My new CNC toy

Thread Starter

spinnaker

Joined Oct 29, 2009
7,830
No, the board will get painted black as it absorbs the most energy. After that paint will get burned off with the laser exposing the copper to be etched away. Using laser should make using very thin traces possible because lasers have very small focal point. Painting the board black allows the use of weak lasers ,generally in range of 200-500mW. And those lasers are very cheap mostly in range of 2-3$.
How do you plan to control melting of the paint where you do not want melting? Seems to me the heat could migrate through the copper.
 

cmartinez

Joined Jan 17, 2007
8,250
This is nice work. Did you do this? How did you do the labeling? Can panels be cut with a conventional router bit? If so, what type is best?
The labeling is made out of a single piece of plastic that has two colored layers in it. When you cut through the white layer, the bottom, dark layer shows up.
Your machine is ideal for this kind of work
 

jpanhalt

Joined Jan 18, 2008
11,087
Hi Spinnaker
*Steve* (a moderator at Electronics Point) tried laser ablation awhile back. He also used colored paint and needed about 20W. The results weren't bad, though. Resolution was not quite as good as one gets with a phototresist method, but some of that resolution loss may be due to his etching process. Here's a link: http://www.electronicspoint.com/threads/laser-ablation-of-pcb-resist.267381/

My suggestion to use a transparent color or colorless clear acrylic lacquer was rejected because of his concern about global warming. In any event, I believe an acrylic lacquer or similar (e.g., Krylon or nitrocellulose clear) will leave less ash residue on the board. You could probably pick a dyed clear coat to maximize absorption of the laser.

John
 

MaxHeadRoom

Joined Jul 18, 2013
28,675
This is nice work. Did you do this? How did you do the labeling? Can panels be cut with a conventional router bit? If so, what type is best?
I do small ones on small engraver with a vee cut engraver bit that came with it.
But for these larger ones I draw them up in AutoCad and I have a local guy do them for me, they are reverse engraved so the legends are filled in with aerosol paint on the reverse so only the legend shows on the front and you can do mixed colours this way.
Hence the yellow and red E-Stop.
The project was a retrofit to an Italian made rolling machine.
Max.
 

Robin Mitchell

Joined Oct 25, 2009
819
Toner is something I cannot condone. CNC all the way for me! So much less stress and no pain in forearms pressing onto an iron.
Double sided is easy and through hole plating is an option too!
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,830
I have a 3020 and replaced the spindle with a dremle at 30,000rpm.
I also had to adjust the axis with formula to properly square the job.

Good to see someone else that has one. So little support for the machine. We should start a forum. These little machines seem to be shunned on other CNC forums.


What made you replace with a Dremel? It has been my experience they have or develop horrendous runout. They serviced mine under warrenty but I have yet to test it.

How did you mount the Dremel?

Can you explain "I also had to adjust the axis with formula to properly square the job"? I am new to this and want to learn more.
 

ISB123

Joined May 21, 2014
1,236
How do you plan to control melting of the paint where you do not want melting? Seems to me the heat could migrate through the copper.
Possibly but 300mW is nothing and copper will reflect most of the light so it should not create much "spreading" on the paint.
 

Robin Mitchell

Joined Oct 25, 2009
819
Firstly the runout is not too bad. It is OK for drilling but milling is something you need to be careful about. The drill I am using is not an official dremle but it cost around £30. Yes, runout exists but for PCBs you need to be using high RPM tools with tungsten carbide. The speed of your spindle (like my old one), is 12000 RPM which is WAY too low.

I agree that we should start a forum on this machine! It is fantastic if you know what you are doing. For example, my spindle system broke eventually and that was when I replaced with the dremel. Wish I did that as soon as I got it! Send me a PM so we can discuss this machine further!

Formula : In mach3 you can actually use formula on each axis. For example, my Y axis has the following equation:
Y = Y + sqrt((x * 0.002))

This helps with scaling issues and squaring of the machine because if you get it to drill four holes in the corners of a rectangle you may find (like I did), that the axis are not perfect 90 degrees to each other. This does not matter for those using milling but if you are like me and do everything via photo masks then this is a serious issue.



How to remove spindle - Do this at your own risk!


To remove the spindle use a large hex key on the two bolts that are next to the spindle. Turn them anti-clockwise and put all your damn strength into it! They will give-way....eventually! Then once they are out you need to...and bare with me here...you need to get a flathead screw driver and pry open the metal clamp that holds the spindle away from the spindle. You should be able to lift it out at that point.

This machine is great value for what it is but it does have some problems.
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,830

How to remove spindle - Do this at your own risk!


To remove the spindle use a large hex key on the two bolts that are next to the spindle. Turn them anti-clockwise and put all your damn strength into it! They will give-way....eventually! Then once they are out you need to...and bare with me here...you need to get a flathead screw driver and pry open the metal clamp that holds the spindle away from the spindle. You should be able to lift it out at that point.

This machine is great value for what it is but it does have some problems.
But how did you mount the Dremel?
 

cmartinez

Joined Jan 17, 2007
8,250
Nice work. Can you share your technique? Maybe post a blog?

Is that your company?
Yup, that's my company... still a work in progress.

Anyway, the technique is no different from the one I describe in "My Etching Process", the only difference is that the time it takes to properly iron a piece of glass is three times as much as the time that it takes to iron a board.
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,830
Yup, that's my company... still a work in progress.

Anyway, the technique is no different from the one I describe in "My Etching Process", the only difference is that the time it takes to properly iron a piece of glass is three times as much as the time that it takes to iron a board.

But how did you "paint the glass"? How did you get all of those shapes in different colors? Did you just use a color printer?
 

cmartinez

Joined Jan 17, 2007
8,250
But how did you "paint the glass"? How did you get all of those shapes in different colors? Did you just use a color printer?
I just used a true laser printer, which uses toner and is not an inkjet, nor a badly-called lasejet.
The complete explanation is in the thread I just mentioned. It's exactly the same process, only difference is the press time when ironing.
I used spray paint on top of that after those colors were transferred to the glass. This so as to provide a back color to the whole arrangement, and to fix and protect what was transferred from scratching.
 

ISB123

Joined May 21, 2014
1,236
Just tested the laser and it's burning through black plastic. Now here is the problem, It's seems that my transistor is faulty because it's "stuck open" it's conducting even when there is 0V on Base and applying 5V to the base does nothing. The regulator equation for constant current is not correct, my LM317 for some reason doubles the current.

Proper equation:
R=1.25V / 0.2A = 6.25R

Equation according to my results:
R=2.5V / 0.2A = 12.5R

Could a faulty transistor cause this?

Part list:
Q1-13007
R1-10R 5W
R2-820R
U1-LM317T
D1-Laser Diode
C1-0.1uF

In case mods feel like this deserves a new topic feel free to move it.
Capture.PNG
 
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