Dangerous Prototypes

General Category => Tools of the trade => Topic started by: teletypeguy on May 20, 2013, 03:28:23 am

Title: Making Chassis Overlays with a Cameo
Post by: teletypeguy on May 20, 2013, 03:28:23 am
After finally getting stencils working with my Cameo cutter, I wanted to try making chassis overlays.  Over the years I have spent good money getting polycarbonate overlays (7 to 10-mil) with rear silkscreen for connector identification and such, a flood-fill color, backed with 3M 467 adhesive, and die-cut with all the openings and outer shape.  It's a great way to allow multiple overlays to work for different products using a single chassis with a flexible common hole pattern, but pricey.

So I have this Cameo that can cut up to 24x12, and an inkjet that can print up to 11x17, and I have found inkjet-printable adhesive-backed plastic sheets in up to 11x17 -- can I make my own overlays?

The Cameo's included Silhouette-Studio program let me get the job done.  First off, Silhouette-Studio has lots of oddities, but it also provides some important "drawing" tools (for drawing your cut lines, that is) -- not just the basics like line, polygon, rectangle/square, and ellipse/circle, but the ability to copy-and-paste-in-front (exactly in front, not offset a bit), and then move the object precisely.  I use this a lot for arrays of connector holes.  But besides just letting you define a cut pattern, they have a feature called "Print-n-Cut."  Now this was designed so crafters could print a pretty picture of a unicorn or something, print it from sil-studio to a printer (maybe on a thin cardstock paper), ADDING REGISTRATION MARKS, then define a cut layer (which for many projects is just an outside edge), then load the printed item on the mat, and load it into the Cameo.  But you are not limited to just an outside edge.  In fact, I found a lot of railroad model makers printing and cutting intricate window frames and stuff.

Here's the important part:  the Cameo has an optical sensor near the knife, and it can find the registration marks on the thing you just printed/loaded, and get precisely-oriented for its cut pass.  You then tell it to cut, and bada-boom-bada-bing, it makes nice.

The Print-n-Cut adds a step to the process of creating your cut file -- first, you open a jpeg (or other bitmap) file.  Then you add cutlines as needed.  You add registration marks, print it out, and so on as previously described.  So for my bitmap file, I wanted the text for my connector definitions, and thin lines where my cuts were to go.  My artwork came from Adobe Illustrator, but I could not export a jpg with decent resolution.  I could, however, open the .ai file in Photoshop, and save-as a jpg.  I used 600 dpi (lower-res was not as clean, and higher res made sil-studio hang).  I had all of my text plus hairlines identifying where to cut.  This worked great for an 8.5x11 sheet but I also wanted to do 11x17 -- this also made sil-studio hang on file open (probably a bug, since their workspace is 24x12), but I could fake it out by dividing the image in two in photoshop, opening them both in sil-studio, copy one, paste into the other, align visually, group, and then I had my 11x17 image ready to go.  Clumsy, but whatever gets the job done.

I opened my image, added reg marks (you need to avoid printing in keep-out areas), and started adding the cut lines for the hole pattern and the perimeter of the overlay.  I put as many overlays on a single sheet as I could fit.  After the hole pattern for one is done, select the whole group, copy, paste-in-front, move, repeat -- it was pretty easy.  There were a few annoying things along the way but I am happy with the results.

The inkjet material I used I found at texascraft.com -- WVF1117KH white waterproof adhesive-backed vinyl 11x17 sheets, $1.44 ea in 100s (but they also sell 10 packs or single sheets).  It is also available in 8.5x11.  They also have laser vinyl, but my laser does not do 11x17, nor does it do color, and I want to try color overlays next.  This stuff is about 4-mils thick including adhesive, which is a bit flimsy, so after printing a sheet, I stuck it onto a second sheet for added thickness, before cutting. Enough talking:

In Sil-Studio, the black is the jpg text, and the red is the cutlines I added.

Some settings.

Printing it on Big-Brother.

Loading it the Cameo (on the optional 24x12 cutting mat)

to be continued...
Title: Re: Making Chassis Overlays with a Cameo
Post by: teletypeguy on May 20, 2013, 03:42:25 am

To check you blade depth, you can use the blue cursor buttons to move the head to an empty area, and tell it to do a test cut.  Then peel out the little section with an xacto to see if the cut looks clean.  This is actually two laminated sheets of the printable vinyl, about 8-mils thick total.  I used a blade depth of 3.

Tell it to find the registration marks (manual worked for me, but auto got confused), then tell it to cut.  It peels off nicely.  Registration was slightly off -- next time I will make a second jpg with no cut lines, and bring it in after building the cut layer.  That way there will be no small black lines visible if reg is off a bit (and reg of the text is not that critical anyway).

And stick it on the chassis.

Not bad at all.  Cost me about a buck for one.  Smaller ones are dirt cheap.  Doing a plastic panel for a pactec box?  Just drill out rough openings in the blank panel and stick a nice overlay on top.  Custom label for the recess in the top of your enclosure?  No problem.  Use your imagination.

