetheless.
Andy Pattantyus, CPIM is president of Strategic Modularity, Inc., a systems engineering consulting firm that works with clients on process oriented Lean Transformation projects, including initiatives to improve administrative workflows. Andy is also an active member of APICS-SFV and The ACA Group. If you would like to get in touch with Strategic Modularity, Inc., contact Andy here.