Page 5 of 9 Helical Interpolation.myCNC software and controllers support helical interpolation  simultaneous twoaxis circular motion with the linear motion along the remaining axes. A sample of helical interpolation is showed below: (Helical interpolation sample) % N10 G90 G0 X0 Y0 Z0 G02 X0 Y0 R50 Z10 ( a circle in XY plane with Z motion ) G02 X0 Y0 R50 Z20 ( a circle in XY plane with Z motion ) G02 X0 Y0 R50 Z30 ( a circle in XY plane with Z motion ) G02 X0 Y0 R50 Z40 ( a circle in XY plane with Z motion ) G02 X0 Y0 R50 Z50 ( a circle in XY plane with Z motion ) G02 X0 Y0 R50 Z60 ( a circle in XY plane with Z motion ) G02 X0 Y0 R50 Z70 ( a circle in XY plane with Z motion ) G02 X0 Y0 R50 Z80 ( a circle in XY plane with Z motion ) G02 X0 Y0 R50 Z90 ( a circle in XY plane with Z motion ) G02 X0 Y0 R50 Z100 ( a circle in XY plane with Z motion ) M30

Similar motion can be programmed by using parametrical programming as shown below (Helical interpolation sample) % N10 G90 G0 X0 Y0 Z0 #40=0 (next Z position) #41=50 (Radius ) #42=10 (Z step) #43=5+1 (number of turns) M98 P333 L#43 (run subroutine 333 [L1]times)
M30
O333 G02 X0 Y0 R#41 Z#40 ( a circle in XY plane with Z motion ) #40=#40+#42 M99 % 
myCNC supports also "spiral" interpolation  some kind of circular interpolation with lenearly varying Radius. A sample is shown below (Spiral/Helical interpolation sample) % N10 G90 G0 X0 Y0 Z0 G02 X10 Y0 I0 Z10 ( a spiral in XY plane with Z motion ) G02 X20 Y0 I10 Z20 ( a spiral in XY plane with Z motion ) G02 X30 Y0 I20 Z30 ( a spiral in XY plane with Z motion ) G02 X40 Y0 I30 Z40 ( a spiral in XY plane with Z motion ) G02 X50 Y0 I40 Z50 ( a spiral in XY plane with Z motion ) G02 X60 Y0 I50 Z60 ( a spiral in XY plane with Z motion ) G02 X70 Y0 I60 Z70 ( a spiral in XY plane with Z motion ) G02 X80 Y0 I70 Z80 ( a spiral in XY plane with Z motion ) G02 X90 Y0 I80 Z90 ( a spiral in XY plane with Z motion ) M30 % 
