Problem with making PCBs at home?

[Fu manchu]

Hi all,

I have been making PCBs for some time now and I managed to get a pretty impressive result every time. Just recently the printer, Epson colour stylus 660, that I used for the artwork broke. Needing a printer for coursework and other stuff and forgetting my hobby I rushed to buy a new printer, HP Deskjet 3500.

Now before I continue with the story I shall explain my equipment and the process that worked so well for me but may not work for you, because every book I have read about this subject seems to contradict itself.

First I use over-head projector transparencies from WHSmiths and like I said printed using an Epson colour stylus 660 set on photo quality glossy film. This was pure perfection I mean the most opaque print I have ever seen.

I use fotoboard 2, available from Maplin or Rapid Electronics, this stuff is difficult to work with because you have to use half strength developer and the exposure times are a little odd compared to other.

I use an exposure unit that I bought from Rapid Electronics this unit has two tubes.

I exposed the board for 1min 30secs, however the rotary dial timer it not the most accurate thing on earth.

Using the developing solution at half strength, i.e. 100ml of water at 20 degrees C and 5g of Developer, the crystal form from Maplin

When the board was placed into the solution the board would quickly turn purple and the soft resist would start to loosen, rocking the board from side to side helped.

If all of the stages were followed correctly the finished result was a copper board with a good quality artwork transferred.

Etching the board from here is easy and I have no problem with that.

Since my Epson broke every board I have made has been a complete failure, why? - well I conducted several experiments which has lead me to the conclusion that the HP Deskjet printing onto the transparencies is just opaque enough, causing ultraviolet light to get through and corrupt the artwork.

Now I could just buy another Epson, but before I do does anyone know a printer,inkjet or laser, that would be good for me.



Thank you all.

 

[spyghost]

well, let me first ask you... what are the stuff that you print? if you need a printer, then know first what it is for you? is it for general purpose printing, photo printing, etc...??? :?:

 

[Fu manchu]

Sorry i didn't explain that correctly, a printer for PCB artwork, using Eagle Cad from Cadsoft.

 

[spyghost]

if you can afford a laser printer, get one... but if budget is under your consideration, then get a good ink jet that has a relatively cheap consumable...

photo quality printers will surely guarantee a black foil pattern for your pcb artwork...

 

[Fu manchu]

im sorry but i disagree, have you not read what i am saying or do you misunderstand the HP 3500 is a photo quality printer, but is the cause of my problem, because the print is to fine and the ink not opaque enough.

so you see if any printer worked i wound not have this problem.

 

[spyghost]

ok... sorry, i didn't understood your post...

anyway, try using another media to print on... or "tweak" the printer settings... for example, if you are printing on transparency media, it does not necessarily mean that you should select "transparency media" on your pinter settings. choose another setting until you get the right printout...

 

[Fu manchu]

yes i have tried this on tracing paper, however the ink seems to soak into the paper the best setting for this seem to be plain paper but thats not opaque enough changing the setting to increase the ink seems to make the artwork run as the printing head moves across it.

i have tried just about everything - except, which has just come to mind and it may solve it, instead of using WHSmiths transparencies using HP ones i will try this tomorrow.

 

[fat-tony]

Also check your quality settings for printing, and ensure that it's on the highest quality setting. This should use more ink and make darker prints. Unless it's the actual ink that is UV transparent.

 

[Fu manchu]

well, from the printer im using at the minute i do get a result, however its kind of faded with necklace like patterns where complete tracks should be?

The inks is stopping the UV but there just not enough to stop it, and this is on all setting.

 

[Crofty]

Checkout my post on UV Film. In this forum.. I think It answers many of your problems. Note, that film is for Epson injets, which use 'Dye-Based' Inks. The HP printer maybe using 'Pigment' based Inks?? which is a no-no, especially for us PCB'ers. This maybe the source of your problems.

Setting printer for 'Transparency' produces naff output, always see-through. Try setting it to PhotoGlossy, this setting works best.
Note: Inkjets can't print to tracing paper, the reason it runs is because it doesn't have the 'resin' coating which absorbs and sets the ink.

My Epson R200 injet produces really dense black, and sticks to this New film very easy... Plus its cheap, and as a bonus, prints on my CDR/DVD-r's.

Normal transparencies are less than useless, especially for fine tracking & pads. I used to use 3M inkjet film, this produces slightly grey-ish blacks, and often needed touching-up. Since finding this super-res film, which I output @5760 dpi, I've had no probs.

Epsons are almost made for UV artwork If you can't get the desired results with your HP? you may need to buy an epson, note: not the R800 as this uses wierd gloss optimizers. The R200 is the kiddie, plus has separate ink carts for all the colours.

Hope this helps

Steve

 

[Fu manchu]

Thanks for your reply Crofty, that’s very helpful.

Just recently I bought an Epson like the one I used to have, and yes back to a perfect print.

Unfortunately this has not solved my problem, which puts me back to square one, so to speak. :x

The print is perfect, so the problem must be with developing the board.

I have made a number of tests from 30secs to 2mins, one with 5g of developer in 100ml of water the other 2.5g in 100ml of water both experiment failed. The result is a very blurred image with a slight shadow? I have wondered if the slight flicker of the tubes is causing this, or have the tubes degraded is this possible?

Also can developing solution degrade, I mean the undiluted granulated substance, I have had this for a few years. However I have some new concentrated solution that I bought from rapid electronics and still the same result.

Still struggling and running out of ideas. :?

 

[Fu manchu]

:!: New developments:

:?: Has anyone who makes PCB, and uses a typical uv tube exposure unit, had to change the tubes, due to degradation.

i ask this because i think this is the anwser......

i switched the artwork round in the uv unit and when i developed it different parts of the pcb were fuzzy, some per perfect.

if one tube was good and the other a bit dodgy then this would explain the different pattern.

We wait with baited breath..............

 

[Crofty]

Hi.. Glad the printer probs are sorted as for the blurring bit, A 2 tube unit should be ok, But, according to info I've found, 2 tube versions need longer exposure. Mines an RS 556-238 4 x 15W tube model, my exposure times are around 2.5 mins. The 2 tube ones (2 x 8W?) need longer, around 3 mins. I would checkout the site were I got all my film, chemicals etc from, They have much help on exposure times for the different UV units. The other trick I use is not to trust the contact force from the lid sponge, when closed. I use a 1/4" piece of foam, sized to fit the PCB, and place it on top, before closing the lid, this makes sure the film and pcb are in good contact.

The link to that site is >> www.megauk.com/producing_a_pcb.php It mentions the different timings for the small/large UV units. I feel your exposure is way too short. The developer is a tricky area, I use the Liquid concentrate version from Mega, this is easier to measure out. This seems to develop less aggressively. I have tried the Rapid developer, and had Naff results. The developer is SENO 4006 Liquid concentrate (1 Ltr makes 10 Ltrs) You only mix enough to do your pcb's, so it last longer.

I hope some of this may sort you out

Steve

 

[Fu manchu]

SUCCESS........


i have changed the tubes and starters and to my surprise it works

i had a few to that failed at first, but they were almost perfect i was just bring picky.

thanks all for your advice....

i can now continue

Rock and Roll.

 

[chemelec]

In my setup, I print onto Mylar. However I found that printing TWO Identical copies and taping them together, one directly over the other Gives me MUCH Better Contrast and Final results.

Maybe you should try this.

Good Luck......Gary