The BGS80CC features a high resolution 4,000 cts/rev rotary encoder with index pulse for precision homing and is the recommended choice for applications requiring accurate bi-directional positioning. For tightest position control, the rotary encoder is directly mounted on the worm screw. This avoids the majority of drive train error sources that affect other stages with indirect position read out. BG Series goniometric cradles rotate on a transverse axis above the platform. Compared to full 360 ° rotation stages, they offer maximum free access to the rotating part and allow construction of very compact multi-axis rotation assemblies. BG cradles are designed so that orthogonal mounting of two adjacent-size cradles (e.g., BGS50 and BGS80) provides two perpendicular rotational axes intersecting at about the same point in space. Mounting a rotation stage under the assembly adds a third orthogonal rotation axis through the same point. Precision rotation is ensured by a precision ground, hardened worm gear drive. Single row ball bearings and precision ground tool-steel races ensure smooth rotation with minimal wobble and eccentricity. A home switch, conveniently located at the center of travel, facilitates the return of the platform to a level position.
For stage to controller compatibility, click here: Stage Compatibility Matrix
BG goniometers are designed so that two adjacent-sized models can be directly mounted orthogonally to each other (for example, BGS80 with BGM120) to pivot about the same point in space. The direct mounting capability saves set-up time, design time, and adapter plate costs. For additional rotation axes, a rotation stage can be mounted under the assembly or on the top BG platform. The video demonstrates an open access, multi-axis tip, tilt and rotation assembly with two BG goniometers and two rotation stages.
The BG series stages provide up to ±45° of transverse axis rotation enforced with mechanical limit switches. The stage is designed for maximum free access to the rotating platform, allowing for simplified stacking and mounting.
Precise rotation is ensured by a precision ground, hardened worm gear drive. In addition to being non-backdrivable, the worm gear drive's advantages include higher MIM, repeatability, and overall accuracy.
Single-row ball bearings and precision-ground, hardened tool-steel races ensure smooth rotation with minimal wobble and eccentricity. This allows for higher load capacities, stiffness, and stability.
DC motors are best characterized by their smooth motion, high speeds, good efficiency and high power/weight ratio. These BG cradles with DC motors offer higher torque and repeatability, and all encoders come with index pulses for precision homing. The BGS50CC uses a miniature DC servo motor, kept in a compact, lightweight package. All other models feature a high resolution, worm mounted rotary encoder which bypasses most drive train errors, resulting in improved bi-directional repeatability. The BGM models use high torque DC motors with a built-in tachometer to provide superior speed stability.
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