Organizations often encounter eight common forms of waste. Here are some techniques you can use to reduce them.
Modern Machine Shop, Wayne Chaneski
From the monthly column "Competing Ideas."
Waste 1: Over-production
• Quick change-over or single-minute exchange of die (SMED). Many organizations solve the problem of long machine setup times by over-producing parts. The rationale is that it is not “productive” to spend several hours setting up a machine that runs only for several minutes. However, SMED techniques reduce setup times, thereby lessening the burden of small production runs.
• Total productive maintenance (TPM). Equipment downtime is another reason why companies purposely over-produce. It seems that key equipment goes down when it is needed the most. As a safety net, some companies run more parts than needed. However, TPM can replace unplanned downtime with planned downtime for maintenance activities, which improves performance predictability.
Waste 2: Excess Inventory
• Inventory obsolescence program. An aggressive program can eliminate parts or products that are not used or do not sell.
• Cycle counting. Excess inventory often goes unnoticed because of poor inventory accuracy. A cycle-counting program can improve inventory accuracy and eliminate unneeded production.
• Pull scheduling. This visual means of replenishing what has been consumed can effectively control inventory. Kanbans or simple reordering signals can help manage the replenishment process.
Waste 3: Over-Processing
• Standardized work instructions. Sometimes time is spent doing more to a part than actually is required. Standardized work instructions ensure everyone knows a part’s true requirements and meets them the same way.
• Quality at the source. Meeting a part’s true requirements during the production run instead of later in the process can eliminate over-processing.
Waste 4: Waiting
• Quality at the source. Sometimes we wait for an “outsider,” such as an inspector, to check the work of machine operators. If that is the case, consider whether machine operators can check parts. Training operators to use key inspection equipment can reduce waiting time.
• Total productive maintenance. TPM can reduce unplanned downtime, which is a common cause of waiting.
Waste 5: Motion
• Workplace organization. Spending time looking for things is a major source of excessive motion. Eliminate search-related motion by organizing workplaces. Remove unnecessary items, and give needed items a designated location.
• Pull scheduling. A visual replenishment system can eliminate the paperwork required to schedule production or initiate purchasing.
Waste 6: Defects
• Quality at the source. This is the most obvious and effective means of reducing defects. Regular production checks enable corrections to be made before large quantities of defects are created.
• Total productive maintenance. Poorly performing machines are often the cause of defective parts. An effective TPM effort can improve the likelihood that equipment can continue to perform “like new” and produce high-quality parts for an extended period of time.
Waste 7: Transportation
• Manufacturing cells. Grouping all equipment needed to produce a part reduces the distance a part must travel during manufacturing.
• Effective plant layout. When manufacturing cells cannot be established, modifying the plant layout to improve product flow can offer numerous benefits. The term “spaghetti diagram” has been used to depict a very complicated product flow. Seek out the most flagrant examples of spaghetti flows, and develop better machine and equipment layouts.
Waste 8: Under-utilized People
• Teams. A team is a group of people with complementary skills that is created for a common purpose. Team members increase their skills by learning from one another. The more people learn, the more valuable they become to the organization and the less likely they are to be under-utilized because of limited skills.
• Quick change-over or SMED techniques. Simplifying the tasks associated with setting up any machine enables more people to become capable of completing change-overs. An operator who has the skills not only to operate a machine but also to set it up should never be under-utilized.