Manufacturing processes typically incorporate a flow, including equipment, conveyance, and manual-work processes, which are organized in ways that convert incoming materials/items into sub-assemblies and/or finished goods. Efficient processes achieve a smooth and uninterrupted flow of work in process. They also achieve defect-free work-in-process at the desired, i.e., planned/scheduled, rates. In short, efficient and effective manufacturing processes are reliable production processes.
In some traditional (old-school) plants with which I worked, there was a tendency to point the finger at the Maintenance Department to reduce the number of failures and make repairs to bring equipment back on line after. In many of these operations, maintenance was understaffed due, primarily, to reactive or repair-based strategies (by design or default).
Improvements in those traditional plants often required the assumption that “maintenance” was the source of (and solution to) problems. When seeking ways to improve production reliability, however, we must look beyond “maintenance” and think “equipment reliability.”
A CASE EXAMPLE
This example from a traditional manufacturing plant may help explain my “bottleneck” perspective. At this site, “maintenance” was perceived as THE problem associated with equipment performance and production interruptions. While the Maintenance Department had issues, i.e., no effective work order system and no maintenance planning or scheduling, there was bigger “low-hanging fruit” to be harvested.
Finding production bottlenecks and their causes was the plan of attack. We engaged a team of production and maintenance leadership, staff, and plant-floor personnel (production, maintenance, mold repair). Top management pointed to one department as the biggest business-related opportunity for improvement: the XYZ Cell. Two separate manufacturing processes fed three presses in that cell, followed by trimming, washing, quality check, and manual packing.
The team first looked at flow through the cell. All fingers pointed to three presses. These older molding press controls had been upgraded over recent years and molds had been improved. But press downtime was perceived as the biggest problem.
When the presses were determined to be the bottleneck of the cell, the next step was to assemble the press-production-downtime data from multiple sources, i.e., production reports, quality reports, operator logbooks, maintenance logbooks, spare-parts usage). Here’s what we discovered.
The top five press downtime reasons in the XYZ Cell accounted for 41% of the theoretically available press time for the year. Was “maintenance” the culprit as assumed? Here’s the breakdown of the top five reasons for press downtime: Mold cleaning/repair (12%), mold change/product change (11%), no stock/no material (10%), no operator (5%), and incoming material problems (4%). These reasons point to 14% of the press downtime caused by incoming materials from within the XYZ Cell. True “maintenance” downtime reasons were less than a fraction of 1% of press downtime.
When digging into these “bottleneck” presses we also uncovered some startling downtime data. “Not Scheduled” was another 10% of available press time during the Monday – Friday three-shift production days for the year.
Whenever you’re hunting down top-priority production bottlenecks, check the flow within the process, as well as upstream and downstream processes. In the case of the XYZ Cell and three presses, reliability-improvement targets (none of which were addressable by the Maintenance Department) were hidden in a jumble of data from multiple sources. Once revealed from actual plant databases and records, the reasons for downtime among the presses were indisputable and provided a clear path for reliability improvement.
As Reliability Pros, we must be able to recognize process-flow bottlenecks, as well have access to accurate and reliable data.TRR
ABOUT THE AUTHOR
Bob Williamson is a long-time contributor to the “people-side” of the world-class-maintenance and manufacturing body of knowledge across dozens of industry types. His vast background in maintenance, machine and tool design, and teaching has positioned his work with over 500 companies and plants, facilities, and equipment-oriented organizations. Contact him directly at 512-800-6031 or email@example.com.
Tags: reliability, availability, maintenance, RAM, asset management, production bottlenecks