As a manufacturer of CO2 laser cutting machines from 2.2 to 6kW and fibre laser machines from 2 to 4kW, Bystronic is often asked about the benefits of both types and which is best for specific applications.
As there is some confusion in the market-place, David Larcombe — managing director of Bystronic UK Ltd, Coventry
(www.bystronic.com) — outlines the pros and cons of the two technologies. “This topic is so much on customers’ minds that we made CO2 and fibre laser cutting comparisons and live tests a key element of our last two Open Houses in Coventry, creating lively debate. Indeed, it occurred to me during one discussion with a customer that, rather than just explain the theory, it would be interesting to analyse the results and experiences of our customers over the last three years, during which time we have sold over 35 fibre machines in the UK alone.”
Briefly, fibre laser light is created by banks of diodes, before being channelled and amplified through fibre-optic cable similar to that used for data transfer. On exiting the fibre cable, the light is collimated (or straightened), then focused by a lens onto the material to be cut. Not only is creating the light 200% more efficient than via a traditional CO2 laser, but delivery is also far simpler, with no need for mirrors; and unlike with a CO2 laser, the focusing lens is sealed in the cutting head and thus not a consumable item.
Relatively new technology
Bystronic first launched its fibre laser in the UK in 2010 as a 2kW machine. This was soon followed by 3 and 4kW machines. Interestingly, 3kW remains the most popular, accounting for 60% of the company’s fibre laser deliveries in the UK.
An examination of the price-to-performance ratio of the different fibre models shows that the main cutting-speed benefit of the higher-power 4kW laser is in mid-range materials from 6 to 8mm thick. There are also small benefits in thickness capacity when cutting non-ferrous materials — typically, an increase of one gauge of material. This power level only benefits users that cut a lot of material in the 6-8 mm range or wish to cover all eventualities with the one laser machine.
Some of the benefits of a fibre laser include: no moving parts or mirrors in the light-generating source, unlike a conventional CO2 resonator or disk laser (this reduces maintenance requirements and operating costs); and much higher electrical efficiency, resulting in considerably lower running costs (a 3kW fibre machine uses one third of the power of an average 4kW CO2 machine).
There are also significant speed advantages when cutting thin material. When cutting 1mm mild steel, galvanised steel or stainless steel in a straight line, a 3kW fibre laser is three-times quicker than a 4kW CO2 machine — and it is twice as fast when cutting 2mm material. A further advantage is provided by the fibre laser’s ability to cut reflective materials without fear of back reflections damaging the machine (this allows copper, brass and aluminium to be cut without problems). Finally, fibre lasers can go for 50% longer before being serviced — and the cost of each service is 50% lower.
In ‘the thick of it’
The disadvantages of fibre compared with CO2 relate mainly to the cutting speed when processing thicker materials, typically above 5mm. Here, the CO2 machine is faster in a straight line; it also has much shorter piercing times at the start of the cut. There is also the advantage of a smoother surface finish with the CO2 machine when cutting thicker materials.
“So, what do we know about our UK customers that have bought Bystronic fibre lasers? Over 70% of fibre laser customers are sub-contractors, the remainder being OEMs,” says Mr Larcombe. “This is surprising, as one would expect OEMs to be more confident about purchasing a fibre laser machine, where the advantages and disadvantages vary greatly, depending on the products to be cut. Sub-contractors can never be sure what the next job will be and what material thicknesses will need to be processed, so the versatility of a CO2 machine would theoretically be more attractive.
“Also, only 31% of the sub-contractors had a single machine after purchasing the fibre laser, whereas 69% were multiple laser users and could decide which machine to put work onto — CO2 or fibre. However, the over-riding reason for purchasing a fibre laser was the speed of cutting thin materials. An important secondary reason was the lower running cost and the lower power consumption, which was particularly important to companies at the top end of the electrical supply limit in their workshops.”
Customer experiences
Danny Fantom, managing director of the Ilkeston-based sub-contractor FC Laser, said: “We were advised by Bystronic’s managing director to complement our existing Bysprint Pro 4.4kW CO2 laser with a 3kW fibre laser. Though sceptical at first about the benefits of this technology with its lower power, we put our trust in this recommendation. The machine has been running alongside the CO2 machine for two months, and I can honestly say that it has exceeded our expectations in terms of quality of cut — ultra-reliable without adjustment — and speed. It is typically twice as fast as our latest CO2 machine on most materials, which enables our growing company to maintain short and reliable delivery times. The ability to process copper and brass has also been extremely useful, as we would not have quoted for this is work in the past.”
Sutton-based Brattonsound Engineering replaced a three-year-old 2.2kW CO2 laser with a 2kW Bysprint Fiber. The company cuts thin materials, mainly up to 2mm, for its range of gas fires and gun safes. Again, the machine exceeded expectations, with some nests of parts cut three-times faster than on the older Bysprint (the average improvement was a doubling of cutting speed).
Moreover, the overall quality of cut parts was as good, even with the faster cutting speeds, and more-consistent quality was achieved across the entire sheet. As predicted, running costs for the machine have also fallen, with the electrical load more than halved (from 37 to 16kW).
Furthermore, as the machine is cutting twice as fast, running costs per part produced have been reduced by two-thirds, taking into account both electricity and cutting gas. Brattonsound’s Gerald Tagg said: “The only problem we encountered was that before the investment, the laser operator had time to assemble kits of parts between each cutting plan, but with the new machine he does not have time to stop. As soon as a sheet is loaded, it is cut — before the parts are removed from the previous sheet.”
From days to hours
Waterlooville-based ICEE Managed Services replaced a similar size of CO2 laser with a 2kW Bystronic fibre machine in mid-2011. ICEE’s Chris Arnold says: “We undertake a regular contract to fabricate electrical enclosures and had always cut the material on an older 2kW laser. The complete order used to take just over 38hr on that machine; with set-ups, it would tie up the machine for the whole week. The first time we ran the batch on the new fibre machine, part way through Monday the operator asked the production manager what he wanted him to do next; he had completed the previous week-long order in just 6hr. This was not an isolated case; another project — in 2.6mm copper, requiring 260 holes to be cut — took just 55sec per part.”
A 3kW Bystronic fibre laser with a 3 x 1.5m capacity was installed in January this year at the Darwen, Lancashire, factory of WEC Group. An on-going requirement to cut stainless steel sheet in the 1.5-4mm thickness range was the main reason for investing in this machine. Gareth Taylor, who is assistant general manager of the company’s laser division and has more than 20 years’ laser cutting experience, says he knew that big savings were possible using a fibre laser to machine this type of material, compared with using one of the company’s CO2 lasers. “We are cutting up to 50% quicker when using Bystronic’s fibre laser to process stainless steel, which is on the machine for about 70% of the time; and as it is running 24hr a day, the fibre laser will pay for itself quickly.”
In conclusion, Mr Larcombe says that the companies most likely to adopt fibre laser technology are either sub-contractors specialising in cutting thin metal, such as for point-of-sale sheet-metal work and white goods, or sub-contractors using a fibre machine’s strengths to complement CO2 laser machines cutting thicker grades of plate. “I certainly do not foresee the death of CO2 laser cutting machines as a result of the introduction of fibre laser technology. The two systems both have their advantages and disadvantages.”