You may think that your workers are fast when it comes to machinery change-overs, but lean manufacturing principles bets you can be better. Lean encourages you to think again. The goal is to identify ways to improve your operation by reducing waste motion and effort.
A changeover is the time it takes to setup a machine to produce one pallet design or lumber dimension that is different from the previous one. In lean jargon, this is known as single minute exchange of die (SMED), since many of the early lean principles were used on metal fabrication.
The first step is to establish a team to evaluate your changeover processes. This should include some management, a foreman, machinery operators and possibly even someone representing the technical department of the machinery manufacturer. Don’t let the team swell too large. Keep it to 4-6 people maximum.
Then you need to determine the full changeover cycle. This is the entire period that will be measured and it starts when the last product or part is made at full speed and ends with the first product/part of the new design/dimension produced at full speed. This measurement arch looks for things like time to return tools, position lumber, load new nails, test new settings, etc.
Workers need to be informed and know what is going on. But they shouldn’t try to do things that will make the process faster or slower than normal. The objective is to study the changeover as it truly exists today. Recording the entire process with video from multiple angles can help you identify things that you might miss with visual inspection. It is good to take multiple measurements and involve different teams if more than one set of operators usually works on a particular line.
Then you evaluate the video and written notes to determine the specific steps required to complete the changeover as well as the average time it takes to do it. The order may vary from operator to operator, and some steps may be left out by some teams. That is okay. You will want to note every step that any operator makes. To facilitate this process you can use a whiteboard or some other method to easily move things around to find the right order and identify what elements can be eliminated or done while the machine is still running at full speed.
This is a critical distinction, steps that can be done while the machine is still running are called “External Steps.” Those functions that can only be done when the machine is idle are called “Internal Steps.” Many times things that are done when the machine is idle could be done while it is in operation. Thus, you want to move all external steps to external. You do have to consider constraints, such as ongoing activities required to keep a machine going, or such as feeding product into the machine or removing finished goods.
The next way to cut waste is to look for steps that can be eliminated or streamlined. For example, maybe you can rearrange how things are placed around the machine to reduce wasted motion by the operators. You may decide to put tools needed for changeover next to the machines in a designated place. Or you may stage lumber differently to facilitate faster changeovers.
At this point, you may want to contact the manufacturer or check the manuals or training videos provided by the machinery supplier to examine your process and see how close it is to what is recommended. You may have eliminated something that is crucial. Once you get an improved process developed it needs to be written down and then tested and examined to see if it works.
Upon coming up with the right new procedures they need to be codified and workers trained so that everyone knows this is the new way to do things. This calls for a checklist and examination by the foreman to make sure the new process is followed. Don’t be surprised if long-time workers struggle to make adjustments. Remember that change is hard even though it is also very necessary for companies to succeed.
Many of the improvements to the changeover process can be done with minimal cost. The real challenge is the difficulty in getting people to try new things and change old patterns. One way to get everyone onboard is to reward employees for passing inspections of the process and meeting new changeover targets. Of course, some machines are designed for faster changeovers. And this is a crucial feature to consider when buying a new nailing or sawmill line. But if you can’t afford new equipment now, there are some ways to improve your process if you just look for them.
Tips to Consider for a Makeover
• Be Prepared: No it’s not just for Boy Scouts any more. When you consider people who have to work quickly, fire fighters and NASCAR pit crews come to mind. One key thing about them is that they are prepared in advance to execute. For example, fire fighters set out clothes and boots so that they can quickly dress when the alarm goes off. NASCAR teams practice every step and have prepped everything from the lug nuts to the tools to reduce wasted motion.
• Storage Solutions: Every tool and item needed for a changeover needs to be stored in the same place, readily accessible and put back in the right location every time. You need to have a way to easily identify missing items as well as reduce the number of steps that employees need to physically take to get to tools and new material needed for a change-over. The key is store with a purpose.
• Checklists Drive Precision: The best way to ensure the new process is followed is to use a checklist that everyone must review. A checklist can also be used to make sure that everything is staged and ready to go before executing the changeover.
• Computerized Setworks: If possible pre-program typical designs into your system and integrate it with other systems so that programming time is done during off peak times or when the machine is running if possible.
• Remove Clutter & Obstacles: The area around machines may be too cluttered with hoses, stacks of lumber, etc. Analyze what is there and ask if it can be elevated, hidden, stored somewhere else or just gotten out of the way. This can reduce trip hazards, make the work space safer and boost productivity.
• Continuous Training & Monitoring: As employees come and go, it is important that best practices are taught and retrained. Plus, it may be good to do a changeover assessment every few years to look for new ways to remove wasted time and motion. It is hard to improve what you don’t measure. Make sure that foremen are looking to ensure that proper procedures are followed.
• Goals Drive Improvement: Establish goals to reduce changeover times, record all changeover times and display them near the machine.
• Move to External: Distinguish between internal and external setup activities and try to convert internal to external setup.
• Simplify Internal Setup: This may involve using pins, cam and jigs to reduce adjustments, replace nuts and bolts with hand knobs, levers and toggle clamps where possible.
• Updated Equipment and Software: Make sure your machinery is loaded with the latest and greatest updates so that bugs are eliminated.
• Double Up: Many times the basic operators are the only ones involved in a changeover. But if deploying more people can boost productivity by decreasing downtime, consider tasking some nearby personnel to help with the process.
• Invest in Tooling: Don’t skimp on hand tools by requiring multiple machines to share one set of tools in the maintenance shed. This adds significant wasted motion. Have tools right there for each machine.
• Dedicated Machinery: The fastest changeover is none at all. If you can put a dedicated machine on one product that is the best way to ensure maximum production.
• The Right Tool: If possible try to replace manual tools with air ratchets and tools that do the same job much faster. Remember the NASCAR teams?
• Why Leave?: What functions require the operator to leave the machine? Can these be eliminated, or done by another person or done while the machine is in operation?
Lean Quotes
From one of the leading founders of lean manufacturing are wise words to live by.
“Improvement usually means doing something that we have never done before.”
“The most dangerous kind of waste is the waste we do not recognize.”
“Unless you change direction, you will end up where you are headed.”
“Those who are not dissatisfied will never make any progress.”
—Shigeo Shingo
