Horizontal Artifacts when engraving acrylic

Machine: K40 5040 version. https://www.toolots.com/co2-laser-engraver-machine-retractalble-laser-head-modlaser-xd-5040.html

Board: Laserboard

Firmware: _Smoothie

Problem/ Question: I’ve been trying to engrave acrylic for a while and I’ve tried slowing down the engrave speed and decreasing the power but it hasn’t worked.

You can see the horizontal artifacts between the F and the T in the word FTC.

I forgot to say I’m using lightburn.

Hi Ishaan, can you tell us about the file you are using, and maybe even post it here? Is there a chance there are artifacts in the file itself? (JPGs often have artifacts that aren’t easily noticeable.)

You mention that you tried to slow down the engraving, can you tell us what speed & power you are running at? If possible, please post a screenshot of the settings in LightBurn so we can see all the settings.

I don’t think that there are artifacts in the file. They are png files created using inkscape. Here’s a screenshot of what it looks like in lightburn for a more recent engraving I did. As you can see, in the engraving, there are a lot of artifacts on the a of Wizards and there’s a pretty large artifact on the b of Oberoi.


It looks like you have a larger machine, I take it you made the necessary changes in the config file?

Please post your config file so we can take a look and make sure there is nothing strange there.

Also, is this repeatable? Does it happen the same way every time, or is it a one-off occurrence?


To post the config file in a reply here please surround it with 3 backticks (that’s the key at the top left of your keyboard where the tilde is) like so:

```
paste your config file here
```

It will make the code nicely formatted like this...
# Stepper module pins ( ports, and pin numbers, appending "!" to the number will invert a pin )
alpha_step_pin            2.0       # Pin for alpha stepper step signal
alpha_dir_pin             0.5!       # Pin for alpha stepper direction
alpha_en_pin              0.4       # Pin for alpha enable pin

Alternatively, you may paste the config file to Pastebin, Dropbox, or Google Drive and provide the link here.

The artifacts aren’t consistently in the same place in the same way, but when engraving they usually happen at least once. Here’s the config i have

#Cohesion3D LaserBoard v0.2

# NOTE Lines must not exceed 132 characters
## Robot module configurations : general handling of movement G-codes and slicing into moves
default_feed_rate                            4000             # Default rate ( mm/minute ) for G1/G2/G3 moves
default_seek_rate                            24000            # Default rate ( mm/minute ) for G0 moves
mm_per_arc_segment                           0.0              # Fixed length for line segments that divide arcs 0 to disable
mm_max_arc_error                             0.01             # The maximum error for line segments that divide arcs 0 to disable
                                                              # note it is invalid for both the above be 0
                                                              # if both are used, will use largest segment length based on radius
#mm_per_line_segment                         5                # Lines can be cut into segments ( not usefull with cartesian
                                                              # coordinates robots ).

# Arm solution configuration : Cartesian robot. Translates mm positions into stepper positions
alpha_steps_per_mm                           157.575          # Steps per mm for alpha stepper
beta_steps_per_mm                            157.575          # Steps per mm for beta stepper
gamma_steps_per_mm                           157.575          # Steps per mm for gamma stepper

# Planner module configuration : Look-ahead and acceleration configuration
planner_queue_size                           32               # DO NOT CHANGE THIS UNLESS YOU KNOW EXACTLY WHAT YOU ARE DOING
acceleration                                 2500             # Acceleration in mm/second/second.
#z_acceleration                              500              # Acceleration for Z only moves in mm/s^2, 0 uses acceleration which is the default. DO NOT SET ON A DELTA
junction_deviation                           0.05             # Similar to the old "max_jerk", in millimeters,
                                                              # see https://github.com/grbl/grbl/blob/master/planner.c
                                                              # and https://github.com/grbl/grbl/wiki/Configuring-Grbl-v0.8
                                                              # Lower values mean being more careful, higher values means being
                                                              # faster and have more jerk
#z_junction_deviation                        0.0              # for Z only moves, -1 uses junction_deviation, zero disables junction_deviation on z moves DO NOT SET ON A DELTA
#minimum_planner_speed                       0.0              # sets the minimum planner speed in mm/sec

