AWC 608 Rotary Adapter Advance Feature

There is a lot of confusion about the Rotate Adapter Advance Feature of the AWC 608 DSP controller from LightObject.com. Most of the confusion can be eliminated when you understand the correct way to set it up. Since I am helping to rewrite the manual for this controller I decided to spend the time necessary to figure out the correct way to set it up and to put it to the test. I am happy to report that, once set up correctly, the feature works very nicely. The following is the chapter of the manual that I wrote regarding the Rotate Adapter Advance Feature.

Rotate Engrave 

The AWC 608 controller provides support for the operation of rotary adapters which allow you to engrave on the curved circumference of cylindrical objects. For most systems, the Y axis motor is disconnected from the Y axis drive and the rotary adapter is connected in its place. This effectively allows the Y axis portion of the AWC 608 controller to control the rotary device. Alternatively, the X axis may be used as the controlling axis for the rotary device.

There are two general types of rotary adapters:

1.       Friction – where the part rests on a driven wheel.

a.       Pros – Diameter of the material piece to be engraved has no impact on the settings as the surface of the material piece will always turn at a constant rate.

b.       Cons – Prone to slippage of the material piece to be engraved as the driving wheels are turned.

2.       Chucking – where the part to be engraved is held in a chuck.

a.       Pros – No slippage when turning the material piece to be engraved.

b.       Cons – The diameter of the material piece to be engraved has an impact on the settings and must be adjusted for each different material piece diameter.

The first two items in the Rotary Engrave Advanced Feature setup are identical for both types of rotary adapter.

Enable Rotate Engrave:  Checking this option informs the controller that you are performing rotary functions. This alters the way the controller handles resets and rotational movements.

Rotate Axis Con(um):    Rotate Axis Con is the Pulse Width (from the Manufacturer Parameters) of the axis you are using to control the rotary device. Since the physical drive mechanism for the rotary adapter is not necessarily identical to the physical drive mechanism of your Y (or X) axis, you will likely have to tweak this value, similar to the way you did the Y (or X) axis in the first place.

NOTE: When using the Y axis as the rotational axis, engraving method MUST be [Y-unilateralism].

When using the X axis as the rotational axis, engraving may be either [X-swing] or [X-unilateralism].

Step per Rotate (pulse): This is the number of steps (pulses) for the motor drive to rotate your cylindrical work piece 1 full rotation (360 degrees). That is, the number of steps required to rotate the work piece a distance equal to the circumference of the work piece.

The type of rotary adapter you have will determine how you calculate and use the remaining two values.

If you have a Chuck Type Rotary Adapter, then the number of steps to rotate the work piece through 360 degrees will remain constant, based on the type of motor, the micro steps, and the number of teeth on the motor and chuck pulleys.

If using a Chuck Type Rotary Adapter, the formula for calculating Step per Rotate is:

{Steps per Motor Rotation} * {Micro Steps} * T_c  /  T_m  *  m  * D

Example –

{Steps per Motor Rotation}   =    400  (0.9 degree motor)

{Micro Steps}                       =        8   (1/8^th step drive)

T_c                                          =      60   (60 teeth on Chuck pulley)

T_m                                                       =      20   (20 teeth on motor pulley)

400 * 8 * 60 / 20 = 9600

If you are using a 1.8 degree motor (200 steps), the value would come out to 4800

Obviously, you need to determine the number of teeth on both the Chuck and the Motor pulleys and substitute them into the formula appropriately.

Again – for a Chuck Type Rotary Adapter, you calculate this once and enter it. You will never need to recalculate it, unless you make a mechanical change to your setup.

If you have a Friction Type Rotary Adapter, then the number of steps to rotate the work piece through 360 degrees will vary, depending on the diameter of the work piece. This is because we are rotating through the circumference of the work piece at a constant rate. Therefore, we need to use a different formula. The formula is easy if you know the number of steps per inch of your setup. If you are using the Y (or X) axis drive, for example, and it is set up for 1000 steps per inch, and you geared your rotary adapter to be the same, then you can simple use 1000 as the steps per inch. If your rotary adapter is geared differently than your Y (or X) axis, then you will have to calculate the Steps per Inch you are actually getting at the drive wheel circumference of the rotary adapter.

With a Friction Type Rotary Adapter, once you know your Steps per Inch, you can use the following formula to determine the Step per Rotate for a specific diameter object:

m * D / {mm per Inch} * {Steps per Inch}

Example – 

Work piece diameter  =          18   (18 mm diameter work piece)
Steps per Inch           =       1000   (depends on your setup)

            mm per Inch              =        25.4

            m                              =    3.1416

3.1416 * 18 / 25.4 * 1000 = 2226

In theory, you would have to recalculate this value for every different diameter object. Fortunately, the controller sees a Friction Type Rotary Adapter as nothing more than a flat plane (like the Y or X axis) that has been wrapped around the cylindrical object. Therefore, we can calculate this ONCE for some arbitrary diameter and then never touch it (or the Current Diameter) again.

Current Diameter:             Diameter (mm) of the cylindrical object to be engraved.
For the example above, this would be 18.

NOTE – How you use Current Diameter is determined by the type of rotary adapter you have.

IF you have a Chuck Type Rotary Adapter, you MUST change this value for every different diameter work piece you use. Accuracy in determining the diameter is important, as internal calculations done by the controller will determine the actual output size.

IF you have a Friction Type Rotary Adapter, you NEVER change this value – you always use the value used when you calculated the Step per Rotate setting. Again, this is because Friction Type Rotary Adapters can be thought of as a boundless flat plane and the Steps per Inch used in the calculation will cause the work piece to rotate consistently, regardless of diameter.

Notes Regarding Vector Cutting on a Rotary Adapter

Notes Regarding Vector Operatoins on a Rotary Adapter

Officially, the AWC 608 does not support vector (cutting) operations when using the Rotate Engrave Advance Function.

In practice, however, when using a Friction Type Rotary Adapter, vector (cutting) operations appear to work very well for some installations. The key appears to be having the gearing (steps per inch) of the rotary adapter to be the same as the steps per inch you normally have on the Y (or X) axis. A common configuration is 1000 steps per inch for both. When they are the same, functions that use vector movements, including outlining vectors/cutting, Box, and Cut Box all appear to work well. Again, this is not officially supported but it may be worth giving it a try on your setup.

Here is a video of the output from a Friction Type Rotary Adapter set up for 18mm diameter. The object engraved/cut is, however, 70mm. No adjustments were made to the setup in the AWC608.