Lean Manufacturing: Eliminating the 8 Hidden Wastes – Part 2 of 8. The O in DOWNTIME

Many manufacturers believe in the traditional long runs of equipment because it is supposed to be more efficient to run a big batch versus running several shorter batches that include change-overs. Long runs require large inventories. Large inventories tie up large sums of money and keep our customers waiting longer. Thus, long runs reduce our ROI! Manufacturers that are leading their industries have found that when change-over times are drastically reduced and simplified, they can change-over more often and please more customers.

Over-Production waste occurs when we manufacture, assemble, or build more than what is needed. We make something just-in-case instead of Just-In-Time (JIT). Inaccurate scheduling, long lead times, long changeovers and not being close enough to our customers to understand their changing needs, leads us to longer production runs. We worry that our customer might need more while we have to suffer with the associated cost of unsold goods or services.

LOOK FOR processes producing more than is being “pulled” by the customer and requires storage between processes.

REDUCE BY improving Change-over and Set-up times and Line Balancing (Balancing Production Lines).

Quick Change-over and Set-up times on smaller and more flexible equipment make it easier to please many customers while reducing the overall cost of holding large quantities of inventory that is waiting for production opportunities. Drastically reduce change-over times requires an in-depth 2 step analysis and documentation of the process. The first step is to identify and move as many of the now internal (“power off”) activities to external (“power on”) activities. This first improvement step cost almost nothing to change, but are sometimes the hardest to implement because of years of old habits and resistance to change. The next step is to reduce the time required to perform the remaining internal activities. A valuable resource available on the subject is A Revolution in Manufacturing: The SMED System by Shigeo Shingo. His referral to SMED stands for Single Minute Exchange of Dies, and he believes the target for all change-overs should be 9 minutes or less. If you put together a cross-functional team from maintenance, operations, quality assurance and the tooling department (if it is separate from maintenance), the results can be amazing. These people have many ideas on how to improve change-overs and reduce the time required. They need to be empowered to suggest, plan and implement these improvements.

Line Balancing is simply leveling the cycle time for all operations within a line or process. It is building the cycle time concept into the standardized operations of a production line for maximum efficiency. Line balancing smooths work tasks and operator motions to create a harmonious and uninterrupted flow of product through the process steps. Workers learn to identify those processes that are out of balance with others and how to bring them back into line. While most companies assign the duties of measuring and improving production lines to process engineers, there ARE things that a team of line personnel can measure and examine for improvement opportunities. These people handle the process daily and understand the impact that balanced flow has on through-put, lead time to the customer and inventory levels, all of which play a very important role in the financial success of the organization.

What financial impact is Over-production having on your organization?

Watch for upcoming articles on Lean Manufacturing and the remaining Hidden Wastes of DOWNTIME…