Pioneers in Machining Technology
MECOF AGENCY LINE PRESENTED
Towards the end of last year, NCMT was awarded the sole sales and service agency in the UK and Ireland for the Italian-built Mecof range of travelling-column, horizontal-spindle milling machines and gantry-type, vertical-spindle machining centres.
MACH 2016 provided a first opportunity for the agent to present the full extent of the machine portfolio. The company also highlighted the many production possibilities across a wide spectrum of applications in aerospace, automotive, rail, mould making, prototyping, power generation and machine building.
Mecof is the first non-Japanese range of metalcutting machine tools to be sold by NCMT and dovetails well with its existing Okuma and Makino machining centre ranges, as the Italian manufacturer’s entry point is machines with four metres in X, rising to 20 metres.
Okamoto ACC 63 SA surface grinder
The Okamoto saddle-type surface grinding machine range, represented at the show by model ACC 63 SA with a table capacity of 605 mm x 300 mm, is defined by their heavily ribbed Meehanite cast iron construction, leading to high precision grinding, reliability and machine longevity.
Grinding wheel spindles are direct-drive and incorporate super precision, pre-loaded ball bearings that are lubricated for life for maintenance free operation. The design offers maximum spindle stiffness for handling light to heavy duty grinding applications. Double-V guideways for the table’s longitudinal and crossfeed travels ensure accuracy of linear movement and maximise the grinder’s built-in accuracy.
The wheelhead assembly is similarly rigidly constructed for long-term precision and is easily accessed for wheel change and maintenance. Wheel diameter and width are 355 mm and 38 mm respectively. Gravity feed lubrication ensures efficient oil distribution to the machine elements.
All control functions are conveniently located on a single panel and are easily actuated by push buttons or switches. Automatic downfeed is selectable in increments from 0.00125 to 0.0375 mm, while the manual increment is 0.00025 mm. Several modes of grinding including surface, traverse, plunge at one or both ends of table stroke as well as rough and finish grinding cycles and spark-out passes can all be set at the control.
Speroni tool presetters
Another feature of the NCMT stand was the Speroni Futura STP 46 tool presetter with CNC control over the 50-taper vertical spindle as well as the X and Z axes, with fine linear adjustment completed by hand-wheels. Of rigid construction and designed for shop floor use, it incorporates a novel taper adaptor and a claw system that accommodates all pull stud designs, allowing changeover for setting different tool tapers in just eight seconds. Repeatability of positioning is to within one micron.
As with all Speroni tool presetters, the thermo-balanced structure is made of artificially aged, pearlitic cast iron to ensure the equipment is fully isostatic and will not deform or distort over time or as the temperature changes.
Unlike most presetter designs, the homogeneous structure avoids the drawbacks of systems that use light alloys and/or granite, which have different and unstable reactions to changes in temperature and the environment. There is consequently no need for frequent recalibrations during a shift due to temperature change.
Modular design and a large number of configurations offer solutions tailored to almost every application, with full upgradability in the future. Both hardware and software are developed and produced in-house by Speroni, whilst peripheral equipment is sourced from the very best suppliers – Schneeberger linear guideways, Heidenhain encoders, Sony CCD camera and Festo Pneumatics.
Bench-top Speroni tool presetter, Magis, was also demonstrated. The ergonomically designed system has an integrated calibration master, pneumatic axis locks, X- and Z- axis fine adjustment, a CCD camera and an integral ISO 50 taper spindle. The single-screen control has an optional touch screen to increase the speed of tool measurement.
The machine has a standard X-axis range of 50 to 350 mm and is available in three column sizes with either 400, 500 or 600 mm travel in the Z-axis. The unit is supplied as standard with a pneumatic spindle brake that allows the operator to lock the spindle at any point in the 360-degree rotation, guaranteeing correct, stable positioning of the tool prior to measurement and / or presetting.
Magis also comes as standard with an episcopic front ring light system that provides a light source for manual inspection of the tool tip / insert on the screen. A variable adjustment knob facilitates inspection of different types of coated inserts. Hand wheels are provided for micron-precise, smooth adjustments of both the X and Z axes throughout the system's range of travel.
Blue Photon adhesive workholding
Last year, a photo-activated adhesive workholding system was introduced by NCMT under a new sole agency agreement. The MACH 2016 show marked the first demonstration of the technique at a national UK exhibition.
Called Blue Photon, it was developed at The Pennsylvania State University to fixture difficult-to-hold parts for tight-tolerance machining and inspection. The process involves applying an adhesive that is cured by ultraviolet light via fibre optic cables. The adhesive can subsequently be melted and the machined workpiece removed by immersion in hot water or by application of another heat source, which optimally should be at 80°C.
Alternatively, the adhesive contact points can be sheared to free the workpiece by rotating the gripper pins in the fixture plate with a spanner. No witness mark is visible where the glue was applied.
Use of the technique has grown rapidly in the aerospace industry in the US and is now spreading to other industries due to its ability to hold components securely with an average shear resistance of 136 kg, yet allow cutters excellent all-round access for machining on five sides. Unlike magnetic clamping systems, it can be used to secure not only ferrous metals but also non-ferrous metallic parts as well as ceramics and composites, including delicate materials.
Blue Photon is ideal, for example, for clamping gamma titanium aluminide, which is being used to produce low-pressure turbine blades for the latest generation of high-efficiency jet engines. The alloy halves the weight of aero components compared with Ti64, providing big savings on fuel burn, but is brittle and difficult to handle.
Other advantages of the clamping process are an absence of workpiece distortion, good damping properties to suppress chatter, reduced cost of fixtures for holding complex parts, and elimination of locating lugs on castings.