Multistep linear transfer system

Citation

(2006), "Multistep linear transfer system", Aircraft Engineering and Aerospace Technology, Vol. 78 No. 6. https://doi.org/10.1108/aeat.2006.12778fab.007

Multistep linear transfer system

Multistep linear transfer system

Keywords: Production equipment, Machining centres

The latest version of the modular constructed Mikron Multistep XS linear machining system is now claimed to be some 20 per cent more productive.

The machine is reported to be easier to program and is able to be reset for another component in around 10min. A massive reduction in nonproductive time has been achieved such as halving the toolchange chip-to-chip time to just 1s and the pallet change reduced from seven to five sees.

The machine, developed by Mikron Machining Technology of Agno, Switzerland, is fully capable of single hit cycles involving five-axis operations enabling 5 1/2 faces of a component to be machined without reclamping. It can combine all the normal capabilities of a vertical or horizontal machining centre with the added versatility of precision with in-cycle deep hole drilling of holes as small as 1.7mm diameter with 120 bar fully programmable through the tool coolant pressure.

The Multistep XS can be combined with manual or automatic loading systems to provide a highly flexible unmanned production cell for parts as diverse as housings, pumps, valves and pneumatic control components. It comprises a series of high performance and flexible machining modules with rapid transfer units that take just 5.5s to complete the pallet manipulation between the integrated machining stations.

The system can be expanded at any time to meet changing demand and in particular, can be planned for staging capital investment to meet projected increases or decreases in output requirements.

The workpiece envelope is within a cylinder of 140mm diameter by 180mm high with a weight limit of 21kg. Each machining module comprises two horizontal spindles able to move independently in the vertical Z- axis and are serviced by their own 11- position quick-change tool magazines. The component is carried on a 600£400mm pallet that is fed through the module located by a high accuracy Erowa interface on a direct driven two-axis (B and C) rotary and inclined table unit that is able to rotate to combine turning with milling and drilling cycles at up to 400revs/min. A further two axes of movement are created by the slide that carries the pallet location. Each axis has a rapid traverse rate of 40m/min with an acceleration of 8m/s².

From a common loading/unloading station the workpiece is transferred between the modules by a twin-arm rotary mechanism that moves the pallets between adjacent spindle positions providing a continuous linear work flow. Within the loading cycle probing sequences determine the machining datum and update the CMC control for the relative position of the material that can be from a forging, casting or billet. This loading and datuming procedure is carried out during the machining cycle.

The spindles in each module operate alternatively which enables a highly efficient simultaneous toolchange to be performed within just one second while the other spindle is cutting. Altogether, up to 22 tools can be applied to a component at each module. Most important in short lead time production is the ability of the machine to perform in-cycle deburring using its five-axis and interpolation capability.

A high speed 35,000revs/min vector controlled, high frequency spindle can be supplied as an alternative to the choice from two types of HSK-40 taper high precision spindles available as standard. These spindles have either a 12,000revs/min high torque drive or a higher speed 15,000revs/min unit.

Multistep XS is controlled via the latest high speed Bosch Rexroth IndraMotion MTX system and drives package with 1,000 block look ahead and Mikron developed software able to supervise up to 64 axes of which 30 can be simultaneous under closed-loop control. The system PLC is able to process up to 1,000 instructions in only 60 u sees. The control is fully integrated with Profibus communications that enables a dynamic and very precise means of tracing complicated machining paths and simplifies diagnostics. Programming or updating can be initiated either at the control or off-line directly on a solid model via Pathrace's well-proven EdgeCAM software.

A range of bowl feeders and robot- loaded systems can be specified with further options such as Renishaw probing, tool breakage control, heavy duty milling, NC-facing and multi- spindle drilling units. Processes such as pressing and joining as well as on- board inspection routines can also be incorporated within the single production cycle to create a finished product in 'one-hit'.

Details available from: Mikron Machining Technology, Tel: +41 91 610 6111, Fax: +41 91 610 6682, E-mail: mag@mikron.com, Web site: www.mikron.com