Designed to convert small, 3-axis, vertical-spindle machining centres (VMCs) into 5-axis production centres, while at the same time allowing them to punch above their weight in terms of the size of component that can be machined,
Kitagawa has launched two new compound rotary tables.
The Japanese-manufactured RKT500 and RKT600 are available in the UK and Ireland exclusively through sales agent
1st Machine Tool Accessories, Salisbury.
The intended host machine is one of the many 30-taper VMCs on the market that only has linear CNC motions, to which the tables add two rotary axes. Smaller 40-taper machines may be similarly converted, or even 50-taper models, provided that the maximum thrust forces during cutting are adhered to.
The RKT500 can accept workpieces up to 500mm in diameter by 270mm high, the respective dimensions for the RKT600 being 600mm and 320mm. Maximum weight of workpiece and fixture is 100kg in both cases.
From detailed discussions with its user base during the design phase of the tables, Kitagawa recognised how important it is to make available a large quantity of services to the faceplate to allow a customer to automate workholding. Both tables are provided with a coolant port and the RKT500 rotary table has six hydraulic or pneumatic ports, with the RKT600 having 10.
Utilising its patented, multi-plate braking technology, on both rotary tables Kitagawa is able to deliver a generous 740Nm of clamping torque for the tilting axis and 600Nm for the rotating axis. Speed throughout the -30 / +120 degree tilt angle is 80rev/min, table rotation being 70rev/min and 50rev/min for the smaller and larger models respectively.
A defining feature of the tables is their high accuracy positioning, to within 30 arc-seconds in both the rotary and tilt axes, with ± 2 arc-seconds repeatability. It is largely down to Kitagawa’s roller gear cam mechanism which, compared with a traditional worm gear drive, offers the advantages of zero-backlash, as well as higher torque transmission efficiency, rigidity and indexing speed. The latter is important to avoid delaying cutter access to the workpiece after a high-speed tool exchange.
Once each axis has arrived at its allotted angular position both quickly and accurately, it is clamped there using Kitagawa’s multi-disc braking technology. It is a key feature that allows the rotary tables to achieve higher clamping torques than competitors’ systems, without increasing the physical size of the unit. By stacking discs together, the total frictional surface area presented for braking is maximised, while the table’s footprint is minimised.