Two Hurco VMX30 vertical machining centres (VMCs) have been added to the subcontract machine shop of Schivo Group in Waterford, on the south coast of Ireland. Compared with a VMX42 installed in 2004, the latest machines are 50 percent more productive, due entirely to the increased functionality of Hurco's conversational programming software, WinMax, incorporated into the control systems.
All of the Hurco machines were supplied through local Irish representative, Michael Gannon. The earlier model, which complemented manual-tool-change mills on site, was equipped with touch probing to speed workpiece set-up and boost productivity. It added machining capacity and high metal removal capability for manufacturing mainly medical devices and instruments in batches of typically 10- to 50-off.
Jack Lyng, Technical Director of Schivo Precision, said that the success of the VMX42 installation prompted the purchase of the two new machining centres. Now, however, the programming software in the proprietary Ultimax twin-screen control has been upgraded to Windows-based WinMax, which is considerably more capable and speeds conversational programming.
CAD data of particularly complex components are supplied by some customers and run through a hyperMILL CAM system at Waterford. Cutter paths are output in DXF format so that the programs can be conveniently downloaded directly into the Hurco control.
For 85 per cent of the time, however, programming is carried out on the shop floor from drawings using the powerful conversational capabilities of WinMax. It displays graphics on the second screen at the same time as programming progresses on the first screen using convenient drop-down menus. The programmer can therefore check in real time that the cycles are being input correctly.
Schivo programmer, Conrad Nolte, is enthusiastic about the facilities built into WinMax, citing so many advantages over the earlier software that the list needs to be curtailed here for reasons of practicality.
A general observation he makes is of the control's user-friendliness, especially the fully-rotatable 3D graphics and tool movement simulation, which allow programming errors to be spotted quickly. Tool set-up is also faster, owing to the software's ability to assign spindle speed and axis feed rates automatically to achieve optimal surface cutting speed and chip load for any given tool type and workpiece material.
New canned cycles speed data entry, such as pocket milling without having to define the boundary of the feature. Input of internal or external, clockwise or counter clockwise thread milling cycles, including for tapered threads, is made easier by restricting the amount of data that has to be input.
Another new cycle allows drilling at different rotational speeds any number of times during a single operation. It was developed by Hurco for machining composite materials to avoid delamination, but comes into its own at Waterford when drilling at an angle using an indexable-insert tool. Slowing the speed during entry improves tool life when the inserts are taking interrupted cuts.
When setting up the next part, bearing in mind that the soft jaws used by Schivo can vary positionally by 20 or 30 microns, or when measuring a critical feature in-cycle, probing speed is dramatically increased using the new 8 m/min rapid approach. This has had a big impact on productivity, according to Mr Nolte.
He commented, "Before, without the facility to rapid the probe, the cycle took typically one minute, whereas now the same is completed in less than half the time. "It not only shortens the overall cycle, but also encourages more frequent use of this function, enhancing product quality."
He said that having WinMax has increased production output by speeding the cycles. What previously took 30 minutes to machine now takes, say, 20 minutes, which makes a massive difference over a large batch. Operators have therefore rewritten most of the old Hurco programs using the new software to speed the cycles on the VMX30t machines, while the VMX42 has been retrofitted with WinMax so that it too can gain the productivity benefits.
Furthermore, WinMax will convert any conversationally prepared program into NC code so that it can be used on other makes of machining centre. Mr Nolte says that it is rather like having a CAM system on the shop floor, while an off-line version for office use is available which Schivo may install to free up the Ultimax controls. A DNC link to the machines is also planned.
Assembly and test in clean rooms forms a major part of the service provided by Schivo, which has held ISO 13485 medical device certification since 2008. Work is also done for the semiconductor, aerospace, computer and oil/gas sectors.