A long-established Newbury-based engineering subcontractor has invested in a DMC machining centre and Edgecam software in order to win long-term new business from a food company.
Engineering Solutions & Supply Ltd were asked to manufacture complete kits of tooling to ensure that glass jars were in the right position at the right time on a conveyor system, to be filled with food products. It included feed scrolls and the associated base plates, base clamps, star heels and centre guides.
The company serves a wide range of businesses; from local industry to the European Space Agency. Workshop Manager Neil Hutt says: “We make parts for agricultural equipment at one end of the scale, while at the other, one of our sensor assemblies is on its way to Mars.”
However, as their existing CNC machinery at the time was not able to produce what was required for the complex feed scrolls, they decided to invest in a DMC DM50V machining centre with a Samchully fourth axis, which Neil Hutt says is vital for that particular component.
“Even with the new machine, I was having issues with our CAM software. In particular, the cycle would not flow.
I knew how I wanted it to work, but could never achieve it with our CAM system. I had to segment the operation and do it in several stages, when what I really needed was to program it, press go and let it run from start to finish with confidence. The surface finish wasn’t good, either, with dig-ins.”
They observed demonstrations from a number of CAM specialists before choosing Edgecam, from Vero Software. This had also been recommended to them by Dave Clarke, of the recently launched CIS Product Proving Centre, which has a CAM partnership with Edgecam.
Neil Hutt says: “Compared to our previous software, Edgecam is more logical, with a user friendly interface. It’s easier to see the way we want to do things and then to carry them out.” Edgecam provides them with a continuous cycle, producing exactly what was modelled, avoiding the dig-ins that were happening previously and giving a perfect surface finish.
Manufactured from black Nylon 6 billets, two feed scrolls of different lengths turn in opposite directions to guide the glass jars to the filler head, so they are at the pocket at the correct time.
“The geometry is a variable pitch equation curve which increases the speed of the4 jar as it passes through the scroll. As each jar enters the scroll we separate them with an offset lug. We found that without this the next jar in line was coming in too quickly, resulting in a blockage. To add to the complexity of the geometry, we needed to make the width of the groove that the jar sits in wider as the pitch gets faster, otherwise the jars would catch on the trailing edge of the flutes. With Edgecam it’s simple to ensure completely accurate geometry.”
During the initial training process Edgecam engineer Dave Currah stored commands for each cycle in separate PCI files. “These are vital for every scroll we do now. I use the same PCIs over and over, just selecting different geometry. Two of the PCIs are used twice – those for roughing and the finish to the bottom and top – with the flute cycle needed only once.
“The scroll starts as a 100mm diameter billet of Nylon 6 which is pre-turned and faced to length. Then we skim to OD down to about 96mm and put the hole through the middle of the shaft which runs on two bushes at either end. It then goes on to a fixture on the face of the fourth axis, with two drive dowels and a tailstock at the other end. The complete job is machined using an 8mm bullnose cutter.
As it’s Nylon we do a constant, roughing helix of a 3mm pitch running the entire length, with a 10mm offset to the finished geometry.
“We then repeat the cycle, but with a 0.5mm offset to the finished geometry which gives us the rough shape. We finish on a 0.5 stepover for the top and bottom of the peaks, with each side of the flutes finished on a separate cycle using a 0.25mm stepover.”
Programming now takes between 30 – 45 using the PCIs. The size and shape of each jar requires its own set of tooling. “There are approximately 100 different variations of the scroll systems already in operation and we anticipate we’ll need to make a full tooling set, including the associated parts that go with it, every six months.”
Neil Hutt says there are multiple food manufacturers nationally which use the same type of scroll to control the flow of jars, bottles and tubs into a specific part of the machine for filling. Edgecam has now given them the confidence to tender for the work.
“We can now provide our own solution to companies, for around half the cost charged for this part of the operation by the manufacturer of the overall conveyor system.”
JIGS AND FIXTURES
Creating their own jigs and fixtures is another of Engineering Solutions’ specialities. One of their major successes in that field was to produce tooling to hold aluminium plates that required machining to suit a specific task for a pharmaceutical company.
“Other engineering companies had tried and failed. We took that as a challenge and created our own unique tooling with Edgecam, to ensure our Matchmaker VMC-820 could perform the task efficiently and cost-effectively. We’ve already made over 10,000, and expect further orders in the coming months.
Finally, Edgecam’s game-changing Waveform Roughing strategy has revolutionised the company’s production process, slashing around a fifth off roughing cycle times.
“This is especially valuable for jobs that are repeated every three to six months. I’ve reprogrammed those in Edgecam rather than continue to use our old CAM software package on them. Plus, all the roughing cycles have been up to 20 per cent faster.”
He says Waveform is also extending cutting tool life – in some cases doubling it. “By ramping up feed and speed rates it would seem that the tools are being used harder, but that’s not the case. Because we’re using the full flute length on the depth of the cut, we don’t get localised wear. We’re also using smaller diameter tools, so it’s reducing our tooling costs all round.”