Harvey,
? I looked at the pics. Nice job. Of course that means more questions though. I see the drill in some pics and the camera in other pics. What was the actual work flow?
Dave
toggle quoted message
Show quoted text
On 3/10/2019 3:45 PM, Harvey White wrote: On Sun, 10 Mar 2019 13:12:03 -0500, you wrote:
No hurry on the pics...it's Sunday. And yes, you have all the bases
covered. I like to try to do things right, but you look like you could
be the designer of some lucrative items.
Added the pictures to an album, DragonWorks Inverted PC board Drill.
Harvey
|
Officially retired? That is when your life usually gets even busier. :)
I have come up with a few ideas that in the end are usually more work than profit.
Did you lathe autostop? work on any lathe? Or only ones that already had a brake?
You seem like you would be a great teacher. :)
toggle quoted message
Show quoted text
On 3/10/2019 2:48 PM, Harvey White wrote: On Sun, 10 Mar 2019 13:12:03 -0500, you wrote:
No hurry on the pics...it's Sunday. And yes, you have all the bases
covered. I like to try to do things right, but you look like you could
be the designer of some lucrative items. Hmmmm, well, I'm retired, officially now, and marketing this stuff
would take a hobby and make it into a business. I'm not happy with
the thought.
The problem with many of the projects, in particular, the PC board
drill is that it uses some very expensive parts, although with China
providing linear rails, it would be less expensive. Then I'd have to
make kits, etc.
I could go and make the project in such a way that it used off the
shelf parts. Did that once with a lathe autostop for threading. I
don't think that anyone ever cared.
I'd rather help other people figure out how to do this stuff. I
prefer teaching someone how to fish than selling them.
I think I'll dig that drill out and set it up a little. Take a few
pictures....
Harvey
On 3/9/2019 7:09 PM, Harvey White wrote:
On Sat, 9 Mar 2019 18:18:11 -0600, you wrote:
You sound like a high tech kind of hobbyist. I like! :) Of course I
won't attempt that big of a project as I have many others on the back
burner already. But I still have a great interest in it. And I am a
hoarder in a sense so I have a lot of old electronics to salvage things
from. Looks like you accomplished your goal with this one. Great job! I'll try to upload pictures into a folder some time tomorrow (sunday
3/10/19).
Yeah, somewhat high tech here. Electronics lab with HP, tektronix,
fluke, (and others). Metcal soldering, binocular microscope, SMT
technology, FPGAs, CPLDs, ARM processors programmed in C (would have
done C++ but the manufacturer's firmware and tools don't like C++).
might as well be serious about it.... <grin>
Lets me do the bigger projects....
Harvey
Dave
On 3/9/2019 11:06 AM, Harvey White wrote:
On Sat, 9 Mar 2019 10:14:09 -0600, you wrote:
Harvey,
? Ok, so after re-reading this again, did you build this from scratch
or from exiting technologies? Scratch. The PC boards for the processor and display driver and so on
are home made double sided. I did not make the linear rail, bought
that. Camera ditto.
Stepper driver was homemade, another PC board, power supply wasn't.
Basic support stand wasn't homemade. Programming was a special
purpose program, don't think I used an operating system on this one.
however the display driver and such were off the shelf, but my shelf.
Box was repurposed from an old disk drive enclosure (which is where I
got the power supply).
Sounds like a pretty complex project. I
won't be attempting that any time soon. :) But I sure would like to see
a pic of it. I'll work on getting pictures of it.
My Apache Laminator arrived yesterday and the kit to modify
it the day before, so I am going to get started on that shortly. Your
project listed below is very cool but I don't know that I would ever
need to go that far into drilling my simple projects. I may see about
putting my USB magnifier to good use though as the eyes are getting older... The techniques I needed to be able to do 10/10 double sided boards
with relatively small vias, and those boards were pretty packed, at
least as far as traces were concerned.
I got tired of not having the top layer match the bottom layer. I
have some ruined boards because of that. Considering the work needed
to make a decent board, well, I wanted to maximize the return on the
effort.
Harvey
Thanks
On 3/8/2019 10:51 AM, Harvey White wrote:
On Fri, 8 Mar 2019 08:25:31 -0600, you wrote
So you use a tv camera now for your
drilling? I have one of those cheap USB cameras that is a magnifier. Is
that what you used? Actually, no. It's a bit more elaborate than that.
I have a linear rail that has about 6 inches of travel, then machined
a holder that holds the clamp for a proxxon drill. The 12 volt
version works just fine. That is driven by a linear stepper motor
(shaft attached, goes in and out of the motor).
That in turn is driven by an old, but standard design (L297/L298
stepper driver system). There are sensors on the linear rail for
bottom sensing and top sensing.
I found an old Pace desoldering stand, the kind used for a hot air
desolderer. It has a fixed height arm with a rack and pinion stage
for lowering the soldering tool.
Cut a hole in that base and mounted the proxxon upside down so it goes
through the center of the hole. Mounted an old vacuum cleaner nozzle
with a flexible extension so it removes debris from the underside.
