MDF Rose Engine Lathe 2.0
Control System for Multiple Stepper Motors
Enabled
Indicates that the selected stepper motor is enabled even when not in use. Touch this to change it to Disabled. The More screen can be used to set this to be continuously Disabled or Enabled. These buttons temporarily override that configuration setting.

Key Note:When using DM542T stepper motor drivers, this needs to be Enabled (especially for work using indexing), otherwise the position will be lost and the movement will not be predictable.


Disabled
Indicates that the selected stepper motor is only enabled when in use, and then disabled. Touch this to change it to Enabled.

Used to turn the spindle counter-clockwise. On a traditional lathe, this is considered forward.

Used to stop the motion of the stepper motor.

Used to return the spindle or the selected axis to the start point of the rose pattern.

When using this function, Be sure to stop and retract the cutter from the cut first. The return path does not always follow the same path as the initial cut. (Backlash and other factors come into play here.)

The speed of the return action is set in the Preferences | Returns screen.


Used to turn the spindle clockwise. On a traditional lathe, this is considered reverse. To change the direction of the spindle, you must stop it first. You cannot directly swap between clockwise and counter-clockwise.

Config
Touch Config on the screen image above to see the details for this screen.
This is used to display or edit the configuration settings for the MaxSpeed and the Acceleration for the respective stepper motors.
Rose Screen
Geometric chuck

Purpose: This screen allows for the creation of a rose or single stage geometric chuck patterns (see also, Wikipedia Rose (mathematics) -- the math explaining how the variables work is explained there).

The B axis is only available when it is set to Linear in the B Axis Configuration page


Key Note: There is some pretty heavy duty math going on here, and some of the combinations of n and d get into calculations which can take the Teensy some time. The result is that it can not be run as fast on the Z axis as with other operations.

 

200 is the recommended starting point for the Max Speed on the Z axis (and also start at 50% on the slider). If the pattern does not turn out as expected, try running at a slower speed.

 

 n  the numerator

Rose curves for various values of n & d

 
 d  the denominator
 
 k  the ratio, n/d
 
 Spindle Revolutions  Number of revolutions the spindle should make before stopping. This functionality very useful is useful for producing partially completed patterns like the one to the right.

If this is set to zero (0), the movement of the cutter will continue until the stop button is pressed. This is useful for setting the depth of cut.

This field was introduced in version 19.

 
 Axis Amplitude  Sets height (distance along Z or X Axes) of each lobe and is dependent upon value entered in Configuration Screen for Distance/360 for the axis you are using. If using the B axis with radial movement, the gear ratio sets this value.
 
 B Radius  B Radius is the distance from the center of rotation to the cutter. This field is only visible when moving on the B axis.

Speed The controls on the left and right side of the screen are for controlling the respective stepper motor's speed and acceleration.

To change the Max Speed, touch the number, and you will be presented with the Number Pad Screen.

The slider is a red bar that can be moved up to increase the speed, or down to decrease it.

Want to understand this better? More details about the stepper motor speeds are on this page.

 
Acceleration The bottom number (6000 on the left; 5000 on the right) is the acceleration for the stepper motor.

To change this value, touch the number, and you will be presented with the Number Pad Screen.


Limit Switches

Limit switches can be used with this function. The pins used for this are configured on the Limit Switches Configuration Screen. (More information about the implementation of limit switches is on that page.)


Specific Axis Notes

Axis Comments
Spindle
Movement continues until the identified movement distance is completed, or the stop button (shown to the right) is used.
Z Movement on this axis is the same as for the spindle.
X Movement on this axis is the same as for the spindle.
B The fields on this screen are used with the fields and settings on the B Axis Configuration screen to calculate how long to run the stepper motor to achieve the desired rotation.

Movement on this axis is the same as for the spindle.


Reference Documents

  1. The geometric mathematics behind this movement are explained by Dr. Frank A. Farris in his 1996 paper, "Wheels on Wheels on Wheels-Surprising Symmetry".

  2. There is also a nice article on this at Wolfram MathWorld.

  3. One good historical reference is Sir Thomas Sebastian Bazley's 1875 book, Index to the Geometric Chuck. There are some great pictures showing the result of the process.