Plasma Cutters Incorporate Baldor Servomotors

Techserv Cutting Systems has delivered four HS 4000 hi-definition precision plasma cutters to the UK's Aircraft Carrier Alliance (ACA). Each cutter employs an advanced fully-synchronised four-axis motion-control system - based on Baldor digital servomotors and drives - to provide the precision of movement needed for tight-tolerance, large-scale profile cutting. The plasma cutters are being used to help fabricate the steel-plate bow sections of two Queen Elizabeth Class aircraft carriers.

Techserv's HS 4000 plasma cutters are capable of producing high-quality cut parts from steel-plate sheets up to 5m wide and up to 35mm thick. They employ precision-extruded aluminium for the chassis and main beam to ensure rigidity and low mass and use a machined track - with racks to both rails - which can be mounted on mid-level pedestals or on a customer-supplied beam. Depending on the thickness of steel plate being processed and the type of plasma unit that is fitted, HS 4000 machines offer cutting speeds of 50mm to 16m/min.

HS 4000 plasma cutters are four-axis systems, with rack and pinion drives to the transverse axes and the synchronised longitudinal axis. The fourth-axis controls the height of the cutting torch above the steel plate. Each of the four axes is powered by a Baldor BSM series AC brushless servomotor, driven by a Baldor Microflex 500W digital servo drive. The servo drives are controlled by a four-axis version of Baldor's NextMove ESB-2 machine controller.

Overall control of each plasma cutter is handled by an on-board industrial-grade PC. Designed specifically for shape-cutting machines, this PC features a 15in touch-sensitive full-colour HMI and employs graphical shape representation to ensure ease of use. The software runs under Windows XP and provides real-time control of all the cutting machine's advanced-motion functions, including contouring, as well as its Kaliburn Proline 2200 plasma unit.

It also controls the torch-height system on the HS 4000, monitoring the arc voltage and automatically adjusting the torch-to-work distance to provide optimum cutting performance and ensure machine safety.

DMC-2153 Improves VLF Waterjet Cutters

CNCMI has selected the compact DMC-2153 five-axis Ethernet motion controller from Galil Motion Control to ensure precision and speed of its VLF waterjet cutters. CNC Machines International's (CNCMI) VLF series is a high-performance waterjet cutter that can precisely cut and inlay intricate logos into carpet and turf. A representative from CNCMI said: 'Waterjet cutters like our VLF system need to keep the water stream tangent to the material for precise cuts.

'This rotary water axis must be kept tangent to the XY motion at all times. 'A unique feature of the machine is that it allows a bevel cut to be specified up to 45 degrees. 'Bevel cutting is useful in carpet cutting when fitting a logo cutout into the base. 'A straight-edge cut would allow the logo to fall straight through the base material.' The DMC-2153 easily handles the motion required by the application: the XY axes control the linear and circular patterns (rack and pinion), the Z-axis controls the height of the water jet and the Y-axis controls two motors for gantry function.

The fifth or rotary axis controls the motion of the water jet stream by keeping it in tangent to the XY motion to maintain precision cutting. In addition to tangential motion, the DMC-2153 handles constant velocity, slaving and linear and circular interpolation. As is common with computer numerical control (CNC) machines, the VLF reads G-codes to enact motion. To accommodate this, CNCMI specified the Mach3 graphical user interface from Artsoft to translate the G-codes into motion commands for the Galil controller.

The software performs all calculations for precise control of up to six simultaneous axes using a trajectory planner that feeds the Galil controller a series of linear interpolation commands that are 4msec apart. The Mach3 software also comes with ready-made drivers for Galil controllers, which reduce set-up time.