======Drilling Cycles for myCNC======

Below is a sample block of code utilizing the myCNC drilling cycle:

<code>
G90 G21 G54.
G0 X50. Y50. Z3.
G0 Z10.
M3 S800
G98 G83 X0 Z-9. R1. Q1 P0.  F500 L1000
G98 G83 X10 Z-9. R1. Q3 J0.5 K1 P0. F500. L1000
G98 G73 X20 Z-9. R1. Q3 J0.5 K1 P0. F500. L1000
G98 G81 X30 Z-9. R1. Q3 J0.5 K1 P0. F500. L1000
G99 X40.
G80
M5</code>

The nomenclature functions in the following manner:

^ Code ^ Meaning ^
| G83 | Drilling cycle command |
| G98 | Raise to starting height at the end of cycle |
| G99 | Raise to height R at the end of cycle |
| R | Position of the R height |
| F | Drill speed |
| L | Lift speed |
| Z | Total drill depth |
| P | Pause (in seconds) |
| Q | Initial cut depth |
| J | Distance to incrementally reduce drill depth by on each pass |
| K | Minimum drill depth per pass | 


The two major differences for the drilling cycle are the G-codes G98 (raise back to starting height at the end of the cycle) and G99 (raise back to height R at the end of the cycle).

====G98 G83====

An illustration of the command utilizing the G98 G83 block:

{{:mycnc:drilling-cycle-001-g98.jpg}}

  - The drill is located at Starting Height
  - Move to Height R
  - Begin cutting, lowering itself by initial cut depth, Q
  - Rise back to Height R
  - Cut additional material, distance from R is (Q + (Q-J)), where J is the incremental distance which is reduced each pass
  - Rise back to Height R
  - Cut additional material, distance from R is (Q + (Q-J*[number of current pass])). Repeat until the (Q-J*[number of current pass]) distance is equal to K, which is the minimum drill depth per pass.
  - Repeat drilling procedure lowering the drill by distance K every pass, until Total Depth Z is reached.
  - Raise drill to initial Starting Height to finish the drilling cycle



====G99 G83====

An illustration of the command utilizing the G98 G83 block:

{{:mycnc:drilling-cycle-001-g99.jpg}}


  - The drill is located at Starting Height
  - Move to Height R
  - Begin cutting, lowering itself by initial cut depth, Q
  - Rise back to Height R
  - Cut additional material, distance from R is (Q + (Q-J)), where J is the incremental distance which is reduced each pass
  - Rise back to Height R
  - Cut additional material, distance from R is (Q + (Q-J*[number of current pass])). Repeat until the (Q-J*[number of current pass]) distance is equal to K, which is the minimum drill depth per pass.
  - Repeat drilling procedure lowering the drill by distance K every pass, until Total Depth Z is reached.
  - Raise drill to height R to finish the drilling cycle

====G81====

A cycle for drilling in one pass (immediately going down to the Total Depth Z). G98/G99 and drill/lift speeds also apply.

{{:mycnc:drilling-cycle-003-g98g81.png}}

{{:mycnc:drilling-cycle-004-g99g81.png}}

====G73====

G73 - cycle with chip breaking. Similar to G83, but G73 differs in that it pulls the tool out not to the very end, but by a fixed (typically a very small, such as 0.5 mm) distance called Clearance Distance. G98/G99 and drill/lift speeds also apply.

G98 option:

{{:mycnc:drilling-cycle-005-g98g73.png}}

G99 option:

{{:mycnc:drilling-cycle-006-g99g73.png}}



====G82====

G82 is the standard drilling cycle with a dwell of time P at the bottom of the hole.

G98 option:

{{:mycnc:drilling-cycle-007-g98g82.png}}

G99 option:

{{:mycnc:drilling-cycle-007-g99g82.png}}


====G85====

G85 boring cycle is similar to G82, minus the dwell time at the bottom of the hole.

G98 option:

{{:mycnc:drilling-cycle-008-g98g85.png}}

G99 option:

{{:mycnc:drilling-cycle-008-g99g85.png}}

====G86====

The G86 cycle is similar to the G82/G85 cycles, with a regular boring cycle down to Total Depth Z and a spindle stop at the bottom of the hole.

G98 option:
{{:mycnc:drilling-cycle-009-g98g86.png}}

G99 option: 
{{:mycnc:drilling-cycle-009-g99g86.png}}