What to consider when buying a laser cutting machine for a job shop
John Powell, technical director of Laser Expertise, on some of the key aspects to consider when buying a new cutting machine for a job shop
Since I was first approached by salesmen in 2006 with claims of a revolutionary new laser cutting technology, the fibre lasers they were talking about have become the dominant player in the material processing market. Fibre lasers provide a fast, efficient and reliable cutting solution for metals offering reduced maintenance downtime and electricity consumption, and this has led to them all but eliminating the traditional high-power CO2-based competition.
In the UK nearly everyone has switched over to fibre lasers. In my own firm, the last two lasers we bought were fibre, and the next one will be a fibre as well. We only have one CO2 laser left, which we’ll probably replace with a fibre laser as it reaches the end of its life.
I’ve also heard that nearly all the job shops in America and Europe have switched to fibre lasers, and this trend towards fibre lasers can also be seen in the literature on the subject: While only a tiny section of my 2008 LIA Guide to Laser Cutting discussed fibre lasers, around half of the most recent version of the book – The LIA Guide to High Power Laser Cutting (2017) is devoted to the technology.
Power isn’t everything
Fibre lasers can be used to process all the metals that job shops are required to cut, but they can’t be used to cut non-metals such as wood or plastic. This is because the light generated by fibre lasers passes straight through most plastics and wooden products without heating them up enough to create a cut. Although CO2 lasers can cut both non-metals and metals, fibre lasers are often more than twice as fast at cutting metal at the sub-3mm thicknesses that job shops usually work with (see table 1). This, in addition to the fact that metals make up around 95 per cent of laser cutting job shop work, means that whether you’re a newcomer or an established job shop looking to buy some new kit, a fibre laser is the way to go.
If you’re looking to purchase new kit as a job shop, I wouldn’t worry too much about investing in the highest-power fibre lasers available. Suppliers are now saying: ‘We’ve got 10kW+ of power now, which can be used to cut 25mm stainless steel.’ However, there aren’t many jobs at that thickness. I’d therefore recommend focusing on the 4-8kW range of power, which can tackle all the general thicknesses (anything below 20mm mild steel and 15mm stainless steel) that you’ll be required to process as a job shop – while not costing as much as the latest higher-power systems.
The majority of job shop laser cutting involves metals below 6mm thick, and a lot of it – as mentioned above – is below 3mm thick, so you’ll want to focus on being fast and productive at these sections. The fact that you won’t be able to cut above 20mm thick steel is generally irrelevant, as those jobs are very infrequent. Even if you could cut those thicknesses, the parts are often far too heavy and impractical to load and unload for the job to actually be worth it!
Laser Expertise was founded in 1984 and was one of the first commercial laser job shops. (Image: Laser Expertise)
In addition, because as a job shop you’ll find that most time is spent simply loading and unloading the jobs, even if you had a 10kW+ system you’d soon find that the higher cutting speeds it can offer for lower thickness jobs don’t have much of an effect on the total job time.
Another point to consider is that the increasing availability of automated loading and unloading capability – which enables ‘lights out’ operation – is really only going to be beneficial for manufacturers looking to produce large numbers of similar items. As a job shop, quite often your machines will be changing jobs every hour or so, and so organising the automation of your ‘lights out’ operation is going to be very difficult. Even if you do manage it, you’ll have to bring in extra personnel the next morning to unload all the jobs that have been completed during the night. In my view ‘lights out’ automation for a job shop is extremely complicated to run compared with just paying a couple of night shift operators.
Check the warranty
When selecting a new cutting system an important aspect you should consider is the warranty length of the laser. This is because fibre lasers (despite requiring a relatively low amount of maintenance compared to their CO2 predecessors due to having no moving parts) can be very expensive to repair when they break down.
This expense led to problems in the past when the warranties of fibre lasers were only one or two years in length, so the manufacturers of these machines have started to put five-year warranties on their lasers. This has proved very effective because after about five years you’ll be thinking about buying a replacement machine anyway. It’s worth adding that generally it’s only the laser itself that has the five-year warranty – the rest of the cutting machine will only have a warranty for one or two years. This isn’t much cause for concern however, as the costs of repairing the mechanical elements of a cutting machine are usually only a fraction of the repair cost of the laser.
Because of the expensive repair costs of fibre lasers I would generally not recommend buying one second-hand, as doing so would often only give you a six-month to one-year warranty, and might lead to all sorts of unknown costs and large repair bills further down the line. You never want to be at the mercy of breakdowns, and you don’t want to be running the expense of them either. Having said that, our first cutting machine at Laser Expertise (in 1984) was in fact a second-hand system that had to be rebuilt before we could use it – the previous owner had attacked it with an axe after he invested all his money in it and then a hardware error led to it cutting all his finished parts in half!
Getting the most out of maintenance
The two main players for laser cutting machines in the UK are Bystronic (who use IPG lasers) and Trumpf (the Trumpf machine uses a disk laser rather than a fibre laser – but from a cutting point of view the technology is similar). There are other companies selling them, however these two firms in particular have large teams of maintenance engineers on hand, which of course will help you minimise your downtime. Whichever firm you choose, maintaining a good relationship with your laser supplier is important for when it comes to scheduling maintenance or repairs. How well these suppliers perform on the maintenance side is a topic we often discuss within the AILU job shop group. Each year a survey is carried out based on the speed, reliability and expertise of the firms’ callout response, the availability and cost of replacement parts, their cost per hour of maintenance, the specialist phone support they provide and our overall satisfaction with them. The results of this year’s survey will be revealed on 3 October, when AILU is holding its Annual Job Shop Laser Business Meeting.
Outsource jobs you can’t do
While the final CO2 laser system in our job shop is still used to cut metals, it’s well-suited to non-metal jobs involving plastics and wood – which make up around two to five per cent of the work we receive. Once the system reaches the end of its life and we’ll probably replace it with a fibre laser, then we’ll then start hunting around for those who do still have CO2 lasers so we can outsource our plastic jobs to them. That way we will be able to keep our non-metal customers without the hassle of having to maintain a high-power CO2 laser.
John Powell co-founded Laser Expertise in 1984. He is the author of three books on laser cutting and is the most recent recipient of the AILU award, which was presented to him at ILAS 2019, recognising him as an individual who has made an outstanding lifetime contribution to the industrial use of lasers in the UK. John ‘wrote the book’ on laser cutting and established one of the first commercial laser job shops after studying at Imperial College under Professor William Steen (interviewed on page 34). John also was an instrumental founder member of AILU and pulled together the UK job shop community by establishing the AILU job shop group.