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Simplified Chinese Setup Laser for Engraving and Cutting
This feature allows a laser to be added to MASSO for engraving and cutting applications. MASSO can switch the laser on and off and control laser power using PWM, which stands for Pulse Width Modulation.
PWM control allows the laser to be used for cutting, general line engraving, dithered engraving, and grayscale engraving. When using grayscale engraving, MASSO can display the image using the Depth Map feature.
Syntax and Parameters
The laser is defined as Tool 111 and this tool number cannot be changed. To enter laser mode, Tool 111 must be loaded.
The M03 command enables the laser output with zero intensity. The S command controls the laser PWM power level and accepts values from 0 to 1000, where 0 represents 0 percent power and 1000 represents 100 percent power. The S command must be used with a G1 move and is synchronised with axis motion. The M05 command turns the laser output off.
Example Program
N10 T111 M06
N20 S0 M03
N30 G00 X0 Y0
N40 G01 X100 Y0 F600 S350
N50 G01 X100 Y100
N60 G01 X0 Y0 S0
N70 M05
Program Description
This program loads Laser Tool 111 and enables the laser at zero power. It then rapids to X0 Y0 before moving to X100 Y0 at a feedrate of 600 with the laser set to 35 percent power. The program continues to X100 Y100 at the same power, then returns to X0 Y0 with the laser power set to zero, and finally turns the laser off.
Hardware Requirements
Any laser with a TTL PWM input can be used. Appropriate laser safety glasses must be worn and must be suitable for the wavelength and power of the laser being used.
MASSO TTL Output Behaviour
When the laser is on, the TTL output provides 5 volts. When the laser is off, the TTL output provides 0 volts.
Configuring MASSO
TTL Output 11 must be configured as the Laser Engraving and Cutting output. No other output can be used for this function because Output 11 includes dedicated hardware required to generate a PWM signal.
An additional output can be assigned to move the laser into position automatically when the laser tool is selected. Another output may be assigned for air assist if required.
To enable laser functionality, navigate to the Multi-Head settings page, select Laser Engraving and Cutting, and enable the feature.
The PWM frequency must be set to suit the laser being used. A value of 10 kHz is recommended for most applications, although the optimal frequency depends on laser power and maximum feedrate. PWM frequencies can be set between 4 kHz and 60 kHz. Since laser power is controlled by rapidly switching the laser on and off, low PWM frequencies combined with high feedrates can result in inconsistent engraving. A frequency of 10 kHz generally provides a good balance.
X, Y, and Z offsets define the distance between the laser and the main spindle or primary tool. These offsets can be measured by zeroing the DROs, marking a spot with the laser, jogging the main spindle to the centre of that spot, and reading the DRO values. The Z offset depends on the laser focus point relative to the spindle Z zero. In many cases, the Z offset is left at zero and the laser is manually zeroed for each job. Offsets are required only when switching between the laser and another tool within the same G-code file.
Once these settings are completed, laser configuration is complete.
Displaying Laser Grayscale Engravings
For grayscale engravings to display correctly, the G-code file must include T111 M06 at the start of the file. If this command is missing, the Depth Map view will be blank.
The display can be toggled between 2D View and Depth Map View using the button at the top right of the display area.
Connecting Your Laser
Laser wiring depends on the specific laser and its interface. A 5.6 k?, ¼-watt resistor must be installed between the PWM output and MASSO GND for all lasers that do not include an internal pull-down resistor. This resistor is required for correct PWM operation.
If it is unclear whether the laser includes a built-in pull-down resistor, adding the resistor will not cause any disadvantage.
The wiring examples provided are for demonstration purposes only. The correct wiring method must always be confirmed using the documentation supplied with the laser hardware.
MASSO uses TTL signals only and controls laser power using PWM.
Installing the PWM Grounding Resistor
The 5.6 k?, ¼-watt resistor must be installed between the PWM output and MASSO GND for lasers without a built-in pull-down resistor. The resistor may be installed at the laser or directly on MASSO. Any exposed resistor should be insulated to prevent accidental contact, and clear heat-shrink tubing is recommended.
Resistor installed on MASSO
Connecting a Typical 3 Wire Laser Module
Many laser modules use three connections: power, ground, and PWM. This configuration is common across most laser driver boards and modules, including those mounted directly on the laser with or without cooling fans.
All such lasers are connected using the same method, and the grounding resistor requirements remain the same. Ensure that power supply wiring is correctly sized to handle the laser’s current requirements.
Connecting other outputs to your Laser
Emergency Stop
If the laser includes an enable input, an E-Stop relay can be used to disable the laser during an emergency. If the laser does not include an enable input, the laser power supply may be routed through an E-Stop relay. Care must be taken when using this method, as restoring the E-Stop will also restore power to the laser, which may cause unintended burning if the laser is not disabled beforehand.
Air Assist
An output can be assigned for air assist if supported by the laser. Air assist improves cut quality and cutting performance. The M8 command enables air assist and the M9 command disables it. An air solenoid may be connected to control airflow.
Laser Up and Down
An output may be assigned to automatically lower the laser into position when Laser Tool 111 is selected and raise it when another tool is selected. When Tool 111 is selected, the Laser Up/Down output goes high. When another tool is selected, the output goes low. The laser can be moved using a pneumatic cylinder or linear actuator. This output may also be used to provide additional laser power isolation for safety.
Generating G-code
MASSO laser G-code is compatible with many GRBL-based laser software packages. LightBurn is a recommended option for engraving images, line art, and cutting parts.
Instructions for configuring LightBurn for use with MASSO are available here: Setting up Lightburn
Notes on G-code Format
The G-code file must include T111 M06 at the start of the program or the Depth Map view will be blank. The S command may appear on its own line or on the same line as the motion command. The S value ranges from 0 to 1000, and dividing the S value by 10 provides the percentage of total laser power. The S command does not take effect until axis movement occurs.
Laser Safety Glasses
Laser safety glasses are essential when working with any laser system. Unlike other CNC tools, lasers can cause permanent eye damage even from reflected or scattered light. High-quality laser safety glasses suitable for the wavelength and power of the laser being used must always be worn.
Troubleshooting
If the laser does not turn on when using S and M3 commands but appears enabled on screen, it is important to understand that M3 only enables the laser output. The laser will not emit until an axis movement command is received. The same behaviour applies to S commands, as power changes are synchronised with motion.
To immediately turn on the Laser without motion use the M4 Gcode command with an S value to specify the power. eg S500 M4 will immediately turn on the laser at 50% power.
A sample test program is provided below to confirm correct laser operation.
T111 M06
G21
M03
U0.1 S1000
G04 P2000
U-0.1 S0
G04 P2000
M30 L0
If the laser turns on and off during this test, the laser and MASSO are functioning correctly. If the laser does not respond, measure the voltage at TTL Output 11 with the laser disconnected, using MASSO GND as the reference. The voltage should change between approximately 4.5 volts when on and 0 volts when off.
The voltmeter must not be set to auto-range, as it may not respond quickly enough to PWM signals. After verifying the output, reconnect the laser and repeat the measurement to confirm correct operation under load.