Title: Re: Making Chassis Overlays with a Cameo
Post by: deball on May 22, 2013, 03:08:20 pm
Great summary! I've been using a similar method, but with 'Sure Cuts A Lot 3'. My cutter doesn't have any optics, but then I did buy it as a non-runner off ebay, one rather old Allegro driver was blown, I decided to replace all four so they were all from common production runs and the same version.

I design the panel, or import it as a PDF/JPEG etc to get the panel component locations, scale to 1:1 and then print the file only the base adhesive vinyl as you do on my A3 HP inkjet. Equally, I could just draw it in Sure Cuts A Lot..

Now comes the tricky part, as I don't have the magic eye, I have set a calibration/cutter head start point and align the page to this point. Then perform the cut, removing the printed detail by hiding that layer(s), leaving just the cut profile.

If I know the panel is going to get wet or be used near solvents, laminate it with a lustre self adhesive film, cold rolled through my office A3 laminater. This does mean there is then twice the amount of vinyl to cut through, there are two or so options. The first is to increase the pressure setting on the blade assembly, ensuring that the blade depth is increased to clear both layers. The speed also needs to be reduced at this time, not too slow or the blade could dig in and become stuck as there isn't enough momentum.

Second option is to cut twice. This isn't my preferred option, these cutters are fairly accurate, but absolute repeatability is a tall order, and you need to stop after the first cut and release more blade to get through the bottom layer.

I've found out the hard way about the depth that they blade protrudes from it's carrier, especially with lots of curves or small circles :(

The results are on a par with most panels I see on commercial product and compared to the low volumes I had screen printed they are much cheaper and the quality is better.
Title: Re: Making Chassis Overlays with a Cameo
Post by: planetjay on May 22, 2013, 05:39:37 pm
Can you post some links to the material, etc?
Title: Re: Making Chassis Overlays with a Cameo
Post by: royco on May 22, 2013, 07:20:51 pm
Instead of using a second sheet for thickness I use a clear laminate to protect the print and give it a more professional finish. It is also a very cool solution for LED holes by cutting the base material but leaving the clear overlay uncut so it has a diffused look when the LED turns on. It also makes the print appear deeper/more saturated.

One tip though, when laying down the clear laminate try not to cover the registration marks, the cutter's vision will have hard time finding them.

There are a couple of choices for the clear laminate overlays.

Here's one of my older overlays using the Silhouette SD with printable vinyl and clear matte laminate.

Title: Re: Making Chassis Overlays with a Cameo
Post by: teletypeguy on May 22, 2013, 07:40:25 pm
The inkjet material I used is made by Papilo, and I got it at http://www.texascraft.com (http://www.texascraft.com).

It is a "white, waterproof, adhesive-backed vinyl, inkjet-printable, and must have some UV protection as well.
I measured it to be about 4-mils thick, including adhesive.  After I printed a sheet, I adhered it to a second sheet before cutting -- this gave me a final overlay that was about 8-mils thick, which works better for me covering unused holes.  I used a blade depth of 3 to cut this 8-mil final thickness.

It is a "permanent" (not removable) adhesive, though it is quite removable and re-positionable for a while.  It sets up with time like lots of permanent adhesives.

I DID NOT get the "contouring" vinyl, which is thinner so it can be applied to non-flat surfaces.

WVF1117KH  11x17 sheets, $1.44 ea in 100s
WVF1117G  11x17 sheets, $2.38 ea in 10s

WVF8511KH  8.5x11 $0.72 each in 100s
WVF8511G  8.5x11 $1.19 each in 10s
WVF8511S  8.5x11 $1.62 for one.

RCWVF1230 is 12"-wide by 30-foot roll (if you have an inkjet that can take it.

Title: Re: Making Chassis Overlays with a Cameo
Post by: teletypeguy on May 22, 2013, 07:46:44 pm
That's nice royco -- I want to experiment with color overlays next.  I like the idea of the clear on top as well.  Have to get some.  What was the base material on which you printed?

What is that plastic enclosure?  Ya, know, the one thing we need from sources like seeed and sparkfun is a variety of decent-looking, reasonablly-priced plastic enclosures.  Pactec's line is pretty dated-looking and pricey.  There are some options from Hammond and others, but I would like to find any other sources anyone has to recommend.

thx,, gil
Title: Re: Making Chassis Overlays with a Cameo
Post by: royco on May 22, 2013, 08:05:16 pm
This is my base material.

The white glossy polycarbonate base material for laser is also nice.

The enclosure is hammond FL 1551 series. Very easy to use as you can sandwich the PCB in between the top and bottom covers and still use the screws that come with the enclosure( just make a hole on the PCB big enough for the screw post). It has a good range of sizes to choose from.
Title: Re: Making Chassis Overlays with a Cameo
Post by: timb on May 23, 2013, 04:57:42 am
If you have a Silhouette SD, you can cut directly from within Adobe Illustrator 10-CS6 and Corel Draw by using the Cutting Master 2 plugin. (Windows (http://http://www.graphtecamerica.com/imaging_software/CuttingMaster2/V192/Windows/CM2_STD_V192.zip) - Mac (http://http://www.graphtecamerica.com/imaging_software/CuttingMaster2/V191/Mac/C-Master2(M)v191a.zip))

This also works with the bigger, more expensive Craft Robo Pro, though you'll want the new version for that. (Cutting Master 3 (http://http://graphtecamerica.com/support/support_ce5000_drivers-downloads.html))

Basically, the way it works is you make your design in AI and put your cuts on a separate layer (which you can hide while printing). The plugin will add registration marks to a new layer for you as well. Once you've got everything printed and ready, you click the cut button, tell it which layer you want, make any adjustments and then it'll take care of the rest. All without leaving AI!

