Go Down

Topic: PCB Etching: Photo-sensitive film, LaserJet, or (?)  (Read 602 times) previous topic - next topic

holesflow

[mods: This is a General Electronics themed forum, though when in it its official title is "Using Arduino", so I'm shooting as close to the fuzzy target as I can]

Experts,

Which method(s) do you use to make your PCBs? 

I asked before about PCB software, and have been trying from the replies to get good with KiCAD (I'm mostly linuxy).

Now that I've figured out how to be dangerous, I am at the point where I have all the etchant, cleaners, etc. but because I own no LJ printer (I can pay for printouts at Staples, etc.), I looked around for alternatives. While the inkjets seem mostly used to create transparencies for the photosensitive blue film (often 'doubled up'), most use LJs and either hacked laminators (depth) or good 'ole clothes irons to transfer (re-melt) the plastic toner to the copper.

I've already spent a lot on this whole workflow-even buying a new drill press-so I would really value the combined/shared experience of those of you who have made all the mistakes already, and have found what works for them. 

I've gone over all the popular videos on YT concerning all the different methods, and I guess like a lot of folks, I'd love to find the holy grail for us inkjet folks (I refill), which like I said above may only be for photo film. I did see a video about a special kind of ink that was yellow, and only one kind of printer could use it (Brother?), but that looked like a big commitment for someone who didn't already have a printer of this model/type.

So I have lots of boards (trying to keep 'test runs' to a minimum!), and I still may end up trying LJ & Photo, but thee is a lot of wisdom, I discovered, in things like timing of UV or sunlight, the perfect temperature of the iron with toner (too hot is as bad as too cool), and of course the laminator hacks (Mr. Carlson comes to mind!) are endlessly fascinating!

Thanks for responding, and as you can see by this long first post in the thread, I am quite serious about my question.

pat
:)
"A wise man can learn more from a foolish question than a fool can learn from a wise answer". ~ Bruce Lee.
"If you drop it and it breaks, it was good." ~ Mr. William Lehr, my Electronics VoTech Teacher, on testing vacuum tubes. RIP

tinman13kup

I think you will find most of the guys here farm out the boards to various places. There are a few here though that make their own.

I mostly make one off's for myself, and I use a LJ with transparancies. Yes, the timing of UV exposure is critical. I made an exposure box controlled by a barebone arduino set to a 45sec exposure (2 sided).

The developer also works better when warm, and I generally have mine about 100*F, which takes about a minute. The ferric chloride is also warmed to 100*, and with single sided boards I just float them. It's real easy to see when they are done. For 2 sided, I have a plastic clamp and I suspend the board slightly under the surface and have to regularly check it. The bottom side will etch considerably faster than the top, as the material drops down while the top is stays on the board. When the bottom half is done, I wipe it off and just float it to finish the other side.

I generally use smd components, and some of the chips have very narrow pins/spacing. There isn't much that can be done about that, but the rest of the traces should be wider rather than thinner. It seems the pre-sensitized boards vary quite a bit. I've had a couple where I had nice crisp .008 traces, but most needed >.015 traces to be viable. Seems quality control is a bit lacking there. I had one board show up without the plastic sheet on it. Imagine my surprise when I pulled it out in a well lit room. Makes it rough cutting to size in the dark.
Tom
It's not a hobby if you're not having fun doing it. Step back and breathe

Southpark

Which method(s) do you use to make your PCBs?
For one-offs or low number prototypes, I was initially thinking of the chem way. But due to the chemicals needed and handling/disposing/safety aspects, I decided to first try the cnc milling method. After a year or so of figuring things out, things are finally coming together very nicely for 2-sided circuit boards. At first, a year ago, I didn't rule out that the milling method could be a total waste of time and money. But now..... my verdict is .... it can require some significant time to get going, and there can be money wasting if we buy the 'wrong' gear. But with the right gear, and without spending huge amounts of money, the cnc milling method is quite good for hobby 1 and 2-sided pcb making.

DrAzzy

I used the laserjet thermal transfer method. Yields were disappointing, the process was labor intensive, and there were always containers of nasty looking chemicals around. Drilling the holes was hell (that's when I stopped defaulting through-hole parts). I burned a hole in the formica counter in the kitchen with some HCl/CuCl2/H2O2 etchant.

Then I found out how cheaply the chinese board houses would make me beautiful looking, double-sided boards with proper surface treatment, soldermask, and so on. Haven't looked back.
ATtiny core for 841+1634+828 and x313/x4/x5/x61/x7/x8 series Board Manager:
http://drazzy.com/package_drazzy.com_index.json
ATtiny breakouts (some assembled), mosfets and awesome prototyping board in my store http://tindie.com/stores/DrAzzy

1steve

Parts use to be bigger so making a board was no big deal. I used the LJ and iron and could do 2 sided 4 x 5 inch boards. Parts have gotten smaller and distance between traces has become smaller, it is harder to get a good board now. Sending the files out are a easier way to go and you get a good looking board, That said, if I want a board now and not wait to have one made, I will do a quick board that I will need to do jumper and repair and looks ugly.   I also go to print shop to get my LJ print outs.

larryd

For one or two boards I use the photo sensitive method.
I Have always used Ferric  Chloride solution for etching.
Use an old sun tanning lamp at 4.5 minutes at 1.5 feet.


