Cutting mylar stencils with a silohuette cameo

Reflow ovens, hot plates, pick and place machines, test rigs, solder stencils. Small scale manufacturing and prototyping tool discussion.

Re: Cutting mylar stencils with a silohuette cameo

Postby timb » Mon May 20, 2013 9:56 pm

Interestingly enough, I'm having a hard time getting gerber2graphtec working with the Craft Robo Pro. It speaks GPGL just like the SD/Cameo, so that shouldn't be an issue. What's happening is it's feeding the page back out the front and asking to "Reload Media" after each stroke of the blade.
timb
Newbie
Newbie
 
Posts: 24
Joined: Sat May 18, 2013 8:09 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby xl97 » Tue May 21, 2013 9:43 pm

hey guys..

well thanks to everyone's help and all the links and reading..etc.. I have some of my own results to report/show.. :)

I wont go into the Windows settings/as thats all been posted here already..

but I have some (what Im referring to as) Idle Loop approach test results:

*this is using the ULP script for CADSoft Eagle to export a .dxf file from your CREAM layer.
*'did' cut all the way through on mylar setting, but same results as most people posted using this approach...(would probably work in a pinch)

Image

Image


Of course the big 'hub-bub is about the 'gerbertographtec' Python approach.. as it has/does much cleaner looking cuts

I tried different settings with blade on setting: 1

*never got a penetrating cut
*not usable

2-passes:
Image

Image


3-passes tried: (same results, no penetrating cut)

Image

Image

as you can see though.. the cuts (outlines) are much crisper/straighter, the pics dont do it justice with the shadow and not being cut out all the way..



bumped up the blade setting to: 2

*but needed to SHRINK the CREAM layer as mentioned.. (this was really a key piece for me, and could only get it down to 4mil shrinkage)

*finally penetrating cuts!
*useable, clean..

*light force pressure on second pass:
Image

*medium force pressure on second pass:
Image

Image



these tests were performed on mylar that I cut off some Pololu stencils for testing..

I am currently testing Apollo Write-On transparencies as well.. (first test cut didnt penetrate either.. blade setting was: 2)

bumped up to: '3' and am re-cutting as now....9:45pm (central time) :)


Apollo test 1 = fail (no penetration again)

I looked at blade.. (seemed to have point still... but noticed it was logged a bit with some vinyl...

YIKES!.. I cleaned it out.. and am re-running the Apollo test again...
xl97
Newbie
Newbie
 
Posts: 31
Joined: Fri May 17, 2013 10:42 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby teletypeguy » Wed May 22, 2013 12:21 am

Hey Jerry: Glad to see you are getting some good cuts now. Not sure why blade depth of 1 did not penetrate for you, but maybe it is related to your mylar -- jesuscf had Canon mylar that was the same thickness as Apollo stuff, but was apparently a tougher plastic and did not cut well.

You can also use the sil-studio program to test material, even little scraps. Load a bit of test material (anywhere on the mat really), fire up sil-studio, and in the send-to-cameo dialog there is a button for a test cut. Use the blue cursor buttons on the cameo to move the knife to where you want to cut, and click test cut. It cuts out a little square with a triangle inside -- you can move the head out of the way (or unload the mat) and dig out the square with an xacto, or peel of your samlple. This is a good way to try different blade depths for different materials.

Are you sure you shrunk your cream layer? I thought I had at first but got the same results -- then I used gcprevue, imported just the top-copper and solderpaste layers (which gcprevue assigns different colors). You want the layer list on the left to have paste above copper (if not drag one layer above/below the other). Zoom in and then you can see clearly whether your paste is shrunken (?), shrinked (?), ahh, reduced-in-size, as you expect.

