Labor is a significant part of the total cost of a preventative maintenance program. The cost of recurring labor for replacing inferior parts quickly consumes the maintenance budget. For the lowest cost of ownership, replacement parts must be top quality and meet design tolerances, material specifications, and code requirements established by the Original Equipment Manufacturer (OEM) to achieve the longest possible service life.
In an effort to reduce the cost of replacement parts, some plants will have local machine shops attempt to duplicate or re-machine old parts. This approach to cost reduction is inherently flawed. A perfect copy of a worn product is another worn part. Even a perfect copy of a new part is at best a copy of one part, which may have been manufactured at the extreme limit of the original manufacturer’s allowable dimensional tolerances.
Similarly, some plants will continue to use and re-use rotary joints that were designed over 50 years ago. The performance of these rotary joints may be better than it was 50 years ago, if OEM parts with technical advancements are used, but the rotary joint performance will still be well below current best practice. Further, the replacement parts for these obsolete, old-technology rotary joints are often more expensive than equivalent parts for the latest new-technology rotary joints.
Still further, a perfect copy of an obsolete part is no better than an obsolete part. It incorporates none of the material or design enhancements that come with replacement parts from the OEM. Instead, the lower cost of cheaper parts is offset by reduced service life. One plant in the Southeast USA documented that copied parts supplied by a local machine shop were approximately 20% lower in purchase cost than OEM parts, but the parts did not fit, many failed on startup, and all had much shorter service life. The initial purchase savings were more than offset by increased downtime, loss of drying capacity, the frustration of continued repair requirements, and the increased cost of additional direct and indirect labor for the repairs.
Product life, reliability, and safety are all put in jeopardy when parts from third party companies are used in production machinery. For the lowest cost of ownership, use genuine, qualified, original equipment parts.