Building a X-Y galvo scan setup for laser marking

So I have two sets of galvos and drives as posted here: http://www.photonlexicon.com/forums/...t=macona+galvo

I would like to build a setup for doing laser marking with these. I do have a couple f-theta scan lenses, one a short 50mm focal length Photon Gear model for 532nm and a huge one made by melles griot that I am pretty certain is for 1064.

Figuring I use my Lightwave 7 watt average @ 10kpps 532nm head and maybe put a 1064 head together out of some other stuff I have.

What can I do to control a setup like this? It seems like I would need a pretty high resolution DAC to get good resolution of the scan. Can I use something like Scanlab's RTC series boards and software to control galvos that are not made by them?

When I built a similar system with my yag, I used a pair of cambridge 6450's and a matching f-theta lens of out a lumonics lightwriter, and gsi 'lightning' amps.

To drive it I am using the etherdream (only 12 bits, but that is still a million points which even at 10khz takes a while), and a custom program written in c++/gtk which loads in a bitmap image and feeds the points to the scanner. Currently the program is in pretty sorry shape, it can't handle images much bigger than 300x300 points before it runs out of memory and dies and most of the buttons don't do anything, but it does the job :rolleyes:

Attachment 36577
(that is on a soda can, about 1cm tall)

That is pretty cool.

How were you driving the q-switch?

I was using one of the color channels (red IIRC), and outputting an 'on' point whenever I wanted a point. I then ran it into a function generator set up to output a 1us pulse at the rising edge of the red signal (experimentally determined to be about the right length for best pulse output), which went into the q-switch driver input. Since your head has a pulse generator built in the function generator shouldn't be necessary if you go that route.

I did not have any pre-pulse kill, so I just ran at a 1kpps so that the crystal was 'fully charged' for each pulse. For a lot of applications it is a bit too much energy (about 10mj), but with the 14" f-theta lens I have a pretty large spot size so the extra power is nice for cutting through soda cans. I ended up using to it to etch pictures into red cups so people didn't get them mixed up, and larser etching logos into some stainless gardening tools for a friend (sadly, don't have pictures on me), and then moved across the country for school so now the rig is sitting in storage.

Also as a side note, to get the best performance out of a f-theta lens you need to have the galvos placed a specific distance from the lens, to get a flat focus (otherwise the edges of your piece will be washed out). You also want to have a massive beam going into the lens, mine was designed for a ~1" beam going into the galvos.

Thanks for the info, these are the two lenses I have, the silver one is about 4" in diameter. Ill have to call up melles griot and see if they have any info they can give me. Betting they wont say as it was made for someone else. Not sure of the focal length, looks like about 8" or so. The one on the right is for 532, I saw a seller on ebay with one and it is supposed to have a 50mm f/l

Business end:

http://farm9.staticflickr.com/8183/8...830405ba_b.jpg
f-theta scan lenses by macona, on Flickr

Galvo end:

http://farm9.staticflickr.com/8194/8...259b2179_b.jpg
f-theta scan lenses by macona, on Flickr

I've got a couple of ScanLab scanheads with Spectra Physics BL10 lasers (3W avg, but short 10ns pulses so >10KW peak power! which marks steel nicely) They are driven by an Scanlab RTC card. RTC connects to the scanners via high speed serial data (XY2-100 protocol) so it won't work with analog input scanners. I think some GSI scanheads also use this digital protocol.

I've been using an open source marking package called BeamConstruct - http://www.beamconstruct.com/. It claims to support EtherDream with a modified firmware.

there were some issues with etherdream support. if i recall correctly, it was due to the beam construct folks not honoring the license agreements.

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Originally Posted by Junktronix

I've got a couple of ScanLab scanheads with Spectra Physics BL10 lasers (3W avg, but short 10ns pulses so >10KW peak power! which marks steel nicely) They are driven by an Scanlab RTC card. RTC connects to the scanners via high speed serial data (XY2-100 protocol) so it won't work with analog input scanners. I think some GSI scanheads also use this digital protocol.

I've been using an open source marking package called BeamConstruct - http://www.beamconstruct.com/. It claims to support EtherDream with a modified firmware.

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That's too bad. It works nicely with the RTC card.

Thanks for the info. That is just what I was looking for. I emailed the company that sells the ETH6608 card to see how much that thing sells for.

Let us know what you find out. I'd love to get my second marker going without buying another >$1000 RTC card!

Quote:

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Item: Laser marking software & marking card

Marking card (Ethernet port) & software ETH, $650

Remark: discount available for quantity order
Price: in US$, not including shipping fee, insurance.
Freight: to be finalised (if the buyer has an account with FedEx/DHL/UPS, he may just tell us his A/C number and do not need to pay for the freight)
Lead time: 2 weeks upon receipt of payment.
Term of payment: prepayment via wire on confirmation of order.
Warranty: 12 months against manufacture's defects in material and workmanship from the date of shipment exclusive of overseas travel expense.
Validity of quotation: 3 months

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So, that's it. It is cheaper.

You Should just use a rhothor system - www.newsonusallc.com.