So, is this little round board going in the nosecone of a rocket?

gil
User avatar
teletypeguy
Jr. Member
Jr. Member
 
Posts: 60
Joined: Tue Mar 26, 2013 12:04 am

Re: Cutting mylar stencils with a silohuette cameo

Postby teletypeguy » Wed May 22, 2013 12:23 am

Andre:

Thanks for your modified optimize.py -- I'll play with that a bit.
User avatar
teletypeguy
Jr. Member
Jr. Member
 
Posts: 60
Joined: Tue Mar 26, 2013 12:04 am

Re: Cutting mylar stencils with a silohuette cameo

Postby xl97 » Wed May 22, 2013 12:51 am

teletypeguy wrote:Hey Jerry: Glad to see you are getting some good cuts now. Not sure why blade depth of 1 did not penetrate for you, but maybe it is related to your mylar -- jesuscf had Canon mylar that was the same thickness as Apollo stuff, but was apparently a tougher plastic and did not cut well.

You can also use the sil-studio program to test material, even little scraps. Load a bit of test material (anywhere on the mat really), fire up sil-studio, and in the send-to-cameo dialog there is a button for a test cut. Use the blue cursor buttons on the cameo to move the knife to where you want to cut, and click test cut. It cuts out a little square with a triangle inside -- you can move the head out of the way (or unload the mat) and dig out the square with an xacto, or peel of your samlple. This is a good way to try different blade depths for different materials.

Are you sure you shrunk your cream layer? I thought I had at first but got the same results -- then I used gcprevue, imported just the top-copper and solderpaste layers (which gcprevue assigns different colors). You want the layer list on the left to have paste above copper (if not drag one layer above/below the other). Zoom in and then you can see clearly whether your paste is shrunken (?), shrinked (?), ahh, reduced-in-size, as you expect.

So, is this little round board going in the nosecone of a rocket?

gil


I have been doing alot of testing..but not 'sure' when the blade got some vinyl in it.. (not sure how skewed my data/results are now?)
either way I swapped out with my replacement/new blade.. and gave it a test again..

on Apollo transparency sheets now (write-on type..I believe to be same brand/type tested with previously here)

after new blade.. blade setting 3 was 'too' much.. ripped/merged holes..etc

blade setting two 'did' result in full penetration..

2-pass
(new blade)
Blade setting: 2
Speed: 1, 1
Force: 8, 16

I got full through cuts..

Im not sure if I should drop to blade setting of 1, and try again?
or keep blade setting of two.. and try light 'force' values?

(if I do a single pass, do I "ONLY" have to have 1 value in the speed & force parameters? (I havent touched the others before, border or matrix..etc..etc)

this Apollo stuff seems much stronger.. and a bit more 'brittle' (at a certain point too.. if that makes sense..LOL)..

Im hoping its good for cuts and keeping shape..etc..


Good point with the Cameo test cuts!!!

Im new to the Cameo in general, as a whole.. I have only cut 3 vinyl pieces:

Image


and the rest has been working playing with stencil stuff right out of the box! :)

I wish the pcb was for a rocket something 'er other! lol.. sounds like some fun! woot!..

but alas.. not as adrenaline pumping at that.. :)

was the end result of a 'goal/project' I gave myself.. to retro fit a Spider-Man webshooter prop with some electronics..

the space was VERY (very) tight.. (height was a killer, since almost no components could populate the top of the pcb.. and the bottom has a microSD card!.. and the pcb isnt much bigger than that!

Was really just a result of a bunch of things I hadnt tried before
custom shape pcb in Eagle (also just square/rectangles)
Arduino +3.3v
Arduino running on internal 8MHz clock
just some things I had not ever tried.. :)

Image

Image


quick vid:
http://www.youtube.com/watch?v=unyKKA1JOnw



I'd like to hear about the results/speed (and then of accuracy after speed) of the optimized.py script as well?

I 'do' believe I have shrunk the cream layer*..

I open up an original and a new one I did after 'shrinking' in Gerbv and sticked and turned on/off the layer.. you can see the original was is 'bigger'...

that being said though... I have NOT been able to shrink it past 4mil?

I type in 6 mil.. and run CAM JOB.. (iTeadStudio CAM file, because thats who I normally use)..

