6 March 2014

Fibre versus CO2 laser cutting

As a manufacturer of CO2 laser cutting machines from 2.2 kW to 6 kW and true fibre laser machines from 2 kW to 4 kW, Bystronic is often asked about the benefits of both types of machine and which is best for specific applications. As there is often some confusion in the market place, David Larcombe, Managing Director of Bystronic UK, outlines below the pros and cons of the two technologies.

He commented, "This topic is so much on customers' minds that we made CO2 and fibre laser cutting comparisons, presentations and live tests a key topic in presentations at our last two open houses in Coventry, which created lively debate.

"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 laser cutting machines in the UK alone."

Briefly, fibre laser light is created by banks of diodes. The light is channelled and amplified through fibre optic cable similar to that used for data transfer. The amplified light, on exiting the fibre cable, is collimated or straightened and then focused by a lens onto the material to be cut.

Not only is creation of the light 200 per cent more efficient than via a traditional CO2 laser, but delivery is also far simpler, with no expensive optical mirrors. The focusing lens is, unlike on a conventional CO2 laser machine, sealed in the cutting head and thus not a consumable item.
Bystronic first launched its fibre laser in the UK in 2010 as a 2 kW machine, which was swiftly followed by a 3 kW and then a 4 kW machine. Interestingly, 3 kW remains most popular, with 60 per cent of UK machines delivered being of this power.

If one examines the price to performance ratio of the different models, the main cutting speed benefit of the higher power 4 kW laser is in mid-range materials from 6 to 8 mm thick. There are also small benefits in thickness capacity when cutting non-ferrous materials, typically an increase of one gauge of material. This benefits only customers who cut a lot of material in the 6 to 8 mm range or who wish to cover all eventualities, as it is their only laser cutting machine.

The benefits of a true fibre laser source include:

  1. No moving parts or mirrors in the light-generating source, unlike a conventional CO2 resonator or disk laser. This has a distinct advantage in terms of reducing maintenance requirements and operating costs.
  2. Much higher electrical efficiency, resulting in considerably lower running costs. A 3 kW Fibre machine uses one third of the power of a 4 kW CO2 machine of average across-the-board performance.
  3. Higher speeds when cutting thin material. Again, compared with the same 4 kW CO2 machine, the fibre is three times quicker in a straight line cutting 1 mm mild, galvanised or stainless steel and twice as fast when cutting 2 mm.
  4. An ability to cut reflective materials without fear of back reflections damaging the machine. This allows copper, brass and aluminium to be cut without problems.
  5. Fifty per cent longer servicing intervals and 50 per cent lower servicing costs.

The disadvantages of fibre compared with CO2 mainly relate to the cutting speed when processing thicker materials, typically above 5 mm, where the CO2 machine is faster in a straight line and also has much faster piercing times at the start of the cut. There are also advantages of a smoother surface finish with the CO2 machine when cutting thicker materials.

So what can be deduced from the statistics and experiences of our UK customers which have bought Bystronic fibre machines so far?

  1. Over 70 per cent of fibre laser customers are sub-contractors, the remainder being OEMs. This is surprising, as one would expect OEMs to be more confident about deciding to purchase 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 theoretically the versatility of a CO2 machine would be more attractive.
  2. Of the sub-contractors, only 31 per cent had a single laser cutting machine after purchasing the Fibre, whereas 69 per cent were multiple laser users and could decide which machine to put work onto, CO2 or fibre.
  3. The over-riding reason for purchasing a fibre was the speed of cutting thin (1 to 2 mm and up to 3 mm) materials.
  4. An important secondary reason was the lower running cost and the lower power consumption, which was particularly important in companies at the top end of the electrical supply limit in their workshops.

Customer experiences
Danny Fantom, Managing Director of Ilkeston based subcontractor, FC Laser, commented, ”We were advised by Bystronic’s managing director to complement our existing Bysprint Pro 4.4 kW CO2 laser with a 3 kW fibre machine.

"Although 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 now for two months and I can honestly say that in terms of speed and quality of cut, the machine has exceeded our wildest dreams!

"The quality of cut is ultra-reliable without adjustment and the speed of the machine is typically twice that of our latest CO2 machine on most materials. It enables our growing company to maintain fast and reliable delivery times.

"The ability to process copper and brass has also been extremely useful, as this is work we would not have quoted for in the past.”

Brattonsound Engineering, Sutton, replaced a three-year-old, 2.2 kW CO2 laser with a 2 kW Bysprint Fiber. The company cuts thin materials mainly up to 2 mm for its range of gas fires and gun safes.

In production, the machine exceeded expectations, with some nests of parts cut three times faster than on the older BySprint. Average improvement was a doubling of cutting speed. 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 reduced. With its solid state, highly efficient fibre power source, the electrical load has more than halved, dropping from 37 kW to only 16 kW. Furthermore, as the machine is cutting twice as fast, running costs per part produced have reduced by two-thirds, taking into account both electricity and cutting gas.

Gerald Tagg at Brattonsound commented; “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”.

The Waterlooville manufacturing plant of ICEE Managed Services is a leader in fabrication, enclosure products and laser profiling. The company replaced a similar size of CO2 laser with a 2 kW Bystronic Fiber in mid-2011.

Chris Arnold, Key Engineering Account Manager at ICEE explained, “We undertake a repeat contract to fabricate electrical enclosures for a regular customer and have always cut the material on an older 2 kW laser. The complete order used to take just over 38 hours on that machine and 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 six hours.

“This was not an isolated case. Another project in 2.6 mm copper requiring 260 holes to be cut took just 55 seconds per part. The machine really is phenomenally quick."

A Bystronic 3kW, 3 metre by 1.5 metre capacity fibre laser machine was installed in January 2013 at the Darwen, Lancashire factory of WEC Group, resulting in significant cost savings. An on-going requirement to cut stainless steel sheet in the 1.5 mm to 4 mm thickness range was the main driver for investing in the machine.

It was apparent to Gareth Taylor, Assistant General Manager of the Laser Division, who has over 20 years' laser cutting experience, that big savings were possible using a fibre laser to machine this type of material, compared with using one of their CO2 lasers.

He said, "We are cutting up to 50 per cent quicker when using the Bystronic to process stainless steel, which is on the machine for about 70 per cent of the time, 24 hours a day. The material is ideal for extracting maximum benefit from fibre lasers, so the machine will pay for itself quickly.

So what are the conclusions to be drawn from this evaluation?

In summary, Bystronic UK's experience so far is that the companies most likely to adopt the new fibre technology are either sub-contractors which specialise in cutting thin metal, such as for point-of-sale sheet metal work and white goods, or subcontractors using a Fibre machine's strengths to complement CO2 laser machines cutting thicker grades of plate.

David Larcombe does not see the death of CO2 laser cutting machines as a result of the introduction of fibre laser technology, as was predicted. The two systems both have their advantages and disadvantages and Bystronic UK is happy to work with customers to ensure the best machine is proposed for individual requirements.

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