# Stepper module configuration
microseconds_per_step_pulse                  2                # Duration of step pulses to stepper drivers, in microseconds
base_stepping_frequency                      100000           # Base frequency for stepping

# Cartesian axis speed limits
x_axis_max_speed                             24000            # mm/min
y_axis_max_speed                             24000            # mm/min
z_axis_max_speed                             24000            # mm/min

# Stepper module pins ( ports, and pin numbers, appending "!" to the number will invert a pin )
alpha_step_pin                               2.0              # Pin for alpha stepper step signal
alpha_dir_pin                                0.5              # Pin for alpha stepper direction
alpha_en_pin                                 0.4              # Pin for alpha enable pin
alpha_current                                0.4              # X stepper motor current
alpha_max_rate                               24000.0          # mm/min
alpha_acceleration                           2500             # mm/sec²

beta_step_pin                                2.1              # Pin for beta stepper step signal
beta_dir_pin                                 0.11            # Pin for beta stepper direction
beta_en_pin                                  0.10             # Pin for beta enable
beta_current                                 0.6                # Y stepper motor current
beta_max_rate                                24000.0          # mm/min
beta_acceleration                            2500             # mm/sec²

gamma_step_pin                               2.2              # Pin for gamma stepper step signal
gamma_dir_pin                                0.20!            # Pin for gamma stepper direction
gamma_en_pin                                 0.19             # Pin for gamma enable
gamma_current                                0.6                # Z stepper motor current
gamma_max_rate                               24000.0          # mm/min
gamma_acceleration                           2500             # mm/sec²

# A axis
delta_steps_per_mm                           157.5           # may be steps per degree for example
delta_step_pin                               2.3              # Pin for delta stepper step signal
delta_dir_pin                                0.22             # Pin for delta stepper direction
delta_en_pin                                 0.21             # Pin for delta enable
delta_current                                0.6                # Z stepper motor current
delta_max_rate                               12000            # mm/min
delta_acceleration                           1000             # mm/sec²

# B axis
epsilon_steps_per_mm                         100              # may be steps per degree for example
epsilon_step_pin                             xx               # Pin for delta stepper step signal
epsilon_dir_pin                              xx               # Pin for delta stepper direction
epsilon_en_pin                               xx               # Pin for delta enable
epsilon_current                              1.5              # Z stepper motor current
epsilon_max_rate                             300.0            # mm/min
epsilon_acceleration                         500.0            # mm/sec²

# C axis
zeta_steps_per_mm                            100              # may be steps per degree for example
zeta_step_pin                                xx               # Pin for delta stepper step signal
zeta_dir_pin                                 xx               # Pin for delta stepper direction
zeta_en_pin                                  xx               # Pin for delta enable
zeta_current                                 1.5              # Z stepper motor current
zeta_max_rate                                300.0            # mm/min
zeta_acceleration                            500.0            # mm/sec²

## System configuration
# Serial communications configuration ( baud rate defaults to 9600 if undefined )
uart0.baud_rate                              115200           # Baud rate for the default hardware serial port
second_usb_serial_enable                     false            # This enables a second usb serial port (to have both pronterface
                                                              # and a terminal connected)
#leds_disable                                true             # disable using leds after config loaded
#play_led_disable                            true             # disable the play led

# Kill button (used to be called pause) maybe assigned to a different pin, set to the onboard pin by default
kill_button_enable                           true             # set to true to enable a kill button
kill_button_pin                              2.12             # kill button pin. default is same as pause button 2.12 (2.11 is another good choice)

#msd_disable                                 false            # disable the MSD (USB SDCARD) when set to true (needs special binary)
#dfu_enable                                  false            # for linux developers, set to true to enable DFU
#watchdog_timeout                            10               # watchdog timeout in seconds, default is 10, set to 0 to disable the watchdog