I know its a bit different than the one you are used to..but it how they have their fab house set-up..so I just roll with it!..
(this is where/how the dimensions 9pcb outline/shape0 layer is included as well for them)..

anyways.. I go to 6mill shrink on CREAM layer.. export.. open and check it against the 4mil.. same thing!..

not sure if running another/different/alternate CAM file will allow this? and theirs blocks/stops/limits it?

I'll try to figure out to do a single pass..

and do another test before trying another export CAM job..


thanks! couldnt have gotten this far without you the help of others here.. thanks!
xl97
Newbie
Newbie
 
Posts: 31
Joined: Fri May 17, 2013 10:42 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby timb » Wed May 22, 2013 6:32 pm

Sweet! Glad you got it cutting dude. :)
timb
Newbie
Newbie
 
Posts: 24
Joined: Sat May 18, 2013 8:09 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby timb » Fri May 24, 2013 12:08 am

I've been doing some research on blades and came across these (http://store-a5fbf.mybigcommerce.com/products/Graphtec-CB09U-60°.html) 60° angled blades that, according to a Scrapbooking forum, should give much more precise cuts with the media we're using for this.

I think that blade should be a drop-in replacement for the Cameo's blade holder, but if not you can grab a CB09U (blue cap) holder on eBay for a few bucks. I'll be ordering a few from Clean Cut Blade to see how they perform.

Edit: The [url] tag didn't like the degree sign in the link; I guess it's not UTF-8 compatible.

Edit 2: You could also pick up a CB15U (red cap) holder and these (http://store-a5fbf.mybigcommerce.com/products/Graphtec-CB15U-60°.html) if you want a stronger blade that will allow you to use more cutting force (to go through thicker material) without binding at the corners. Either way a 60° will give you much more precise cuts compared to the standard 45° blades.
timb
Newbie
Newbie
 
Posts: 24
Joined: Sat May 18, 2013 8:09 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby xl97 » Fri May 24, 2013 7:43 am

thanks..

yeah I have been thinking of getting one..

Im not familiar with red cap/blue cap?

is this the same thing you mean (the holder)?

this is what I am planning to buy..

http://www.ebay.com/itm/Graphtec-CB09-B ... 0632177982

same thing..yes?



at this point.. Im 'ok' with the results I have..

Id still like to:

1.) try the 60 degree blade to see about the tighter/smaller cuts.. (always better)

2.) like to try exporting my gerbers using another CAM job instead of the iTeadStudio one..

(Im trying to figure out why the 6mil shrink on the cream layer isnt any different than the 4mil shrink one I did and exported..

(when viewing them both in gerbv.. they are the same 'sizes'.. (although smaller than the OK without shrink version)

but it seems I am capped/limited at shrinking to 4mil? (odd, but havent looked into too much yet)
xl97
Newbie
Newbie
 
Posts: 31
Joined: Fri May 17, 2013 10:42 pm

Editing with Inkscape before sending to silohuette cameo

Postby jesuscf » Fri May 24, 2013 6:33 pm

Wow, there have been a lot of useful posts on this topic lately. Too bad I missed them. (By the way teletypeguy , I use the same type of paint scaper as a solder paste spatula!)

Just want to mention that it is possible to 'edit' what is sent to the Silhouette Cameo cutter. This is useful when some components are not populated or you wish to change some of the hole sizes in your stencil. First, in addition to all the programs needed to run Gerber2Graphtec mentioned in previous messages, you'll need Inkscape. Download it from here:

http://inkscape.org/

The idea is to create a pdf from a Gerber file, edit the pdf with Inkscape, convert the pdf to Graphtec using a modified python script, and finally send to the Silhouette Cameo.