On the top slide, I mounted a surveilance TV camera, this one runs on
12 volts too (most run on 24vac, and they're NOT kidding about the VAC
part because there's a small transformer in there that won't tolerate
DC). With an extender, it short focuses enough that I get
magnification. The small monitor is mounted above the camera.
The electronics allow you to home, and set maximum travel. Pressing a
footswitch starts a drill cycle, turns on the drill, moves it to the
up position, then back to a rest position.
You need to recalibrate the xy position each time you change the drill
bit, however.
With that, I can get very very close (say .001, I think) to the center
of a hole by using the crosshairs on the monitor. Some 3D printing
would help out the project, since the original design was to use the
vacuum to hold the board down once the drill bit moved up. That
didn't work as well.
So no, no USB camera. You could use one easily enough. The
electronics could be duplicated easily enough with an arduino, but I
used a board that was designed to run a small graphics display that I
had a few of....
So you get to see the position, and where it is in the cycle.
A bit of overkill, perhaps, but it has proven its worth in board
drilling. It does, by design, completely eliminate the parallax
problem which was a great inconvenience.
Harvey
|
HOME BREW PCBS
home brewing PCBs
in the home
brewing PCBs
sort of means to me that we are interested in home brewing a PCB
and as a hobby tinkerer will likely not purchase a $133 Sensitive
Drill Feed and 1/8" (3 mm) Keyless Drill Chuck
??? ???????
or any $1,000 micro-drill-press
unless of course you REALLY need one......
but
given the nature of this hobby and how easy it is to make home
brewed PCBs
and get the desired result using a $20 tool like:
I definitely am attracted to the idea of using a plunging drill
press motion for a DREMEL.
and
it never occurred to me to use foot control that would leave both
hands free to position the PCB.
On 03/11/2019 01:03 AM, Craig Lundquist
wrote:
toggle quoted message
Show quoted text
I don't think a cable or other foot
controlled mechanism is such a workable idea for the drill sizes
we are talking about. If you are not going to use a power feed
to get a precise and constant feed rate you need to be able to
feel what is going on or have a mechanism to precisely advance
the drill by tiny amounts (such as a fine screw feed) or you
will be breaking drills left and right. This is why they sell
sensitive feed attachments for use on regular drill presses with
small drills such as:
or sensitive drill presses such as .
I have an older Cameron drill and it works quite well for PCB
size drills. The reason I built the one shown in the photo album
and described in prior messages was to have a better method of
aligning the drill to where the hole needs to be drilled. It
does not use a power feed and the feel is more sensitive than
the Cameron drill, in part due to it being inverted with gravity
returning the drill to its "home" position and therefore no
return spring to compress and in part due to the linear stage
mechanism instead of a standard quill mechanism. The linear
slides and linear stages I mentioned in a pervious post are very
low friction. I don't know about some of the CNC or Z axis
assemblies sold on eBay which is another reason I would be wary
of using them.
?
Craig L
On Sun, Mar 10, 2019 at 08:43 PM, Rob wrote:
Brake cable foot pedal
drill press vertical control.... I like that idea. Thank
you.
Plus pulleys to make 4 to 1 advantage.....????? really got me
thinking on this.
?
On 03/10/2019 10:13 PM, Mike wrote:
Harvey,
? if
you want low cost for DIY and are willing to live with
less perfect tolerances, you could try the circular linear
bearings and precision metal rod like the reprap and
homebrew 3D printers use. Two 8mm rods mounted to a
vertical base, 4 circular bearings mounted to a smaller
plate that is just big enough to mount the drill onto and
drive mechanism to control plate movement.
?
One
could even eliminate the stepper motor and computer
control and for something purely mechanical and simple
like a spring return and foot pedal to pull the drill
down. That would be very simple to build from cheap,
available parts. A bike brake cable between the foot pedal
and the main base plate to drill slide would be enough.
Better would be to run the cable from where the sheath is
secured to the main base plate through a pulley on the
bottom of the drill slide, down through a second pulley on
the main base plate then back up to attach to the drill
plate. That will a 4 to 1 increase in pull (not needed)
and 4 to 1 decrease in movement to provide more precision
and control. Or just direct connect the cable ends and go
very carefully for that last 1/4 inch.
?
For a
vertically mounted camera just below the PCB and drill,
add a foot operated bellows next to the drill control
foot pedal to puff air across the camera lens. Still
leaves both hands free to manipulate the board.
--
"Creativity is intelligence having
fun." — Albert Einstein
|
I don't think a cable or other foot controlled mechanism is such a workable idea for the drill sizes we are talking about. If you are not going to use a power feed to get a precise and constant feed rate you need to be able to feel what is going on or have a mechanism to precisely advance the drill by tiny amounts (such as a fine screw feed) or you will be breaking drills left and right. This is why they sell sensitive feed attachments for use on regular drill presses with small drills such as: or sensitive drill presses such as . I have an older Cameron drill and it works quite well for PCB size drills. The reason I built the one shown in the photo album and described in prior messages was to have a better method of aligning the drill to where the hole needs to be drilled. It does not use a power feed and the feel is more sensitive than the Cameron drill, in part due to it being inverted with gravity returning the drill to its "home" position and therefore no return spring to compress and in part due to the linear stage mechanism instead of a standard quill mechanism. The linear slides and linear stages I mentioned in a pervious post are very low friction. I don't know about some of the CNC or Z axis assemblies sold on eBay which is another reason I would be wary of using them.
