PCB at home (freaking me out)

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I understood today that before you print the artwork you should check the mono at the page setup that is really important and affects the printing cause mono uses only black and white but other uses some other stuff too
so be sure you use mono that is really important it is going to have a huge difference
and increases the chance of transmitting the artwork to copper
here is where it is

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I don't need a Handkerchief; i have no more tear to shed anymore - Solid Snake

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Quote:
I understood today that

I hope you are not printing from *.jpg :) Use some graphical software (GIMP) for printing/tweaking.
Do not forget to mirror the artwork before printing (that page setup is not mirrored).
You should also mark the edges of the PCB to ease cutting later.
I initially drill all the holes with same small drill diameter (0.5mm) and then the bigger holes are increased with bigger drill, with good centering after small drill. For that you need all drill marks ( for big and small pads) to have small holes in artwork to precisely align small drill so correct that or you will not be able to drill bigger holes precisely..
Your minimal tracks clearance is small when compared to the copper pour clearance. Why is that so?

No RSTDISBL, no fun!

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Do not forget to mirror the artwork before printing (that page setup is not mirrored)

that is altium designer print preview
i just wanted to tell about the mono thing that might help others
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Your minimal tracks clearance is small when compared to the copper pour clearance. Why is that so?

yeah i agree that is my mistake
i understood that i finished routing

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I initially drill all the holes with same small drill diameter (0.5mm) and then the bigger holes are increased with bigger drill, with good centering after small drill. For that you need all drill marks ( for big and small pads) to have small holes in artwork to precisely align small drill so correct that or you will not be able to drill bigger holes precisely

that's smart you choose 0.5mm for the drill zone and you just increase the size of pad around it yes?

this was my first time that i designed a pcb ,for my next projects i will use all the things i learned here

I don't need a Handkerchief; i have no more tear to shed anymore - Solid Snake

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you choose 0.5mm for the drill zone

I use 0.5mm drill. The mark (a hole in the printout) is much smaller than drill diameter or I am not be able to drill the hole precisely. The etched mark is just big enough to drive the drill at the exact location. The idea is that no matter how big the final pad or its hole diameter is - I use same size hole/mark in the printout.

As a sidenote - same DIY technology but different purpose. Here is one of tensometers (half of it) I tried to make recently. It is a sheet of Cu etched so that it works as a thin wire of almost 2 metres in length (as you can see this one was damaged).

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No RSTDISBL, no fun!

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valusoft wrote:
westfw wrote:
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I guess my time is worth more than any perceived expense in going with a consistently reliable method.

Well, the "learning curve" for photosensitive is expensive too. It's one thing to pay more for consistent results, and another to be paying $10 for each of your initial mistakes. YMMV if you have readily available APPLY-ABLE photomasking; here in the US there seems to be exactly one supplier of sensitized PCB material, with rather limited selection. Nowadays, I'd just ship out most boards to Seeed or OSHPark. Or run the boards off on my LPKF if they're simple enough.
And just for the record, it sounds like you get ripped off in the US. Last order, I paid A$3.50 for a sheet of 4.5" x 6.5" pre-sensitised stock. And A$0.60 for the artwork printed on overhead transparency stock at my local copy centre. I can have an etched and drilled board finished in under 90 minutes including the visit to the copy centre with my artwork as a pdf file. I ALWAYS produce a prototype assembly before starting the coding. And I can supply a photo to my clients as evidence of progress within a couple of days of contract award. No pcb production mistakes... except of my own doing/design. I have considered a CNC machine alternative, but on balance, they offer me nothing beneficial. Just another thing to maintain. Production quantity pcbs are outsourced of course.

Cheers,

Ross

I get similar prices to Ross by ordering boards from Digikey, and I buy 25 transparencies for $9.00, so no ripoffs involved. I don't know where Westfw gets his $10 figure from. Total costs for materials/chemicals to make 1 homemade board don't come to that...unless you buy a big presentized board.

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Quote:
As a sidenote - same DIY technology but different purpose. Here is one of tensometers (half of it) I tried to make recently. It is a sheet of Cu etched so that it works as a thin wire of almost 2 metres in length (as you can see this one was damaged).

Well you know it's just so much work for me to do all the stuff of DIY pcb at home and it also takes time and patience i due respect to people who do this this is really an artwork but i'm planning on making a CNC pcb machine (well I suppose it is not easy at all !!)
you just put the copper board and you can go , when you come back it is done with a high precision
you have no cutting ,no acid stuff ,no ironing or laminating ,no drilling (i hate this part specially if you have nothing but an small dc motor ) , no transferring paper ,no worrying about your transferring quality(whenever i transfer the thing i just say please be transferred good )
even you can do doubleside pcbs at home in no time
is there any disadvantages that i'm not aware of?
i mean if this thing is this much cool then why we still do the "classic " way?

I don't need a Handkerchief; i have no more tear to shed anymore - Solid Snake

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To verify your statement let me tell you about my epic fail.
Yesterday i finally finished my first double sided board, it was ready for population when i had to realize that i just cannot place my 100-pin TQFP micro (UC3C1) in correct position on its footprint.
Three sides were ok but the fourth was always misaligned (i rotated the footprint with 45°).
It turned out (okay, i believe) that during the lamination process due to the excessive heat the copper layer strongly dilated (the board literally bent) unlike the transfer paper, and when it cooled down the image on the copper has shrunk by at least 0.5mm (my board size is 80x100mm).
I've read many articles, forum posts about the topic but i cannot remember if this pitfall was mentioned in any of them.
(Maybe it is because i used two 0.5mm single sided boards, etched them separately and then glued together.)

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Next time put some fiducial markers on an artwork layer and verify the dimensions. I have never experienced any noticeable change in dimensions during printing or during transfer.
Besides, the bigger chip, the thicker PCB is needed. And 0.5mm PCB or even 1mm PCB for TQFP100 is IMHO too thin.

No RSTDISBL, no fun!

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Wow. Haven't tried the 100 pin ones. 32 and 44 pin packs come line up fine, but take some fiddling. Just have to get it to within 1 pin align on each side, or the silly thing will solder on 1 pin off. On professional board with a solder mask, it's easier.

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On professional board with a solder mask, it's easier.

I do not think even a professional TQFP100 footprint relies on any solder mask. Not the ones with <=0.5mm pitch (>80 pins) so there is not much difference if it is with or without a solder mask. Just apply tiny amount of solder paste and heat it up.

No RSTDISBL, no fun!

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Next time put some fiducial markers on an artwork layer and verify the dimensions.

You are absolutely right, i'll have to make some experiments to find the proper scale factors for both the printer errors and the dilation errors (the latter one might be quite difficult).

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And 0.5mm PCB or even 1mm PCB for TQFP100 is IMHO too thin.

Yes, but when i glued them together with a two component adhesive the result was a surprisingly robust board.

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Wow. Haven't tried the 100 pin ones. 32 and 44 pin packs come line up fine, but take some fiddling. ... On professional board with a solder mask, it's easier.

I was so stupid to start such a challenging task without any skill and preparation. Actually i wanted to fabricate a small socket board which i could have used in other projects.
Yes, i think i'm going to visit a board house.

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Your solder mask doesn't need to go between the pins to make it easier to position, just cover any copper at the corners so a pin won't stick to it.

If you don't know my whole story, keep your mouth shut.

If you know my whole story, you're an accomplice. Keep your mouth shut. 

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