I have tried making PCBs with toner and and iron, and for me it just wasn't good enough. I want to be ableto make PCBs up to about 250mm square, I want some proper equipment but I'm on a very tight budget about £200. I want a UV exposure unit and probably and etch bath. I only do single side analogue stuff so I don't need anything mega.
I saw THIS only ebay it does look too cheap but it has a years warranty but I don't want to be sending it back to Japan every 5 mins.
Is this possible on my budget?
I saw THIS only ebay it does look too cheap but it has a years warranty but I don't want to be sending it back to Japan every 5 mins.
Is this possible on my budget?
The key for the UV exposure is to get a UV source that illuminates the target evenly and brightly. I suggest building a small box that's big enough to fit the largest board you plan to make and mounting some UV tubes in it. Line the insides with aluminum foil. Then you need a sheet of (quartz?) glass to press the layout positive to the board. That takes care of exposure.
Developing is usually done with sodium peroxide (NaOH) which I've found in European grocery stores as drain cleaner. I seem to recall using 7 g/L of NaOH to water. Use cold water as the dilution is exothermic (not sure what process is going on, but it is exothermic).
Etch with ferric chloride or HCl+H2O2.
Developer trays work well for etch baths and developing work.
~Tom
Developing is usually done with sodium peroxide (NaOH) which I've found in European grocery stores as drain cleaner. I seem to recall using 7 g/L of NaOH to water. Use cold water as the dilution is exothermic (not sure what process is going on, but it is exothermic).
Etch with ferric chloride or HCl+H2O2.
Developer trays work well for etch baths and developing work.
~Tom
*dons his chemist hat*
Dissolving any acid or base is exothermic, typically the stronger the acid/base the more exothermic. Variety of causes the most of which are a result of the dissolution of the ions.
Also, tom makes a good point. It has to be quartz glass. Regular glass does not really transmit UV very well
Dissolving any acid or base is exothermic, typically the stronger the acid/base the more exothermic. Variety of causes the most of which are a result of the dissolution of the ions.
Also, tom makes a good point. It has to be quartz glass. Regular glass does not really transmit UV very well
A UV lightbox with timer.
http://www.diyaudio.com/forums/construction-tips/172590-led-uv-lightbox-inkjet-stencils-smt-pic-16f887-bcd-code.html
I built that one with LEDs, the illumination is a bit patchy, I'd probably go with 12V fluorescent the next time, I used them in the past with success. The LEDs probably make for better collimation though, if you can make a single PCB to carry them you'll get less problems with patchiness, instead of the perfboard strips I used. You don't need quartz, glass from a picture frame is fine.
w.
http://www.diyaudio.com/forums/construction-tips/172590-led-uv-lightbox-inkjet-stencils-smt-pic-16f887-bcd-code.html
I built that one with LEDs, the illumination is a bit patchy, I'd probably go with 12V fluorescent the next time, I used them in the past with success. The LEDs probably make for better collimation though, if you can make a single PCB to carry them you'll get less problems with patchiness, instead of the perfboard strips I used. You don't need quartz, glass from a picture frame is fine.
w.
Nice thanks, I was about to ask can I wack a load of LEDs in a box and turn them on!
Strange but true - You can use monosodium glutamate to etch PCB's. A solution of MSG by itself will etch the copper in a few days. The process is slow because it needs oxygen from the air to work. For quick results just add some hydrogen peroxide (which is sometimes sold as color safe clothing bleach).
I can get MSG very easily in the supermarket because I live in Asia where it is the staple food. I don't know if it is available in it's pure form in European/US supermarkets.
I can get MSG very easily in the supermarket because I live in Asia where it is the staple food. I don't know if it is available in it's pure form in European/US supermarkets.
Hello everyone..
I has one easy method of making the pcb, after designing the pcb layout using suitable softeware (ultiboard/diptrace/.. etc) print in the pcb layout (only the copper bottom layer, in reflected view(bottom view)). Then sent the copper trace to the sticker shop.. there, they scan and plot the vinyl sticker ( p-cut machine Creation PCUT Vinyl Cutter) the copper trace. the after the trace sticker done, the trace pasted on copper board. Then the etching process as usual. after the unused copper surface cleared, the protective sticker removed- voila... done...
Disadvantages: not suitable for thin trace >1mm
P/S: I'm using aquarium air pump to enhance etching process( bubble etch techniques)
I has one easy method of making the pcb, after designing the pcb layout using suitable softeware (ultiboard/diptrace/.. etc) print in the pcb layout (only the copper bottom layer, in reflected view(bottom view)). Then sent the copper trace to the sticker shop.. there, they scan and plot the vinyl sticker ( p-cut machine Creation PCUT Vinyl Cutter) the copper trace. the after the trace sticker done, the trace pasted on copper board. Then the etching process as usual. after the unused copper surface cleared, the protective sticker removed- voila... done...
Disadvantages: not suitable for thin trace >1mm
P/S: I'm using aquarium air pump to enhance etching process( bubble etch techniques)
I just use a two-tube fluorescent fixture, with F15T8BL tubes. Those are like black light bulbs but without the dark blue coating. 4 would be better if you want to do very large boards. Before that I used incandescent "sun" lamps as used for tanning (and before that, a home movie photoflood lamp). Those can sometimes be found at yard sales and thrift shops for cheap.
