Which is the best hobby do-it-yourself method for making PCB's?

[Jim Thompson]

In the past I have been using the toner transfer iron on technique.
The best I have gotten is 75-80% of the board done ... the remaining
20 - 30% is rework for missing/broken traces etc.

I am just wondering what is the best hobby do-it-yourself method?

Someone hinted at photo transfer

What has worked for you guys in the past?
What gives the best results on a fairly consistent basis?
How about double sided boards?
Thanks

About a year ago I bought a Roland SX-8 (vinyl) sign-cutter for some
Scout activity signs AND as stencils for glass etching (via sand
blaster).

Works just ducky for both of those applications, but I'm tempted to
try it as stick-on resist.

Anyone tried such a scheme?

...Jim Thompson

 

[Chuck Harris]

..erm that's exactly what I was saying.... you NEED holes in the pads to be able to drill them
sensibly

Oops! I saw "centre marks" and thought center marks (eg. cross hairs).

Sorry!

-Chuck

 

[Chuck Harris]

About a year ago I bought a Roland SX-8 (vinyl) sign-cutter for some
Scout activity signs AND as stencils for glass etching (via sand
blaster).

Works just ducky for both of those applications, but I'm tempted to
try it as stick-on resist.

Anyone tried such a scheme?

...Jim Thompson

Yes, and no. I use an IBC-912 Boardmaker, which is a PCB mill. It
engraves an outline around the traces to isolate them from the rest
of the ground plane.

You would be doing much the same thing with your Roland, except you
would be peeling away the parts you didn't want to etch. The problem
is in your PCB cad package. They generally are based on the photoplot
plan for making boards, that is that traces and pads are separate
entities, and multiple exposures are still black. What will happen,
is when you plot onto your Roland, first will come an outline of all
of the traces, and next will come an outline of all of the pads. The
pads will chop off the ends of the traces, and you will have a stencil
that is nothing but tiny pieces.

What you need is a program that acts like a photoplotter, and puts the
ultimate silouette image into memory, and then creates the vectors that
are necessary to make the true outline. There is a program like that
available on MIT's website for the "how to make almost anything" course
that the university offers. It is even targeted to the Roland plotter.
The author is a real abrasive peacenik character, but his software is
top notch.

Alternatively, Christian Zinner has a program called PlatinCNC which
does the same job (only much much better). His program is geared towards
the CNC routed PCB's, like my IBC makes. I have been using it for quite
awhile now, and it is a complete and total marvel! He has it priced for
under $200 last I looked.

-Chuck

 

[Jim Thompson]

Yes, and no. I use an IBC-912 Boardmaker, which is a PCB mill. It
engraves an outline around the traces to isolate them from the rest
of the ground plane.

You would be doing much the same thing with your Roland, except you
would be peeling away the parts you didn't want to etch. The problem
is in your PCB cad package. They generally are based on the photoplot
plan for making boards, that is that traces and pads are separate
entities, and multiple exposures are still black. What will happen,
is when you plot onto your Roland, first will come an outline of all
of the traces, and next will come an outline of all of the pads. The
pads will chop off the ends of the traces, and you will have a stencil
that is nothing but tiny pieces.

What you need is a program that acts like a photoplotter, and puts the
ultimate silouette image into memory, and then creates the vectors that
are necessary to make the true outline. There is a program like that
available on MIT's website for the "how to make almost anything" course
that the university offers. It is even targeted to the Roland plotter.
The author is a real abrasive peacenik character, but his software is
top notch.

Alternatively, Christian Zinner has a program called PlatinCNC which
does the same job (only much much better). His program is geared towards
the CNC routed PCB's, like my IBC makes. I have been using it for quite
awhile now, and it is a complete and total marvel! He has it priced for
under $200 last I looked.

-Chuck

The Roland came with a program called Stika that can do outlines.
I've only used it on BMP's, but maybe I can make it all play through
Universal Document Converter.

Plus ExpressPCB can be cajoled into printing "solids", making
outlining much easier.

I have an advantage... my sight in inadequate to do less than 50mil
traces ;-)

...Jim Thompson

 

[petrus bitbyter]

In the past I have been using the toner transfer iron on technique.
The best I have gotten is 75-80% of the board done ... the remaining
20 - 30% is rework for missing/broken traces etc.

I am just wondering what is the best hobby do-it-yourself method?

Someone hinted at photo transfer

What has worked for you guys in the past?
What gives the best results on a fairly consistent basis?
How about double sided boards?
Thanks

IMHO there is not such a method as the "best" hobby DIY. Both method and
result depends highly on the experience and tools available. I ever started
using nail polish and nitric acid. Did several types of photografic methods
and also tried out toner transfer. The latter worked well as long as I had
access to an HP Laserjet 5000. This one put enough toner on the sheet to
work as an etch resist. Other laserprinters I tried, including the Laserjet
4Si, did not. Now I'm back at the photo method using two overlayed
transparancies for the positive. The best site on the net I'm aware of is:
http://www.electricstuff.co.uk/pcbs.html
(Almost) all you need to know about etching PCBs at home.

petrus bitbyter

 

[samIam]

An additional issue with that is what to do with all the chemicals

afterwards. Some people store that forever and then one day the
container rusts out or the cat knocks it over.

