? Four axis (compounded X-Z-Y with fourth axis moving base three rail slide arrangement)
Special multi-axis slide and spindle arrangement for Boeing A-10 Re-wing project. Features include rotating nut with precision ballscrew for vertical travel. Closed loop counter-balance system with 5-gallon accumulator. (Cylinders not shown). All axises include precision class heavy pre-load recirculating roller way elements. Fourth axis includes pneumatic and manual clamping features for vibration, positive locking, and positional repeatability for the three-axis unit. (Walk-on-way covers with hinged plates not shown).
? Three axis (X-Y-Z slide with angle plate arrangement)
For a three-axis motion system, two slides are mounted directly together, and then a third is mounted vertically atop the two using an angle plate. This provides three axes of linear motion.
Slide / Spindle Modules
? Single axis vertical slide and spindle units
This type of module features a motorized spindle, vertical slide and precision angle plate or column to provide a single axis of linear motion. The module can be of three configurations:
? Horizontal cartridge spindle mounted in the saddle of a vertical slide
? Horizontal block spindle mounted atop a precision angle plate, both mounted to the saddle of a vertical slide
? Vertical block / cartridge spindle mounted directly to the saddle of a vertical slide
? Single axis horizontal slide and spindle units
Typically used for drilling and boring operations, a motorized spindle is mounted atop a horizontal slide.
? Three axis modules with spindles
A three axis module consists of two compounded slides with a precision column and motorized spindle. The spindle may be horizontal or vertical, and may be of a block or cartridge design.
Design of Multi-Axis Modules
? Pyramid Profile
- Slide overhang
When slides are compounded, one of the two units will not be supported for its entire length. This cantilevered section must be considered when sizing the slides.
- Slide size order
For maximal stability, wider slides are used on the bottom of a multi-axis assembly than are used on the top. This minimizes deflection and increases accuracy.
? Counterbalance for Vertical Axis
Definition A counterbalance is a mechanism that continuously supports the weight of a saddle and spindle.
Rationale The vertical axis slide supports the weight of its own saddle, and that of the motorized spindle. For vertical axes driven with an electric motor, the motor must constantly energize a field to support the static weight. The motor and drive must be oversized to handle the thermal load of this condition. In a loss of power situation, the vertical axis may fall if a brake is not used on the motor. Each of these situations can be changed with the addition of a counterbalance.
Design The counterbalance may be of four types: weight stack, pneumatic cylinder, hydraulic cylinder, or air over hydraulic cylinder.
? A weight stack counterbalance connects a stack of steel plates to the reciprocating weight via chains or cables, and pulls the saddle upward.
? Pneumatic cylinder counterbalance connects one or two air cylinders to the reciprocating weight, and requires a constant supply or air pressure to operate.
? The hydraulic counterbalance substitutes hydraulic cylinders for the pneumatic cylinders. Constant hydraulic pressure is required to operate.
? An air over hydraulic counterbalance uses a hydraulic cylinder supplied with pressure from a charged accumulator. This system is self-contained and does not rely on external air or hydraulic pressure. Because the lifting power comes from an accumulator, the amount of counterbalance is not constant.