Pulsar Stuff

[AtomSoft]

cool! cant wait to test it out.

 

[bryan]

Hi Atomsoft,

Thats a lot of Dollars for pcbs.

Have used toner transfers, but no experience of the Pulsar system; wondered if you have considered the uv pre-sensitised boards, not cheap but consistent results.

With the availability of cheap uv leds a diy exposure box is very easy.

Sample of the kind of work I've done with uv leds shown below.

Ditto on Richards suggestion about Photo-resist and a UV led box, results are much better with Photo-resist, especially for fine traces.

 

[MrDEB]

PULSAR will do fine traces

my last etching I made some .006 traces. Just for the fun of it seeing how I just did an outline of my main circuit.
came out as advertised.

 

[AtomSoft]

definitely do a filled plane with wide clearances between planes and traces.
be sure to burnish the edges of the board to avoid any high spots.
print out in a high density like 5 on an HP 1320 laser printer.
I perfer the 1 part murtic acid to 2 parts hydrogen peroxide (ADD the hydrogen peroxide TO the acid) in a plastic container. The Pulsar site mentions using a plastic bag.
run the boards through the lamina tor in opposite directions several times like 3 - 5 x's
CLEAN the boards ( I perfer a drop of dish soap and green scotch brite pad. A 600 wet dry paper works good to.
do not get finger prints on the board surface.
allow about 5mm clearance around the perimeter of your board design and traces Traces should be for a 1st board .25-.30 inches wide.
don't forget to mirror the bottom design.
depending on how heavy your copper boards are (the ones in the kit are 1/2 oz I believe, the etching will take 2 - 5 minutes and the etchant will turn green
use the green foil after you have applied the toner transfer.
cool the board immeditaly after using the lamina tor at eac step.
when all done then I like using liquid tin to prevent corrosion and it seems to aid in soldering.
If you need any help then call PULSAR. Great support.
I know a lot of this is repeated but it all is important to know
most important - let us knopw and see your results

That is how i etch. I have the muric acid and hydrogen peroxide already.
I have UV lights for photo but then i need those presenstized boards and other chemicals. Too much stuff if ya ask me. Since photo boards cost so much it sux in price.

I know they have a spray but i wouldnt trust it. And that applicator is pricy too.

 

[MrDEB]

I thought you had the PULSAR kit?

or how come you havn't got it etched yet??-lol
I see someone is doing the board in express pcb and sending you a printed sheet.
I am interested in your schematic so I can have fun designing a board.
Can't see why any jumpers are being used??
if you have the kit I believe you have some 2x boards as well.
2x are not that hard to do.

 

[vne147]

I have used this product many times before with varying success. You can aviod most problems by following some basic board design rules. I would agree with the advice you got from several other people so far about avoiding right angles. Also, I have found that the thicker you make your traces, the less likely you are to have problems. I would aviod routing traces in between pins or through tight spaces if it is aviodable. One other thing that I've noticed is that it seems that the closer the traces are to the edge of the board, the more likely you are to have problems. What I have started doing is fusing the etch resist to the board with the laminator before I trim the board to size. That way even if I layout the board with traces close to the edge they won't actually be close to the edge when I run it through the laminator. True, this wastes some of the usable board area but that doesn't make much of a difference for my purposes. Maybe that won't be the case for you, I don't know. Something worth mentioning I think is I did not buy the laminator from the website. I bought a similar one from Office Depot that the guy from the website told me would work. I will say the guy from PULSAR is very good at answering questions and providing good advice. When I asked him about purchasing other laminators he didn't seem to care that I wasn't going to buy the laminator from him and still gave me good advice. There is another product that I have also used that works as good as the PULSAR paper and that is the Press n' Peel Blue. I usually use the PnP when I'm going to make 2-sided boards because it's thinner and light shines through. For 2-sided boards, I'll fuse the etch resist to one side, drill the vias, put the board on a light box and use the light that shines thorugh the vias to align the second side. You have to protect the first side when you run the board through the laminator the second time to fuse the second side but this method seems to work pretty good for me. I'm sure there is more than one way to do this though. There's my 2 cents.

 

[MrDEB]

good rule of thumb

leave 5-8mm around the board perimeter.
how thick are your traces and what weight board are you using?

 

[3v0]

vne:

The caution about not running traces between pins tells me you are not getting the results you should. Pulsar can do fine lines.

As you mentioned trim the PCB after it is etched.

3v0

 

[vne147]

The caution about not running traces between pins tells me you are not getting the results you should. Pulsar can do fine lines.

