The Sledgehammer – Version 2.0

November 25, 2010

Everything’s Cooler When You Add Lasers: Making Custom Laser-Cut Christmas Ornaments

Filed under: Art, Design — Tags: , — Brian Lutz @ 4:35 pm

It’s a bit hard to believe, but by the time this gets posted another Thanksgiving will have come and gone by.  I’m actually writing this several days in advance of Thanksgiving itself, but I’m saving the post until after the annual Thanksgiving get-together when these ornaments are handed out.  If all goes well, Thanksgiving should be a pretty typical family gathering with all sorts of turkey and trimmings, an inescapable Cowboys game on the TV (normally I can’t stand the Cowboys, but given the fact that they’re standing at a 3-7 record while I write this there’s not much point in flogging that particular dead horse at this point) and the annual tradition of exchanging Christmas ornaments.  As I may have discussed a time or two in the past, I come from a family of what could be considered very crafty people.   In fact, several of my aunts have actually made a small business out of their craft hobbies, creating a large variety of different decorative products through woodworking and a vinyl cutter.  This means that a significant number of the ornaments in these annual exchanges will be custom-made, often with quite a bit of skill (and these days, often with quite a bit of custom cut vinyl.)  

I’ve actually tried the handmade ornament approach before, but the results have been decidedly mixed, mostly owing to complications related to the possession of a Y chromosome.  While I must admit that decoupage does provide some interesting design opportunities in the right hands, I’m pretty sure I am not in possession of said hands.  There’s also the fact that the acquisition of such materials generally requires an ill-fated excursion into one of the several arts and crafts stores found around town.  These, as you quickly find out upon entering, tend to smell like potpourri.  Strong, unmistakable, soul-scarring potpourri, the kind of stuff that can cause floral-scented nightmares for any man who gets exposed to the stuff for too long. Fortunately I’m pretty sure the stuff can’t actually kill you, only make you wish you were dead (or, if you happen to be female and/or domestically inclined, it can really help add that special touch to a room.)  The whole experience is a lot more survivable than I’m making it out to be here, but as a guy and an occasional nerd, I figure there’s got to be a better way.  Sure enough, it turns out that if I can manage to throw enough technology at the problem, there is.  Roughly a year ago, a place opened up on Capitol Hill in Seattle that provides hobbyists access to a number of various machines they might not otherwise be able to easily find anywhere, including a laser cutter and 3D printers.  While 3D printing is just a little bit out of my league right now, I actually found out that with free software and a quite reasonable learning curve I could actually put together a project that I could “print” on the laser cutter and create my own completely custom-made ornaments without having to go anywhere near a craft store. 

I should probably add the disclaimer that this post is not necessarily intended to provide a how-to for the process of making ornaments like these or other similar items, but I’ll try to share what I learned in the process and hopefully help out anyone who might try something like this in the future.  I’ve found that the available information on the Internet regarding laser cutting can be a bit spotty, and there were a few things that I had to figure out on the fly.  That said, if you can manage to find your way around a vector drawing program it’s actually not that difficult to do.  After the jump, a detailed look at the process behind the custom ornaments you see above.

This particular project actually stems from a much more elaborate idea I’ve had in the back of my mind for the past couple of years now, but haven’t really had the means to do until now.  In a bit of a roundabout way, my interest in laser cutting came from the above mentioned vinyl cutting business.  Both a vinyl cutter and a laser cutter (or, for that matter, a pen plotter) operate on basically the same principle of turning a vector drawing into a series of instructions that control motors which operate a cutting (or drawing) head.  In fact, the same designs in the same files could theoretically be used on all of these machines, as long as they could be converted into whatever file format the device in question specifies as input.  The most popular vector drawing tool for hobbyists making laser cutting jobs seems to be Inkscape, which I have found to have a few annoying user interface quirks here and there, but when compared to other popular vector drawing programs it does come with the one great big advantage:  It’s free.  It certainly does take some getting used to, especially given the fact that for most of the graphics work that I do I still use Paint Shop Pro 8 (I have a copy of Paint Shop Pro X around here somewhere, but I tried it out for a while, didn’t like it much for one reason or another, and then managed to lose the CD at some point before building my current PC.)  I use PSP8 mostly because it’s what I happen to be used to, but it tends to be temperamental (especially on 64-bit Windows 7) and has a few annoying crash bugs.  Oh, and it also seems to quite noisily choke and die the minute you throw any sort of SVG files from Inkscape at it, so it’s pretty much useless for this job.

