Subcontractor invests in high-speed turnkey package

At the Gosport factory of Norjon Precision Engineering, a high-speed DA300 vertical machining centre from Makino, Japan, the first of its type in the UK, has been supplied as a turnkey package by sole agent NCMT complete with an Erowa storage and handling system for 24 pallets.

It is the subcontractor's ninth trunnion-type, 5-axis machine and is intended primarily for highly productive milling and drilling of aluminium components, but is equally capable of machining stainless steel for long periods.

Kevin Fox, Norjon's managing director says: “We only buy high quality machines, which we have always needed as most of our customers demand a high quality finish. Makino has a reputation for being at the top end of machine tool suppliers in terms of accuracy and reliability and this particular model is very fast, with 60 m/minute rapids and 20,000rpm spindle.

"Another reason for investing in this equipment is that we already deal with the supplier, NCMT, having bought two Okuma lathes from them over the past two years, one of which is a multi-tasking machine. Their technical support and service backup is absolutely fantastic. On the rare occasion we've had a maintenance issue, they are onsite within 24 hours."

He went on to explain that the DA300 is built with automation in mind as it is prepared with pneumatic ports in the table, so interfacing the Erowa Robot Compact 80 was seamless. It provides quick, efficient component exchange, maximising machine utilisation.

If production work is involved, Norjon would in future not consider installing a machine tool that does not have automation, as in Mr Fox's opinion it is essential to achieve the required output. Without it, and the extra 60 hours unmanned production every weekend, the subcontractor would not be able to keep pace with customer requirements.

The alternative would be to install additional machine tools, which would be added expense and in any case there is little spare room on the shopfloor. Moreover, as operators are free to attend to other jobs, automated pallet handling is important for minimising the labour cost content of component production.

When the Gosport factory was visited, a family of aluminium prismatic components was being produced in the Makino/Erowa cell. Mr Fox continues: "We set the job up initially on a Friday evening and inspected the first-off component. The cell ran continuously over the weekend and the following Monday we measured the first component produced that morning. The dimensions were exactly the same, so the accuracy we are achieving in the cell is excellent."

The Makino DA300 is capable of fully interpolative 5-axis production of complex components. Equipped with integral, direct-drive motors for the swivelling +30 to -120 degree A-axis trunnion and also for C-axis rotation of the 340mm by 300 mm table, the machine deploys a 20,000rpm, 22 kW, HSK-A63 spindle capable of rigorous milling, drilling and tapping. A 60-tool magazine ensures availability of an extensive selection of cutters to tackle the most complex of parts or component families.

The Fanuc-based Professional 6 CNC system provides streamlined screen layouts, operator assistance and macros to accelerate productivity. For example, a G-code drilling cycle enables the tool to arc from hole to hole instead of following a square path, reducing non-cutting time when drilling a typical hole pattern. A vision sensor outside the machine's work zone detects broken tools to ensure cutter integrity without impacting cycle times.

Workpieces up to 450mm in diameter and 400mm high with a maximum weight of 250kg can be machined within the 450mm x 620mm x 500mm working volume at feed rates up to 60m/minute. Even the rotary A- and C-axes are fast at 100 and 150rpm respectively. Acceleration and deceleration to and from full speed takes just 1.5 seconds, minimising chip-to-chip times. Accuracy is ensured by scale feedback in all axes.

Other intelligent machine functions include Inertia Active Control designed to speed machine motions further based on dynamic attributes and Collision Safe Guard, a real-time crash-avoidance feature that has a look-ahead function and takes real machining conditions into consideration.

Additional standard features include temperature control by cooling of the machine structure, spindle, ballscrews, bearings and drives.

Norjon Precision Engineering www.norjon.co.uk

NCMT www.ncmt.co.uk