Speaking in front of his new Amada laser-punch machine, Brian Campbell, managing director of Hull sheet metal subcontractor W Campbell & Son, poses the essential question about buying a combination machine: Why buy equipment that can only carry out a single task at any given moment, when, for a similar price, you could have twice the productivity with two separate machines?
His answer – and this isn't the only one – is that when material comes out of the company's new Amada LC2515 C1 AJ machine with 2 kW fibre laser (01562 749500), it is finished: not only cut, but also countersunk and formed. If the company cut its part on a single-function laser profiler and then placed it into another machine, it could risk forming the part in the wrong place.
In fact, Campbell sometimes does need to do extra bending on parts processed by the combination machine on a press brake (it has four). Happily, the operator will know which way to bend it, as one of the 46 tools in the turret of the 20-tonne servo-electric Amada C1 AJ, the first in the UK and scarcely a month old in mid-May when visited, is a centre punch, so a mark is made on the top or bottom of the part.
Another reason why W Campbell & Son bought the machine is to support the other profilers in its factory. Its two other laser machines, a Bystronic ByStar 4020 with 4.4 kW CO2 laser (0844 848 5850) and Salvagnini L3 with 3 kW fibre source and sheet automation (01989 767032), are run flat out, so each requires about two days' maintenance per month. During those down-times, the Amada can provide cover, lasering (or punching) over a 3 m by 1.5 m working area.
W Campbell also chose a laser punch because it lacked a punching machine, despite an extensive shop inventory that includes a plasma bed cutter, small and large pipe rollers, pyramid rolls, Amada 4 m guillotine, Fladder grinder and deburrer, bandsaws, old Ajax drill press, as well as a welding station.
"We try to make everything in-house, rather than being beholden to someone else," says Campbell. After the company's old Strippit punch (only) machine died, the lasers picked up most of the workload. When hole countersinking was required for a regular consignment, workers initially did the job with a hand tool, though as the metal shavings started to pile up on the shopfloor the firm sent the work out to another factory. Recently, Campbell discovered that his company was spending £3,000 per month on countersinking – quite a large sum for such a small task.
So a laser-punch was what it needed; and it turned out to be the right time to buy because of the current business climate. After a good year in 2014, Campbell decided to take advantage of the 100% Inland Revenue capital allowances system for plant and machinery to buy the new equipment, confident that orders would carry on to keep the new purchase busy. (Capital allowances cover investments up to £500,000; that limit is due to be reduced to £25,000 on 1 January 2016).
Although the machine has only been in a few weeks, already Campbell is starting to see the benefits, and he calls Amada's approach to the sales process "a breath of fresh air".
Buckinghamshire-based Stratford Tools also recently bought the UK's first model of another combination machine – a Trumpf TruMatic 6000 with 2 kW TruFlow CO2 laser source (01582 725335). This business, at similar scale to W Campbell, with 42 employees and £4.2 million turnover, had a laser-punch before, as did W Campbell a decade ago, and like Campbell got rid of it at the end of its useable lifetime. Stratford Tools didn't replace its, because at that time – six or so years ago – the work that was coming in favoured standalone lasers.
Then, the work started to change, to require both punching and laser profiling. "We are completely reliant on the clients and their products, as a subcontractor, and we have a fair idea of the new work coming in, but we need to be able to adapt," company manager Stephen Cooke explains. "A range of machines in the portfolio is an advantage."
Initially, Stratford Tools responded to customer demand for more complex metalworking by punching, tapping and countersinking on another Amada single-function punch machine, and then moving the sheet to a laser for profiling. It soon became apparent that this practice was not an efficient production method. "That was double-handling and, as the work built up, it was problematic for capacity, and labour-intensive as well."
So, like Campbell, the accumulation of more complicated types of work requiring multiple operations led to Stratford Tools' decision to buy its laser-punch. Now, the machine is being used to process everything from small brackets to large panels in all materials and in thicknesses ranging from 0.7 to 3 mm. The medium-format machine has a capacity of 2,500 by 1,500 mm, cuts sheets up to 8 mm thick and moves at speeds of 90 m/min X, 60 m/min Y and 108 m/min combined. Positioning accuracy is 0.10 mm; repeatability 0.03 mm.
Explains Cooke: "Our feeling is, if we can eliminate ongoing processes, such as bushings or countersinking, then we'll use the combination. If we can eliminate ongoing processes to keep the cost down for the customer, the combination machine will come into its own."