# Only needed on a smoothieboard
currentcontrol_module_enable                 true             #

## Extruder module configuration
extruder.hotend.enable                          false          # Whether to activate the extruder module at all. All configuration is ignored if false
extruder.hotend.steps_per_mm                    157.575        # Steps per mm for extruder stepper
extruder.hotend.default_feed_rate               60000          # Default rate ( mm/minute ) for moves where only the extruder moves
extruder.hotend.acceleration                    3000           # Acceleration for the stepper motor mm/sec?
extruder.hotend.max_speed                       1000           # mm/s

extruder.hotend.step_pin                        2.3              # Pin for extruder step signal
extruder.hotend.dir_pin                         0.22             # Pin for extruder dir signal
extruder.hotend.en_pin                          0.21             # Pin for extruder enable signal

# extruder offset
#extruder.hotend.x_offset                        0                # x offset from origin in mm
#extruder.hotend.y_offset                        0                # y offset from origin in mm
#extruder.hotend.z_offset                        0                # z offset from origin in mm

# firmware retract settings when using G10/G11, these are the defaults if not defined, must be defined for each extruder if not using the defaults
#extruder.hotend.retract_length                  3               # retract length in mm
#extruder.hotend.retract_feedrate                45              # retract feedrate in mm/sec
#extruder.hotend.retract_recover_length          0               # additional length for recover
#extruder.hotend.retract_recover_feedrate        8               # recover feedrate in mm/sec (should be less than retract feedrate)
#extruder.hotend.retract_zlift_length            0               # zlift on retract in mm, 0 disables
#extruder.hotend.retract_zlift_feedrate          6000            # zlift feedrate in mm/min (Note mm/min NOT mm/sec)
#delta_current                                    1.8              # First extruder stepper motor current

# Second extruder module configuration
#extruder.hotend2.enable                          true             # Whether to activate the extruder module at all. All configuration is ignored if false
#extruder.hotend2.steps_per_mm                    140              # Steps per mm for extruder stepper
#extruder.hotend2.default_feed_rate               600              # Default rate ( mm/minute ) for moves where only the extruder moves
#extruder.hotend2.acceleration                    500              # Acceleration for the stepper motor, as of 0.6, arbitrary ratio
#extruder.hotend2.max_speed                       50               # mm/s

#extruder.hotend2.step_pin                        2.8              # Pin for extruder step signal
#extruder.hotend2.dir_pin                         2.13             # Pin for extruder dir signal
#extruder.hotend2.en_pin                          4.29             # Pin for extruder enable signal

#extruder.hotend2.x_offset                        0                # x offset from origin in mm
#extruder.hotend2.y_offset                        25.0             # y offset from origin in mm
#extruder.hotend2.z_offset                        0                # z offset from origin in mm
#epsilon_current                                  1.5              # Second extruder stepper motor current


## Laser module configuration
laser_module_enable                           true            # Whether to activate the laser module at all. All configuration is
                                                              # ignored if false.
laser_module_pin                              2.5             # this pin will be PWMed to control the laser. Only P2.0 - P2.5, P1.18, P1.20, P1.21, P1.23, P1.24, P1.26, P3.25, P3.26
                                                              # can be used since laser requires hardware PWM
laser_module_maximum_power                    1.0             # this is the maximum duty cycle that will be applied to the laser
laser_module_minimum_power                    0.0             # This is a value just below the minimum duty cycle that keeps the laser
                                                              # active without actually burning.
#laser_module_default_power                   0.8             # This is the default laser power that will be used for cuts if a power has not been specified.  The value is a scale between
                                                              # the maximum and minimum power levels specified above
laser_module_pwm_period                       200             # this sets the pwm frequency as the period in microseconds

switch.laserfire.enable                       false
switch.laserfire.output_pin                   2.6
switch.laserfire.output_type                  digital
switch.laserfire.input_on_command             M3
switch.laserfire.input_off_command            M5

## Temperature control configuration
# First hotend configuration
temperature_control.hotend.enable            false            # Whether to activate this ( "hotend" ) module at all.
                                                              # All configuration is ignored if false.
temperature_control.hotend.thermistor_pin    0.23             # Pin for the thermistor to read
temperature_control.hotend.heater_pin        2.7              # Pin that controls the heater, set to nc if a readonly thermistor is being defined
temperature_control.hotend.thermistor        EPCOS100K        # see http://smoothieware.org/temperaturecontrol#toc5
#temperature_control.hotend.beta             4066             # or set the beta value
temperature_control.hotend.set_m_code        104              #
temperature_control.hotend.set_and_wait_m_code 109            #
temperature_control.hotend.designator        T                #
#temperature_control.hotend.max_temp         300              # Set maximum temperature - Will prevent heating above 300 by default
#temperature_control.hotend.min_temp         0                # Set minimum temperature - Will prevent heating below if set

