Arduino Firmware to Control Galvanometer Drivers
Posted by marinusdebeer
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Arduino Firmware to Control Galvanometer Drivers April 01, 2018 02:06PM |
Registered: 6 years ago Posts: 2 |
Hi,
I am building a CNC Laser Engraver that is operated by galvo mirrors. Kind of like this: [www.instructables.com]. But instead of it being a laser show I want to engrave metal. Also it must take an image as an input and turn that into g-code (I already have that software) once it is converted it needs to be sent to an arduino which will analyze the g-code and send the corresponding signals to the servo drivers.
GRBL only works with stepper motors..
Any help is appreciated,
Marinus
I am building a CNC Laser Engraver that is operated by galvo mirrors. Kind of like this: [www.instructables.com]. But instead of it being a laser show I want to engrave metal. Also it must take an image as an input and turn that into g-code (I already have that software) once it is converted it needs to be sent to an arduino which will analyze the g-code and send the corresponding signals to the servo drivers.
GRBL only works with stepper motors..
Any help is appreciated,
Marinus
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Re: Arduino Firmware to Control Galvanometer Drivers April 01, 2018 04:19PM |
Admin Registered: 16 years ago Posts: 13,884 |
Hi Marinus,
we can discuss this here too -- quoting the last post from LPF:
"... for XY-galvos I'm using the E1701D from HAlaser - [halaser.de]
And did some "tinkering" with this super-cheap cinese galvos, an Easylase LC USB and programming a flow-plugin for BeamConstruct ..."
Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]
Call for the project "garbage-free seas" - [reprap.org]
we can discuss this here too -- quoting the last post from LPF:
"... for XY-galvos I'm using the E1701D from HAlaser - [halaser.de]
And did some "tinkering" with this super-cheap cinese galvos, an Easylase LC USB and programming a flow-plugin for BeamConstruct ..."
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: Arduino Firmware to Control Galvanometer Drivers April 01, 2018 04:42PM |
Registered: 10 years ago Posts: 14,672 |
@VDX, is 11 and a half bits (1 part in 3072) sufficient resolution for the galvo? What "step" rate do the galvo axes need to be driven at?
I understand that standard servo-type galvo drivers use 0-10V differential inputs. The SAM4 processors used in the Duets have 2 on-chip DACs, so I have been wondering whether they could be used to drive galvos via a couple of op amps.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
I understand that standard servo-type galvo drivers use 0-10V differential inputs. The SAM4 processors used in the Duets have 2 on-chip DACs, so I have been wondering whether they could be used to drive galvos via a couple of op amps.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Arduino Firmware to Control Galvanometer Drivers April 01, 2018 04:57PM |
Admin Registered: 16 years ago Posts: 13,884 |
... depends on your working area - for lasermarking 100x100mm is a common size -- so: 100mm/3072 = 32,55 microns between two "pixels" ... not so precise - but could be enough for a DIY setup.
For the "step-rate" or marking speed - common scanning speeds are from 1m/s to 10m/s -- for 1m/s and 30microns per "step" this will be something like 34kHz ...
Edited 1 time(s). Last edit at 04/01/2018 05:01PM 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]
For the "step-rate" or marking speed - common scanning speeds are from 1m/s to 10m/s -- for 1m/s and 30microns per "step" this will be something like 34kHz ...
Edited 1 time(s). Last edit at 04/01/2018 05:01PM 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: Arduino Firmware to Control Galvanometer Drivers April 01, 2018 05:02PM |
Registered: 10 years ago Posts: 14,672 |
Quote
VDX
... depends on your working area - for lasermarking 100x100mm is a common size -- so: 100mm/3072 = 32,55 microns between two "pixels" ... not so precise - but could be enough for a DIY setup ...
Thanks!
What sort of hardware do folks typically use to drive galvos from a microcontroller then? External 16-bit DACs are readily available, but I would have thought that getting sufficient data rate over SPI would be difficult. I2C would be even worse. [EDIT: I just saw your addendum about scanning speed. I guess SPI is practical after all with around 14 bits resolution, especially if DMA is used.]
Edited 1 time(s). Last edit at 04/01/2018 05:13PM by dc42.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Arduino Firmware to Control Galvanometer Drivers April 01, 2018 05:09PM |
Registered: 10 years ago Posts: 14,672 |
PS - how easy is it to focus a laser spot to better than 30um? Obviously impossible using a CO2 laser; but possible for near-IR diode lasers perhaps?
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Arduino Firmware to Control Galvanometer Drivers April 01, 2018 05:55PM |
Admin Registered: 16 years ago Posts: 13,884 |
... actually only possible with fiberlasers ... or single-mode laserdiodes with only some ten to hundred Milliwatts, not with the high-power multimode diodes 
Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]
Call for the project "garbage-free seas" - [reprap.org]
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: Arduino Firmware to Control Galvanometer Drivers April 02, 2018 06:13AM |
Registered: 10 years ago Posts: 14,672 |
Thanks. So for DIY use, it sounds like a resolution of 1 part in 3072 would be adequate.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Arduino Firmware to Control Galvanometer Drivers April 03, 2018 03:25AM |
Registered: 8 years ago Posts: 5,232 |
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Re: Arduino Firmware to Control Galvanometer Drivers April 03, 2018 08:10AM |
Admin Registered: 16 years ago Posts: 13,884 |
... not much for a driver with voltage input -- but up to 3 or more Amperes for common galvos, if you have to drive it directly ...
Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]
Call for the project "garbage-free seas" - [reprap.org]
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: Arduino Firmware to Control Galvanometer Drivers April 03, 2018 12:44PM |
Registered: 10 years ago Posts: 14,672 |
Quote
VDX
... not much for a driver with voltage input -- but up to 3 or more Amperes for common galvos, if you have to drive it directly ...
Sounds like a job for a switching regulator chip then.
Do common galvos provide position feedback for use with servo drivers, or are they driven open loop?
Edited 1 time(s). Last edit at 04/03/2018 12:44PM by dc42.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Arduino Firmware to Control Galvanometer Drivers April 03, 2018 02:57PM |
Registered: 9 years ago Posts: 978 |
My saved links for Galvos... hope they're useful. I don't think any of them are particularly laser-cutter specific though.
[youtu.be]
[www.instructables.com]
[www.instructables.com]
[laserpointerforums.com]
[www.fab-favreau.com]
[hackaday.com]
[www.photonlexicon.com]
[www.laserfx.com]
[youtu.be]
[www.instructables.com]
[www.instructables.com]
[laserpointerforums.com]
[www.fab-favreau.com]
[hackaday.com]
[www.photonlexicon.com]
[www.laserfx.com]
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Re: Arduino Firmware to Control Galvanometer Drivers May 05, 2018 02:53AM |
Registered: 7 years ago Posts: 3 |
From the research I have done, it seems that 12bit DACs will not work, and you need to use 16bit DACs. Someone in the Marlin development has already started created code to drive Galvos:
[github.com]
And from what I seen it is not to difficult to hook up the DACs to the Arduino, or atleast so it seems.
And an interesting read:
[forums.reprap.org]
Edited 1 time(s). Last edit at 05/05/2018 03:10AM by minifiredragon.
[github.com]
And from what I seen it is not to difficult to hook up the DACs to the Arduino, or atleast so it seems.
And an interesting read:
[forums.reprap.org]
Edited 1 time(s). Last edit at 05/05/2018 03:10AM by minifiredragon.
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