As time goes by, emphasis on manufacturing precision grows

“This day and age we’re living in Gives cause for apprehension With speed and new invention And things like fourth dimension. Yet we get a trifle weary With Mr. Einstein’s theory. So we must get down to earth at times Relax, relieve the tension.” “As Time Goes By,” words and music by Herman Hupfeld The scope and pace of today’s plant engineering funct...

11/15/2007


“This day and age we’re living in
Gives cause for apprehension
With speed and new invention
And things like fourth dimension.
Yet we get a trifle weary
With Mr. Einstein’s theory.
So we must get down to earth at times
Relax, relieve the tension.”
“As Time Goes By,” words and music by Herman Hupfeld

The scope and pace of today’s plant engineering function has come a long way from how things were done just five or 10 years ago. In the old days the maxim was “If it ain’t broke don’t fix it.” Machines were run until failure and then a mad rush was made to repair them. This was costly in terms of downtime and overtime, but was expected because “that’s how we have always done things around here.”

As time went by, the realization that this was an expensive way to do business became evident. The first steps were to begin depending on the mechanic’s and operator’s ears to “predict” failure. This was an unsophisticated method that was not reliable but was all that was available at the time.

As more time went by, instrumentation enabled preventive and predictive maintenance to increase machine uptime. This failure avoidance maintenance caused an increase in productivity with an attractive ROI.

Power transmission belts and sheaves have long lives if properly aligned. This used to be achieved using straightedges and string. If carefully done by an experienced plant engineer, the results were satisfactory. Today, lasers are used to precisely align components. The benefits of this procedure are not only longer belt and component life, but increased bearing life and reduced power consumption.

Roller bearings used to be greased with “a couple of pumps” on the grease gun, which usually resulted in too little or too much grease, leading to premature failure. Today, with ultrasonic equipment, we can listen to the bearing being lubricated and provide the right amount of lubricant.

Air compressor purchases used to be driven by the lack of compressed air in a plant. The assumption was the system was not able to keep up with demand. Many times the compressor purchase resulted in disappointing results: still not enough air, and increased energy consumption. Today, an air system analysis can predict the volumes and pressures a compressor is required to supply. The result usually is adding non-energy-consuming storage and proportioning controls that make the system perform as required with a minimum expenditure.

Compressed air piping was typically black iron pipe, resulting in leaks, contamination from internal rust and difficulty in adding access points. Today, modern air piping uses plastic and aluminum extrusions to eliminate leaks and corrosion, and provide convenient entry points for additional equipment.

Hydraulic oil tanks were sometimes changed out annually or when the oil looked “dirty.” Dirty meant particles greater than 40 microns. However, hydraulic systems can be damaged by particles in the 2- to 20-micron range. The annual change out could be too little too late. Oil sampling used to be done by a lab and required several weeks time. Serious component and system damage could occur.

Today, portable oil samplers are accurate enough to signal impending system damage due to contamination and avoid downtime. Other advantages include on-time filter changes, minimum reservoir change outs and reduced downtime.

Today industry is concerned with the “brain drain” as older, experienced personnel retire. This was recognized by alert Plant Engineers a long time ago. The headline of a Tips and Tricks suggestion from Oct. 1990 said, “Put your stars on camera.” The Tip was: “Use retiring craftsmen in preparing training videos. This provides a record of what to do and not do to perform specific procedures on your own equipment by experienced personnel. The tapes can be edited, supplemented and updated as required.”

Today, sophisticated equipment is being monitored and maintained by plant engineers using innovative instruments that allow more time to go by without downtime.