Coil and Helix by cnc command G14 / G15

Coil function G14 = CW and G15 = CCW

This is a helical coil programmed with the CncPlayer's G14/G15 function
G14 (CW = ClockWise)
G15 (CCW = CounterClockWise)

Img. 1

In the 2D view above we don't know much how the coil actually is. The next image shows the same coil but spinning. I removed the ruler, title bar and frame from the image because otherwise the animated *.gif file would have been 350 kb in size. The image shows the window's client area only.

This is an animated *.gif image of 157.041 byte

Img. 2

You get the same spinning view in your CncPlayer when you switch to 3D rotation and when you use the cursor keys to rotate the object. The rotation in the *.gif image is just around the Y axis but the CncPlayer lets you rotate around all 3 axes (XYZ). Of course the CncPlayer lets you 3D mill the coil. The images provided herein are just to illustrate the coil thing a little bit.

Here is the CNC code that creates the two coils

% # 2 coils N100 G00 X0 Y0 Z0 # move to 0/0/0 N110 G15 I0 J0 T5 P-30 W10 # first coil N120 G00 X0 Y0 Z0 # move to 0/0/0 N130 G15 I0 J0 T5 P30 W10 # second coil M30

The second coil is the same as the first coil though the Pitch parameter P is inverted (+ / -).

The coil parameter:

• Coil start point is the current tool position
• I, J is the coil center relative to the current start point
• T is the number of turns (fractions e.g. 3.679 allowed). No - values allowed.
• P is the pitch of the coil (fractions e.g. 0.75 allowed). The sign (+ or -) determines the direction. In other words: P lets you stretch the loops in Z direction.
• W is the width of the end radius. In other words: W lets you stretch the loops in XY direction.

Some programs only allow full 360° turns but the CncPlayer also gives you control over the angel of the start- and endpoint of the coil. Coil, Helix, fractions of it ... much can be done with G14/G15.

Img. 3

This is a simple ccw (counter clockwise) helix created with the CncPlayer's G15 function, displayed in 3D. The helix got 5 x 360° turns (= T5.0), Pitch is 30 mm (= P30.0), Width is 0.0 (= W0.0) which makes it a helix but not a coil.

Here is the CNC code that creates the helix

% # helix N100 G00 X50 Y50 Z0 # move to 50/50/0 N110 G15 I50 J50 T5 P30 W0 # the helix M30

A little tutorial about G14 / G15 programming

Let's start to mill a simple circle. No, not by G02/G03 but by G14/G15. Yes, you can do that. The circle will start where the current tool position is. Imagine the tool is at 0/0/0. That means the circle starts at 0/0/0. Now we define the center by the I J values (I = X position, J = Y position). Say I 50 J 0 (that's the same I J you know from the G02/G03 circle programming). Since we want a single, full 360° turn we say T1.0. So we get

G14 I50 J0 T1.0

This mills a full 360° cw circle. Easy, isn't it? Well, since the CncPlayer's expects 5 values (I, J, T, P, W) we actually write

G14 I50 J0 T1.0 P0 W0

to avoid an error message. Now we change T1.0 to T4.0 to get 4 x 360° circle. That means we are milling the same circle 4 times. Pretty boring. So let's increase the Pitch P value to stretch our circle a little bit in Z direction with P-2.5. That means for each circle our Z axis moves down -2.5 mm.

G14 I50 J0 T4.0 P-2.5 W0

(Question to myself: Shall I rename the P value to Z value since Z is more obvious???)

4 x -2.5 mm = -10.0 mm. That means when your 4 circles have finished the Z axis moved down 10.0 mm total. In other words: The P value lets you stretch the loops in Z direction. Well, we have created a helix, similar as shown in Img. 3 above.

So what's about the W value (W = width)? Well, W lets you stretch the circle in XY direction. Have a look to Img. 1 above. There is W10 and that means each circle gets 10.0 mm bigger than the previous one.

Well, it's just 5 values (I, J, T, P, W) but lets you do a lot of nice "loopings". You want to mill a 300 mm hole in a 10 mm aluminum plate? Use, for instance, a G14 helix.