Good point.
I tracked down the hazardous material depot in my county. I am going
to visit them some time next week to "unload" some used ferric
chloride

Once I know how much it costs and how often I can bring it to them,
Ill get serious about manufacturing test boards I design at home.

 

[Anton Erasmus]

In the past I have been using the toner transfer iron on technique.
The best I have gotten is 75-80% of the board done ... the remaining
20 - 30% is rework for missing/broken traces etc.

I am just wondering what is the best hobby do-it-yourself method?

Someone hinted at photo transfer

What has worked for you guys in the past?
What gives the best results on a fairly consistent basis?
How about double sided boards?
Thanks

I have found that using pre-clad boards with positive resist work
quite well. With the spray on positive resist, it is difficult to get
a nice even coating without any bubbles and dust.
http://www.bungard.com/ have very good quality pre-sensitised
PCBs. (Both single and double sided with a long shelve life)
Print the layout on a transparency using an inkjet printer. Clamp
the transparency against the PCB (photo resist) side with a piece
of transparent glass. Expose in sunlight for about 45 seconds.
(Experiment a bit). Develop PCB, and etch. I have had very good
results with even 10mil tracks and 10 mil spacing.
When doing double sided, one must make very sure of the alignment of
the 2 sides.

Regards
Anton Erasmus

 

[samIam]

When I tried the iron-on method, I had to go back and

fix up a couple of traces but nowhere near 20-30% of em.

lol
Maybe its a bit of an exaggeration but I would wager at LEAST
15% of the board' traces needed repair

My board size was 4x6

I learned a lesson with the last board, from now on (for hobby
boards) I use 15-20 mil traces and leave 50-75mil space between
trace lines ... in case I have to go over it with an etch resist
or permanent marker.

I am aiming to get it as near perfect when it etches so I dont
have to do fixes afterwards.

We will see with my next design 6502sbc thats 8x8 in size and
double sided ... tons of vias ...

 

[samIam]

11) SMT components can be soldered by hand, but I've had far better luck

using solder paste and a toaster oven. Digikey has it (KE1507-ND) but
as a rather high price ($42 for 35g), and you'll need to find a syringe
tip to use, the smaller the better. I'm still getting a feel for
exactly how much paste to use for different parts, and the
time/temperature constant of my toaster oven is abysmal, so the process
is still evolving, but it's worked fairly well so far.

I've taken a few closeup pics of some of my most recent boards, both
good and bad:

http://www.omegacs.net/misc/pcbs/

Thats pretty impressive ... I thought SMT were off use for hobby work
without some really expensive oven/manufacturing equiptment.

Again, NICE work

I haven't done any yet, but I plan on doing some attempts eventually.
The process would be to put the toner and film on one side, drill 3+
reference holes, then transfer the other side. The problem may be what
the laminator will do to the first side when going through the second
time. It may be necessary to use even more extra dimensions on the PCB
and transfer films and carefully tack the two pieces of transfer paper
down through the drilling process, and laminate the two sides at the
same time.

Heres my second to last attempt ... its been redesigned since
then and will be placed on a .062 FR4 copper board.

http://www.geocities.com/asa386/My6502Sbc_Anubis/pcb_manufacture/

With vias I just drill holes ... place a small wire on one end, solder,
solder other end ... snip off the remainder

I write low level code for a living ... so this is just hobby work

 

[Joel Kolstad]

Thats pretty impressive ... I thought SMT were off use for hobby work
without some really expensive oven/manufacturing equiptment.

Generally speaking, SMT parts are actually faster to use than leaded parts.
Where I've worked in the past, the production workers preferred the SMT
boards!

Those PCB pictures the guy posted are nice... kinda reminiscent of what milled
boards look like!

 

[:-)]

Thats pretty impressive ... I thought SMT were off use for hobby work
without some really expensive oven/manufacturing equiptment.

Again, NICE work

Nice ! That was one of my goal, a xilinx XC95xxx, now I know it's
possible to do

 

[Erik Walthinsen]

Nice ! That was one of my goal, a xilinx XC95xxx, now I know it's
possible to do

For some reason that one didn't work so well. Some kind of scum left on
the outside of a few rows of the pins, and I didn't restrict the copper
pour underneath, so there's an entire row of pins all bridged to each
other under the chip. I'll be carefully re-doing that one, as well as
tweaking the Eagle printout by 1/128 of an inch (0.8%) to correct for
the undersized artwork. The row of 22 pins causes the board to curve
quite badly, so I had to break them up and file off a gap between groups
of pins for this particular board. Besides, there are several broken
traces ;-(

 

[:-)]

For some reason that one didn't work so well. Some kind of scum left on
the outside of a few rows of the pins, and I didn't restrict the copper
pour underneath, so there's an entire row of pins all bridged to each
other under the chip. I'll be carefully re-doing that one, as well as
tweaking the Eagle printout by 1/128 of an inch (0.8%) to correct for
the undersized artwork. The row of 22 pins causes the board to curve
quite badly, so I had to break them up and file off a gap between groups
of pins for this particular board. Besides, there are several broken
traces ;-(

You righ I didn't check this picture in details .
To bad for this board, yours others ones were good !