?
Craig L
On Sun, Mar 10, 2019 at 08:43 PM, Rob wrote:
Brake cable foot pedal drill press vertical control.... I like that idea. Thank you.
Plus pulleys to make 4 to 1 advantage.....????? really got me thinking on this.
?
On 03/10/2019 10:13 PM, Mike wrote:
Harvey,
? if you want low cost for DIY and are willing to live with less perfect tolerances, you could try the circular linear bearings and precision metal rod like the reprap and homebrew 3D printers use. Two 8mm rods mounted to a vertical base, 4 circular bearings mounted to a smaller plate that is just big enough to mount the drill onto and drive mechanism to control plate movement.
?
One could even eliminate the stepper motor and computer control and for something purely mechanical and simple like a spring return and foot pedal to pull the drill down. That would be very simple to build from cheap, available parts. A bike brake cable between the foot pedal and the main base plate to drill slide would be enough. Better would be to run the cable from where the sheath is secured to the main base plate through a pulley on the bottom of the drill slide, down through a second pulley on the main base plate then back up to attach to the drill plate. That will a 4 to 1 increase in pull (not needed) and 4 to 1 decrease in movement to provide more precision and control. Or just direct connect the cable ends and go very carefully for that last 1/4 inch.
?
For a vertically mounted camera just below the PCB and drill, add a foot operated bellows next to the drill control foot pedal to puff air across the camera lens. Still leaves both hands free to manipulate the board.
--
"Creativity is intelligence having fun." — Albert Einstein
|
Brake cable foot pedal drill press vertical
control.... I like that idea. Thank you.
Plus pulleys to make 4 to 1
advantage.....????? really got me thinking on this.
On 03/10/2019 10:13 PM, Mike wrote:
toggle quoted message
Show quoted text
Harvey,
? if you want
low cost for DIY and are willing to live with less perfect
tolerances, you could try the circular linear bearings and
precision metal rod like the reprap and homebrew 3D printers
use. Two 8mm rods mounted to a vertical base, 4 circular
bearings mounted to a smaller plate that is just big enough to
mount the drill onto and drive mechanism to control plate
movement.
One could
even eliminate the stepper motor and computer control and for
something purely mechanical and simple like a spring return
and foot pedal to pull the drill down. That would be very
simple to build from cheap, available parts. A bike brake
cable between the foot pedal and the main base plate to drill
slide would be enough. Better would be to run the cable from
where the sheath is secured to the main base plate through a
pulley on the bottom of the drill slide, down through a second
pulley on the main base plate then back up to attach to the
drill plate. That will a 4 to 1 increase in pull (not needed)
and 4 to 1 decrease in movement to provide more precision and
control. Or just direct connect the cable ends and go very
carefully for that last 1/4 inch.
For a
vertically mounted camera just below the PCB and drill, add
a foot operated bellows next to the drill control foot pedal
to puff air across the camera lens. Still leaves both hands
free to manipulate the board.
--
"Creativity
is intelligence having fun." — Albert Einstein
|
On Sun, 10 Mar 2019 19:13:14 -0700, you wrote: Harvey,
if you want low cost for DIY and are willing to live with less perfect
tolerances, you could try the circular linear bearings and precision metal
rod like the reprap and homebrew 3D printers use. Two 8mm rods mounted to a
vertical base, 4 circular bearings mounted to a smaller plate that is just
big enough to mount the drill onto and drive mechanism to control plate
movement.
Got some of them. Likely to use that to make a board holder for a PC board preheater for rework. I had (one of) the particular linear slide, so I used it. (see pictures). One could even eliminate the stepper motor and computer control and for
something purely mechanical and simple like a spring return and foot pedal
to pull the drill down. That would be very simple to build from cheap,
available parts. What? Simple? *hack* *hack*.... Seriously enough, I had the linear stepper (someone had butchered the shaft), already had the stepper driver, had the power supply and box, used an existing Mega PC board and display driver. I think I had to make some small adaptor boards, but those weren't all that bad to do. A bike brake cable between the foot pedal and the main
base plate to drill slide would be enough. Better would be to run the cable
from where the sheath is secured to the main base plate through a pulley on
the bottom of the drill slide, down through a second pulley on the main
base plate then back up to attach to the drill plate. That will a 4 to 1
increase in pull (not needed) and 4 to 1 decrease in movement to provide
more precision and control. Or just direct connect the cable ends and go
very carefully for that last 1/4 inch. A choke cable for a lawnmower would also do it, I think.
For a vertically mounted camera just below the PCB and drill, add a foot
operated bellows next to the drill control foot pedal to puff air across
the camera lens. Still leaves both hands free to manipulate the board.
