An advanced facility for the manufacture of injection moulds, has a robotically-loaded Roeders high-speed machining centre, recently joined in February this year by a second, similar RFM 600 model.

One of the most advanced facilities in Ireland, or for that matter in Britain, for the manufacture of injection moulds is to be found at Avenue Mould Solutions, Sligo, where a robotically-loaded Roeders high-speed machining (HSM) centre, installed in 1999, was joined in February this year by a second, similar RFM 600 model. The original Fanuc 6-axis robot now feeds both machines, 24 hours a day, with tools and pallet-mounted components, all of which are housed in a store that has been expanded to accommodate 100 pallets on six levels and 80 tools on four levels. Sales and service in Britain and Ireland for German-built Roeders machines is through Hurco Europe, High Wycombe, which in 2003 supplied two of its own VMX 42 machining centres to Avenue Mould through local Irish agent, Michael Gannon.

They replaced older Hurco machines installed in the mid-90s, which were slow by today's standards albeit they still held tolerance well.

The investments have allowed Avenue Mould to expand its machining capacity to keep pace with increasing demand for injection moulds from the medical sector, which it predominantly serves; only 10 per cent of turnover is automotive.

The company not only supplies moulds to its customers, but also manufactures post-launch quantities of plastic medical components such as syringes and drug delivery devices.

Sometimes, longer-term production remains with the Sligo company, which holds the relevant ISO 13485:2003 in addition to ISO 9001:2000.

On the toolmaking side, HSM has transformed Avenue Mould's production, which until 1999 was exclusively by spark erosion, a traditional bottleneck in the industry.

Some EDM remains, as deep cavities, small radii and various other features cannot be machined in any other way.

However, wherever possible, Avenue Mould adopts HSM to cut costs and lead-times.

Said Technical Director, Billy Gaffney, 'An example of the savings to be made is in the manufacture of a curved core for a tracheostomy mould, which we machine from 2344 chrome-molybdenum-vanadium alloy steel, case-hardened to 52 / 54 Rc.

'In the past, we would have machined a complex electrode for a C-axis sparking cycle that would have taken several days, followed by a long polishing process taking several days more.

'Now we cut the part unattended overnight at up to 42,000 rpm on one of our Roeders machines, leaving 10 microns which is subsequently polished off in less than half the time it takes to finish the hard crust left on a spark-eroded core.' So successful is HSM at the Sligo factory that 70 per cent of parts produced on the Roeders machines are cores and cavities, with copper and graphite electrodes accounting for a minority of throughput.

Pallet-mounted components are loaded by the robot either into an Erowa fixture mounted on the table, or into a second fixture on the dividing table if 4-axis machining is required.

The requirement for robot loading and unloading is not obvious from the long cycles discussed so far.

Its justification stems partly from the need for a large number of sister tools to be used on such cycles - more than can be accommodated in a standard tool magazine.

Furthermore, some graphite electrodes take less than half an hour to machine, and shorter cycle times dictate frequent component changeovers that are more economically performed by robot than by operators over three shifts.

Two seats of Delcam PowerMill on the shop floor are used to program complex 3D shapes and download the cutting cycles to the Roeders machines.

Programming of the Hurco machines, on the other hand, is shared 50 : 50 between (i) a seat of MasterCam that sends DXF files of 3D die and cavity cycles directly to the Ultimax CNC system, and (ii) manual data input (MDI) of 2D programs at the control itself for the production of mould bases and other relatively simple parts.

In contrast, MDI is not so easy using other control / machining centre combinations on the shop floor, so in practice the MasterCam facility is also used to program simple cutting cycles for running on non-Hurco machines.

The twin-screen Ultimax CNC is renowned for its ease of use, which Avenue Mould's VMX 42 operator David Loughney endorses, pointing out that new recruits to the company are quickly able to pick up Ultimax programming.

Cycles are built up using menu-driven commands on a touch-screen while on an adjacent screen, a graphic representation of the component is displayed with options for manipulating it and simulating the cutting cycle.

Established in 1988, Avenue Mould is owned by five directors including Managing Director, Felim McNeela.

Early on, a policy was adopted of investing in the best production equipment available, which saw the first full Mouldflow MPI software suite installed in Ireland.

It works alongside five seats of SolidWorks running IMOLD knowledge-based mould design software.

Avenue Mould has twice won the toolmaker of the Year category at the Plastics Industry Awards and has been a finalist on four other occasions.