Multi-head tool units reconditioned and re-engineered by Inca Geometric

In support of the service, the company is making full use of its SolidWorks CAD, and installed facilities involving machining via jig boring, gear cutting, broaching and splining and internal/external finish grinding, assembly and testing with the added facility for locally externally sourced heat treatment. Explains managing director Michael Cain: "Our business grew out of multi-head and special-purpose machine design and build since 1956 and much our success was due to the ability to develop very close pitch centre multi-head units, comprising between two and 308 spindles. We built large numbers of boring, fixed and adjustable heads for gang drilling, reaming and tapping spanning a wide range of material types from cast iron and aluminium to high grade steels." Inca has supplied and re-engineered bespoke multi-drill heads for drilling the likes of multiple holes from 1 mm diameter in automotive carburettor bodies to U-drilling and finish boring 60 mm diameter holes in bevel gears, with the largest unit built in-house weighing some 1,500 kg. As well as geared and gearless heads, fixed centres, universal adjustable centres, corrected speed ratios, hollow bore, collet and morse taper types, a large number of bush plate and bolster assemblies supplied with customised machine mounts have been produced. Adds Mr Cain: "We were called upon recently by an automotive manufacturer to re-condition and re-engineer two 45- and 21-spindle tapping multi-heads for engine block production, which included new spindles and gears and upgraded lubrication systems to prolong bearing life and reliability in service." Prior to the production line being stopped and two heads being delivered to Chartham, the customer could only supply from its records a general arrangement drawing and a parts list. From this basic information, Inca's design engineers worked out bearing dimensional details and drew up all the various working parts in each head to enable prior machining, gear cutting any heat treatment and grinding. As part of the process, full size drawings were spread out and all internal components that had been produced were checked as being available and for rough position. These parts included five decks of gears, spindle input shafts, idler spindles, bearing spacers, the replacement auto-lubrication pump and filter plus the 90° gear-driven cam plate, dog mechanism and limit switches to activate the reverse motion of the tapping process. Once the actual multi-heads were delivered to Chartham, they were stripped, each bearing diameter jig bored and re-bushed in the housings and the units assembled and tested prior to despatch back to the customer's engine line. Inca engineers also produced multi-heads able to be stored in the magazines of CNC machines to improve productivity and spindle utilisation by combining pitch drilling into one cycle. Says Mr Cain: "There can be restrictions in respect of weight, size, lubrication and radial location of a multi-head in this type of application and the unit has to be purpose designed to suit the arm of the toolchanger, which is where our specialist knowledge is important to obtain a practical solution."