As you mentioned trim the PCB after it is etched.

3v0

3v0,

I have been able to successfully route traces between the pads of an SOIC SMD IC before using the PULSAR paper but I won't say I've never had problems doing it and I generally won't unless I have to. I just thought it would make things more simple for a beginner not to. I did not mean to imply it should never be done. Aside from that, I have also found that the quality of the printer or xerox machine you use to print onto the paper can greatly affect the results. For example, there is one xerox machine at work that almost always produces perfect results for me but another that I always have problems with. I don't know if they use slightly different toner or what but it definitely makes a difference. I suppose that could have contributed to some of my less than favorable results. At any rate, I'm only one voice so take it for what it's worth.

 

[MrDEB]

maybe the density is set differently?

I found the density has a lot of influence on the quality of the traces especially when doing most anything smaller than .015"
As I mentioned before I have done .006" traces but not really practical IMO

 

[AtomSoft]

Thanks guys. I plan to use this for the not to heavy boards. Boards with a 100 pin LQFP will be sent to a board house. Dipmicro will offer board service soon! so i plan to test his service when i make LPC boards.

But for DIP devices and SOIC type stuff i plan to use this. Even with SMD resistors, caps, diodes. Ill use this.

Ill try to avoid small traces all together really. if anything ill do it like ive seen on some boards. which are small traces from pin to larger traces about .5mm away from pins. This way most of the board stays with larger traces and more reliable.

I plan to test between pins and use a microscope to see how they look. Not a real microscope but RadioShack sells this nice little one with a light that would do the job. And with a 30% discount it wont cost much

Illuminated Microscope - RadioShack.com

It would help me verify these type of things.

I dont own the kit yet. I plan to test some other before i spend that money lol

vne147: Which one from office depot? What does the laminator have to fit? Like what specs should i look for?

Heated roller? Thickness? anything like that?

 

[DirtyLude]

8mil is as small as I've ever practically had to go and even that was a special case that I can't see happening again soon. Otherwise 10mil for QFP and QFN and 12mil for SOIC.

Watch out with the microscope. Make sure it can focus on things far away from the base. I've had trouble with even backwards loop lenses that don't have far enough focusing distance. You can't get the microscope close enough to the pad without bumping it into the component itself, or the components on the board that are in the way.

 

[BeeBop]

A pair of 3+ reading glasses found in a dollar store works well.
When things are very fine, those in concert with an illuminated magnifier and...

 

[AtomSoft]

the microscope has a hole on the bottom like a big notch. I tested it on hair at the job and works well!

Im about to go buy it now lol

It has 2 focus knobs also

 

[3v0]

Ignore

What about ignore do you not understand

 

[3v0]

For about twice the price of the optical unit you linked to you can get a digital blue that displays on your computer and takes pictures.

It is not the worlds best unit either but works well enough that I like it. The older, cheaper, units do not have VISTA drivers. I run a virtual XP box to use mine.

You may have seen some of the images I posted.

3v0

 

[DirtyLude]

the microscope has a hole on the bottom like a big notch. I tested it on hair at the job and works well!

Yes, but it looks like its meant to be placed flat against the object you want to focus on. You can't place it flat against the pad you want look at when there's a chip in the way. Just make sure it focus' far enough away to compensate that it can't be flat against the thing it's looking at. Since there's a focusing knob I'm sure it'll be okay.

You might want to order some cheap high quality tweezers from DealExtreme if you are going to be doing some SMD work.

 

[AtomSoft]

Thats a small picture

Im sure i can modify a old digital camera to it and take pictures also. If anything i have a cam that can take pictures really good. Ill take a pic of a pcb now (traces) and show you how close i can go.

Some quality sux but i had to put as JPEG so i can show all here unless you want a 4 mb file

 

[AtomSoft]

i expect to check the PCB before any chips are on it to ensure there arent any cracks or broken traces. And if there are i plan to use a trace repair pen or something like a small thin flat wire to repair it. Even if i have to flatten a normal round wire under pressure and make a nice flat trace

 

[DirtyLude]

i expect to check the PCB before any chips are on it to ensure there arent any cracks or broken traces. And if there are i plan to use a trace repair pen or something like a small thin flat wire to repair it. Even if i have to flatten a normal round wire under pressure and make a nice flat trace

Sorry, thought you were talking about checking the SMD solders and joints.

Every time I've had break in a trace its been pretty easy to spot. Hardest things I've had to spot are little bridges.