It would allow you to integrate the Lightwave 7 W green and has one of the best resolutions out there, comes with Software Dev. Kit that allows you to mark bar codes, dxf etc... all for under 5000




Neal

This thread is quite old but may be the information is still helpful to somebody: The guys from http://www.halaser.eu/e1701.php offer a scanner controller card that is cheaper than ETH6608 and works with the free BeamConstruct software.

This is a DAC board attached to a Beaglebone Black so it ought to be pretty reasonably priced. I've been trying to get prices from them, but have not gotten any response. Are these real? Do you know the price? Who do I order one from?

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Originally Posted by Tommm

I got a response from them quite fast. Price for the baseboard is Euro 250 (one can drive Co2 or YAG lasers with it). For Fiber lasers and/or digital I/O extension boards are required which cost Euro 130 each.

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very interesting! i've been toying with the idea of building a scanning galvo engraver.

there was a group using etherdream dac's (made by a PL member). their work looked really promising, but they refused to honor the opensource licensing terms of the DAC so j4cbo pulled the plug on them.

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Originally Posted by Tommm

I would be REALLY carefully with such public statements, especially when they are based on third party information only...

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oh? then tell me why did beamconstruct stop releasing their firmware for the etherdream?

First of all: sorry for making this thread off-topic, may be somebody can split and move it.

A customer pointed us to this threads and some statements herein, we want to comment/correct:

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Originally Posted by swamidog

there was a group using etherdream dac's (made by a PL member). their work looked really promising, but they refused to honor the opensource licensing terms of the DAC so j4cbo pulled the plug on them.

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The short version: Yes, there has been a firmware version which accidentially contained some GPLed sources. After we have been aware of this, we immediately stopped publishing it and removed the related download. This is an absolutely correct procedure to solve such a license issue. And: we stopped the cooperation with j4cbo, not he "pulled the plug".

The longer version:

Some time ago we stumbled upon Etherdream which looked like a nice piece of hardware which could be interesting of users of our free laser marking software BeamConstruct. We contacted the vendor of it and agreed a cooperation to extend it by everything that is required for (low cost) industrial laser marking. Following we contributed many compatible changes to his firmware to make it usable for our purposes. The amazing thing: we never got any response on that, no feedback, no suggestions, no hints what could be done different, just nothing. Not even our contributions have been added to the public repository. So whenever we updated the sources from his public repository, we had to re-integrate our changes manually (we also provided a free tool with a graphical user interface which listed all Etherdreams within the current network together with their state and gave the possibility to comfortable update the firmware and also got no feedback on this tool, but this is a different story).

Because of this "cooperation" we decided to have our own - this time non-GPLed - firmware and to rewrite it completely. This is not as difficult as it seems to be since wide parts of Etherdream-firmware are non GPLed third party sources (like lwIP TCP/IP stack, Chan's FatFS file system, the hardware-related macros and other things more). Only fetching of streamed data, buffering it and writing it to the hardware had to be re-implemented which was not that complicated. The more complex things always have been done on host side within BeamConstruct's plug-in (micro-vectorisation of the data, adding of laser- and scanner-delays to the microvectors, calculation of scanfield correction, calculation of wobble-modulation, calculation of marking on-the-fly offsets,...).

And then it happened: we released one firmware version that accidentially contained a few of the old, GPL'ed sources. This was caused by a merge-problem of our version control system and never was done by intention. After we have been noticed that there is something wrong with this firmware, we immediately stopped publishing it and removed the download. A few days later it was replaced by a new firmware version which was clean again.

But also after this issue has been solved we got some "feedback" from the vendor of the Etherdream now, which has been that rude and unfriendly, that we decided to stop all cooperation with him, stop our development and to drop support for Etherdream. The reason for that was not the (completely solved) license issue but the fact that we have been blamed that way after we put nameable efforts in this project (about one year development for firmware, additional tools and BeamConstruct plug-in) without getting anything back. Or in other words: we tried to help j4cbo to sell his scanner card in industrial area without getting paid for it, without getting nameable support from him, for laser marking software that itself is available for free, and have been badmouthed for that.

And to answer this question too:

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Originally Posted by swamidog

oh? then tell me why did beamconstruct stop releasing their firmware for the etherdream?

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The license-issue free firmware and the plug-in for BeamConstruct has been available for more than one year after we stopped further development of it. So this was not stopped, we kept everything available for existing users. Meanwhile it was removed from the newer software packages since it is really outdated and would miss some of the new functions and features of BeamConstruct. But the old software versions that contain support for Etherdream are still available for download.

To say that clear: we definitely respect the idea of open source and its licenses. More than this: we like this idea and therefore publish many things as open source too. We offer an SDK for free that contains many souces and provide a public GIT repository on fedorahosted.org, all open to the public. So why should we steal a relatively simple piece of source like the core-implementation of Etherdream firmware?

Thanks for letting me clarify that here.

Michael

I sent another request. I hope they get back to me since I've got 2 nice marking machines here that I'd like to get running.

Quote:

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Originally Posted by Tommm

I got a response from them quite fast. Price for the baseboard is Euro 250 (one can drive Co2 or YAG lasers with it). For Fiber lasers and/or digital I/O extension boards are required which cost Euro 130 each.

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