If I were to do that, I'd still want upside down and mount the camera over the board. However, it depends on whether or not you want to have the drill automated. Taking your design, you could put a mirror under a plate, mount the camera horizontally, and then just make it a stage on a microscope type of replacement for the base of the drill press. All you're building is the camera/optics, using the top for the drill press table. All you'd need is a fast enough drill press. If they weren't so expensive, an old unimat could be set up to do just this. (has a higher speed spindle). Nice ideas, and nowhere near so technology based. Harvey
|
Harvey, ? if you want low cost for DIY and are willing to live with less perfect tolerances, you could try the circular linear bearings and precision metal rod like the reprap and homebrew 3D printers use. Two 8mm rods mounted to a vertical base, 4 circular bearings mounted to a smaller plate that is just big enough to mount the drill onto and drive mechanism to control plate movement.
One could even eliminate the stepper motor and computer control and for something purely mechanical and simple like a spring return and foot pedal to pull the drill down. That would be very simple to build from cheap, available parts. A bike brake cable between the foot pedal and the main base plate to drill slide would be enough. Better would be to run the cable from where the sheath is secured to the main base plate through a pulley on the bottom of the drill slide, down through a second pulley on the main base plate then back up to attach to the drill plate. That will a 4 to 1 increase in pull (not needed) and 4 to 1 decrease in movement to provide more precision and control. Or just direct connect the cable ends and go very carefully for that last 1/4 inch.
For a vertically mounted camera just below the PCB and drill, add a foot operated bellows next to the drill control foot pedal to puff air across the camera lens. Still leaves both hands free to manipulate the board.
-- "Creativity is intelligence having fun." — Albert Einstein
|
Photo Resist Preparation - thanks for the suggestions
Hello,
Thanks to all who provided suggestions on how to eliminate or get rid of air bubbles between the photo resist and PCB. ?
?Already from the initial look at some of the suggestions I'm finding additional information of how I can improve my application of using the photo resist technique to make printed circuit boards.? Look forward to reviewing all of the suggested material.
Again, thanks for all the good suggestions and sharing your experience.
?? V/R, ?? Mike, K4GMH
-- Mike, K4GMH
|
Hamfests still go on. There was just a very large one yesterday near me, at the Washington State Fairgrounds. There are many more smaller ones around, too, as small as a parking lot and people selling out of their trunks (or a boot sale, if you are from the UK).
You can search for them on the ARRL website, for a start.
http://www.arrl.org/hamfests-and-conventions-calendar
--
Steven Greenfield AE7HD
|
Re: Photo Resist Preparation
I've used photoresist film for the past 8 years or so. I mostly work with brass and stainless steel sheets that are 6 x 12 inches wide and .015 inch thick creating artsy bits of stuff. I've made a few circuit boards for friends, and some other thinner designs over the years. What I'm saying is - I've used the film for a long time and might be able to help.
?
The best way is to clean your work table. Use a spray bottle and spray your work area with water. Clean your board with soap and hot water. Rinse and put on your work area. Peel off the back layer of the film. Put it on your work area with the peeled side up. Spray both board and resist with filtered water (no debris). Flip the resist onto the board. Squeegee several times looking to get bubbles out. I'd they don't come right out, you can peel back the resist and reapply. Sometimes there are flakes that get on the film. Use your finger to slide it off the film. This is the first part. If everything at this point is bubble free, you're not out of the woods just yet.
?
Put your board between 2 pieces of paper and tape the edge that goes through the laminator first. Check the specs to see how hot the laminator should be and put the paper with your board in the laminator when it's heated up to the right temp. If your laminator is too hot, or if you run it through several times, you may get bubbles that weren't there before.
?
Now you have a laminated board that still if everything was done to the best of your abilities, may still have a bubble. If that happens, the best thing to do is get an x-acto knife and poke (not cut) a hole in the middle of the bubble. Use your finger to push the film flat. Most of the time this works without issue. The finger pressure might be enough to adhere the film to the board, ?or you may want to put it through the laminator again on lower or no heat at all. Sometimes finger pressure at this stage is enough. Excessive heat causes bubbles.
?
Sorry to be so wordy, but this is an issue even with 2 inch pieces that I make. Bubbles are a pain, but they can be dealt with.
?
Sven
|
When I did my upside down drill I started with miniature precision
drill press that can drill with 0.010" carbide drills -- so runout
is extremely low.? Then milled the table underside? with a larger
cavity under the hole in the base for the drill to go thru.?
Plugging into my laptop a simple USB webcam camera with adjustable
lens that could focus down to about 3/4"inch and a? led ring around
the lens for lighting.? Because the spindle/motor combination is
moved on the fixed post from the base and as I move it occasionally
for other types of drilling, the optical alignment is subject to
change.? Also coupled with fact I did this quickly so he camera
mounting is rather slip shod and leaves something to be desired.?
Centering, focusing, and angular are all touchy.?
The solution I came up with was to cut a 3 or 4" square flat piece
of transparent plastic out of the lid of an old used? container for
things like lettuce, some take out containers, etc.? that is
typically PET recycled from soda bottles.? Tape this to the drill
table.? Setup your drill, then drill one hole through the plastic.?
Now you know absolutely where the drill is going in the image of
your camera.? Place the PCB upside down and center your pad on the
hole and drill away.? It becomes very easy to get the drill exactly
right especially if you focus closely enough that the image on your
laptop is a magnified image of the hole. The plastic is cheap
(actually free as it's being re-purposed) and until you move the
drill/motor relationship to the table does not require changing or
moving.?