This was the first version of the design which I used to make my prototype ornament.  I’ll refrain from going too much into the specifics of the design (the whole “Vanderhoeven Machine” thing is a bit of an ongoing family in-joke, and the windmill is there mostly to be Dutch,) but there’s a few things to emphasize here:  First of all, if you’re going to be creating a design specifically for use on a cutter of some sort (be it a laser or a vinyl cutter,) you’ll want to simplify things as much as possible.  While the laser cutter does allow for some surprisingly close tolerances, it does have its limits, and you’ll get the best results if you have smooth lines with curves that can be followed relatively easily by the cutting head.  You’ll also want to make sure that you don’t have any lines overlapping each other, because if you do those lines will be gone over twice by the laser, which can cause all sorts of problems.  You’ll also need to make sure that all of the paths (sets of points and curves) that you’re using in your drawing are closed, since the cutter has to be able to start and end at the same point when cutting the shapes.  This holds true even for laser engraving, For most shapes you’ll be using (including letters) this won’t be a problem at all, but it does mean that you can’t just add lines to your drawing that aren’t connected to anything.  I made this mistake on the first version of my design, and the red lines (intended to be highlights on the windmill shape) had to be deleted.  Since we’re dealing with highly precise tools here, it also means that it’s best to make the lines as thin as possible (one laser cutter suggests that the lines should be 0.003 inches thick, so that’s what I’m using here.)   The software that was being used to drive the laser cutter also had some issues with doubling the lines on the text.  The laser cutter operator suggested that the best way to counteract this would be to just make the lines invisible and use a solid fill.  Your mileage may vary on that one, but it seemed to work.  There’s a good chance that no matter how well follow the guidelines and put things together you’re still going to need some tweaking before the job goes to the cutter.

Image credit: Flickr user jimapics, Creative Commons license

 Most of the actual shapes used in the drawing above are made out of various shape primitives and curves joined together using Inkscape’s path tools, mostly the union and exclusion tools (which merge two shapes together into one or “cut” the outline of one shape into the body of another respectively.)  Inkscape comes with a built-in tool for rendering gears, which is what I used for the outside edge of the ornament.  There was also extensive use of the Align and Distribute tools in Inkscape to get things centered properly, which can make life a lot easier in some ways, and just make a mess of things in others.  The text was actually a bit of a pain to do, as Inkscape’s handling of text placement on paths is a bit tricky to deal with.  The windmill itself is based on a smock mill design, which is one of the more common designs that people would think of when they think of a windmill. To be a bit more specific, I based it largely off the windmill found at Marymoor park, which you can see above.

Anyway, with what I believed to be a workable design in hand, I stopped by TAP Plastics to grab a couple of sheets of 1/8″ thick acrylic, and made my first trip over to Metrix Create:Space.  Metrix Create:Space is a neat little place on Capitol Hill in Seattle with all sorts of cool stuff like Makerbots (3D printers,) really fast Internet and a vending machine full of cool electronic components I wouldn’t have a clue what to do with.  Most importantly for my purposes, they had a laser cutter, without which this whole exercise would have been pointless.  Needless to say, the first design had some bugs in it, mostly that I wasn’t aware that the cutter couldn’t deal with non-closed paths like the straight lines I had put in for highlights on the windmill body.  There was also some trouble sorting out exactly what to do with the window and door, but ultimately the bugs were worked out, and we could proceed with cutting out a prototype.

Here you can see the cutting of the prototype ornament in progress.  On this version, the text (and the window and door on the windmill) were being rendered as solid etching, which was done after the cutting was finished.  You actually have to wear special laser safety goggles if you’re in the room with the laser while it’s cutting.  After all, if it can do that to a 1/8″ thick sheet of acrylic, you wouldn’t want to find out what it could do to an eye.

After roughly six minutes of cutting (a number I was clearly going to need to reduce, given the relatively high cost of cutting time) this was the result.  Most of the time was actually a result of the filled-in engraving, which is basically the laser head going back and forth engraving the design roughly .1 millimeter at a time  The window and door didn’t get cut out properly, but I didn’t care too much since this one was just a prototype.  To the right, you can see some of the leftovers from in between the cut-out areas.  The other big issue I ran into with this version was that the holes on the windmill and the blade were too small to fit any standard sized fastener, and would need to be enlarged.

For comparison, here’s what the cut-out pieces of the prototype looked like compared to a printout I made before cutting.  When you see it in this form, you start to get an impression of just how much accuracy you can get out of the laser cutter.  But at the same time, there were some issues with the design that needed to be fixed before going into production, so it was on to that next.

A bit of tweaking later, this was the second (and ultimately final) design.  At least on my monitor, what you see here is roughly actual size.  There were a number of changes made here:

  • As noted above, the hole sizes for the windmill and blade were enlarged in order to accommodate a #4-40 machine screw to use as a fastener;
  • The circumference of the inner circle was reduces to provide a bit more space for the text, and to make the ornament a bit more substantial;
  • I added a little point to the top of the windmill, as this seems to be common on this style of windmill;
  • I turned all the text into paths to engrave them as vectors ( which should be a lot faster than the back-and-forth engraving on the last one) and made complete paths on the windmill details.  I also just turned the windows into cutouts.
  • I added a couple of spacers to use for attaching the windmill blades.  I wanted to have these be able to spin, but this didn’t really work out in the finished product.

