Maintenance Snippets
Machinery shafts that are difficult to rotate by hand can often be turned more easily with the help of a pipe wrench.
This is faster and easier than a strap wrench or chain wrench since there's no need to loosen and re-tighten it each time. The pipe wrench will simply slide back when the leverage is relaxed. To protect the shaft's vulnerable surface finish, glue a couple of strips of rubber into the pipe wrench jaws.
Even where shafts are turning easily, they may need to be held in a fixed position while tasks like checking soft foot or monitoring a move are undertaken. A pipe wrench will serve as an ideal counterbalance to the weight of brackets and /or laser components at such a time.
(Inspired by a previous tip from Ludeca Inc)
Managing the maintenance inventory function...
When the maintenance inventory function reports through a corporate procurement organisation, the typical advantages are a properly organised and structured management system for spare parts, plus improved negotiating with vendors to achieve lower prices and improved delivery times.
Disadvantages emerge when the procurement organisation does not recognise the unique requirements that apply to maintenance spares. This typically results in lower service levels and increased work delays due to part shortages and/or machine outages. The work delays create higher downtime and related loss of operational availability.
The only practical solution for such issues is to communicate with more clarity. Key procurement personnel need to gain an understanding of how the maintenance and spare parts functions are related and how they impact on availability and ultimately, the throughput of assets.
Without this type of proper dialogue, the company will continue to under-perform in this critical function and asset operations will continue to be sub-optimal.
(Inspired by a previous tip from Terry Wireman of Genesis Solutions)
Leading and lagging indicatorsIndicators are used as a management tool, measuring performances for comparison, action and decision making purposes. In the maintenance context:
Lagging indicators look at the history of what maintenance has achieved. This may or may not help in sustaining current performance or indeed creating an understanding of how to create future improvements. Sme examples are maintenance hours worked; number of breakdowns rectified; hours run since last failure; cost of consumables per machine; hours worked per breakdown; equipment availability to production.
Leading indicators look at what has been done so far that can be expected to reduce future breakdowns or some other financial impact of maintenance. Typical examples are the number of predictive maintenance points around a plant, % completed preventative maintenance tasks; number of hours input to improvement projects by maintenance staff; lifetime cost trends.
Neither of these types of indicator should be seen as superior to the other - they both have a role to play and a maintenance should have a strong hand in developing what actually matters for your location!
(Inspired by a previous tip from MC Associates International)
Unbalanced 3-phase, a faulty motor or the power supply?Identify the current readings of each phase (let's say they are A = 12, B = 10, C = 15 Amps). Switch the conductors so that Phase A moves to Phase B, Phase B moves to Phase C and Phase C moves to Phase A. This preserves the rotation of the motor. Restart and re-measure.
If the current balance remains the same (A = 12, B = 10, C = 15) then the unbalance is due to the motor. If the unbalance has rotated (A =15, B = 12 and C = 10) then it is due to the power supply.(Inspired by a previous tip from Howard Penrose of T - Solutions)
Quality vibration readings for condition monitoringMount sensor pads on a machine to define test locations. The best places are on rigid surfaces as close to the target bearings as possible. Don't place them on motor housings, cowlings or other non-rigid structures. For good data transmission, fix them with an adhesive that sets solid.
Finally, create and file away a diagram of their locations and orientations. This will help with replacements if the previously marked locations disappear at a later date.
(Inspired by a previous tip from DLI Engineering)
AC Inductor motor rebuildsAfter rebuilding an AC induction motor, compare the phase resistance readings from before and after repair. Smaller than original windings will ease the rewinding task but increase the phase resistance and so reduce the operating efficiency.
If so, there is a higher cost of power and the saving from rewinding instead of buying new will not be so good after all!
(Inspired by a previous tip from PdMA)
Troubleshooting - what's changed?When troubleshooting any sort of maintenance problem, be ready to think about what may have changed since previous times. If the machine was running reliably for a long period and now seems to fail more frequently, this key question will probably help to identify the source of the problem.
Perhaps the machine has been moved; perhaps it was vibrating and somebody added bracing to stiffen it. Perhaps the process has changed so now this machine is less loaded than it was in the past. Perhaps a new supplier provided a different brand of spares. Perhaps the lubrication procedure was changed or a new sort of lubricant is being used.
Whatever it is, asking what's changed can lead to a better understanding.
(Inspired by a previous tip from Mobius Institute)