1) To create a pdf file from a Gerber paste mask type in a command window:

"C:\Program Files (x86)\gerbv-2.6.0\bin\gerbv" --export=pdf --output=myfile.pdf --border=0 myfile.gtp

Or if you prefer, create a 'createpdf.bat' file and add this single line:

"C:\Program Files (x86)\gerbv-2.6.0\bin\gerbv" --export=pdf --output=%~dpn1.pdf --border=0 %1

and type

createpdf myfile.gtp

A file named 'myfile.pdf' should be created.

2) Run Inkscape. Open the newly created pdf file and modify as you wish. Save it.

3) Copy gerber2graphtec.py to cutpdf.py. You can do this from a command window also:

copy gerber2graphtec.py cutpdf.py

Then edit cutpdf.py and modify these four lines from:

temp_pdf = "_tmp_gerber.pdf"
temp_pic = "_tmp_gerber.pic"

os.system("\"C:/Program Files (x86)/gerbv-2.6.0/bin/gerbv\" --export=pdf --output=%s --border=0 %s" % (temp_pdf,input_filename))
os.system("\"C:/Program Files/pstoedit/pstoedit\" -q -f pic %s %s" % (temp_pdf,temp_pic))

to these two lines:

temp_pic = "_tmp_gerber.pic"

os.system("\"C:/Program Files/pstoedit/pstoedit\" -q -f pic %s %s" % (input_filename,temp_pic))

4) Run the newly created script. It needs the pdf file you created/modified as input:

cutpdf myfile.pdf > result.txt

5) Send 'result.txt' to the Cameo as outlined in previous messages.
jesuscf
Newbie
Newbie
 
Posts: 26
Joined: Mon Apr 01, 2013 6:22 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby timb » Fri May 24, 2013 6:48 pm

xl97 wrote:thanks..

yeah I have been thinking of getting one..

Im not familiar with red cap/blue cap?

is this the same thing you mean (the holder)?

this is what I am planning to buy..

http://www.ebay.com/itm/Graphtec-CB09-B ... 0632177982

same thing..yes?



at this point.. Im 'ok' with the results I have..

Id still like to:

1.) try the 60 degree blade to see about the tighter/smaller cuts.. (always better)

2.) like to try exporting my gerbers using another CAM job instead of the iTeadStudio one..

(Im trying to figure out why the 6mil shrink on the cream layer isnt any different than the 4mil shrink one I did and exported..

(when viewing them both in gerbv.. they are the same 'sizes'.. (although smaller than the OK without shrink version)

but it seems I am capped/limited at shrinking to 4mil? (odd, but havent looked into too much yet)


Yes, the "blue cap" is the CB09U holder and a "red cap" is the CB15U holder. If you get that CB09U package, make sure it includes three springs (one for each blade). (Note: CB15U blades do not need springs.)

While the aluminum holders are nice, those cheap Chinese blades won't last very long, in fact some even come from the factory dull! I highly recommend shelling out a few extra dollars and buying from Clean Cut Blade; they're really fantastic blades, all made in-house and have always outlasted OEM blades for me (and my fiancé, who does a lot of scrapbooking).

The sharpness (and ability to stay sharp) is directly proportional to the preciseness of your cuts.
timb
Newbie
Newbie
 
Posts: 24
Joined: Sat May 18, 2013 8:09 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby jesuscf » Sun May 26, 2013 5:50 pm

teletypeguy, is the suction cup in your vacuum pickup tool homemade?

Image
jesuscf
Newbie
Newbie
 
Posts: 26
Joined: Mon Apr 01, 2013 6:22 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby teletypeguy » Mon May 27, 2013 1:26 am

Hey Jesus:

The little eyedropper-like gizmo I got for manual pick up is many years old -- forgot where I got it, but it might have a name on it -- I'll look when I get in on Tuesday. Kinda similar to this very-expensive tool (almost two dollars!) on ebay:
http://www.ebay.com/itm/190776608479
or, an even-more-expensive variant:
http://www.ebay.com/itm/330566776703

Here is another tool I like a lot:
http://www.circuitspecialists.com/csi825a.html
It is a hot-air rework station ($109) that has a hot-air gun and a few nozzles, and also includes a vacuum pickup wand with a few tips. I have not used the vacuum pickup part, as my little eyedropper pickup works quite well. The hot-air section is great for both removing chips and re-flowing a replacement chip. It comes with some wire doo-hickey to fit under the part when you are trying to remove it, but that didn't really fit so I don't use it.

