Background on this piece. This is the Italy “boot” in neon mounted to Walnut with engraved text. It is to commemorate a family vacation I took to Italy this year with the engraved text coming from sayings that we picked up from the trip.

Some detail on the process. The bending of the glass tube took roughly 15 hours over the course of a week. The Walnut was purchased rough, planed and jointed at the makerspace to get the boards square, and glued up into a panel. The panel was then cut down to size and run through the drum sander to even out any imperfections from the glue up. The engraved text was designed using inkscape and imported into CorelDraw for printing on “Katy Perry”, the 30W laser cutter. This panel was at the max cutting area for Katy Perry at 32″ x 18″. The cut took nearly 6 hours to complete. A box was constructed for the back of the panel to be used for concealing the electronics as well as a mounting point for the French cleat.

Total time to complete this piece was roughly 50 hours over the span of 2 weeks. Total material cost including glass, transformer, wood, stain, filling the tube with neon gas, and time on the laser cutter was roughly $200.

A few weeks ago a friend asked if I could help with a project for his wife’s new salon and I jumped at the opportunity.  I had been looking for a project that would mean using the big new 100W laser since it was donated.  My friend sent over a design and I got to cutting.

This is by far my favorite laser we have.  The software is easy to use and the laser makes aligning the uncut piece in the laser bed a breeze.  This project was also a chance to show off some of the new things I am learning in Blender to make a nice rendering of the final product.

We recently added a multi-stage filter to our laser cutter exhaust system which gave us an opportunity to buy things from American Science & Surplus and build a handy electronic gizmo.

More info about the project can be found on our wiki:
Laser Cutter Exhaust Filter Pressure Drop Monitor
Laser Cutter Venting System v6.0

I built a QWERTY keyboard that types the letters Q, W, E, R, T and Y, and nothing else. No space, no return, no escape.

It’s a fully-functional USB device, you know, as long as you just want to type words that can be composed with Q, W, E, R, T and Y. (WET, WRY, YET, TRY, there’s a bunch of them!)

I wrote plenty more about this project on my blog, and if you want to read about the history of the QWERTY layout, and its connection to Milwaukee, and why the way we interact with technology is interesting and sometime ridiculous, well… I got that too.

Often laser cut parts get attached at 90 degree angles, using finger joints, or screws and t-slots, but there may be times when you want to stack pieces of wood and have them aligned…

Pegs might be the answer!

Here’s a few photos of the pegs I’ve been experimenting with. For these pieces I don’t have a lot of room to have multiple pegs at opposing angles, but I can see where that might be useful. For these pieces the peg is really just for assembly alignment when gluing it all together.

Several months ago, a humorous request went out for a Zamboni that could be used on the Nerdy Derby track.

Last year the Milwaukee Makerspace held a Maker Fest and a Nerdy Derby track was made for the occasion. The design allowed the track to be disassembled in 4 foot long sections.

When the track was reassembled, earlier this year, for the South Side Chicago Maker Faire, it was found that the joints did not match up as well as when it was first put together. Small ledges, that went up and down, would cause the cars to bounce off the track or hit the bottom of the car. Both of these scenarios prevented the cars from traveling freely down the track.

As many of you know, we just had a GREAT Maker Faire here in Milwaukee last month and the Nerdy Derby track was needed again!

We produced, and ran, over 1000 Nerdy Derby cars over the 2 day event. Wow!

A month or so before the event I started working on an idea for a Zamboni type of device. My first thought was of a custom contoured planer that could be used at each joint to smooth them out. This idea seemed like too much work so I proceeded forward with my second design. This consisted of a simple sled hat used a drum sander, which smoothed out the high spots. Wood putty was then used to fill in any low spots.

The Barrister Free Mulligan Token

You see, I work at a board game & toy store.  In the world of collectible card games, taking a mulligan essentially means putting back the hand you were dealt and drawing a new one.  We figured our staff could use a second chance if they were ever caught in the wrong place at the wrong time.  With plenty of help from Shane, I was able to laser-cut a bunch of wooden tokens.

Standing up to your boss can be difficult.  But there are times when it’s appropriate, and now each employee is well-armed against fickle fortune.  Shane called our idea “very forward-thinking.”  My favorite part was at last week’s staff meeting, where everyone got do decorate their own personal token:

To expend a token, we simply drop it through the slot in the top of the pencil case, which is bolted to the backplate.  Once you take your Mulligan, the boss owes you a second chance, an apology, and (for good measure) a sandwich.  Expended tokens may be reclaimed by attending a staff meeting.  Who knows how much use they’ll see?  Even as just a symbol, it gave us a way to talk about the elephant in the room.

And play with the glitter glue.

