- 09 octobre 2019
- By BEP
At BEP, we do everything we can to receive, inspect, repair and return damaged rolls as effectively and efficiently as possible. We understand the costs of downtime, which is why we advise our customers to keep spare rolls.
Unfortunately, there are many unforeseen complications when repairing rolls, which can only be addressed on inspection. The initial repair procedure is to remove the damaged material by turning and grinding, so that we are down to a clean shaft. It then needs plating with nickel to build back up the diameter, followed by chrome plating to provide the hard-wearing longevity for future use.
The surface finish is then put on the roll, which can range from superfinish, gloss to matt finish. Surface coverage varies from light mirror pocket to full coverage. Depending on roll size, we have been known to polish rolls for up to 4 days.
Roll inners are frequently blocked due to corrosion on the inside of the roll. Our solution is to pump the roll through with a concentrated acid for anything up to 12 hours, then flush thoroughly afterwards to remove any acid. Whilst this process nearly always unblocks the roll, it can’t be guaranteed, as poor cooling water quality will impact on the roll inner and the internal structure of the roll will eventually fail as a result. Finally, we replace the roll seals, but this is not always possible due to the roll construction.
In short, repairing the journals, repairing the body, resurfacing and cleaning the internals can take between 3 to 4 weeks. Not always what our customers want to hear!
When considering spare rolls, ask yourself:
How much have you invested in your plant to date?
How much revenue are you losing when unable to operate?
What costs are you incurring whilst the machinery is static?
How much is a spare roll or two as a percentage of your plant investment?
Spare rolls are the most effective investment you are likely to make to ensure your plant stays operational.
Contact Garry Aspinall on 07428 786430 to discuss your options.