The cost of downtime versus the cost of a new part – are these the only options?

Bradley McBain, managing director of MBA Engineering, explains how the refurbishment of cutting heads can provide an economical alternative to buying replacement parts

Laser cutting machines are very costly investments, often with particularly large upfront costs. If the investment is worthwhile, the machine will pay for itself with a rise in production levels, but what about the ongoing cost of servicing and maintaining these machines? Common faults, such as

problems with laser heads, can cost a manufacturer up to £30,000 to replace. As a faulty head can cause so much downtime leading to a loss in income, purchasing a brand- new part can seem like the only option to get the machine up and running again as quickly as possible. But this is not the case.

Small particles, big problems There are a number of elements that can reduce the lifespan of a fibre laser cutting head. It goes without saying, the higher the power, the higher the stress on the optics, which is also heightened by fibre lasers having a much smaller spot size than CO2 lasers. But there are a lot more factors that can massively affect the head’s integrity. Due to the small spot size of the laser beam and the optic composition, fibre laser cutting heads are extremely sensitive to contamination. Particles so small they can only


Cutting heads not only require large investment initially, but are also known to develop faults as much as twice a year, leading to costly downtime

be seen through a microscope pose serious problems, so cleanliness is paramount. To assist with this need for cleanliness, purge gases are used to positively pressurise the chamber to try and prevent small contaminants from entering the cutting head. Unfortunately, this isn’t always a reliable solution, as the gases can also carry pollutants capable of negatively effecting the optics. These factors show that a

fibre laser head will run into contaminant issues at some point in its life. There are companies working towards improving the sensitivity of the

optics, which we should see in the market in the near future, but coating and machining optics are proving to be a juggling act with suppliers, adding pressure to improve the power handling and heat dissipation, as well as keeping the costs down. Optic composition does not

lend itself to heat dissipation, so companies are still exploring cooling methods to improve the lifespan of a cutting head, but the cooling is often limited to the laser head coupling point.

What can be done? What can manufacturers do to ensure they are prepared

when they run into any of these issues? The first step would be to

understand how often you are likely to experience these faults. Based on a 6kW laser cutting machine as an average, the optics typically need changing once or twice a year. This may differ for lower and higher power machines, but ultimately the higher the power of the cutting head, the more stress on the optics – similar to a car with a fine-tuned engine. It’s also worth researching the warranties provided with the cutting heads. Most companies will offer warranty on the head as a whole, but


MBA Engineering

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