While the Craft Robo Pro is expensive ($800+), you can easily find great deals on the now discontinued Silhouette SD.

Unfortunately, none of the Cutting Master plugins work with the Cameo, but I've found a hack to make it work! Cutting Master 2 and Cutting Master 3 both have an option called Output PLT to File... These PLT files are directly compatible with the file2graphtec program that's included in the gerber2graphtec (http://https://github.com/pmonta/gerber2graphtec) package! All you need to do is export to PLT and run file2graphtec on it, it's that simple. :D

So, if you own a Cameo/Portrait, now you can cut from directly inside Adobe Illustrator!
Title: Re: Making Chassis Overlays with a Cameo
Post by: planetjay on May 23, 2013, 05:47:28 am
Title: Re: Making Chassis Overlays with a Cameo
Post by: timb on May 23, 2013, 09:16:19 pm
Just tried the PLT trick on my fiancé's Cameo and it seems to word perfectly. Finally, having three digital cutting machines has payed off! (I've got a Craft Robo Pro and a Silhouette my fiancé gave me when she upgraded to the Cameo.)

You know, you can use a fiber tip pen on these machines (effectively turning them into a plotter). Has anyone tried using one to draw circuit traces on copper clad board for etching? I bet that would work a treat. I've got a fiber tip pen for my Craft Robo Pro, but it's water based so I'm not sure if it would survive the acid bath... Anyone have some thoughts on that?

Edit: Haha, well, that issue is solved: Sharpie Marker Holder Adapter for Graphtec Vinyl Cutter (http://http://www.ebay.com/itm/Sharpie-Marking-Pen-Marker-Holder-Adapter-Sleeve-For-Graphtec-Vinyl-Cutter-/140959812864?pt=LH_DefaultDomain_0&hash=item20d1dc0d00)
Title: Re: Making Chassis Overlays with a Cameo
Post by: teletypeguy on May 24, 2013, 02:31:41 am
Etching circuit boards?  Really, don't waste your time.  I say that as an old fart who actually did etch a lot of my own boards.  In fact, my first board layouts were on a light table at 2x size with sticky dip patterns and black tape (and my first programming class was fortran with hollerith punch cards).  A few of us got together and copied the Apple ][ PCB this way (late 70s) and made a dozen or so before the clones came out (it was easy to copy the apple proms).  Shot the 2x artwork with a big graphic camera to 1x negative for contact printing to photosensitive copperclad.

Then things got high tech with computer layout, but it still went to 1x negative, expose, develop, etch...  Nasty crap.  And even then, you needed to plan ahead so you could solder pins on both sides of the board, or put eyelets in -- and the resolution is crap too.

My current fav board shop is http://www.myropcb.com (http://www.myropcb.com) -- do a quick online quote for 2, 4, 6-sided or whatever boards, with nice 8-mil or better mins, 15-mil or smaller holes -- office in Canada, fab in China.  Quality has been superb.  Gotta convert to millimeters for some stuff, but I am grudgingly getting more used to mm.

Even on small quantities, Myro lets you spec a laminate and stackup.  So when I wanted controlled-impedance (without paying the extra for it), I could spec the final rohs laminate I'd be using, and the prepreg and core thicknesses, so I could layout for specific impedances (with appropriate trace widths, for those who may have never thought of a pcb as the electromagnetic component that it is).  I did test trace coupons for 50-ohm, 75-ohm, 90-ohm-diff, 100--ohm-diff, etc -- the boards came back from myro and the impedances were very close on my HP TDR.

Here's a little QC tip if you are specing a stackup and a wondering whether they actually did it or just paneled you into some other guy's generic 4-layer job -- put a little triangle or square on each layer at one of the board corners.  When the board comes back, file a bit off the corner to expose the copper, get out a good magnifier and look to see if the prepreg really looks to be 9.5 mil or so (or whatever you spec'd).  I made a little "ruler" with a pcb scrap that had 8-mil-traces and 7-mil spaces.

Title: Re: Making Chassis Overlays with a Cameo
Post by: timb on May 24, 2013, 07:44:46 am
Thanks for the link, that's pretty good pricing. That's a really cool story about cloning the Apple ][ PCB, I bet that was a blast. You reminded me of the first PCB I ever etched. Radio Shack used to sell a kit that included a Sharpie, copper clad board, acid and a sheet of stick on traces and eyelets. My first board was for a bench power supply I made (based on a book from RS if I recall) which I drew by hand with a ruler and Sharpie.

I know it's a lot easier to order boards, but you can't beat etching for fast turnaround! Plus, if you use a plotter to draw all the traces you don't have to worry about using photo sensitive boards.

I think I might still order a Sharpie holder and give it a try...