posts tagged with the keyword ‘lasercutter’

2016.11.21

ART

“LaserCut LetterPress” (for lack of a better name) is a project I worked on in 2014/2015 which was an idea to create a full letterpress set using a laser cutter capable of cutting 3mm Baltic Birch plywood. The idea was that the files would be released that allowed anyone with access to a laser cutter (even lower-powered cutters with small beds) to create the set.

I know there are many ways to create things, but at the time I wanted to limit production to one method, and one particularly fast method, vector cutting with a laser cutter. (Note: If you’re fascinated by the production of wood type, check out Moore Wood Type.)

I mentioned some of the process in a post titled Measure Twice, Laser Once… but never wrote up the whole thing, so here we go.

LaserCut LetterPress Example Print

The typeface I chose was OpenDyslexic, which was inspired by a friend who is Dyslexic. I also thought it would be interesting to use a typeface that was new, and didn’t exist in the time that wooden type was widely used.

Art Letters

I did the design in Inkscape, creating the letter and the pieces that fit under the letter so it could slide into a tray.

Letter and Tray

Wood is such a wonderful material, except when it isn’t. Tolerances caused a number of issues, but I kept going forward, and didn’t worry too much about having things fit together perfectly. (I won’t say this was my downfall, but I spent a lot of time fighting it.)

Art Letters Tray

Here’s the design for the small tray. Ultimately I wanted a larger tray that had multiple lines so you could do an entire poster. That of course would have required an entire alphabet, and multiples of most letters, and punctuation, and… letterpress is hard.

Oh, somewhere along the way I also started to write code that would generate all the characters needed by outputting the needed SVG files. In theory it was totally doable, but in practice it served as a distraction that I eventually ignored.

Art Letters

With the plan to turn this into a kit that one would assemble, I thought about how one would determine what pieces would go together, and thought that etching the letter onto each piece would be a good idea. (I didn’t get to this step due to being stuck in the prototyping phase.)

Tray

Here’s the letter “A” sliding into the small tray I made. Tolerances were good with the first batch of letters, but with subsequent pieces not so much.

ARTS+TECH

You can see a bit of the height difference with this batch of letters…

Height Comparison

…and you can really see it with these. Yes, this is all 3mm wood. Again, as mentioned with the previous post, there can be quite a difference when the layers add up.

ARTS+TECH

I did manage to create enough letters for one of the Arts + Tech Nights at UWM.

TEACH ART

And oddly enough, I was able to arrange the letters into “TEACH ART”, which I ended up doing six months after I abandoned this project.

LaserCut LetterPress Example Print

Here’s a few test prints I did. They worked fine, which made me think I may have overthought how “perfect” it had to be. In the process of talking to printmakers (who were very interested in the project) they got me thinking about type height, which is useful for a press (and I considered using these letters on a press) but in the end I think I should have stuck with my “hacker ethic” and just made it work with the minimal amount of success.

I don’t consider this a “failed” project because I learned a lot in the process (and got to meet & work with some awesome people) but I’d love to see someone else run with this idea… or maybe it’s something I’ll pick up again in one form or another.

Remember kids, Keep on Making!

2015.03.30

It’s been a few years since I’ve posted about laser cut files, and by that I mean, the files I prepare to be used for laser cutting, so I thought I’d do an update.

Right now I typically use a few different laser cutters in the Milwaukee area. At Milwaukee Makerspace there’s a 60 watt ULS and 50 watt ULS, but using a Windows PC with CorelDraw for control, and at Brown Dog Gadgets there’s a 90 watt Chinese laser cutter using CorelDraw (and LaserCut 5.3) though it seems to be a much newer version than used at the Makerspace. I also use a 40 watt Epilog Zing at UWM’s DCRL. The Zing uses Rhino instead of CorelDraw, which may sound weird, but it works.

I’ve got a file workflow that can work with all of these machines… which I’ll explain below.

Panel Mount

Here’s what my vector art looks like in Inkscape. You’ll notice that the inside lines are blue, and the outside lines are black. This is so we can set a manual cut order for machines that don’t automatically cut inside lines first. (Some software is smart, and always makes inside cuts first, other software… is not.)

lcfiles02

I should note that while doing the design work I may end up with multiple layers. Often I’ll use layers to hold pieces or revisions of a design. For our final file though, we want a single layer.