# safety control is enabled by default and can be overidden here, the values show the defaults
#temperature_control.hotend.runaway_heating_timeout      900   # max is 2040 seconds, how long it can take to heat up
#temperature_control.hotend.runaway_cooling_timeout      900   # max is 2040 seconds, how long it can take to cool down if temp is set lower
#temperature_control.hotend.runaway_range                20    # Max setting is 63?C

#temperature_control.hotend.p_factor         13.7             # permanently set the PID values after an auto pid
#temperature_control.hotend.i_factor         0.097            #
#temperature_control.hotend.d_factor         24               #

#temperature_control.hotend.max_pwm          64               # max pwm, 64 is a good value if driving a 12v resistor with 24v.

# Second hotend configuration
#temperature_control.hotend2.enable            true             # Whether to activate this ( "hotend" ) module at all.
                                                              # All configuration is ignored if false.

#temperature_control.hotend2.thermistor_pin    0.25             # Pin for the thermistor to read
#temperature_control.hotend2.heater_pin        1.23             # Pin that controls the heater
#temperature_control.hotend2.thermistor        EPCOS100K        # see http://smoothieware.org/temperaturecontrol#toc5
##temperature_control.hotend2.beta             4066             # or set the beta value
#temperature_control.hotend2.set_m_code        104              #
#temperature_control.hotend2.set_and_wait_m_code 109            #
#temperature_control.hotend2.designator        T1               #

#temperature_control.hotend2.p_factor          13.7           # permanently set the PID values after an auto pid
#temperature_control.hotend2.i_factor          0.097          #
#temperature_control.hotend2.d_factor          24             #

#temperature_control.hotend2.max_pwm          64               # max pwm, 64 is a good value if driving a 12v resistor with 24v.

temperature_control.bed.enable               false             #
temperature_control.bed.thermistor_pin       0.24             #
temperature_control.bed.heater_pin           2.5              #
temperature_control.bed.thermistor           Honeywell100K    # see http://smoothieware.org/temperaturecontrol#toc5
#temperature_control.bed.beta                3974             # or set the beta value

temperature_control.bed.set_m_code           140              #
temperature_control.bed.set_and_wait_m_code  190              #
temperature_control.bed.designator           B                #

#temperature_control.bed.bang_bang            false           # set to true to use bang bang control rather than PID
#temperature_control.bed.hysteresis           2.0             # set to the temperature in degrees C to use as hysteresis
                                                              # when using bang bang

## Switch module for fan control
switch.fan.enable                            true
switch.fan.input_on_command                  M106             #
switch.fan.input_off_command                 M107             #
switch.fan.output_pin                        2.4              #
switch.fan.output_type                       pwm              # pwm output settable with S parameter in the input_on_comand
#switch.fan.max_pwm                          255              # set max pwm for the pin default is 255

switch.misc.enable                           false             #
switch.misc.input_on_command                 M42              #
switch.misc.input_off_command                M43              #
switch.misc.output_pin                       2.4              #
switch.misc.output_type                      digital          # just an on or off pin

# Switch module for spindle control
#switch.spindle.enable                        false            #

## Temperatureswitch :
# automatically toggle a switch at a specified temperature. Different ones of these may be defined to monitor different temperatures and switch different swithxes
# useful to turn on a fan or water pump to cool the hotend
#temperatureswitch.hotend.enable              true             #
#temperatureswitch.hotend.designator          T                # first character of the temperature control designator to use as the temperature sensor to monitor
#temperatureswitch.hotend.switch              misc             # select which switch to use, matches the name of the defined switch
#temperatureswitch.hotend.threshold_temp      60.0             # temperature to turn on (if rising) or off the switch
#temperatureswitch.hotend.heatup_poll         15               # poll heatup at 15 sec intervals
#temperatureswitch.hotend.cooldown_poll       60               # poll cooldown at 60 sec intervals


## Endstops
endstops_enable                              true             # the endstop module is enabled by default and can be disabled here
#corexy_homing                               false            # set to true if homing on a hbot or corexy
alpha_min_endstop                            1.24^            # add a ! to invert if endstop is NO connected to ground
alpha_max_endstop                            1.25^            # NOTE set to nc if this is not installed
alpha_homing_direction                       home_to_min      # or set to home_to_max and set alpha_max
alpha_min                                    0                # this gets loaded after homing when home_to_min is set
alpha_max                                    200              # this gets loaded after homing when home_to_max is set
beta_min_endstop                             1.26^            #
beta_max_endstop                             1.27^            #
beta_homing_direction                        home_to_max      #
beta_min                                     0                #
beta_max                                     400              #
gamma_min_endstop                            1.28^            #
gamma_max_endstop                            1.29^            #
gamma_homing_direction                       home_to_min      #
gamma_min                                    0                #
gamma_max                                    500              #

alpha_max_travel                             500              # max travel in mm for alpha/X axis when homing
beta_max_travel                              500              # max travel in mm for beta/Y axis when homing
gamma_max_travel                             500              # max travel in mm for gamma/Z axis when homing

# optional order in which axis will home, default is they all home at the same time,
# if this is set it will force each axis to home one at a time in the specified order
#homing_order                                 XYZ              # x axis followed by y then z last
#move_to_origin_after_home                    false            # move XY to 0,0 after homing

# optional enable limit switches, actions will stop if any enabled limit switch is triggered
#alpha_limit_enable                          false            # set to true to enable X min and max limit switches
#beta_limit_enable                           false            # set to true to enable Y min and max limit switches
#gamma_limit_enable                          false            # set to true to enable Z min and max limit switches

alpha_fast_homing_rate_mm_s                  50               # feedrates in mm/second
beta_fast_homing_rate_mm_s                   50               # "
gamma_fast_homing_rate_mm_s                  4                # "
alpha_slow_homing_rate_mm_s                  25               # "
beta_slow_homing_rate_mm_s                   25               # "
gamma_slow_homing_rate_mm_s                  2                # "

alpha_homing_retract_mm                      5                # distance in mm
beta_homing_retract_mm                       5                # "
gamma_homing_retract_mm                      1                # "

#endstop_debounce_count                      100              # uncomment if you get noise on your endstops, default is 100

## Z-probe
zprobe.enable                                false           # set to true to enable a zprobe
zprobe.probe_pin                             1.28!^          # pin probe is attached to if NC remove the !
zprobe.slow_feedrate                         5               # mm/sec probe feed rate
#zprobe.debounce_count                       100             # set if noisy
zprobe.fast_feedrate                         100             # move feedrate mm/sec
zprobe.probe_height                          5               # how much above bed to start probe
#gamma_min_endstop                           nc              # normally 1.28. Change to nc to prevent conflict,

# associated with zprobe the leveling strategy to use
#leveling-strategy.three-point-leveling.enable         true        # a leveling strategy that probes three points to define a plane and keeps the Z parallel to that plane
#leveling-strategy.three-point-leveling.point1         100.0,0.0   # the first probe point (x,y) optional may be defined with M557
#leveling-strategy.three-point-leveling.point2         200.0,200.0 # the second probe point (x,y)
#leveling-strategy.three-point-leveling.point3         0.0,200.0   # the third probe point (x,y)
#leveling-strategy.three-point-leveling.home_first     true        # home the XY axis before probing
#leveling-strategy.three-point-leveling.tolerance      0.03        # the probe tolerance in mm, anything less that this will be ignored, default is 0.03mm
#leveling-strategy.three-point-leveling.probe_offsets  0,0,0       # the probe offsets from nozzle, must be x,y,z, default is no offset
#leveling-strategy.three-point-leveling.save_plane     false       # set to true to allow the bed plane to be saved with M500 default is false

## Panel
panel.enable                                 true             # set to true to enable the panel code

# Example for reprap discount GLCD
# on glcd EXP1 is to left and EXP2 is to right, pin 1 is bottom left, pin 2 is top left etc.
# +5v is EXP1 pin 10, Gnd is EXP1 pin 9
panel.lcd                                   reprap_discount_glcd     #
panel.spi_channel                           0                 # spi channel to use  ; GLCD EXP1 Pins 3,5 (MOSI, SCLK)
panel.spi_cs_pin                            0.16              # spi chip select     ; GLCD EXP1 Pin 4
panel.encoder_a_pin                         3.25!^            # encoder pin         ; GLCD EXP2 Pin 3
panel.encoder_b_pin                         3.26!^            # encoder pin         ; GLCD EXP2 Pin 5
panel.click_button_pin                      1.30!^            # click button        ; GLCD EXP1 Pin 2
panel.buzz_pin                              1.31              # pin for buzzer      ; GLCD EXP1 Pin 1
panel.back_button_pin                       2.11!^            # back button         ; GLCD EXP2 Pin 8

panel.encoder_resolution		    4

# pins used with other panels
#panel.up_button_pin                         0.1!              # up button if used
#panel.down_button_pin                       0.0!              # down button if used
#panel.click_button_pin                      0.18!             # click button if used

panel.menu_offset                            0                 # some panels will need 1 here

panel.alpha_jog_feedrate                     6000              # x jogging feedrate in mm/min
panel.beta_jog_feedrate                      6000              # y jogging feedrate in mm/min
panel.gamma_jog_feedrate                     200               # z jogging feedrate in mm/min

panel.hotend_temperature                     185               # temp to set hotend when preheat is selected
panel.bed_temperature                        60                # temp to set bed when preheat is selected

## Custom menus : Example of a custom menu entry, which will show up in the Custom entry.
# NOTE _ gets converted to space in the menu and commands, | is used to separate multiple commands
#custom_menu.power_on.enable                true              #
#custom_menu.power_on.name                  Power_on          #
#custom_menu.power_on.command               M80               #

#custom_menu.power_off.enable               true              #
#custom_menu.power_off.name                 Power_off         #
#custom_menu.power_off.command              M81               #


## Network settings
network.enable                               false            # enable the ethernet network services
network.webserver.enable                     true             # enable the webserver
network.telnet.enable                        true             # enable the telnet server
network.ip_address                           auto             # use dhcp to get ip address
# uncomment the 3 below to manually setup ip address
#network.ip_address                           192.168.3.222    # the IP address
#network.ip_mask                              255.255.255.0    # the ip mask
#network.ip_gateway                           192.168.3.1      # the gateway address
#network.mac_override                         xx.xx.xx.xx.xx.xx  # override the mac address, only do this if you have a conflict

digipotchip	mcp4451 
digipot_factor	95.521	# DO NOT CHANGE FOR LASERBOARD 
digipot_max_current	1.2	# Maximum current (Amps) the digipot will allow for all axis 

switch.spread1.enable                        true
switch.spread1.output_pin                    2.6
switch.spread1.startup_state                 true

switch.spread2.enable                        true
switch.spread2.output_pin                    2.7
switch.spread2.startup_state                 true

switch.spread3.enable                        true
switch.spread3.output_pin                    2.8
switch.spread3.startup_state                 true

switch.spread4.enable                        true
switch.spread4.output_pin                    2.13
switch.spread4.startup_state                 true

#switch.spread1.input_on_command              M106     # any command that starts with this exact string turns this switch on
#switch.spread1.input_off_command             M107     # any command starting with this exact string turns off the switch

Ishaan, I checked your config file and it looks like you’ve edited the beta_max and gamma_max to accommodate your larger bed, but all other values are still default.

For a larger machine you might also need to consider making changes to the max speed, acceleration, and motor current, in that order.

Check the section Updating the Config File in this guide for notes on how to change those values.

The artifacts you are seeing are a bit strange, and I can’t say we’ve seen them before. If the file is clean and it’s not repeatable, it’s difficult to say what is causing them, but the LaserBoard should not be the cause. It might be the LPSU, as many of the lasers we’ve seen do not have the highest quality LPSUs installed, so if it is somehow not operating properly that could be the cause of the artifacts.

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