The lowest cost source of UV light is sunlight. Seriously, it works. Glass cake pans work for etch bath but even cheaper ar zip lock bags.
Yes, but you've no idea how much you're getting, so unless the black parts of your stencil are completely opaque, you can't judge the exposure which won't overexpose the traces and pads. You need a calibrated source unless you're prepared to waste a lot of board, or at least resist, in test exposures. Sunlight is just too inconsistent for serious work unless perhaps you buy a UV meter - why not buy a source instead? You can buy enough LEDs to cover an A4 sheet for $10 US.
w
The sun on a clear day is remarkably stable. Measure it once and you will know it's brightness. The simple way to measure is the way photographers used to do when making prints by hand. You expose a narrow but long strip of scrap to the light but cover most of it with a piece of metal or whatever. Then every 5 or 10 seconds you move the shade to expose more of the strip. After ten times your strip has a patch with 10, 20, 30, 40 and so on seconds of exposure. Run this through the process and pick an exposure. As long as the sky is clear and the sun is within a couple hours of local noon your test results will be valid.
You can also measure the sunlight if you have a camera with a built-in light meter. Get a "gray card" lay it flat and see what the meter says.
The biggest problem with using sunlight is that you can only work during a short period in daylight in good weather. Unless you really understand the part about using the light meter and with automated camera few people understand meters
Just found this thread...
I've been operating PCB prototyping for years, so here's my recommendations...
Get an ordinary fluorescent light fixture for twin 50 cm tubes, - build a small box with the light fixture in the bottom and a glass plate appx 1.5-2" above, - and another glass plate to hold your artwork and PCB. This should cost you no more than appx 30£....if you can find 3-4 single tube fixtures and space them appx 3" that would be even better - wire all in parallell.
You don't really 'need' a timer, as exposure will be in the order of 3 min +/-, but a simple mechanical clock timer will do just fine.
Most PCB materials these days are positive - developing with NaOH as described earlier - although I wouldn't use the drain cleaner - regular caustic soda are sold in paint shops in the UK too..?? 7 grams to the liter us the ususal recipee.
Etching can be done in a flat dish, - a solution of 1:1:2 of concentrated muriatic acid ( HCl) - strong hydrogren peroxide and water is one etching solution. Ferric chloride ( Fe3Cl), sodium peroxide are other ways, but these needs to be heated to appx 50C , and best used in a vertical jar with air flow from e.g a aquariom pump......
I'll give you the Osram code for the UV tubes in a couple of days...
( I just don't remember them directly... )
For printing artwork, there's a film product called LaserStar, that gives a lot better quality for fine lines than the traditional transparent foils... you find it here.. :
http://www.megauk.com/artwork_films.php
( Mega also have everything else you need - it will just cost some money....
I've been operating PCB prototyping for years, so here's my recommendations...
Get an ordinary fluorescent light fixture for twin 50 cm tubes, - build a small box with the light fixture in the bottom and a glass plate appx 1.5-2" above, - and another glass plate to hold your artwork and PCB. This should cost you no more than appx 30£....if you can find 3-4 single tube fixtures and space them appx 3" that would be even better - wire all in parallell.
You don't really 'need' a timer, as exposure will be in the order of 3 min +/-, but a simple mechanical clock timer will do just fine.
Most PCB materials these days are positive - developing with NaOH as described earlier - although I wouldn't use the drain cleaner - regular caustic soda are sold in paint shops in the UK too..?? 7 grams to the liter us the ususal recipee.
Etching can be done in a flat dish, - a solution of 1:1:2 of concentrated muriatic acid ( HCl) - strong hydrogren peroxide and water is one etching solution. Ferric chloride ( Fe3Cl), sodium peroxide are other ways, but these needs to be heated to appx 50C , and best used in a vertical jar with air flow from e.g a aquariom pump......
I'll give you the Osram code for the UV tubes in a couple of days...
( I just don't remember them directly... )
For printing artwork, there's a film product called LaserStar, that gives a lot better quality for fine lines than the traditional transparent foils... you find it here.. :
http://www.megauk.com/artwork_films.php
( Mega also have everything else you need - it will just cost some money....
Last edited:
How do you create the transparency that goes between the light source and the PCB?
In the past before hearing about toner transfer I've had trouble with getting the black to be black enough to completely block the light. We had to go with litho film but that is a complex and expensive process. Good if you plan to make 100 PCBs but not for 1.
In the past before hearing about toner transfer I've had trouble with getting the black to be black enough to completely block the light. We had to go with litho film but that is a complex and expensive process. Good if you plan to make 100 PCBs but not for 1.
I would not have suggested sunlight except that the stated total budget was $50. With that budget you need to improvise every step of the process. Spending even $20 on lamps takes to much of the total budget considering that chemicals and other supplies are also needed.
You can print them on laser printer or inkjet printer transparency material, the little dots on the inkjet material make no perceptible difference in traces down to 10 thou, I use inkjet at home. You have to be careful with the exposure as it is possible to overexpose through the black areas resulting in all the resist being removed. It's a delicate balance, but far from impossible.
w
w
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.