No technical PMs.
The last thing you did is where you should start looking.

larryd

No technical PMs.
The last thing you did is where you should start looking.

uxomm

But now..... my verdict is .... it can require some significant time to get going, and there can be money wasting if we buy the 'wrong' gear. But with the right gear, and without spending huge amounts of money, the cnc milling method is quite good for hobby 1 and 2-sided pcb making.
After many years of etching I would like to try the cnc milling method now. I have done some research but the best thing is to get information from people who walked "the same road".
So please could you elaborate on 'wrong' and 'right' gear! I would be most interested in your thoughts about the 'right' gear. :)
Thank you!
Always decouple electronic circuitry.

Southpark

#8
Jun 15, 2018, 02:36 am Last Edit: Jun 16, 2018, 02:10 am by Southpark
After many years of etching I would like to try the cnc milling method now. I have done some research but the best thing is to get information from people who walked "the same road".
So please could you elaborate on 'wrong' and 'right' gear! I would be most interested in your thoughts about the 'right' gear. :)
Thank you!
Sure can. My meaning about 'wrong' gear is getting something that wasn't quite right, or doesn't perform as we expected. So for CNC machines, there are discussions about lead-screw and ball-screw systems. Ball-screw is probably the 'right' system to get.

A rigid-as-possible structure/frame is good....and very strong and rigid guiding rails. The relatively inexpensive system I've been using is a 3040Z-DQ ballscrew system. It works well, even though my machine doesn't have 'linear rails'.

At the moment, I'm finding no need for linear rails. But if I do ever get another machine (for some reason), linear rail guides and ball-screw system will be the one I'd get, such as the one here:

https://www.omiocnc.com/x4-800l-usb-cnc-desktop-engraver.html

Wrong gear also means buying things that we thought we'd need. I incorrectly thought that the process of 'tramming' a spindle was critically important, so I bought a bunch of measuring devices for this purpose. But it turns out that this actually isn't very important at all for pcb work, so basically wasted my money and time on that. On the other hand, measurement devices (dial test indicator, and snugs, and flat 'triangle' (square)) will be needed for manual testing and alignment the x-axis of travel with the y-axis of travel...... and these measurements will involve the need to lock the spindle so that it doesn't rotate. So a 3-D printed spindle lock --- like this one... https://www.youtube.com/watch?v=thy53GjV0_Q&t=152s can be handy. But this requires the spindle fan to be removed, so an external circlip removal plier is needed....... but those pliers need to have small-enough diameters for the inserts to fit the small circlip holes. But all this might not be important for you, since the kind of system you might get (if you do get one) could be much different to what I'm using.

There are a lot of things to pick up (for ourselves) if starting out new.... and tutorials (videos etc) don't always tell us everything. Things such as even what sort of clamps to buy .... eg 'CNC Engraver Router Table Clamp' (from ebay stores), and suitable bolts (with particular style of bolt head) for inserting into the extruded T-slot aluminium guides are not often discussed....... ie. the 'hammer T-bolts' (or T-slot drop in bolts).

For double-sided boards, any vias that I need to pop-in is done using a 'riveting' tool. The one I ended up getting is branded as 'favorit'. Works just fine. I personally don't mind putting in vias. I have lots of patience.

larryd

I have made quite a number of PCBs on a CAM tool.
The method can be a bit iffy to make double side boards.
Single sided boards come out quite good but small traces should not be attempted.

If you have used the photo sensitive method, suggest you stick with that, 5 thou traces are attainable.




No technical PMs.
The last thing you did is where you should start looking.

ted



I am using this one's, easy to work

https://www.aliexpress.com/item/10PCS-A4-Sheets-Heat-Toner-Transfer-Paper-For-DIY-PCB-Electronic-Prototype-Mak/1848289788.html?spm=a2g0s.9042311.0.0.27424c4dg8cXnH

The problem I have is no mirror printing option in my printer , so I am drawing in mirror version.
Which laser printers have mirrored printing options ?

allanhurst

#11
Jun 15, 2018, 03:31 am Last Edit: Jun 15, 2018, 03:36 am by allanhurst
I designed 30GHz datalinks a while back,and the firm I worked for subbed manufacture to China . On fancy expensive substrates

But <0.1 thou etching accuracy is necessary for eg printed filters and waveguide launches

The Chinese couldn't achieve this reliably, so we brought it back to the UK.

Allan



tinman13kup

The problem I have is no mirror printing option in my printer , so I am drawing in mirror version.
Which laser printers have mirrored printing options ?
My printer won't mirror print either, but that isn't an issue. The mirror print is done through the pcb software in print setup. The biggest issue I have is only being able to print one side of the board at a time.
Tom
It's not a hobby if you're not having fun doing it. Step back and breathe

ted


Go Up