For chip removal, I just put the blade of an xacto under the chip, apply a SMALL amount of torque for lifting force, and start heating the snot out of the chip (I set the air to about 320C for leaded solder and 370C for lead-free). It only takes a minute or so before the chip pops off the board. If you apply too much lifting force, you will either crack and split the chip, or lift pads, or both (and then you will call yourself an f-ing asshole, and be really pissed that you ruined a board), so just be gentle and wait for the chip to release nicely. Practice on scrap boards. Clean the pads with solderwick when the chip is off. Get some good solderwick from mouser or digikey (I got some stuff from dx.com that was complete crap and I threw it away).

For chip replacement, I made some solderpaste chip stencils on the cameo out of that adhesive vinyl that I used for chassis overlays -- first results were poor, as I just cut the chip patterns as I would for an original mylar stencil. The little chads got stuck everywhere and the mask was unusable. So next, before I peeled the cut stencil from the backing, I used an xacto to cut a rectangle out for the array of pads on each side of the chip. Sheesh, I can't count the number of times a day I use an xacto knife -- what a handy tool. With this "rectangular-pin-array" mask, I spread paste over this larger area which included paste between pins. I got a plastic putty knife from home depot and cut it with scissors to make a nice little squeegee for just fitting the chip pins. I was able to use the hot-air tool to reflow it and it worked pretty well, except for some shorts between pins (which I removed with solder wick).

For my next chip replacement time, I plan to make some special rework stencils that provide a rectangular area over the pins, but only on the OUTER-HALF rectangular area of the pins -- this will reduce the total amount of paste and it will hopefully reflow without shorts. Will keep you all advised. I think I will still use that adhesive vinyl -- even though it is a bit "stretchy," I think that adhesive is important for keeping the solderpaste contained well. The stretchy adhesive vinyl is also good for fitting into a chip area that has adjacent components sticking up (a flat mylar stencil would never work).

So why did I have to replace an smt chip recently? Well, sometimes I have a need to rebuild a board with a dead micro or something, but here is a recent scenario you do not want to repeat: I had a new proto, freshly-built, fully-tested, a code-coming-to-life sort of board sitting on my bench. My new golden board -- you know, one of those special boards that seems to talk to you, giving you little insights along the way as you tweak code and such, helping you get it running. One of those magical, special first boards. Or maybe that's just me, but anyway, for me, a scenario not unlike many, many over that last thirty years. And then I did a stupid, stupid thing: I forgot that I had the board powered-up on the bench as I went to solder a cable onto an lcd module or something -- the solder fell across the board, hitting headers and other stuff. There was an audible arcing noise -- that's never a good thing. And there was that smell of burning electronic-something -- that's never a good thing either. No, not something as simple as a backwards electrolytic cap that blew its load; this was more insidious. I realized that I had let my solder fall across the board, probably connecting 12V, 5V, 3.3V and various logic-level signals in an orgy of gate-oxide-vaporizing, protective-diode-frying, silicon-melting destruction, the likes of which I had not seen in many years. It was nasty, but the survivors, who should get honorable mention, were an Intersil HIN202, a TI 74LV08A, and an Atmel AT25256 -- on the destroyed side were an AT45DB45081 flash, a PIC micro, a 25AA mac/eeprom, a 23xx sram, an ENC28J60 ethernet chip, and an NXP 74HC04. It was just sad. But with a little bit of hot air, an xacto knife, and some good solderwick, my board came back to life.

ps: when I got the hot-air tool, I also picked up these extra nozzles, all of which have proven useful:
A1125 - for QFP-44 etc (10mm x 10mm)
A1131 - for SOIC/SOP (4.4mm x 10mm)
A1132 - for SOIC/SOP (5.6mm x 13 mm)
A1260 - for SOIC/SOP (8.6mm x 18mm)