I like Mike's solution with a 45 degree mirror as that would help
with the small amount of drilling debris that comes down on the
lens, but that mirror would also cause you to be further away from
the board hence the hole image would be getting smaller in the
screen. There are camera optics that can work at a distance with
high magnification, but they take you out of the cheap solution
class. ? Debris happens, but my experience it's never really been a
big problem as the debris goes up above the PCB due to the drill
flutes doing their job.? When it does get to be enough, a quick air
blast cleans it out and drilling resumes.
Regards,
Charles R Patton
On 3/10/2019 11:32 AM, Dave wrote:
toggle quoted message
Show quoted text
Mike, do you have any pics? I just bought a Proxxon drill press
and will be using a 10mm Jumbo LED in (below) the hole in the
base. Underwater ROV's...interesting. My neighbor just gave me a
flat screen monitor that didn't have HDMI for his ROKU plans. I
took it as it have all the RCA inputs and I figured it would be
good for something someday.
Thanks
On 3/9/2019 2:09 AM, Mike wrote:
I have use
a similar but opposite system myself. I have been playing
with under water ROVs for some time now and part of that
requires video cameras for which I typically use the 12V,
composite video, board camera modules. For mine I mounted
the camera horizontally, mounted a mirror at a 45 degree
angle in front of it then clamped it below the table of a HF
bench top drill press. Took a few tries to get the camera
centered under the center hole and I put some tape to mark
the center point on the old TV I used for the display.
With a
clamp-on work light on top shinning down on the board it was
almost like a live X-ray, I could clearly see the traces on
both sides and it seemed like I could even see some light
through the traces themselves. It quickly showed how bad the
two sided etching had gone but also allowed you to shoot for
the overlap region. It also should that the drill press
quill was not well aligned and that there was probably some
runout due to the chuck being slightly angled from the
shaft, but then again it was a bottom priced HF so these
things are pretty much a given anyhow.
Mounting
the camera off to the side with only the angled mirror under
the holes eliminated the need for a vacuum and also meant
that I could easily mount/unmount boards or position them by
hand for each hole so that I had more control. Also the top
side was open and clearly visible so I could switch back and
forth between TV screen and looking straight at the board
and drill bit.
The CMOS
camera modules are about a inch cubed and are typically
$40. There are similar USB cameras but they tie up a whole
computer, not just a throw away old tv set.
--
"Creativity
is intelligence having fun." — Albert Einstein
|
Re: Photo Resist Preparation
James,
I think we were both doing the same thing at the same time. It
was just a matter of who posted first.
On 3/10/2019 1:30 PM, James wrote:
toggle quoted message
Show quoted text
Sorry my reply wasn't intended as a reply to Harvey's post
specifically, Gmail is a bit misleading when it comes to
replying to threads.? Also didn't notice Harvey had already
linked to my tips :-)
On Mon, Mar 11, 2019 at 9:20
AM James via Groups.Io <bitsyboffin= [email protected]>
wrote:
On Mon, Mar 11, 2019 at
8:48 AM Harvey Altstadter < hrconsult@...>
wrote:
|
On Sun, 10 Mar 2019 13:12:03 -0500, you wrote: No hurry on the pics...it's Sunday. And yes, you have all the bases
covered. I like to try to do things right, but you look like you could
be the designer of some lucrative items.
Added the pictures to an album, DragonWorks Inverted PC board Drill. Harvey
|
Re: Photo Resist Preparation
Sorry my reply wasn't intended as a reply to Harvey's post specifically, Gmail is a bit misleading when it comes to replying to threads.? Also didn't notice Harvey had already linked to my tips :-)
On Mon, Mar 11, 2019 at 9:20 AM James via Groups.Io <bitsyboffin= [email protected]> wrote: On Mon, Mar 11, 2019 at 8:48 AM Harvey Altstadter < hrconsult@...> wrote:
|
Re: Photo Resist Preparation
As described in my tips document
?
I find a mister bottle of water is the best way.? Mist the cleaned PCB with water, don't need much, lay the film down preferably making first contact in the middle, squeeze out the water and bubbles with a squeegee from the middle out, then clothes iron/hot air to bond the film.? You can pull up and reposition to a degree before you apply heat.? Clothes iron must be only warm, too hot and the moisture will make a mess of things, just warm and the film will adhere fine.? Laminator would work fine too I expect if you use one already, I have one somewhere but find clothes iron more convenient.
I just use a wad of paper towel for my squeegee, not an actual squeegee.
bigclivedotcom on youtube has shown similar method to mine a number of times if you search his videos for ones where he makes a PCB in the last couple years (before that he used pre-sensitised boards).
On Mon, Mar 11, 2019 at 8:48 AM Harvey Altstadter < hrconsult@...> wrote:
Mike,
Even though it goes without saying, your boards must be cleaner
than clean for this to work. Small particles will lift the film.
One tip that shows up repeatedly is to test the cleanliness of the
board by spraying a light layer of water on the surface to be
laminated. If the board is reasonably clean, it will support a
continuous film of water. The film will pull away from spots that
have oil or grease, and from around particles. The water you use
must be clean enough that it doesn't introduce particles on it's
own. Filtered or distilled water should do the trick.
