Bridgeport Anilam Crusader II CNC Mill Pgrm & Ops

Chapter 7 -- Circular Interpolation

Whenever the Crusader is given a command to cut a two dimensional (2D or 2 axis) arc, it will assume that the current tool location is the starting point of that arc. Obviously, you should therefore make sure that the current tool point is located where you want the arc to begin. Thus, each circular interpolation statement must contain the X & Y axis, X & Z axis, or Y & Z axis locations of

  1. the center point of the arc and
  2. the end point of the arc.

The Crusader can cut 2D arc paths that pass through quadrant lines (0°, 90°, 180°, or 270°) in a single command; arc sector angles may be programmed up to 360 degrees.

Although the Crusader II can be programmed to cut arcs operating in the absolute positioning mode (G90), it is often simpler to use the incremental mode (G91).

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Anilam Format:

Enter the arc center location BEFORE the arc end location. (Opposite order from RS-274-D format.)

  1. Press Arc to toggle LED on, then toggle direction Clockwise or Counter Clockwise as required, and press Event Enter.

  2. Enter the X and Y locations of the arc CENTER point Event Enter.

  3. Enter the X and Y locations of the arc END point Event Enter.

  4. Press Arc Event Enter.

Example:
Program a 90 degree 1" radius arc counterclockwise from the
6:00 to 3:00 o'clock position at 15 IPM (see Figure 1).
Event Press the following keys (Toggle as required to activate)
1 Feedrate 1 (one) 5 (five) . (decimal point) Event Enter
2 Arc Counter Clockwise Event Enter
3 X axis Active 0 (zero) Y axis Active 1 (one) . (decimal point) Incremental Feedrate Event Enter
4 X axis Active 1 (one) . (decimal point) Y axis Active 1 (one) . (decimal point) Incremental Feedrate Event Enter
5 Arc Event Enter

Figure 1
Figure 1 - Circular Interpolation

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EIA-274-D format

Enter the arc end point (X-Y-Z) BEFORE the arc center point (I-J-K). (Opposite order from Anilam format.)

  1. The direction of arc cut must be stated.
    Use G02 for clockwise arc path or G03 for counterclockwise arc path.
    Both are modal.

  2. The location of the end point of the arc is stated in terms of the usual X and Y axis commands and can have negative values.

  3. The location of the arc center (called the "arc center offset") is stated using I and J commands and can have negative values.
    1. The "arc center offset" along the X axis is the I command.

    2. The "arc center offset" along the Y axis is the J command.

    3. I or J commands that have zero (0) values can NOT be omitted.

Example:
Program a 90 degree 1" radius arc counterclockwise from the
6:00 to 3:00 o'clock position at 15 IPM (see Figure 1 above).
N0001 G03 G91 X1. Y1. I0 J1. F15. [EOB]
where [EOB] is "End of Block" or the basic text end of line.

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Copyright © 2003 George C. Stanton & Bill Hemphill
All Rights Reserved

Last updated on Jan. 21, 2003 by Bill Hemphill