- Materials & Industrial Technology
Repair Or Replace? What To Do When Your Industrial Gearbox Breaks Down
Industrial gearboxes are instrumental pieces of equipment for many firms and, when they break, the cost of downtime and repairs can be severe.
Here we ask the questions ‘is it ever worth simply replacing your gearbox instead of opting to repair it?’ and ‘what exactly should a company do when their industrial gearbox breaks?’
First of all, it is important to note that regular maintenance and due care will significantly reduce the chance of your industrial gearbox breaking down and requiring repair or replacement. By regularly checking and replacing sealant and lubricant you can minimise oil leaks and wear, prolonging the operational life of your gearbox. It is estimated that up to 25% of all gearbox failures are down to poor lubrication or contamination of the gearbox, demonstrating just how important preventative maintenance is.
If it is too late for preventative maintenance often most industrial gearbox repairs are still much cheaper than simply replacing the entire gearbox unit. Professional industrial gearbox repair companies can fix housings and casings, keyways and shafts for up to half the price. If your company does not have a capable in-house technician, requesting a quotation from a gearbox repair firm is almost always worthwhile, even for more serious damage and wear.
A newly ordered gearbox is not only expensive, it is also going to take a considerable amount of time to arrive on the shop floor. Whilst a repair company might take under a week to send out an engineer to restore your gearbox to its original capacity in situ, a brand new gearbox might take up to 6 months to be delivered. As is the case in any industry, time is money and most companies simply cannot afford such a prolonged period of downtime and unproductivity.
So is there ever a case for simply replacing an industrial gearbox?
Like any piece of machinery, an industrial gearbox has a finite life expectancy. Consequently, should a gearbox reach the end of the manufacturer’s recommended operational period it is advisable to completely replace it. Towards the end of a gearbox’s life it is likely to begin to breakdown more frequently and with greater severity until there reaches a point when it is no longer economical to keep on repairing.
In addition, severe misalignments or thermal degradation may also warrant a complete gearbox replacement. Use your own experience and prowess along with the manufacturer’s guidelines to judge exactly when it is time to replace the gearbox. If you are unsure, a reputable repair firm will be able to aid you in making such a decision.
To summarise, repairing a gearbox is almost always going to be cheaper than replacing one in terms of both time and money. Naturally, every gearbox will at some point come to the end of its operational life, at which point replacement is simply inevitable. By carefully maintaining a gearbox, however, a company can hope to maximise this operational life and minimise the chance of breakdowns and downtime.
Gearbox Lubrication and Contamination
It is estimated that up to a quarter of all industrial gearbox repairs are required as a result of poor gearbox lubrication or contamination due to inadequate sealants. Whilst lubrication and sealant may appear to be separate issues, in reality it is often difficult to separate these two causes of gearbox failure as becomes evident later in the article.
Firstly, vents and breathers on the gearbox are a major source of contamination particularly where gearboxes are operated in outdoor environments. As temperatures fall (either at night or due to precipitation) moist air is sucked into the gearbox through the vents causing failures, particularly in the bearings. Even the smallest amount of moisture can cause bearing failure. Sealed gearboxes or gearboxes with bladder type breathers are most effective at preventing such contamination.
Unfortunately, many companies pay little attention to their industrial gearbox’s sealing largely due to the fact that simple lip seals are often adequate for oil retention and basic contamination exclusion. It is worth noting, however, that in harsh or corrosive environments (including outdoor operation) resistant sleeves for the shaft are advisable to prevent corrosion rendering seals useless.
In terms of lubrication, over application can be as severe a problem for industrial gearboxes as under application. Excessive amounts of oil can induce high temperatures on high speed shafts, seriously damaging the gearbox.
The actual viscosity of lubricant is also an issue, although rarely life-threatening as long as it is within an ISO grade. It is not rare, however, for a lubricant with too low a viscosity to cause serious damage to a gearbox and hence it is always best to err on the side of caution. Study the gearbox manual and use only the ISO grade lubricant viscosity that the manufacturer recommends. This is particular important in hypoid gears where there are large amounts of sliding.
Whilst horizontal shaft gearboxes in smaller engines are lubricated adequately by splash lubrication systems, larger gearboxes and those with vertical shaft systems typically require force feeding lubrication through a circulation system. If the pumps in these systems become contaminated or clogged with debris, lubrication can be unevenly distributed and overheating can occur.
Whilst preventative maintenance is desirable, it is not always possible to detect lubrication or contamination issues before they cause a problem. Should your industrial gearbox begin overheating check for signs of these two issues or consider calling out an industrial gearbox repair engineer to investigate. Often companies can fix small lubrication and contamination problems onsite, restoring your gearbox to an operational capacity in the shortest possible time.