As I read your post, I remembered that I saw some processes for
dry film application. You didn't mention if you wet the film/board
before application, but I remember seeing a few posts somewhere
about that.
I did a search, and found this one on Instructables:
.
The first part seems to be a justification for how the OP arrived
at the process, and can be skipped. This method seems to be very
flexible in terms of the ability to go back and re do if there a
problem, but it is very labor intensive.
Here is a second article, rather verbose, but he also uses a wet
method:
This page from Dupont has a PDF titled "Riston Processing Guide"
that talks about cleaning and laminating, among other things:
Think and Tinker has a very complete manual on PCB production,
including a section of Dry Film laminating. Find them here:
I hope this helps
(The other) Harvey
On 3/10/2019 9:22 AM, Michael Sims
wrote:
Hello,
Recently,
started using photo resist technique for making printed
circuit boards (PCB).? One of the steps in this technique I'm
having difficulty with, is making sure there are no air
bubbles between the photo resist sheet and the PCB.? So far
I've only been successful on small boards, 4" x 5", 3" x 6",
etc? in clearing the air bubbles, but not larger boards,
e.g.,? 6" x 8".? I would like to use the photo resist
technique to make larger boards in the 8" x 11" range but, I'm
hesitant to try due to my lack of understanding of how to
remove all air bubbles on the larger boards.?
I've made a
6" x 8" board but, could not remove all the small air bubbles,
approximately 1/8" dia. or less,? between the photo resist
sheet and the PCB.? The board did turn out okay but, believe I
got "lucky" with no small air bubbles on any of the traces or
component pads.? Prior to being exposed to the UV light the
PCB with the photo resist sheet was run through a laminator
but, the remaining small bubbles were not removed.? Not sure
my luck would hold if tried to make another 6" x 8" board.?
I have used
toner transfer for larger boards, but had too many broken
traces and spotty transfer of the toner on the board.? Neither
using a clothes iron nor a variable temperature laminator gave
consistent good transfer of the toner to the larger boards.?
YouTube was
searched for an answer and a number of videos on making PCBs
using the photo resist technique have been reviewed.? However,
only small boards, less than 6" x 8", were in the videos.?
There were several different approaches used to get the photo
resist on to the board and removing air bubbles, but again,
these approaches were used for less than 6" x 8" PCBs.? I'm
sure I haven't seen all the YouTube videos on making PCB using
photo resist, so maybe there is one or more showing how to
apply the photo resist to the larger PCBs and end up without
any air bubbles, small or large, between the photo resist and
the PCB.?
? V/R,
? Mike, K4GMH
--
Mike, K4GMH
|
Re: Photo Resist Preparation
Mike,
Even though it goes without saying, your boards must be cleaner
than clean for this to work. Small particles will lift the film.
One tip that shows up repeatedly is to test the cleanliness of the
board by spraying a light layer of water on the surface to be
laminated. If the board is reasonably clean, it will support a
continuous film of water. The film will pull away from spots that
have oil or grease, and from around particles. The water you use
must be clean enough that it doesn't introduce particles on it's
own. Filtered or distilled water should do the trick.
As I read your post, I remembered that I saw some processes for
dry film application. You didn't mention if you wet the film/board
before application, but I remember seeing a few posts somewhere
about that.
I did a search, and found this one on Instructables:
.
The first part seems to be a justification for how the OP arrived
at the process, and can be skipped. This method seems to be very
flexible in terms of the ability to go back and re do if there a
problem, but it is very labor intensive.
Here is a second article, rather verbose, but he also uses a wet
method:
This page from Dupont has a PDF titled "Riston Processing Guide"
that talks about cleaning and laminating, among other things:
Think and Tinker has a very complete manual on PCB production,
including a section of Dry Film laminating. Find them here:
I hope this helps
(The other) Harvey
On 3/10/2019 9:22 AM, Michael Sims
wrote:
toggle quoted message
Show quoted text
Hello,
Recently,
started using photo resist technique for making printed
circuit boards (PCB).? One of the steps in this technique I'm
having difficulty with, is making sure there are no air
bubbles between the photo resist sheet and the PCB.? So far
I've only been successful on small boards, 4" x 5", 3" x 6",
etc? in clearing the air bubbles, but not larger boards,
e.g.,? 6" x 8".? I would like to use the photo resist
technique to make larger boards in the 8" x 11" range but, I'm
hesitant to try due to my lack of understanding of how to
remove all air bubbles on the larger boards.?
I've made a
6" x 8" board but, could not remove all the small air bubbles,
approximately 1/8" dia. or less,? between the photo resist
sheet and the PCB.? The board did turn out okay but, believe I
got "lucky" with no small air bubbles on any of the traces or
component pads.? Prior to being exposed to the UV light the
PCB with the photo resist sheet was run through a laminator
but, the remaining small bubbles were not removed.? Not sure
my luck would hold if tried to make another 6" x 8" board.?
I have used
toner transfer for larger boards, but had too many broken
traces and spotty transfer of the toner on the board.? Neither
using a clothes iron nor a variable temperature laminator gave
consistent good transfer of the toner to the larger boards.?