Here some questions form a noob side ;-)
(who wish to learn stuff before making to much errors )
I guess you used to much paste for the back.
Is it true that when you oven board chips place themself correctly over
traces ?
Might not work I guess if to much paste is used and if it flood few
traces togedther...

why do you have broken traces, is it because of heating in the oven ?
Expension and contraction of copper traces?

A smily noob

 

[Rich, Under the Affluence]

In the past I have been using the toner transfer iron on technique.
The best I have gotten is 75-80% of the board done ... the remaining
20 - 30% is rework for missing/broken traces etc.

I am just wondering what is the best hobby do-it-yourself method?

Someone hinted at photo transfer

What has worked for you guys in the past?
What gives the best results on a fairly consistent basis?
How about double sided boards?

I've only done this once, a thousand years or so ago, but I made my
originals on plastic with tape and a little bit of india ink. They
were 2X. I took them to a photo shop and got positives, six-up,
registered for double-sided. I stapled the negatives together, got
a piece of photosensitive board at Radio Shack, slid the board
between the negatives, and exposed it to the sun for about a half-
hour on each side. I don't remember what the next step was -
developing the resist and washing it, or some such, but then I
etched it in a cake pan with about an inch (2.5 cm) of Ferric
Chloride solution (also from RS - in their etch kit -- Hey! I
said it was a long time ago!), and did get a little bit of
undercutting, and drilling it right was very, very interesting,
but it did work. (the product died on the vine, however. )-; )

Good Luck!
Rich

 

[Erik Walthinsen]

Here some questions form a noob side ;-)
(who wish to learn stuff before making to much errors )
I guess you used to much paste for the back.

Yeah, it's interesting trying to get the right amount on the SSOP/QFP
packages. I have what's probably too big a needle to dispense, so I've
been using a dental pick to shove the paste around and try to get a
consistent amount.

Is it true that when you oven board chips place themself correctly over
traces?

I haven't seen any chips move, but it would surprise me if they didn't
move a little. Then again you can see that the CPLD didn't center
itself very well. I've definitely seen 1206 parts shuffle around a
little, probably as the solder melts from one side to the other.

Might not work I guess if to much paste is used and if it flood few
traces togedther...

Yeah, that's where the cleanup comes in. Small-tip temp-controlled
iron, very small solder wick, dental pick, and an acoustic continuity
checker with stickpins for probes. Oh, and lots of patience.

why do you have broken traces, is it because of heating in the oven ?
Expension and contraction of copper traces?

No, something went wrong in the transfer process and I foolishly figured
it wasn't a big enough problem. Issues like that seem to stem from a
few causes:

- not a consistent enough scratching up of the board before laminating
- fingerprints etc. at various stages
- bits of dust on the board between the toner and the copper
- impatient removal of the backing paper from the toner while soaking

 

[:-)]

Thanks

Another question,

Are you putting something on you board after it is finished,
vanish of some kind ?

 

[Deefoo]

1) *Laser* print the *positive* artwork onto the transfer paper, cut to

size and taped (Avery laser label bits) to a piece of backing paper
(both to feed into the laser, and for positioning).

Before you laser print anything definite do a test print! My experience with
(cheapish, I admit, Lexmark & Minolta) laser printers is that they do not
print 1:1 in both directions whereas my inkjet does.

--DF

 

[Erik Walthinsen]

Before you laser print anything definite do a test print! My experience with
(cheapish, I admit, Lexmark & Minolta) laser printers is that they do not
print 1:1 in both directions whereas my inkjet does.

Yup. I found that the laser I'm using (NEC Superscript 1400, retired
from office use due to feed problems) is 0.8% off horizontal, and I
haven't calibrated it for vertical yet. Makes a row of 20 pins across
not quite fit, though you can cheat by snapping them in a few places and
filing down period gaps.

 

[Erik Walthinsen]

Are you putting something on you board after it is finished,
vanish of some kind ?

Nope, just the Liquid Tin. Not sure I want to go the route of putting
paint on the board that I'll just have to smell as it burns off later...
These are all prototyping boards anyway, I'll be using a board house
to do later consolidated boards.

 

[Joerg]

Hello Sam,

Good point.
I tracked down the hazardous material depot in my county. I am going
to visit them some time next week to "unload" some used ferric
chloride

But please tell them honestly what it is that you bring. Else it can
cause accidents and contamination.

Regards, Joerg