Let’s pretend my design file is named “Panel Mount.svg”, and it has more than one layer. When I’m happy with my work, and have all the things that will be cut on one layer, I’ll save that file, duplicate it, renaming the dupe to “Panel Mount LC.svg” and then open that file. My original design file (Panel Mount.svg) is now safe and sound, but my new file (Panel Mount LC.svg) is about to get altered.

Files

I usually set all the objects to have no fill. This may not be required for all workflows, but I like to be consistent.

Files

For the stroke I’ll set the outside lines to black… (This may be different depending on your laser cutter software.)

Files

And I’ll set the inside lines to blue. Again, this may depend on the laser cutter software & driver you use. Some allow you to set the order of colors, and some may not. If I need more colors I can use red, green, etc. (Also, if you’re working with a laser cutter operator who is colorblind, ask them what colors they prefer.)

If you want to selectively cut things and only have one color, you can use this trick: Load the file into the laser cutter software (CorelDraw, or whatever) and delete the parts you don’t want to cut, then cut. Then “undo” until all parts are back on the screen, then delete other parts, cut again, and repeat. Not the cleanest method, but it totally works. Don’t move any parts, though you may have to ungroup them, and obviously do not move the thing you are cutting.)

Stroke 0.03mm

Once I’ve applied all the colors, you can select everything and set the stroke. I set it to 0.03mm. This should set it to “hairline” when you import it into CorelDraw. Rhino also seems to do the right thing. If your stroke is too thick it can cause issues. (Always check for the lines to be set to “hairline” after you import your PDF.)

View

After you change the stroke the lines may appear very faint. If you can barely see them switch the Display Mode to “outline” which makes every stroke appear a black and sort of beefs up the lines.

At this point I run down the checklist…

  1. The file has one layer (If it had more, I duped the file and then adjusted the dupe to have just one layer.)
  2. The file has all objects set to no fill.
  3. The file has all objects set to 0.03mm stroke.
  4. The file has different colors for inside and outside cut lines.

Obviously you can do all the file prep stuff (line colors, stroke, etc.) in your master file, and then dupe that one and delete any extra layers. The order isn’t the most important thing here.

PDF Export

Once we’ve made all the changes, we can save our “LC” version of the file. After that, it’s time to use the File menu’s Save a Copy… command to save it as a PDF file. Note that “Convert texts to paths” is selected. This should create a PDF that does not rely on any fonts being installed. If you used text in your file, this is helpful. It does however mean that you cannot edit any text when you import the PDF into other software, as it will have been converted to lines.

PDF

Oh, one more thing! Some older versions of CorelDraw seem to have issues importing PDF files created in Inkscape. On Mac OS X, I just open the PDF that Inkscape created, and export it. It somehow fixes the PDF so CorelDraw likes it. Whatever… it works, so I do it!

Simple Dual Axis Solar Tracker

(BTW, the piece I used an as example was for the Simple Dual Axis Solar Tracker from Brown Dog Gadgets.)

2014.12.19

iterate

The Golden Rule from Phillip Burgess at Adafruit Industries: Iterate, iterate, iterate.

Don’t be discouraged when your case doesn’t work on the first try. Or the second. Once I thought I’d nailed a design on the third try, but was wrong. The most extreme has been our Pi Box enclosure for the Raspberry Pi…this took 23 attempts to get just right! The first few didn’t even hold together. Other projects were initially so discouraging, one was known behind the scenes as the “Piece-o-Crap-o-Tron 9000” …but many attempts later it’s become one of my favorite kits.

Fail quick, fail hard, fail often. Failure is part of the process — perhaps even key to the process. It’s how we learn and improve, and ultimately make a better product. Make mistakes now so your customers don’t have to.

I’ve known for a long time that design is an iterative process, and sometimes I think that’s what I love about it. I tend to be a fan of the process.

I remember once I asked Michael Curry how many attempts it took him to design something and 3D print it before it worked. I thought he said “two or three times”, but maybe he really said “twenty three times”. ;)

But seriously, there’s a lot of great tips not just for laser cutting things, but for designing things in general.

2014.12.19

Pegs and Pieces

I’ve been working on a project that involves stacking of laser cut pieces of wood to create blocks. In theory the laser cutter is a precise CNC machine that has an (almost) negligible kerf. (The kerf is the part that gets cut away. With a saw it’s the width of the saw blade, and you need to account for it.)

Height Difference

Typically I’ve been using this 3mm Baltic Birch plywood from Woodcraft, and it’s been pretty darn close to 3mm, at least within 0.1mm. For most projects this is fine. Even at 3.2mm things will fit together, though perhaps a bit snug. You can always sand things a bit to make them fit.

