What controller are you using on your chinese laser cutter?
Posted by Downunder35m
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What controller are you using on your chinese laser cutter? February 03, 2016 11:22PM |
Since I started modding my machine I found quite a few project pages on the web that show these chinese laser cutters can be quite good - if the right controller is used.
Some people even fork out a few hundret bucks to put a DSP controller in them.
My aim with this thread is to provide info for people who want to convert their machine as well.
Basically just a little comparison of the things possible and electronics involved.
Let me make the start
The basis was a chinese K40 laser cutter with the digital display instead of the analog meter.
As I had a few around I decided to use an Arduino Mega with Tyrkey Tyranny firmware, which was setup to match my machine.
The only real modification to this point was to add some pullup resistors to the endstops.
As the motors are actually 0.9° models and not the standard 1.8° I was a bit confused with setup of the stepping but that was easy to solve.
For the electronics it was a simple swap over after adding some connector to the cables that can be used on the Arduino.
What's working:
Still waiting for the display and SD slot to make it stand alone but I was able to set the speeds to around 3600mm/s without missing steps or mechanical issues.
My usual speeds however are a bit slower, engraving around 2400 and vector works at around 2000 - not because I have to but because it is less noisy
The base for all jobs is an SVG file to be processed by the Turnkey Tyranny Inkscape plugin.
Unlike solutions like Laserweb the actions are defined by the layer name or the defaults in the plugin.
This means it does not matter what colors are used
The accuracy is really good but to get good vector cuts it is important to create your paths correctly.
E.g.: If you create a closed shape with the line tool then it will be handled as such.
But if you use a lot of single lines you combine into one path it means every line is cut seperately - quite annoying if you have a few hundred short lines and the head jumps all over the place instead of doing in a nice order.
A very important thing to remember is that you have to convert everything you want to use as vector to a path, also to combine the path for the above reasons.
Only very thin lines are recognised as a single line, everything thicker will result in a vector cut of the shape - I use 0.01mm for the line width of everything I want as vector lines.
Whats not working sooo well:
Doing raster engravings can be a slight pain.
For obvious reasons the starting point should already be a greyscale image but even with them the plugin struggles.
It is only possible to do bimaps in 2 colors but not true greyscale engraving with power levels based on the pixel brightness.
So all images need to be converted to a bitmap with a proper dither applied so the laser will fire if the is a dot and not fire for empty spaces - the result is what you see in newspapers with a magnifying glass.
But with a good bitmap in the right resolution the result is quite impressive, especially combine with the PPM control - helps a lot on glass and other hard materials!
One problem with using other programs or web services for the control of the machine, especially for 8bit photo engraving, is that nothing is really fully compatible.
There are some good solutions available that won't cost money, like Picengrave for example, but most of them are only for one hardware platform.
Of course that means the resulting G-code might not work at all on the machine unless you are willing to flash different firmwares all the time.
So far the most promising candidate IMHO is Laserweb as it supports quite a few different harware platforms, does vector and raster jobs but so far struggles to connect to my machine properly.
I can use the generated G-code but since the y-axis in Laserweb is going up all jobs are upside down and it is quite hard to get the layout right - but that should be solved shortly I hope.
So what is your setup, how did you get rid of the dongle?
Some people even fork out a few hundret bucks to put a DSP controller in them.
My aim with this thread is to provide info for people who want to convert their machine as well.
Basically just a little comparison of the things possible and electronics involved.
Let me make the start
The basis was a chinese K40 laser cutter with the digital display instead of the analog meter.
As I had a few around I decided to use an Arduino Mega with Tyrkey Tyranny firmware, which was setup to match my machine.
The only real modification to this point was to add some pullup resistors to the endstops.
As the motors are actually 0.9° models and not the standard 1.8° I was a bit confused with setup of the stepping but that was easy to solve.
For the electronics it was a simple swap over after adding some connector to the cables that can be used on the Arduino.
What's working:
Still waiting for the display and SD slot to make it stand alone but I was able to set the speeds to around 3600mm/s without missing steps or mechanical issues.
My usual speeds however are a bit slower, engraving around 2400 and vector works at around 2000 - not because I have to but because it is less noisy
The base for all jobs is an SVG file to be processed by the Turnkey Tyranny Inkscape plugin.
Unlike solutions like Laserweb the actions are defined by the layer name or the defaults in the plugin.
This means it does not matter what colors are used
The accuracy is really good but to get good vector cuts it is important to create your paths correctly.
E.g.: If you create a closed shape with the line tool then it will be handled as such.
But if you use a lot of single lines you combine into one path it means every line is cut seperately - quite annoying if you have a few hundred short lines and the head jumps all over the place instead of doing in a nice order.
A very important thing to remember is that you have to convert everything you want to use as vector to a path, also to combine the path for the above reasons.
Only very thin lines are recognised as a single line, everything thicker will result in a vector cut of the shape - I use 0.01mm for the line width of everything I want as vector lines.
Whats not working sooo well:
Doing raster engravings can be a slight pain.
For obvious reasons the starting point should already be a greyscale image but even with them the plugin struggles.