With my tweaked graphics (and another sheet of plastic) in hand and most of a Saturday to kill, it was time for another trip out to Metrix Create:Space.  Since I wanted to make sure I had things exactly the way I wanted them before going into production with this, I decided to cut one more prototype, which you can see in progress here.

And this was the second prototype that resulted, fully assembled for the first time. 

Here’s a close-up to give you a better idea of what the engraving looks like.  On some of these the engraving actually managed to make pinholes all the way through at the edges, but this isn’t really noticeable unless you actually look for it, so it’s not a big deal.  As a side effect of using transparent green acrylic, you can also see a really cool looking refracted image of the ornament on the paper behind this.  Satisfied that everything was now in order, I was ready to go into production with these.  I had two fresh sheets of acrylic (an 11″x15″ sheet of transparent green, and an 11″x17″ sheet of transparent red) and I was able to arrange these in a way to be able to get eight ornaments and eight windmill blades on each sheet.  I also ended up making a couple of extra windmill blades, which came in handy later on, as we’ll see.

Upon completion of cutting on the first sheet (a process which took a little less than 32 minutes of total cutting time) I was left with this.  In a way, I thought that these looked pretty cool on their own, but for obvious reasons the backing was going to have to go. 

Peeling off the backing proved to be easily the most time-consuming part of the process (especially the backs of the blades on which the backing paper had been scorched by the laser making removal especially annoying,) and really made a mess of my fingernails too.  As you can see here, there were also a couple of mistakes along the way, which meant that both of the spare windmill blades that I made had to be used. 

It actually took most of the afternoon to get everything cut out, mostly due to quite a few people coming in to use the laser cutter that day.  Eventually I got everything cut out though, and since I thought it might be nice to have a bit of contrast, I decided to alternate the ornament and windmill blade colors.  If you take a look at the windows inside the windmill body, it should give you a good idea of just how precise the laser can be, as the gaps between the windows are only about half a millimeter thick.  And the gaps between the squares on the windmill blades aren’t much more than that.

After getting all the stuff home, it took a couple of hours to get the backing off of everything.  In particular, the red windmill blades proved troublesome, but eventually I got it all done.  You can also see a couple more ornaments that I assembled to check the contrasting colors, and the bag full of spacers up top.

Finally, several hours and another trip to Home Depot for more machine screws later, everything was fully assembled, 8 of each color (plus the all green prototype seen above, making a total of 17.)

Here’s another close-up of the finished ornaments, giving a better idea of how the contrasting colors look.

Overall, I really like the way that these turned out, but there are a few things to keep in mind if you decide to embark on a project like this:

  • Don’t plan on saving any money over buying premade ornaments by doing it this way, especially if you have to pay for use of the laser cutter by the minute like I did.  If I had to do this again, I probably would have drastically reduced the number of teeth on the gear outline to reduce the amount of cutting time necessary.  If I had to do these at the original 6 minutes each from the prototype, this probably would have been way too expensive to be feasible.  It also would have cost a lot less to do these in birch plywood (which would have been quite a bit faster to cut and doesn’t come with a “stink” surcharge) instead of acrylic.  But also keep in mind that there are pretty strict guidelines as to what can and can’t be cut on one of these.  Some items can actually be dangerous to use a laser on (for example, any item with chlorine in it can emit hazardous chlorine gas when cut with a laser.) 
  • Make sure you follow the guidelines that are specified for the cutter in order to ensure that you have a viable design for cutting.   The Metrix Create:Space site has a Wiki page that discusses these and links to another site with even more info.  Even if you follow everything to the letter, don’t be surprised if some tweaking to your design is needed though.
  • Don’t make things too small.  Although the windmill blades in this design are generally pretty sturdy, they do have obvious weak points, as seen above. 

As for whether or not I would take this approach again, I would definitely consider it, but don’t expect it to be cheap (at least not unless you can somehow get access to a laser cutter without having to pay for it.)  But still, anytime you have a chance to make some really cool looking custom ornaments completely from scratch without having to go anywhere near a craft store you’ve just got to take it, right?

(If by any chance anyone else might want to try making some of these, let me know and I’ll see about putting the design up on Thingiverse or some other similar site.)

About these ads

4 Comments »

  1. These are AWESOME! Probably my favorite ornament ever!! Thank you Brian!

    Comment by Valerie — November 27, 2010 @ 6:33 am

  2. [...] lasercut design newbie, Lutz took the dive into making a lasercut design for the first time and shared his learning process on his blog, The Sledgehammer (which I came across in my Google alerts for [...]

    Pingback by LaserCut Designs : Christmas Ornaments from a Lasercutting Newbie — December 12, 2010 @ 7:51 pm

  3. cette objet est superbe comment pui-je en avoir un svp?

    Comment by vanderhoeven — February 8, 2011 @ 8:30 am

  4. many thing about laser engraving machine

    Comment by laser cutter — February 22, 2011 @ 12:30 am


RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Theme: Shocking Blue Green. Get a free blog at WordPress.com

Follow

Get every new post delivered to your Inbox.

Join 269 other followers

%d bloggers like this: