Grayscale Engraving on Mini-60 20160503

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Mauri
Posts: 7
Joined: Wed Oct 21, 2015 2:25 am

Re: Grayscale Engraving on Mini-60 20160503

Post by Mauri » Sun May 08, 2016 4:45 am

Ken,
This info is for those that are reading this forum.
I have now Tested XP Pro/Vista/Windows 10 and 2 Version of RDWorksV8 V11 and V17, plus 2 Controllers all have the same problems with “Direct Output”.
All Fail if you Send the Data using "Start" with both Ethernet and USB.
Failure = Random Laser Head movement as well as Laser Head Slowdown/Jitters and then returns to normal speed both inside and outside the engraved picture area.
If left to continue the Laser will Stop with the "Not enough extend space" as the Laser Head Moves way outside the Laser engraving area.
This Engraving procedure will work Only, if the RD File size is less than the available memory of the Controller and Only if the RD File is "Downloaded" to the Controller and you Run it from the Controller.
This is a software issue has been confirmed by the manufacture and is particularly associated with "Direct Output" being selected.
Regards,
Mauri

Danansmith
Posts: 1
Joined: Wed May 18, 2016 2:42 am

Re: Grayscale Engraving on Mini-60 20160503

Post by Danansmith » Wed May 18, 2016 7:45 am

Thank you very much. Great job, thanks to spend your time to help us!!!


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scruffy
Posts: 2
Joined: Sat May 21, 2016 3:27 pm

Re: Grayscale Engraving on Mini-60 20160503

Post by scruffy » Mon Jun 20, 2016 12:48 pm

Using Eleks / Benbox Laser Engraver with GRBL0.9j

If you want to try greyscale engraving (PWM) you will need to swap the link on the motherboard to V0.9 and change the firmware on the Arduino Nano card to GRBL v0.9. Two methods available to do this:
1: You can either download the pre-compiled version from https://github.com/grbl/grbl - the JTP lasertool version 0.9j as a HEX file. Then copy to notepad and use Xloader to program the card - note only works at 57600 baud for some reason so check that the serial port is set to 57600 in Device Manager / Ports (Serial Baude rate will be 115200 for normal operation).
2: Or download the source from https://github.com/grbl/grbl.git and compile with Arduino IDE then upload to the card (having set IDE to the Nano card and set the serial port number). You can use the Arduino ISP or a separate programmer to do this. I use the USBASP programmer to do this - available from ebay for £5.

In either case you now need to configure GRBL to suit the Eleks engraver. In case 1: above this can be done by sending commands to GRBL via a Sender program (I use 3dpBurnerSender) the new commands will overwrite the existing commands and be retained. Or in case 2: above the source files can be edited before compilation (located in C:\Users\your name\Documents\Arduino\libraries\grbl).
Edit "defaults_generic.h" to suit the machine, I have used the following with sucsess:
// Grbl generic default settings. Should work across different machines.
#define DEFAULT_X_STEPS_PER_MM 80.0
#define DEFAULT_Y_STEPS_PER_MM 80.0
#define DEFAULT_Z_STEPS_PER_MM 80.0
#define DEFAULT_X_MAX_RATE 40000.0 // mm/min
#define DEFAULT_Y_MAX_RATE 40000.0 // mm/min
#define DEFAULT_Z_MAX_RATE 40000.0 // mm/min
#define DEFAULT_X_ACCELERATION (2000.0*60*60) // 10*60*60 mm/min^2 = 10 mm/sec^2
#define DEFAULT_Y_ACCELERATION (2000.0*60*60) // 10*60*60 mm/min^2 = 10 mm/sec^2
#define DEFAULT_Z_ACCELERATION (1000.0*60*60) // 10*60*60 mm/min^2 = 10 mm/sec^2

Leave other setting alone for now.

If using the pre-compiled HEX file or if you want to change the settings later send the following commands:

$100 = 80
$101 = 80
$102 = 80
$110 = 40000
$111 = 40000
$112 = 40000
$120 = 2000
$121 = 2000
$122 = 1000

Goto https://github.com/grbl/grbl/wiki/Configuring-Grbl-v0.9 for an explanation of Gcode.

This setup will allow Pulse Width Modulated (PWM) control of the laser via pin D11 of the Nano card. The laser will be switched on with M3 command and off with M5. The PWM is controlled with Sxxx where the value of 1 to 1000 will control the laser power.

You now need to create some grey scale pictures and generate Gcode for sending to your engraver.
I have been using Inkscape v0.91 with the Raster 2 Laser GCode generator plugin. Use "Path / Trace Bitmap and select Grays to create a trace file (don't forget to delete the original after it is done). Then setect Extensions / 305 Engineering / Raster to Laser GCode Generator. Set conversion to Grayscale and a resolution to 256 and apply. This should produce a GCode file with embedded laser control commands. These are text files and so can be checked with Notepad to confirm that the M and S commands are there.

Note that Raster to Laser GCode Generator will only produce PWM in the rang 0 to 255 ie 255 = max power and 0 = off.
The default spindle rev range (which is being used to control the laser via the S command) is set to 0 to 1000 although there are only 256 discrete levels (8 bit register). Thus for full power range using Raster to Laser GCode Generator the Config.H file needs to be edited prior to compilation -
Comment out the line :

#define SPINDLE_MAX_RPM 1000.0 Max spindle RPM. This value is equal to 100% duty cycle on the PWM.

with // and add the line :

#define SPINDLE_MAX_RPM 255.0 // Max spindle RPM. This value is equal to 100% duty cycle on the PWM.

The Gcode produced will now control the full range of laser power available. If othe Gcode generators are used remeber to set maximum laser power at 255.

Hopefully a future release of GRBL will move the spindle speed setting to the Defaults page under a $ command so it can be changed without requiring a re-compilation.

Dellorik1992
Posts: 12
Joined: Sat Aug 06, 2016 10:39 am

Grayscale Engraving on Mini 60 20160503

Post by Dellorik1992 » Fri Aug 19, 2016 5:03 pm

How about using a laser? Ive seen some pretty fancy laser engraving machinery on a TV program called How It Works.

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