I am sort of surprised to see the amount of activity on this thread. I have this harbor freight shear/brake and like it.



I have nothing against photo transfer PCB making. I use the pulsar system. Which is better for you depends on a few things.

First you wanted to see a real PCB. This work in progress is the 44 pin TQFP board. I did a shitty job on the 805 parts (do not work when angry). The processor chip is spot on. The unpopulated pads are for a serial EEPROM. Note: If I cared about what people think I would not post this image. This my first shot at this board. The next time I will do a solder mask and everything will be beautiful. I will even clean off the flux




Some of the header pins are soldered top and bottom. The bread board holds the loose pins in alignment during soldering. For vias I used .025 in holes stuffed with header pins that are held in by friction. Again ugly but faster than messing with wire. The plastic on the 2x5 header is above the PCB because the pins are soldered on both side.

The following is about the two methods. It has more toner transfer detail because that is what I have been using for the past few years. I have tried to be fair to both.

It used to be that you could get more resolution from the photo method. I do not think that is true anymore. Pulsar Toner transfer puts the toner on the copper. Photo relies on contact print. I am not including P&P here.

Resolution is limited by the printer and the ability of the PCB to hold a narrow trace. Now all PCBs are created equal.

Both methods have steps you have to get right. With photo you need to get the exposure and developing correct. With photo transfer you have to get the toner to stick to the PCB and enough of it.

If you do this on the cheap I would have to say you are more apt to have success with the photo method. Toner transfer using an iron is an art, and a lot of work. Will I get flack for saying that?

One problem with photo is that the photo resist chemicals/coatings age. If you make a board or two a year, or a board every two years this could be an issue.

With photo you need lights to expose the resist. With toner you need the laminator. You can go cheap on either with mixed results. There are people who can and do do it on the cheap, but do not expect it to be easy to master.

Next is the cost. The pulsar paper and foil cost under 3 cents a square inch. How much you pay for the PCB stock depends on where you go.

I have not used the photo method recently enough to speak about the cost.

Alignment for 2 sides PCBs is always an issue. There are several solutions. It can always be done.

I drill my holes first then apply toner to one side and mask the other side. Then I mask the etch sided and apply the toner to the other. For masking I use common/cheap (not scotch or UPS) box tape. Some people apply toner to both sides and etch once.

If you do not have predrilled holes you can align the 2 toner images to form a pouch. I have not tried it.

Regarding fine lines with the Pulsar system. As I said earlier the limitation is not the paper but the printer and the PCB. I like to stay at .010 and larger. It is possible to put finer traces on the PCB but you can easily lift them when soldering. There is a greater possibility that that printer will not print the line well enough to etch.

Note that the starch coating on Pulsar paper does not absorb liquid toner. If an insufficient amount of toner is present it will tend to bead up rather than make a line. With a good toner cartridge this is not a problem.

When doing toner transfer use a brand name toner cartridge. There has been a report (here) of a refill brand that works but I do not recall the name. It is best to use a fresh cartridge for printing PCBs and then move it on to regular use when it gets somewhat used up. I do not do that but it would not hurt. It is all about delivering maximum toner.

3v0

My 0805's tend to look like crap whether I'm angry or not.

I have a similar board, but I've let the chip hang off the edge of the breadboard to squish the pins together so I have room to plug in wires on the sides. I also have a SAM7 board that I did but I made it cross over 2 breadboards so I could keep some room for plug in wires.

Why do you care about tinning and masking? Usually, if I know I'm keeping it for a while, I just spray on the acrylic. Otherwise I just let them tarnish, but even my oldest boards aren't that bad.

DirtyLude,
My breadboards are setup 3 wide with a power bus between each. This processor module spans a power bus with pins in two BB's.

I spray all the non SMD boards with a very thin acrylic coat prior to soldering. I tried MG Chemicals Liquid Tin for the first time on this PCB. I seems to be OK. Too early to tell but lot easier to use then Tin It.

I have been using spray acrylic on most everything once it is finished. For stuff that goes in the garage and maybe outside I have some actual conformal coating.

Originally Posted by DirtyLude

My 0805's tend to look like crap whether I'm angry or not.

I have a similar board, but I've let the chip hang off the edge of the breadboard to squish the pins together so I have room to plug in wires on the sides. I also have a SAM7 board that I did but I made it cross over 2 breadboards so I could keep some room for plug in wires.

Why do you care about tinning and masking? Usually, if I know I'm keeping it for a while, I just spray on the acrylic. Otherwise I just let them tarnish, but even my oldest boards aren't that bad.

Originally Posted by 3v0

DirtyLude,
My breadboards are setup 3 wide with a power bus between each. This processor module spans a power bus with pins in two BB's.

Ya, that's how I did that SAM7 board. Unfortunately I did not home etch it. It would just expand into a monster home etched, with too many vias.

Your board looks very nice. Good work. The tinning does look nice and like I said, my 0805's and 0603's don't look any better.

EDIT: With boards like this I've started using really long header pins that stick up above the board. It makes it easy to clip on a logic analyzer, or even just a DMM while working.

I have now ordered 1206 resistors.

on the photo you see one 0805 turned by 90 degree's-
but it's a perfect electrical connecition.

what is really messy are the half-size SMD diodes.

now the next revision will again use conventional parts, maybe retain pads for 100nF SMD capacitors, but trimmer resistor will be conventional.

the SMD parts requires a bit of exact size.

well uhm the PCB is not self-made, i got them for 23 cents each.

Originally Posted by nike6

I have now ordered 1206 resistors.

Don't go 1206, they're huge.

I've gone to 0603 for all my caps, since I can put them closer to the IC. I'd move from 0805 to 0603 for my resistors as well, if I didn't have so many of them. It's easier if they are all the same, so I don't have to mess with part selection when making up a board.

I have to give Boncuk credit fot the layout for this PCB. He does a nice job and is much better at making parts.

The header pins on this PCB are in the same order as on the chip to reduce the via count. We have a similar PCB with the ports on contiguous pins but it required vias under the TQFP. I am still searching for a good way to make flat vias for under SMD chips.

I will order some of the longer header pins.

3v0

Originally Posted by DirtyLude

I use Staples Photo paper. They've changed it to Gloss paper or something; I think it's in a purple envelop now. I'm not certain. I have a stack of the old stuff.

I think if you are starting out, the Pulsar paper is a good deal. If you want to move to cheaper alternatives later you can.

Double siding and other details are all in older posts.

You can always change the pad sizes in the Eagle footprint libraries if it doesn't match your requirements for etching. I had to adjust a few of them for a boardhouse with 8mil trace/spacing limits.

Really, I don't have many chips that aren't QFP, QFN, or TSSOP, all with 0.5mm spacing. If I couldn't etch for them, I'd be screwed.

EDIT: Generally I can do smaller spacing than I can do traces, so for 0.5mm leads, I do 10mil traces and let the spacing suffer. I also find with 8mil traces, the copper can seperate from the board much easier, so you can get pads that break loose if you are a little hard on them.

I have been doing PCbs with ordinary a4 sheets and got best results, But the method is too lengthy and annoying, So I asked if anybody has tried transparencies...?