It is only possible to do bimaps in 2 colors but not true greyscale engraving with power levels based on the pixel brightness.
So all images need to be converted to a bitmap with a proper dither applied so the laser will fire if the is a dot and not fire for empty spaces - the result is what you see in newspapers with a magnifying glass.
But with a good bitmap in the right resolution the result is quite impressive, especially combine with the PPM control - helps a lot on glass and other hard materials!
One problem with using other programs or web services for the control of the machine, especially for 8bit photo engraving, is that nothing is really fully compatible.
There are some good solutions available that won't cost money, like Picengrave for example, but most of them are only for one hardware platform.
Of course that means the resulting G-code might not work at all on the machine unless you are willing to flash different firmwares all the time.
So far the most promising candidate IMHO is Laserweb as it supports quite a few different harware platforms, does vector and raster jobs but so far struggles to connect to my machine properly.
I can use the generated G-code but since the y-axis in Laserweb is going up all jobs are upside down and it is quite hard to get the layout right - but that should be solved shortly I hope.
So what is your setup, how did you get rid of the dongle?
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Re: What controller are you using on your chinese laser cutter? February 04, 2016 04:33AM |
... so far I've modified and built several laser-cutters/engravers - here a chronological list:
- started 1986 with an Isel CNC-mill+CO2-laser and writing converters, drivers and last a complete CAD/CAM for AtariST.
- built a XY-plotter+CO2-laser with a 6502 controller around 1990.
- modified several other Isel CNC-mills for higher precision with 1/8 microstepping drivers and again modified drivers and programmed converters.
- with RepRap-electronics/software - built several adapters for replacing the Isel controller with Gen3 or Arduino Mega ... used first version of Pronterface as software
- built a controller with a STM32F4discovery board and a comercial firmware+software combo (Editasc10)
- built an XY-galvoscanner engraver with a cheap chinese galvo-head and a comercial DAC for show-laser applications, programmed a plugin for BeamConstruct.
- built another XY-mirrorhead-engraver with servos instead of galvos, used it with Editasc10
- tested the (comercial) drivers from HAlaser, designed for BeamConstruct - have a A1701P-XY-plotter-driver waiting to replace the controller of one of this chinese CO2-lasercutters
- built another machine for paste-dispensing and laser-engraving based on RADDS with RAPS128 stepper drivers and modified Pronterface+Marlin4Due
All of this electronics and softwares (without the galvoscanner-drivers) could/can be used for "refurbishing" the chinese CO2-lasercutters, as it's essentially the same type of mechanical setup with limiting-/ref-switches and stepper-driven linear axes
Edited 1 time(s). Last edit at 02/04/2016 04:34AM by VDX.
Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]
Call for the project "garbage-free seas" - [reprap.org]
- started 1986 with an Isel CNC-mill+CO2-laser and writing converters, drivers and last a complete CAD/CAM for AtariST.
- built a XY-plotter+CO2-laser with a 6502 controller around 1990.
- modified several other Isel CNC-mills for higher precision with 1/8 microstepping drivers and again modified drivers and programmed converters.
- with RepRap-electronics/software - built several adapters for replacing the Isel controller with Gen3 or Arduino Mega ... used first version of Pronterface as software
- built a controller with a STM32F4discovery board and a comercial firmware+software combo (Editasc10)
- built an XY-galvoscanner engraver with a cheap chinese galvo-head and a comercial DAC for show-laser applications, programmed a plugin for BeamConstruct.
- built another XY-mirrorhead-engraver with servos instead of galvos, used it with Editasc10
- tested the (comercial) drivers from HAlaser, designed for BeamConstruct - have a A1701P-XY-plotter-driver waiting to replace the controller of one of this chinese CO2-lasercutters
- built another machine for paste-dispensing and laser-engraving based on RADDS with RAPS128 stepper drivers and modified Pronterface+Marlin4Due
All of this electronics and softwares (without the galvoscanner-drivers) could/can be used for "refurbishing" the chinese CO2-lasercutters, as it's essentially the same type of mechanical setup with limiting-/ref-switches and stepper-driven linear axes
Edited 1 time(s). Last edit at 02/04/2016 04:34AM by VDX.
Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]
Call for the project "garbage-free seas" - [reprap.org]
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Re: What controller are you using on your chinese laser cutter? February 04, 2016 05:44AM |
... the 'history list' is even longer - but not related to lasers.
My first 2-color pen-plotter for red-green-anaglyphs was based on a Brother-HR1 typewheel-printer with a program on a C-64, written in Simon's Basic.
... and the first attempts for "3D-printing" was an Okimate-20 thermo-transfer colour printer with wax-color-ribbons, driven by a VC-20
Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]
Call for the project "garbage-free seas" - [reprap.org]
My first 2-color pen-plotter for red-green-anaglyphs was based on a Brother-HR1 typewheel-printer with a program on a C-64, written in Simon's Basic.
... and the first attempts for "3D-printing" was an Okimate-20 thermo-transfer colour printer with wax-color-ribbons, driven by a VC-20
Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]
Call for the project "garbage-free seas" - [reprap.org]
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