17 March 2010

LVD slashes setup times at Electrium

LVD press brake technology has cut setup times by 70% and improved production speeds by 10% at a leading manufacturer of electrical equipment. Wythenshawe-based Electrium, now part of the Siemens group, has installed three LVD Easy-Form CNC press brakes to help it stay competitive in the face of ever increasing part variety and lower batch sizes.

Originally created as a management buyout from the Hanson Group, Electrium brought together a number of well-known electrical manufacturers, including Crabtree, Wylex and Volex. Under the MBO the emphasis had been on off-shoring high-volume production and consolidating the lower volume production at Wythenshawe. Since the site had originally been set up for volume production – predominantly using hard tooled power presses – it was very inefficient at coping with these lower volume demands.

Following its takeover in 2006, Siemens gave Engineering Manager Graham Hodgkiss the responsibility for completely reorganising the site to improve efficiencies and bring the facilities in line with the manufacturing requirement.

As Graham explains: “It was originally a medium to high-volume site, so we had to change our way of thinking to handle the influx of this new work. It was a massive investment after a period of downsizing.”

The key drivers were variety and volume. Customers wanted more variety in smaller volumes and more specials tailored to their specific needs – contributing to a sizable slice of the site’s production. More products were going direct to the retail trade too, which required a high degree of flexibility to meet its demands.

Graham says that, overall, the volume of cabinets, enclosures and so on produced is pretty much the same as it has always been, but with much greater variety.

“Gone are the days when we were making ten or fifteen thousand of the same thing. We can literally be processing orders for ones or twos one minute; followed by orders for five or six hundred-off. So we needed equipment that was going to reduce the impact of the setup on the overall operation.”
Because it was designed for high-volume manufacturing, the existing equipment was really inefficient, with the setup time representing a significant proportion of the overall run time.

Graham’s first move was to take most of the work away from hard tooling onto punch presses – and he was able to streamline this very effectively by rationalising the tooling used and sharpening up the quality of programming.

That left forming as the weak link, with five old press brakes creating a real bottleneck. The average setup took 45 minutes and at around 50 setups a week that added up to a lot of lost production time.
As Graham explains: “Because of the variety of parts and massive setup times we weren’t cost-effective. I wanted to stop the rot, and the only way to do that was to get our efficiency right.
There is only so much you can do with soft fixes; there comes a point where you have to invest in new capital equipment and get the latest technology to help you.”

He reviewed the market and asked various suppliers to carry out bending trials on parts they hadn’t previously seen. LVD was the only one that was able to make the parts right first time, which convinced him it was the right solution.

The initial investment was in two 100t 3m bed LVD Easy-Form CNC press brakes and LVD CADMAN-B 3D offline programming software, which were followed six months later by a further 135t Easy-Form machine.

The majority of the work going through the sheet metal fabrication section is cabinets and enclosures. These range from 150 by 150mm for the smallest domestic unit up to 1.2m by 1.5m for industrial cabinets – and, as Electrium is actively developing new products, the equipment has been specified to handle panels up to 2.4m. Most parts are made from 1.00mm to 1.2mm cold rolled mild steel, although the trend is towards material up to 1.6mm as industrial unit production grows.

When the first two LVD Easy-Form press brakes were delivered they were installed alongside two of the old machines, so Graham had the chance to make a direct comparison. He set two trained industrial engineers to work, using certified methods to make independent studies on a typical benchmark part.

He says: “They both came up with the same results and backed up everything LVD had promised. We got a 70% reduction in setup times, and I was surprised to find that we also got a 10% reduction in run time. I knew the machines had a fast approach, but I didn’t think that it would add that much to our efficiency.”

The study was carried out on what was a typical component at the time. Since then more complicated products have been run where the setups on the old machines could take close to an hour. With the LVD machines, that was reduced to less than ten minutes – including programming.

Graham says that these impressive results are down to the combination of LVD’s CADMAN-B 3D offline programming software and the Easy-Form’s real-time laser bend angle measurement system.
“Offline programming removes the guesswork. When you watch a skilled press brake setter you see that the way they set up the job is very subjective. It’s all down to the setter’s skill, experience and judgement how he approaches the job. Nine times out of ten he will get it right, but in doing so he will probably waste three, four, maybe five blanks before he gets the first good one (the nature of the beast with old technology machines). The LVD technology eliminates that because you are getting it right first time every time.”

The CADMAN software calculates the best way to make the part from the 3D digital model. It selects the correct tools with the right radius, automatically adjusts for spring-back, and the Easy-Form laser system ensures that the right bend angle has been achieved.

“It’s not subjective any more,” says Graham. “The software knows the quickest route to achieve that part. It selects the tool segments and even tells the setter where to put them. What’s more, the Easy-Form laser moves along the bed and shows exactly where the tool should be placed. There is no guesswork to it.”

He adds that the Easy-Form’s bend angle measurement system is absolutely essential to allow for variations in the material.

“The biggest problem is variability in the thickness of the material, particularly in the thin gauges we are using. I think it is worse now than it was because steel is sourced globally and you don’t get the same consistency as before. You don’t know from one batch to the next where it has come from, even from the same supplier. The tensile strength will vary too, so we need the technology of the machines to take out that variability.

“Also, because we are nesting components on the cold rolled sheet you could be bending across the grain, with the grain or at an angle to the grain, all on the same sheet. Those sort of things can cause you problems, The Easy-Form compensates for that as well.

“If you look at the setters, when they are running the old machines they are constantly having to check the parts – measuring bend angles during the run, not just on setup – they don’t have to do that now.”

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