DivisionMaster, shown above connected to a converted Vertex HV4 rotary table, is an automatic indexer, capable of driving a rotary table, a dividing head, or a headstock dividing attachment,
via a bipolar stepper motor, allowing rotary positioning of workpieces
to be achieved at the push of a button. This can avoid the trauma often
associated with "losing your place" when using manual dividing methods,
leading to premature conversion of a workpiece into scrap.
can work with a wide variety of rotary devices, and can be configured
for any drive ratio between 1:1 and 5000:1. For a rotary table with a
90:1 worm drive, with a 200 steps-per rev stepper motor, the resolution
is 1/100th of a degree per motor half-step; however, DivisionMaster
would be equally happy working with other drive ratios, 40:1, 60:1 and
72:1 being other common ratios seen in commercially available indexing
tools. DivisionMaster can also be configured for a wide variety of
different stepper motors.
DivisionMaster has "multiple
personalities"; 4 different sets of configuration parameters can be
stored, allowing fast switching between different rotary devices that
need different motor current settings, speeds, drive ratios etc.
always calculates moves to the nearest motor half-step. This means that
the theoretical positioning accuracy is always within a quarter of a
motor step of the desired position; i.e., within 1/200th of a degree
with a 90:1 worm drive ratio. Actual positioning accuracy will
ultimately depend upon the mechanical accuracy of the rotary device.
Positioning errors are not cumulative, but are spread evenly over a
full rotation of the rotary axis.
DivisionMaster can be used as:
a stand-alone indexer, directly driving stepper motors at up to 2A/phase, or
stand-alone indexer, indirectly driving more powerful stepper motors
via an external power stage, using the step-and-direction output
signals it can generate, or
rotary axis motor driver for stepper motors up to 2A/phase, controlled
by a parent CNC machine. This can be achieved by using
step-and-direction motor control signals output by the parent machine's
controller, or by using contact closure inputs that replicate the
function of DivisionMaster's indexing command keys.
Copyright 2006 Tony Jeffree.