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Maybe sharing this idea after building a prototype would be much better.

As many of you know, there is a technique to make a PCB with laser CNC. You spray a matte black paint onto PCB, and burn that paint at some points to create tracks.

The problem is that me, and I am sure, many other people doesn't have laser engraver. Either too expensive to buy one, or building a quality one at home is not that easy. This entry is about easing this process, and making it very cheap. My proposed method is as follows:

  1. Cut a PCB at the size of a DVD. Inner hole should be cut as well.
  2. Spray the PCB with black matter paint.
  3. Put the PCB into DVD writer.
  4. Start the DVD writer program that reads what to be written onto DVD (PCB) from gerber file.
  5. Laser of DVD burns each bit on DVD that removes paint from there.
  6. Take out the DVD (PCB). Etch it with chemicals.

Actually, to be able to understand this procedure, one needs to use his imagination. Above idea came to me 5 minutes ago. So, it is not perfect maybe.

Please check this picture first: http://en.wikipedia.org/wiki/DVD#mediaviewer/File:Comparison_CD_DVD_HDDVD_BD.svg

In this procedure, problems are as follows: 1. Minimum diameter of a point a DVD writer can focus is 400nm. 2. There is 420nm distance between top and bottom points. 3. Fume of burning paint cannot escape from DVD writer while it is already being burned. 4. Inner circles of DVD has less sectors than outer ones. Conversion from gerber file (e.g. black-white image) to bits on sectors can be hard.


I know this as less like a question, but a blog post, though has anyone experienced doing anything like this? I don't have enough big PCB and spray paint right now unfortunately.


Question is that is there anyway to modify DVD writer's head moving mechanism to remove that 420nm space, so that it can draw a seamless track?

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  • \$\begingroup\$ Is the DVD laser powerful enough to etch a circuit board? \$\endgroup\$ – Funkyguy Jul 30 '14 at 18:11
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    \$\begingroup\$ What is being etched is the paint, not the copper. A lot of homemade Laser cutters use bluray laser for this. Though, since DVD writer can precisely come onto same "bit" again, even in one go it doesn't remove paint very well, process can be repeated. \$\endgroup\$ – tcak Jul 30 '14 at 18:18
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    \$\begingroup\$ This question appears to be off-topic because it is not really a question. \$\endgroup\$ – Matt Young Jul 30 '14 at 18:20
  • \$\begingroup\$ What's the question? "Has anyone experienced doing anything like this?" That's not a good question because it is asking for opinions. \$\endgroup\$ – JYelton Jul 30 '14 at 18:20
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    \$\begingroup\$ I may be mistaken, but I am under the impression that CD/DVD drives tend to use the media itself as their position encoder and focus reference. If you paint the media, I don't know that you can move the head very accurately using its linear motor actuator open-loop. Or is that not the case for this type of drive? \$\endgroup\$ – Chris Stratton Jul 30 '14 at 19:50
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Sorry, teak, but no go. Chris Stratton hit the weak spot. Even blank writable CDs/DVDs have a series of readable bits already on the disk. This establishes what is called the data spiral. If you cover this up, the electronics will have no way to sync up to the disk position.

On a related note, your idea is actually something close to LightScribe, http://en.wikipedia.org/wiki/LightScribe but as far as I can tell not close enough.

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  • \$\begingroup\$ Hmm. Yes, the idea is same as LightScribe. Well, at least the half of idea is possible it seems like. By using bluray disk writer, maybe the number of write operation could be reduced to 1, though probably the firmware of driver would complain about not being able to read those bits still. \$\endgroup\$ – tcak Jul 30 '14 at 21:37
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You can do something similar to what you describe using not one but instead a few DVD drives as the mechanical motion control system. The difference from what you describe is that the drives are used as mechanical linear motion control components and an external computer or microcontroller is used to provide position control. There is a large amount of code and experience available to allow this to be done with relative ease and acceptable levels of performance.


Open source Linux CNC software:

LinuxCNC.org

  • LinuxCNC is a software system for computer control of machines such as milling machines, lathes, plasma cutters, cutting machines, robots, hexapods, etc, released under the terms of the GNU GPLv2 (General Public License version 2).

    LinuxCNC is a descendent of the original NIST Enhanced Machine Controller software, which is in the Public Domain.

    LinuxCNC has many exciting new features and brings a lot of new functionality (a flexible and powerful Hardware Abstraction Layer that allows you to adapt it to many kinds of machinery, a software PLC controller, easier-than-ever installation, a new trajectory planner, and more.)

    LinuxCNC is precompiled with Ubuntu LTS (long term support) versions for ease of installation and longevity. Note: Do Not upgrade Ubuntu from the installed version as it will prevent LinuxCNC from working


DVD drive based DVD-LASER engraver:

Here is a DVD drive based engraver using 2 x DVDs for the XY positioner and a DVD LASER assembly for the engraving. The dg logo lying on the work surface was etched by the LASER.

Here is a you tube video of it in action

Here is the same machine described on Instructables

enter image description here


Multi-part You Tube series - Parallel port driven Floppy disk and CD ROM drive based engraver:

Here is A series making a low cost CNC machines using floppy disk drives and CD ROM drives [!!!]

Part
1
2
3
4
5
6
7
8
9
10


Some other examples - mostly You Tube videos:

Impressive - Pen driving CNC made with 3 x floppy drives

"CNC from junk" - made from 'old printer parts ' he says.

Homemade CNC made from scanner and printer

Large open CNC with DVD LASER engraver - this has the advantage of being far from compact so you can see the motor and belt drives - and he is engraving a CD case and you can see the plastic kerf curling away from the cut line.


Related:

DVD LASER cutting Balsa wood on a low cost CNC.
They do not here say how the CNC is done but the LASER capability is impressive.
AND the sound of the CNC drive motors working is worthwhile all by itself !!!!!!!!!!!! :-)

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People have used dvd writers to create graphene, and used software such as lightscribe to control it.

Similarly, people have used laser printers to fuse electronic circuits onto sheet copper which were then etched by immersion in an acid. It works well for home DIY pcb construction.

In principle I believe you could use a dvd writer to etch. However, I would be concerned with the ablating carbon black depositing on the laser head.

Still, I think it would work

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