Businesses don't need to demonstrate a 50:50 ratio of punch to laser work to profit from a combination laser-punch machine, according to Cooke: "There's no established ratio, no set decision point" at which Stratford Tools automatically assigns a particular job to a combination laser punch, or a standalone laser or punch.
During sheet processing, the decision of whether to laser or punch first rests with the Trumpf TruTops software, which automatically produces a cutting path. Stratford will review that for clashes or quality issues, but ends up approving it 90% of the time, reports Cooke.
Amada operation software, as used at W Campbell & Son, can be customised with a bias toward punching or laser, depending on customers' preference, says Amada European product manager Matt Wood.
"It is not black and white; we can be much more flexible," he offers.
FIBRE ON THE RISE
What has shifted since laser-punches were first introduced is the dominance of the punch process, says Wood. Although the machines used to be essentially a punch with a laser tacked on, the opposite is now the case, offers Wood. Fibre lasers, with their high speed cutting and lower electricity consumption than CO2-powered lasers, are becoming the tool of choice.
Explains Wood: "In the past, I think people saw CO2 laser combination machines as a punch with a laser attached; because people are comfortable with the punch process, they would punch and then would laser cut when they needed to. For me, when I speak to customers, the fibre laser combination is more the other way around. It's a different mindset. People are more comfortable with a fibre laser process, but sometimes they need to tap or form."
Prima Power (024 7664 5588), whose LPe6X combination laser-punch launched in the UK last year, also points out that each cutting technology has its own strengths and weaknesses. While punching can tap, countersink, form, rib, extrude, hem and louvre quickly and efficiently, laser cutting leaves no burrs, nibble marks or sharp corners, plus there are no tool or die clearance issues.
Indicators International engineer Sean O'Loughlin with a typical exterior bus panel, produced by the Prima Power LPe6f laser punch
Edges were a particularly concern for one of its customers, sheet metal subcontractor Indicators International, which recently installed a Prima Power LPe6f servo-electric punch with 3 kW fibre laser combination cell in its Magherafelt, Northern Ireland factory. It makes parts for a major international bus manufacturer, as well as for architectural and construction suppliers.
Where possible, the company is moving more towards laser cutting and punching in one operation on the combination machine. Director Tom Diamond explains: "Edge quality is very important, and from trials it was clear that the fibre laser gave much better results. One of the roof panels we make has thousands of 3 mm holes in it. We punch these, using a 60-hole cluster tool. The profile is then laser cut and the finished part unloaded using the robot."
Finland-based machine manufacturer Prima Power states that the main benefit of integrated punching and laser cutting is versatility. "You can use the turret punch press where it is easier or faster and the laser where it is most flexible. Depending on the manufacturing task at hand, you can always choose the most productive manufacturing method. This amounts to flexibility for fulfilling varying requirements, cost-efficiency and competitiveness."
The Prima Power LPE6X, which is based around its E6X series turret punch press (working area 1.5 m by 3 m) comes in either CO2 (2.5 or 3 kW) or fibre laser (2 or 3 kW) variants, although the combined laser and punch working area is reduced (1.5 by 1.9 m). A second series, LPEF, comes with 2, 3 or 4 kW fibre laser sources, and in two sheet sizes (3 by 1.5 m for the LPe6f; 4.3 by 1.5 m for the LPe8f), although both have the same combined working area of 2.4 by 1.5 m.
WHAT TO CONSIDER WHEN CHOOSING A LASER PUNCH
Combination laser-punch machines offer the benefits of both of its technologies, albeit for a price premium compared to a single-function machine. Their very capability can complicate the purchase decision: a combination machine might be up against both a standalone laser and a standalone punch. Machinery asked manufacturer Trumpf (01582 725335) how to go about making a comparison between them. We asked, is it just a matter of comparing the time to do a job on a laser-punch with the time to do the same job in sequential operations on two separate machines?
Apparently not. Trumpf says: "A potential client should not just look at how much faster he can produce a part on a combination machine but should also look at the additional flexibility the combination technology offers. Companies can enhance their capabilities and win new business by offering components that others can't manufacture." It says the comparison needs to include several factors:
- Cutting speed: run benchmark programs
- Part characteristics: forming requires a punching head; intricate or complex contours are better done on a laser; thickness of sheets; quality requirements, and so on
- Business model of the company: a job shop needs more production flexibility, an OEM would choose the best machine for its portfolio
- Automation: in the punch/combination area, automation, especially for part sorting, is faster and more reliable
- Operating cost: a punch doesn't need any process gas, while a combination machine can do two processes at once, without any cost for logistics in between processes.
First published in Machinery, June 2015
