Last week threw an interesting array of Engineering Maintenance jobs at us, below is a selection. Most of the week was taken up working on Shut Down work. A food factory that we have a close working relationship with had a window of opportunity to get some maintenance done – basically, after the Corona Panic Buyers had filled their cupboards and freezer they stopped buying so this reprieve has given this factory and many others some breathing space to work on the machinery and get it ready for the next on-slaught of flat out production.
Given the time frames we had to work to it meant that we needed to be working on Critical defects, ones that needed doing before they took the machinery out of commission and effectively made the decision for us.
The SEW Gearbox Saga
One such issue I came across was a SEW motor gearbox unit with bearings gone in the drive side of the gearbox. I later found out that it had been attempted to be removed before but with little success.
Anyway, there wasn’t any option because this wasn’t going to run forever and was a critical piece of kit – there was no spare. When it finally gives up it would take the line down with it.
Caused in all likely hood a couple of hours of downtime on the production line – not really ideal.
But it wouldn’t budge. No matter what we tried, Bearing pullers, Pry Bars, a little bit of heat to the shaft – ordinarily heat would have freed it up, these seize on due to corrosion around the bore and keyway.
Enough heat will break this seal and you will be able to get it off – unfortunately with this type of drive too much heat will also mess up the seals and bearings etc but as the gearbox was in a poor state due to the internal bearings wearing damaging it more didn’t really matter.
Unfortunately for this Motor/Gearbox unit, we had to resort to caveman tactics and cut it off – being careful not to damage the shaft.
This really is a last resort but unfortunately, sometimes it is unavoidable.
Bearings, Bearings and more Bearings…
Most of the rest of the week consisted of replacing bearings on machines – this type of environment is really hard on the bearings, not only is it a chilled factory but when the cleaners wash the lines down at the end of the day everything warms up, the water in the high-pressure hoses is heated and they use caustic chemicals to make sure everything is clean.
This combination is really quite toxic for a bearing and if you add to that poor maintenance and protection they can wear out in no time at all. Often they are then left too long and by the time they get replaced, the shaft has been damaged and either needs some repair or replacement.
This can be avoided by careful greasing – too much grease is worse than none at all! and by ensuring there is some mechanical protection around the bearings, such as the caps that fit on the housing, these work fairly well.
Depending on the environment you could also look to change the type of bearing and the seal/insert. We’ve had success before using bearings with a sealed-for-life oil-impregnated insert.
For more information on over greasing bearings check out this post on Bearing Maintenance
The Auger Debacle
So upon arriving on site one-day last week we learned that an Auger that feeds a mixer had sheared the stub shaft on the end that the drive attaches to. This was a relatively large auger for a food industry application – approximately 5m long and 300mm diameter with a stub shaft diameter of 60mm.
For someone that knows what they are doing and has the right equipment, this is a pretty straightforward job.
However, this company doesn’t use us for this type of work, despite having an expert machinist on hand with the right equipment and a lot of experience making and repairing augers up to 1500mm in diameter. Why? because they use a “preferred contractor” for all of this type of work.
So we got it out and it went off to them, this was the Thursday before Easter so it would of been held up slightly, however, if required we would have worked on it over the easter holiday (especially this year given that we can’t do anything else).
I’m writing this the next weekend 9 days after the shaft broke and was taken out for repair.
It’s still not back, the Engineering company that took the auger isn’t actually able to do this work themselves so they have passed it off to another company.
This just doesn’t make business sense (or any other type of sense) in all likelihood we could have got this back into production by the beginning/middle of the week after easter and for a LOT less cost to the company than their “preferred route” this absolutely astounds me.
It’s not just that we’ve been overlooked I don’t expect to get every job, but we would have been able to get the plant back operational in a much faster time frame and for a lower cost. Surely using the right people for the right jobs is best for everyone including the business?