FWIW,

gil
User avatar
teletypeguy
Jr. Member
Jr. Member
 
Posts: 60
Joined: Tue Mar 26, 2013 12:04 am

Re: Cutting mylar stencils with a silohuette cameo

Postby jesuscf » Mon May 27, 2013 1:00 pm

Hi Gil (aka teletypeguy),

I asked about the suction cup because it looks as it is made with silicone. I built my pickup tool with an aquarium air pump, a solenoid air valve, a pedal switch, an air needle (the kind used to inflate toys with hand pumps), and a Pilot Fineliner pen. It turns out that the body of the Pilot Fineliner pen fits perfectly both the air needle and the air line from the pump. I bought a hand pickup tool (just for the suction cups) from ebay but it hasn't arrived yet, so I made a few suction cups using oogoo (http://www.instructables.com/id/How-To-Make-Your-Own-Sugru-Substitute/), a mix of type 1 silicone and corn starch. They work extremely well, but they don't look that good:

homemade_suction_cups.jpg
Homemade vacuum cups for SMD pickup tool.


I you need to remove lots of ICs from a PCB, the best option is to place the whole thing in your griddle, wait for it to reflow, and then remove the ICs. Beware, some suction cups may not be able to take the heat, for example if they are made with oogoo! If you want to remove everything, just pick the whole PCB with pliers and tap it against the table!
jesuscf
Newbie
Newbie
 
Posts: 26
Joined: Mon Apr 01, 2013 6:22 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby jesuscf » Mon May 27, 2013 4:34 pm

2blmaster wrote:Hi all,

I solved my recent problem with the Cameo (see ~2 pages backwards), not cutting every area of the stencil correctly.

I did so, by modifying the optimize.py of the gerber2graphtec tool.
The tool by default adds *plenty* of "knife-positioning" cuts just outside the area of the stencil. This takes a lot of time, and also needs to move the cutting mat back and forth again and again. Somehow (??) my cutter messed up with that, and made the cuts not straight...

I modified the python code to just do a single "training" cut per cutting angle that is used in the file, and then do all cuts with this angle in a row. This needs the mat to be moved completely only once per angle.

I don't know, whether Peter (author of gerber2graphtec) added this by purpose or not (already contacted him), but for me it works reasonably faster and better without the zounds of training cuts in between.

Please find my modified version attached - maybe it is useful for some of you.

Cheers
Andre


I just cut a test stencil using the modified version of "optimize.py" posted by Andre. The results are almost as good as with the original script file (except for very minor distortions). The advantage of the new script is how fast it produces a stencil. It took only 25 minutes compared to 1 hours 40 minutes before! Thanks Andre, I'll be using the modified script from now on.

(By the way Andre, check that the blue lever inside your Cameo is all the way up. It is the only thing I could think of it may have caused your original problem.)

Jesus
jesuscf
Newbie
Newbie
 
Posts: 26
Joined: Mon Apr 01, 2013 6:22 pm

Re: Cutting mylar stencils with a silohuette cameo

Postby xl97 » Mon May 27, 2013 7:21 pm

I found that I too was getting inconsistent cuts using the original G2G script..

it was only certain areas... or certain 'angles/cuts' that were off though..

(not so bad the stencil wasnt usable though..to be clear)

after many (many) tests in the same area..

I attributed it to two factors:

1.) not a clean blade (make sure you unscrew the white cap and clean whatever is in there, out)..
2.) sticky/tacky in that area..

Is the OFF-SET parameter the correct way to place where the cut is made/placed?

I no longer want it started in the top/middle area...

the place of the mat is getting worn-out.

:)

I'll try the new optimized script soon!
xl97
Newbie
Newbie
 
Posts: 31
Joined: Fri May 17, 2013 10:42 pm

PreviousNext

Return to Tools of the trade