YouTube was
searched for an answer and a number of videos on making PCBs
using the photo resist technique have been reviewed.? However,
only small boards, less than 6" x 8", were in the videos.?
There were several different approaches used to get the photo
resist on to the board and removing air bubbles, but again,
these approaches were used for less than 6" x 8" PCBs.? I'm
sure I haven't seen all the YouTube videos on making PCB using
photo resist, so maybe there is one or more showing how to
apply the photo resist to the larger PCBs and end up without
any air bubbles, small or large, between the photo resist and
the PCB.?
? V/R,
? Mike, K4GMH
--
Mike, K4GMH
|
On Sun, 10 Mar 2019 13:12:03 -0500, you wrote: No hurry on the pics...it's Sunday. And yes, you have all the bases
covered. I like to try to do things right, but you look like you could
be the designer of some lucrative items. Hmmmm, well, I'm retired, officially now, and marketing this stuff would take a hobby and make it into a business. I'm not happy with the thought. The problem with many of the projects, in particular, the PC board drill is that it uses some very expensive parts, although with China providing linear rails, it would be less expensive. Then I'd have to make kits, etc. I could go and make the project in such a way that it used off the shelf parts. Did that once with a lathe autostop for threading. I don't think that anyone ever cared. I'd rather help other people figure out how to do this stuff. I prefer teaching someone how to fish than selling them. I think I'll dig that drill out and set it up a little. Take a few pictures.... Harvey
On 3/9/2019 7:09 PM, Harvey White wrote:
On Sat, 9 Mar 2019 18:18:11 -0600, you wrote:
You sound like a high tech kind of hobbyist. I like! :) Of course I
won't attempt that big of a project as I have many others on the back
burner already. But I still have a great interest in it. And I am a
hoarder in a sense so I have a lot of old electronics to salvage things
from. Looks like you accomplished your goal with this one. Great job! I'll try to upload pictures into a folder some time tomorrow (sunday
3/10/19).
Yeah, somewhat high tech here. Electronics lab with HP, tektronix,
fluke, (and others). Metcal soldering, binocular microscope, SMT
technology, FPGAs, CPLDs, ARM processors programmed in C (would have
done C++ but the manufacturer's firmware and tools don't like C++).
might as well be serious about it.... <grin>
Lets me do the bigger projects....
Harvey
Dave
On 3/9/2019 11:06 AM, Harvey White wrote:
On Sat, 9 Mar 2019 10:14:09 -0600, you wrote:
Harvey,
? Ok, so after re-reading this again, did you build this from scratch
or from exiting technologies? Scratch. The PC boards for the processor and display driver and so on
are home made double sided. I did not make the linear rail, bought
that. Camera ditto.
Stepper driver was homemade, another PC board, power supply wasn't.
Basic support stand wasn't homemade. Programming was a special
purpose program, don't think I used an operating system on this one.
however the display driver and such were off the shelf, but my shelf.
Box was repurposed from an old disk drive enclosure (which is where I
got the power supply).
Sounds like a pretty complex project. I
won't be attempting that any time soon. :) But I sure would like to see
a pic of it. I'll work on getting pictures of it.
My Apache Laminator arrived yesterday and the kit to modify
it the day before, so I am going to get started on that shortly. Your
project listed below is very cool but I don't know that I would ever
need to go that far into drilling my simple projects. I may see about
putting my USB magnifier to good use though as the eyes are getting older... The techniques I needed to be able to do 10/10 double sided boards
with relatively small vias, and those boards were pretty packed, at
least as far as traces were concerned.
I got tired of not having the top layer match the bottom layer. I
have some ruined boards because of that. Considering the work needed
to make a decent board, well, I wanted to maximize the return on the
effort.
Harvey
Thanks
On 3/8/2019 10:51 AM, Harvey White wrote:
On Fri, 8 Mar 2019 08:25:31 -0600, you wrote
So you use a tv camera now for your
drilling? I have one of those cheap USB cameras that is a magnifier. Is
that what you used? Actually, no. It's a bit more elaborate than that.
I have a linear rail that has about 6 inches of travel, then machined
a holder that holds the clamp for a proxxon drill. The 12 volt
version works just fine. That is driven by a linear stepper motor
(shaft attached, goes in and out of the motor).
That in turn is driven by an old, but standard design (L297/L298
stepper driver system). There are sensors on the linear rail for
bottom sensing and top sensing.
I found an old Pace desoldering stand, the kind used for a hot air
desolderer. It has a fixed height arm with a rack and pinion stage
for lowering the soldering tool.
Cut a hole in that base and mounted the proxxon upside down so it goes
through the center of the hole. Mounted an old vacuum cleaner nozzle
with a flexible extension so it removes debris from the underside.
On the top slide, I mounted a surveilance TV camera, this one runs on
12 volts too (most run on 24vac, and they're NOT kidding about the VAC
part because there's a small transformer in there that won't tolerate
DC). With an extender, it short focuses enough that I get
magnification. The small monitor is mounted above the camera.
The electronics allow you to home, and set maximum travel. Pressing a
footswitch starts a drill cycle, turns on the drill, moves it to the
up position, then back to a rest position.