Stacking presents a new problem though, because the extra height adds up and throws everything off. For the last batch of blocks I assembled I wasn’t aware of the issue, even when the pegs wouldn’t fit. I assumed I screwed up the peg slots, so I just sanded the pegs down a bit until they fit. Even then, they were not the right height in the other direction.

Height Difference

After assembly I noticed that the blocks were different heights than the first batch I created! I went back and measured the sheet of wood and it was 3.4mm. I checked a few more and got ranges between 3.0mm and 3.4mm. The image above shows what happens if you use 3mm wood and 3.3mm wood to construct the same block. At just four layers you’re already off by 1.2mm. For small things that can make a huge difference.

So what’s the solution? I can attempt to sand the sheets before cutting, or partially assemble the blocks and sand them to the proper height before the final step. A colleague suggested getting one large sheet of wood assuming the height would be consistent across one piece. I may try all three solutions, but will probably start with the first, and apply the second solution if required.

So yeah, even with digital fabrication, and laser cutters with almost no kerf… Measure twice so you only have to cut once!

2014.11.28

I needed a single stroke font for some laser cutting. You’d think that would be an easy thing… Well, keep reading.

When laser etching, any font could be used. You can raster etch the type, or “vector etch” the type. Raster etching takes a long time, and vector etching (basically doing a low-power vector “cut”) is fast. If you’re doing 3,000 pieces, the time can make a huge difference!

Regular font

Here’s a normal font in Inkscape. Fonts consist of an outline which is then filled with a color. In this case, the outline of the font is filled with black and you see what you normally see when viewing a font on a computer screen.

Regular font

Here’s the normal font with the fill set to none and the stroke (outline) set to a thin line. You could laser etch this (and some people do) but you’re now outlining the letters instead of just etching them with a single stroke. This is fine, but takes more time. Since going really fast is our goal, this doesn’t work.

At this point, you may be thinking “No problem! Our pals at Evil Mad Scientist Laboratories have us covered with Hershey text, and engraving font!” Indeed, Hershey text is awesome, but not always the right solution. I use Hershey text often, and it’s lovely, but let’s keep exploring…

CamBam font

I found these CamBam fonts, which probably work quite well for a spinning bit that is cutting material, but there’s an issue:

All the fonts are built using a 100% overlap in the font design, which tricks my TrueType font design program into thinking they are really looped TrueType fonts, when they really don’t have an inside and outside loop.

CamBam font

A spinning bit cutting material is quite different than a laser cutting material. If you use this font to laser etch, it will double up, which mean you’re lasering the same thing twice. This takes longer, and cuts your material twice. No good.

You can manually go in and delete the overlaps, but it’s a time-consuming pain, and you’ve got better things to do.

Machine Gothic

I found Machine Tool Gothic, which looks a bit weird when you first select it, but we’ll fix that. Remember that fonts are typically outlines that are filled with a color. That’s what is happening here.

Fixing Machine Gothic

We just need to set the fill to none, and give it a thin stroke. Much better! We’ve nearly got our clean single-stroke engraving font.

Fixing Machine Gothic

Let’s fix the weird lines that connect everything and close the paths. First you’ll want to convert the type to outlines (that’s the “Object to Path” command in Inkscape) and then select the two nodes at each end of the line you want to delete and use the “Delete segment between two non-endpoint nodes” feature to remove the line.

Fixing Machine Gothic

Oh, it’s worth noting that when you convert the type to paths, you lose the ability to edit it as type. More on that later. Here’s the “L” with no extra line connecting everything.

Now, it may look like only certain letters need the extra line deleted, but they all do. Go through each letter to delete the extra lines! If you’re doing a one-off project this may not matter as much, but if we are laser cutting 3,000 pieces, even an extra 5 or 10 seconds per piece will make a huge difference.

Type on a curve

Here’s the real reason I wanted to use an editable typeface rather than the Hershey text extension. With text, you can place it on a path. This means you can curve the text onto a circle or some other shape. We want to make sure we’ve got the text exactly as we want it before removing the extra lines. (Remember that we need to change the editable type into outlines before we remove those extra lines.)

Type on a curve

Don’t forget to remove the circle, or whatever path you used to place your text on.

Type on a curve

Fire up the laser! Here’s our clean and ready to vector-etch single-stroke type.

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