I’ve worked on it off and on for a few months, but finally decided to finish it this weekend.  On Saturday, I tweaked some dimensions and laser-cut the final enclosure.  I wasn’t happy with the button holes and text I had on the front of the first iteration, so I got rid of them for the final.  You can adjust the time by slipping a jeweler’s screwdriver or a paper clip through a gap in between the plexiglass sides and pressing the buttons to add hours or minutes. 

I added a small single-pole, double-throw toggle to switch between bright and dim, then soldered the connections before closing it up.  The whole thing is clamped together by a single #10-32 machine screw and a wingnut.  The final result doesn’t look half bad.

Check out this video of the laser cutter in the middle of cutting 10000 circles!  Note the mysterious logic employed by the laser cutter to determine the order of its cuts.

I imported a photo into GIMP, and desaturated it to produce a black and white image.  After bumping up the contrast and darkening it slightly to nearly saturate the darkest areas (and avoid any totally white areas), I brought it into Inkscape.  Inkscape can create halftones in a two step, manual process.  The first step is to draw an 8 pixel by 8 pixel circle in the upper left corner of the 1133×720 pixel image, and select Edit->Clone-> Create Tiled Clones.  To create a rectangular grid of halftone dots whose sizes are set by the color of the image below, use these settings:

From a quick test cut of a particularly dark area, I found that I needed to add an offset between each row and each column to account for the kerf of the laser.  I.e. the laser beam has a cutting width that is wider than that of the line, and so in the darkest areas of the photo the halftone dots overlapped, causing a large section of the paper to fully detach. That led me to make this test strip with 11 shades of grayscale, evenly spaced between pure black and white.  I laser cut this test strip with various offset distances between the rows and columns in order to arrive at the optimal 10% extra offset between adjacent rows and columns shown in the above settings. Note also that the smallest size circles may not even be exported from Inkscape due to their infinitesimal dimensions (i.e. if you export as a .pdf).  The minimum gap between circles with 42% speed and 100% power on an 1133 pixel wide image blown up to 24″ is 0.79 pixels, which is 0.017″.

Applying these same settings to the image created a 128 by 81 array of circles, for a grand total of 10368 vector objects.  In my first trial run last weekend, I found that sending this much data to our 60 Watt Universal Laser takes 5 minutes and results in a print error I noticed only after hitting start!  After 1.3 hours of vector cutting, I found that a few of the rows and columns were shifted a bit from their intended location.  It’s not clear whether this had to do with the print error, or if the paper moved slightly during the cutting process.

In order to improve the second version (shown at top), I chose to move away from the rectangular grid of halftone dots – recall that Kays and London teach that hexagonal close packing is for champions.  The reason to abandon the rectangular spacing is to improve the dynamic range (i.e. to make the blacks blacker).  For example, rectangular grids of circles pack at an “efficiency” of Pi/4, which is 79%, whereas hexagonal close packing results in a pi/6*sqrt(3) packing, or 91%.  That means that the darkest sections of the image will be darker, as more of the light colored “front” piece of paper can be cut away.  See the image below, and note that the hexagonal pattern does indeed appear darker.

It turns out that Inkscape doesn’t easily permit this.  I ended up spending an hour or two fiddling with the column and row offset settings using my 11 black/white tone test strip to find settings that gave the hexagonal offset with the closest, even hexagonal spacing between adjacent circles.  The following settings worked great for an 8 by 8 dot on the darkest square of the test strip:

I test cut this yesterday, sending ¼ of the data at a time to the laser to avoid printing errors. However, part way through the cutting, cut-out paper circles stuck to the long air assist nozzle of the laser head (ironically) hit a washer I was using to weigh down the paper to prevent movement while cutting. The paper shifted by about 1mm, which was enough to make some adjacent halftone dots overlap and cause others to have a visibly wider spacing.

In the process of cutting that photo, Shane happened by and mentioned that vector cutting 10368 objects may be just as fast as the typically-very-slow raster cutting time.  With three clicks, I turned off the vector outline of the halftone dots, and selected a fill color.  After test cutting a row, I found that he was right.  Check out the difference between raster  (100% speed, 100% power) and vector (42% speed, 100% power) in the darkest section of the image – the area with the closest spaced circles:

The vector halftone dots are perfectly circular, though the edges are a bit rough.  Some of them have a very small border and so are a bit fragile.  The raster halftone dots are not very circular, but the edges are very smooth and the boarders are slightly wider.  I chose to raster cut the 24″ x 18″ image, and found that the raster cutting time of 1.4 hours was nearly equal to the 1.3 hour vector cutting time.

Note that many programs can create halftones, though often the results will not be suitable for laser cutter use:

The next step is to laser cut this image into wood.  Also, Inkscape will let you draw any shape to create tiled clones from – so please do share photos of any halftone images you create with star shapes!