You need to recalibrate the xy position each time you change the drill
bit, however.
With that, I can get very very close (say .001, I think) to the center
of a hole by using the crosshairs on the monitor. Some 3D printing
would help out the project, since the original design was to use the
vacuum to hold the board down once the drill bit moved up. That
didn't work as well.
So no, no USB camera. You could use one easily enough. The
electronics could be duplicated easily enough with an arduino, but I
used a board that was designed to run a small graphics display that I
had a few of....
So you get to see the position, and where it is in the cycle.
A bit of overkill, perhaps, but it has proven its worth in board
drilling. It does, by design, completely eliminate the parallax
problem which was a great inconvenience.
Harvey
|
Re: Photo Resist Preparation
Try wet lamination. One person on the net describes submerging both the film and the board completely in water, another just sprays some water on the board. I have only experimented a little with the photosensitive film. Spraying a small amount of water and working any bubbles with a squeegee before laminating does seem to work. One person said to let the board dry overnight, however in their literature Dupont states that if you use wet lamination the board should be processed "without delay". Even if you are not using Dupont (Riston) film you may find some of their instructions and information useful in working out a process that works for you.?
?
Start with:
f
?
Some of their other product specific literature may also be worth looking at. If you work out a process that works for you please post your results.
?
Craig L
On Sun, Mar 10, 2019 at 09:22 AM, Michael Sims wrote:
Hello,
?
Recently, started using photo resist technique for making printed circuit boards (PCB).? One of the steps in this technique I'm having difficulty with, is making sure there are no air bubbles between the photo resist sheet and the PCB.? So far I've only been successful on small boards, 4" x 5", 3" x 6", etc? in clearing the air bubbles, but not larger boards, e.g.,? 6" x 8".? I would like to use the photo resist technique to make larger boards in the 8" x 11" range but, I'm hesitant to try due to my lack of understanding of how to remove all air bubbles on the larger boards.?
?
I've made a 6" x 8" board but, could not remove all the small air bubbles, approximately 1/8" dia. or less,? between the photo resist sheet and the PCB.? The board did turn out okay but, believe I got "lucky" with no small air bubbles on any of the traces or component pads.? Prior to being exposed to the UV light the PCB with the photo resist sheet was run through a laminator but, the remaining small bubbles were not removed.? Not sure my luck would hold if tried to make another 6" x 8" board.?
?
I have used toner transfer for larger boards, but had too many broken traces and spotty transfer of the toner on the board.? Neither using a clothes iron nor a variable temperature laminator gave consistent good transfer of the toner to the larger boards.?
?
YouTube was searched for an answer and a number of videos on making PCBs using the photo resist technique have been reviewed.? However, only small boards, less than 6" x 8", were in the videos.? There were several different approaches used to get the photo resist on to the board and removing air bubbles, but again, these approaches were used for less than 6" x 8" PCBs.? I'm sure I haven't seen all the YouTube videos on making PCB using photo resist, so maybe there is one or more showing how to apply the photo resist to the larger PCBs and end up without any air bubbles, small or large, between the photo resist and the PCB.?
?
? V/R,
? Mike, K4GMH
--
Mike, K4GMH
|
Re: Photo Resist Preparation
You will find things much easier if you use precoated laminate.
|
Mike, do you have any pics? I just bought a Proxxon drill press
and will be using a 10mm Jumbo LED in (below) the hole in the
base. Underwater ROV's...interesting. My neighbor just gave me a
flat screen monitor that didn't have HDMI for his ROKU plans. I
took it as it have all the RCA inputs and I figured it would be
good for something someday.
Thanks
On 3/9/2019 2:09 AM, Mike wrote:
toggle quoted message
Show quoted text
I have use a
similar but opposite system myself. I have been playing with
under water ROVs for some time now and part of that requires
video cameras for which I typically use the 12V, composite
video, board camera modules. For mine I mounted the camera
horizontally, mounted a mirror at a 45 degree angle in front
of it then clamped it below the table of a HF bench top drill
press. Took a few tries to get the camera centered under the
center hole and I put some tape to mark the center point on
the old TV I used for the display.
With a
clamp-on work light on top shinning down on the board it was
almost like a live X-ray, I could clearly see the traces on
both sides and it seemed like I could even see some light
through the traces themselves. It quickly showed how bad the
two sided etching had gone but also allowed you to shoot for
the overlap region. It also should that the drill press quill
was not well aligned and that there was probably some runout
due to the chuck being slightly angled from the shaft, but
then again it was a bottom priced HF so these things are
pretty much a given anyhow.
Mounting the
camera off to the side with only the angled mirror under the
holes eliminated the need for a vacuum and also meant that I
could easily mount/unmount boards or position them by hand for
each hole so that I had more control. Also the top side was
open and clearly visible so I could switch back and forth
between TV screen and looking straight at the board and drill
bit.
The CMOS
camera modules are about a inch cubed and are typically $40.
There are similar USB cameras but they tie up a whole
computer, not just a throw away old tv set.
--
"Creativity
is intelligence having fun." — Albert Einstein
_._,_._,_
|
Steven Greenfield AE7HD
Leon