Welcome to our simple guide on the M30 CNC code. Whether you are new to CNC programming or an experienced machinist, understanding the M30 code is essential.
This guide will explain everything you need to know about this unit mode command—what it is, when to use it, and why it matters.
(Step-by-step.)
Key Takeaways
- M30 is a program end command that signals the completion of a program and returns the machine to a default state.
- M30 sets axis offsets to zero, origin offsets to default, and selected plane to XY, turning off cutter compensation and stopping the spindle.
- Executing an M30 command resets the machine state to its default settings, zeroing axis offset values and halting active coolant or spindle operations.
- M30 can be used with L value parameters to repeat a program a specified number of times or create an infinite loop.
- After executing M30, selecting Cycle Start will restart the program back at the beginning of the file.
Program Stop Commands
When working with CNC G-code, you frequently need to pause a running program to inspect the tool condition, display important information, or simply to intervene in the machining process.
You can use M00 and M01 commands to temporarily stop a program. M00 stops the program regardless of the optional stop switch setting, while M01 stops the program only if the stop switch is on. This allows you to check the tool condition before an automated tool change.
When you stop a program using M00 or M01, selecting Cycle Start restarts the program at the following line of the G-code program. You can also add comments after M00 or M01 to display information at the bottom of the tool path preview screen, which is useful for displaying setup instructions or other relevant information to the operator.
Program Stop With Image Display
You can take your CNC machining process to the next level by incorporating visual aids into your program stops.
By adding an image file name in a comment after an M00 or M01 command, you can display an image in the tool path preview screen. The image file must be located in the same folder as the G-code program file, a folder called images within the G-code program files folder, or a folder called images within the home directory.
For example, M01 (Op1_Setup.jpg) displays an image file named Op1_Setup.jpg. This feature is useful for displaying setup instructions or other relevant information to the operator.
Program End Commands
You’ll use program end commands to signal the completion of a program and return the machine to a default state.
M02 and M30 are the two program end commands, with distinct differences in their effects on the machine’s state.
Program End Commands
Program end commands, M02 and M30, signal the termination of a program and prepare the machine for its next operation.
When you use M02 or M30, you’re telling the machine to stop executing the current program and get ready for the next one.
Both commands set axis offsets to zero, origin offsets to default, and selected plane to XY. They turn off cutter compensation, stop the spindle, and set the current motion mode to G01.
After executing M02 or M30, no more lines of code in the file are executed, and selecting Cycle Start will restart the program back at the beginning of the file.
M02 leaves the next line to be executed as the M02 line, while M30 rewinds the G-code file.
The choice between M02 and M30 depends on the specific machine and program requirements, so it’s vital to understand their differences.
M02 Vs M30
M02 and M30 both signal the end of a program, but their differences lie in how they handle the post-program operation.
When you use M02, the program ends, and the machine returns to the beginning of the program, ready to restart.
In contrast, M30 not only ends the program but also rewinds the program tape, effectively erasing the program from memory. This means you’ll need to reload the program if you want to run it again.
Additionally, M30 often triggers a tool change, whereas M02 does not.
Command Effects
When a program reaches its finale, the command effects of M02 and M30 come into play.
These commands have significant effects on the machine state, ensuring a safe and default state.
- They set axis offsets to zero, origin offsets to default, and the selected plane to XY.
- They turn off the spindle and set the current motion mode to G01.
- Coolant is also turned off, and the program execution stops at the M02 or M30 line.
- Distance mode is set to absolute, feed rate mode to units per minute, and feed and speed overrides to on.
- Selecting Cycle Start will start the program back at the beginning of the file, ignoring any lines after the M30 command.
Effects of Program End Commands
When you execute an M30 command, you’ll see the machine state reset to its default settings.
Additionally, axis offset values will be zeroed, and any active coolant or spindle operations will come to a halt.
These effects can significantly impact your CNC machining process, so it’s essential to understand them thoroughly.
Machine State Reset
Your CNC machine’s state is reset when a program end command, such as M02, is executed.
This reset is vital, as it guarantees a clean slate for the next program. The M30 command, in particular, is designed to end the program and reset the machine state.
When the machine state is reset, the following occur:
- The spindle stops rotating
- All axes return to their default states
- Any active feed rates and spindle speeds are canceled
- The program ends, and the machine waits for new instructions
- The CNC system is ready to accept a new program or command
Axis Offset Zeroing
Having executed a program end command like M30, you’re left with a reset machine state, which has a profound impact on axis offset zeroing.
The axis offset, which is the distance between the machine’s coordinate system and the tool’s reference point, is reset to zero. This means that any Tool Length Offset (TLO) or Length Compensation values are also reset, effectively canceling any previous adjustments.
When the machine state is reset, the Coordinate System is also reinitialized, which can affect the accuracy of subsequent machining operations.
It’s essential to reestablish the correct axis offset and tool length offset values after executing an M30 command to guarantee precise machining results and to verify precise machining results.
Coolant and Spindle Stop
You’ll find that program end commands like M30 and M02 have a significant impact on coolant and spindle stop.
These commands not only reset the machine state to a default or safe state but also affect the coolant and spindle operations.
- They turn off the coolant, ensuring no unnecessary fluid flow.
- The spindle is stopped, bringing the machining process to a halt.
- Cutter compensation is turned off, and the current motion mode is set to G01.
- Feed rate mode is set to units per minute, and feed and speed overrides are turned on.
- Distance mode is set to absolute, ensuring precise movements.
