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home soldering beast: 0.5mm SM

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Hi Rob,
I dont no how you worked & I didnt make self a photochemically prcessed PCB, but friends told me, that the resolution is better (you will have finer lines) if the emulsions layer of your film will direct contact the copper surface_I think for that you have before mirrored to print...
K.
 

karesz said:
Hi Rob,
I dont no how you worked & I didnt make self a photochemically prcessed PCB, but friends told me, that the resolution is better (you will have finer lines) if the emulsions layer of your film will direct contact the copper surface_I think for that you have before mirrored to print...
K.
Click to expand...

Yes, I print the artworks mirrored so the toner is against the etch-resist :). It does produce a more crisp image.

I think the limiting factor for this level of PCB production is the quality of the artwork print. Even with high-end copiers/printers toner ends up where I don't want it.

After stripping the resist I gently rub the board with a cloth soaked in developer, this helps a lot.
 

Rob B said:
[...I think the limiting factor for this level of PCB production is the quality of the artwork print. Even with high-end copiers/printers toner ends up where I don't want it....
Click to expand...
Yes, I believe it too.
We found out that an, self as "better" categorised, in jet printer film was not enough black printing fot that goal...
We maked it (longer time ago) with a Laser printer, & it was "to black to set" the toner adjusting! Today Laser & LED printers must know the needed resolution; question is the black covering of their output/film.
Its very important by such "transfer methodes" that your film is 100% "black", it can cover secure from light the sensitive layer_ so is a practicable limite maybe at 0.2-0-3 mm for us...
Otherwise I believe, that is important too, how did you cleaned the bar PCB, is its surface really fat free & fine polished, not cratched!?
Than if a surface is not enough fine, you will beome light "underetchings", so is the small or fine copper line eventually no more on your the finished PCB, or is discontinued.
K.
 

karesz said:
Hi,
Can you tell pls. more over your source, link datasheet?
K.
Click to expand...

Karesz, I just searched it in ebay, I've not yet did it myself, I first have to make my UV box :D

you can easily find it in ebay, searching for:
UV Solder Mask Repairing Paint Prevent corrosive Arcing

this is one of those links, but probably will expire soon and not valid:
**broken link removed**
 

Hi,
What seems me to be a problem with an UV-LED LightBox;
1,
its needed deepness to stray the light for enough "monotonicity...
2,
I dint no, but if its possible to stray with a milk plexy i.e., it will be similar low profile as an incandescent lamp box...
3,
In my opinion is very important that thefilm is thightest on the glass, especially by so fine lines as fin pitch PCB has!
It need than a vakuum adapter as by "professional" solutions_ not very easy & cheap. :-(
4,
If you know some older (HP & others) X-Y Plotter, their have had an electrostatically charged "table" with _I think so 1..200V_it worked (instead of more complexer vakuum table) good for normal paper- maybe for films too?
5,
Dont forget pls a good controllable timer is to build in...:)
K.
 

karesz said:
Hi,
What seems me to be a problem with an UV-LED LightBox;
1,
its needed deepness to stray the light for enough "monotonicity...
2,
I dint no, but if its possible to stray with a milk plexy i.e., it will be similar low profile as an incandescent lamp box...
3,
In my opinion is very important that thefilm is thightest on the glass, especially by so fine lines as fin pitch PCB has!
It need than a vakuum adapter as by "professional" solutions_ not very easy & cheap. :-(
4,
If you know some older (HP & others) X-Y Plotter, their have had an electrostatically charged "table" with _I think so 1..200V_it worked (instead of more complexer vakuum table) good for normal paper- maybe for films too?
5,
Dont forget pls a good controllable timer is to build in...:)
K.
Click to expand...

Hi all,

Well, I'm not sure if I understand half of what Karesz wrote, but the UV box I am going to build is here:
https://radikaldesig.blogspot.com/2006/10/insoladora-uv-leds.html

any comments? :D
 

By "stray" he means to disperse the light :).

A timer is critical for repeatabiliity as Karesz posted.

It will be interesting to see if you get uniform exposure with the LEDs.
 

Hi Rob,
Best thanks for my interpretations! :)
Right, I meant the relative bad light uniformity of (for me knowed) LED light boxes.
The uniformities (of lighting & plan planarity from film/paper on the glass) are surly the key factors for high density/fine PCBs.
Of course, the copper surface preparation isnt irrelevant too...
I cannot open today the linked lightbox side (h**p://radikaldesig.blogspot.com), will see it tomorrow...
Im waiting with big interesting too!
Good progress!
K.
 