Other G-Code Commands
Beyond the fundamental motion commands, several other G-code commands are essential for efficient and accurate CNC machining. You’ll use these commands to fine-tune your machining process and guarantee precision parts.
| Command | Description | Usage |
|---|---|---|
| G28, G28.1 | Return to predefined position (homing) | Referencing machine axes |
| G30, G30.1 | Rapid positioning to predefined location | Moving to specific location |
| G38.x | Straight probing | Detecting part surface or feature |
You’ll also use G40, G41, and G42 for cutter compensation, adjusting the tool path for the cutting tool’s radius. For dynamic cutter compensation, use G41.1 and G42.1. These commands guarantee accurate cutting conditions. In your G-code file, you can include these commands to optimize your CNC machining process, especially when using manual tool change or control mode.
Group 1: Program Control
Group 1: Program Control commands enable you to manage your CNC machining program’s flow and structure.
These commands allow you to start, stop, and modify the program’s execution.
You can use these commands to:
- Start a program from the beginning with ‘M02’
- Stop the program with ‘M00’ or ‘M01’
- Switch to a different program mode with ‘M03’
- Specify the program’s units with ‘G70’ or ‘G71’
- Repeat a block of code with ‘M99’
CNC M Codes Overview
You’ll use M codes to control various aspects of your CNC machine, and understanding their functions is vital for efficient programming.
M codes can be broadly categorized into two groups: M code functions, which control the machine’s actions, and auxiliary machine control, which manages external devices and systems.
M Code Functions
Three primary categories of M codes exist: preparation, action, and setting functions.
These categories enable you to control your CNC machine with precision.
Preparation functions prepare the machine for operation, action functions perform specific tasks, and setting functions configure the machine’s settings.
You’ll use M codes to:
- Select a tool with M06, which prompts the machine to change to the specified tool
- Set digital output signals with M62-M65, controlling external devices
- Set the machine’s units with M70-M72, choosing between inch or millimeter units
- Specify the tool’s offset with M43-M49, ensuring accurate cuts
- Initialize the spindle with M03-M05, setting its rotation and direction
Auxiliary Machine Control
As you delve into the world of CNC machining, understanding auxiliary machine control becomes crucial for precise operation.
This control is achieved through M Codes, which direct functions like coolant and spindle control, and are used in conjunction with G Codes. You’ll use M Codes to control spindle rotation, coolant, and tool changes, with each machine having custom codes, but a standard set remains the same.
When programming, bear in mind that only one M Code can be activated per block of code. For instance, you’ll use M Codes to synchronize digital output with spindle and feed, or to program back coolant and spindle functions.
Program Stop and Optional Stop
Most CNC machining operations require occasional interruptions to allow for manual interventions, such as tool changes or lubrication.
You can use the M00 and M01 commands to control the program flow and allow for these interruptions.
– The M00 command stops the machine and program, ideal for manual tool changes or adding tapping oil to a tap.
Be careful to start the spindle after an M00 command.
- The M01 command is an optional stop, giving you the choice to stop the machine, typically used to check tool condition before an automated tool change.
- Both M00 and M01 can be programmed in MDI mode, but the effect may not be noticeable.
- If a program is stopped by an M00 or M01, selecting Cycle Start restarts the program at the following line of the G-code program.
- M00 and M01 are essential for controlling the program flow, allowing you to intervene or pause the program as needed.
Spindle Control and Tool Change
You’ve stopped the machine using M00 or M01 commands, and now it’s time to focus on spindle control and tool change. The spindle speed and feed can be controlled using S and F codes, respectively. For example, S500 sets the spindle speed to 500 RPM, while F100 sets the feed rate to 100 mm/min.
| Command | Function | Description |
|---|---|---|
| M03 | Spindle On CW | Turns the spindle on in a clockwise direction |
| M04 | Spindle On CCW | Turns the spindle on in a counterclockwise direction |
| M05 | Spindle Off | Turns the spindle off |
| M06 | Tool Change | Initiates a tool change using the tool changer |
| M08 | Mist Coolant On | Turns the mist coolant on |
Remember to always specify the correct tool in the spindle before resuming the program. The tool changer will take care of the rest.
Program End and Subprograms
Every CNC program eventually reaches its termination, and that’s where the M30 command comes in.
You use M30 to signal the program end and rewind, stopping the spindle and turning off coolant.
- M30 is used exclusively for program end and rewind on some machines, while M02 is used for program end and stop without rewind on most machines.
- M30 defaults all modal commands, including axis offsets, origin offsets, and feed rate mode.
- M30 can be used with L value parameters to repeat a program a specified number of times or create an infinite loop.
- M30 is part of the G-code language, controlling the CNC machine’s movements and actions.
- M30 is often used in conjunction with other G-code commands to create complex programs and subprograms.
CNC Codes Similar to M30
|
Code
|
Mode
|
|---|---|
| M00 | Program Stop |
| M01 | Optional Stop |
| M02 | End of Program |
| M03 | Spindle On, Clockwise |
| M04 | Spindle On Counterclockwise |
| M05 | Spindle Stop |
| M06 | Tool Change |
| M07 | Coolant on (mist) |
| M08 | Flood Coolant On |
| M09 | Deactivate coolant system |
| M10 | Clamp On |
| M11 | Work Table Rotation Unlocked |
| M13 | Spindle On (clockwise rotation) and Coolant On |
| M19 | Spindle Orientation |
| M29 | Rigid Tapping |
| M40 | Spindle gear change |
| M68 | Set an analog output immediately |
| M69 | Hydraulic chuck open |
| M98 | Call Subprogram |
| M99 | End Subprogram |
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