Hi all!

Rob, Karesz remind uniformity:
I am just a little confused reading different sites' info :D some say you need 4 UV bulb, others: just some LEDs, others: no need for special bulb as in this video:


I think I'll go incremental way: first just get a Positive 20, developer, and try to use the the bulb that above movie suggested to make a 5cm x 5cm test board. Then if it didn't work I'll switch to the box I gave the link to, in prev. posts.

May be you are sure that the lamp the youtube video suggest won't work, not worth to try?
 

Hallo,
Maybe it works_you must try it pls...
One thing is sure, these pcb hasnt high resolution, a the photo layer wasnt perfect!
After that the etchant too! :-( Check pls. i.e. at 6:55...
In all case it can works, but the person isnt the most precise worker...
I ask me only, is these process good for 0.3-0.5mm resolution too?
K.
 

Not sure where you are but over here in California it's cheap to get PCBs made. We're talking less than $100 for multiple PCBs. Way less if you want one, you can use batchpcb.com and get them made for $20 or $30 for one.

Matt
 

Hi all,

Karesz, thanks for clear points like always :) as I understand you, the only problem with his process is not using a suitable bulb right? I liked the idea of using the photo frame.

Dksoba, I'm in Ukraine and I am crazy enough to sit for 14 days trying to draw lines with edding 1800 of 0.1mm tip, just for the sake of the challenge :D

I'll be ok with ordering them after I learn how to do them at least approximately :D
 

Thja,
"East peoples" have some things others to try...:)
The lamp and hes lights uniformity is, I think the most sensitive point.
You must find a good solution which has relative light possibility to spares and is not so expensive source, but you know it.
I think the only one way is to try it experimentally! :)
For me is a UV LED solution not a bad version, only a question of price and uniformity, but uniformities to organize, as by wp100 too! :).
I think a normal lamp is not usable, because after buying the next one you will have another type (maybe with same labels) & it means another spectrale data too and you can begin with experimentings for exposition time & energy...
How is it in Kiev, dont you have some UV light tubes? this is practically the simplest way to make the ligth box, by their you must play only with a timer..
K.
 

Hi all!

Karesz,
I still don't understand that a normal florescent bulb is what we can declare UV-A type or not, but I found both UV-LED and standard UV bulbs on ebay, so I can simply order them.

If normal florescent bulb is UV-A type, then yes, in Kiev you have quite a lot of them ))
 

Hali.
I think not that a normal bulb is UV type because UV rays arent good for our eyes!_other question is if its type a or b... but do you know for what a wavelength is Positive 20 (or other photoresists)more sensitive?_I dont know!
I believe that the question of light sources is a really good stuff to experimentell soluting! :)
Clearly: somebody has to try it in versions with the existing components, and will see what the resultat is/or can be...
You know, I have hade some doubt with uniformity of UV-LEDS & the therfore needed relative high deepness of the LED box; maybe is better to montage their back to the film, but they will light onto a (shiny)metallic reflector and so can be more diffuse light on the film?
K.
 

Ok the best way i found is with solder paste and a hot air gun mod you will need to cover the plastic parts fith tin foil to protect them Farnell sells smallish tubes ofsolder past it does seam like a bit to spend but the stuff works well.

MOD:Signature is removed
 

Hi,
Fein! :)
Apropos; if the solderpaste is stored in a refigerator, you will have it mostly for 1-2 yearrs with usable quality.
Otherwise their are for only a half year specified...
Some negative; you must plan your solderings because it need some houres for "tempering" in your room! :)
K.
 

Karesz,

to conclude: you're idea is that UV-LEDs are better than UV-bulbs right?
 

You see;
as calculable long-lifetime component surly & if you have found the system for distances to film & enough good dispersed/uniformized light on the film; you will have it practically so long you are in life, but the lamps are relative bulky & sensitive + expensive & time to time to renew, eventually new to find the settings than it will be some later a (light)different specified bulb...
K.
 

    K

    kievari

    Points: 2
    Helpful Answer Positive Rating
Karesz,
Thank you, I'll try with UV-LEDs to see how it will work for me.
 

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