Model #360

I’ve been plugging away at my next puzzle, Model #360, for some time now. I made the first prototype out of wood, oak I think, back in the late 1990’s and it was pretty bulky. It sat in a box until I found a machinist to make me some slimmer models from delrin. Then I changed jobs and other interests and responsibilities consumed my time so it sat on a metaphorical shelf for another couple of years. Anyhow, after I built my 3D printer I decided to revisit the design, print some new versions, and eventually refined it to the point where it made sense to have some SLS prototypes made. Here is the family portrait:

The leftmost one is oak, the next two are delrin, the white one on its side in front is white nylon (SLS), the blue one is off of my 3D printer, the black short one is a dyed nylon version (also SLS) from Shapeways, the purple one is from my 3D printer, and the rightmost one is the latest version.

Most of the changes from version to version are internal and I can’t talk about them without giving away the solution. But I can give you this close-up of the final version:

My plan is to have it made of nickel-plated aluminum which I think will look pretty slick. Those of you who solved Model #808 may remember the red disc inside, the “proof of work”! Well, Model #360 has a bigger prize, a turquoise sphere which you can see in the picture. I’m a little worried that variation in their diameter may mean that some won’t fit but they should arrive today and then I’ll be able to check.

Like Model #808 this one will also be made on a limited edition basis. There will only be about a 100 and yours truly will be assembling, numbering, and initialing each of them by hand. I had hoped they would be ready before Christmas but that’s looking mighty unlikely; I think late January is more realistic at this point.

That’s it for today. Now I just need to put the quote out to bid and pick a machine shop to make them!

More Prototypes

Though I haven’t blogged in about a year, at least I have been making progress on my puzzles. Pictured here are Model #808 (the rectangular one with two holes), Model #518 (the multi-colored cube), Model #921 (the circular one), and Model #360 (the thicker rectangular one with the red logo).

prototypes

The internal design of Model #808 (formerly known as Model #873) continues to evolve and I’m hoping to get a prototype today that will confirm the reliability of the new design. I guess it’s no surprise but getting a puzzle mechanism to work in theory is easy, getting it to work once or twice in an actual mechanism is doable, but getting it to work dependably and reproducibly is really hard. I’m on Rev. 9 on this one.

Model #360 turned out to be easier to get working than I expected and it may be the first one to reach production in aluminum. Models #518 and #921 still have a ways to go.

In other news, I now have an FDM type 3D printer (the i3PRO from MakerFront) to shorten the cycle of revise design / make new prototype / test new prototype. I’m still learning how to get good quality prints from it but I look forward to being able to get a physical prototype of a puzzle design within hours instead of days. I’ll post some videos of my experiences with it in case anyone else is contemplating buying one of these things.

On the Asymptote to Perfection!

I just received my latest prototype back from the 3-D print service I use (i.materialise – whom I recommend highly) and I’m very happy with this latest revision (the sixth I think!)

The puzzle has two major pieces, the top and bottom, and the biggest design challenge I’ve had so far has been to keep the two pieces aligned while the puzzle solver is manipulating the puzzle. If the pieces move out of alignment, it can put the puzzle into an unsolvable state or it can keep the puzzle in a partially solved state when it oughtn’t. In a previous puzzle I used Vlier pins to hold everything in place and they worked beautifully. Unfortunately, they’re much too expensive so I’m experimenting with some other approaches. Here’re what the top looks like:

873-top

I’ve never used this material before. It’s nylon (polyamide) mixed with aluminum powder and it’s called “alumide”. I like the metallic color but overall the finish isn’t as nice as with the matte white nylon so I’ll probably go back to that. Here’s a picture of the bottom:

873-bottom

If you squint you can see the model number embossed on the right end: “Model #873”. If you really squint, you can make out “www.pyrigan.com” embossed on the left. The low print resolution makes it hard to read the text but this is just a prototype. The final version will likely be made from machined aluminum and engraved with the text on the back and the logo on the front.

The good news is that the puzzle mechanism works very reliably so I will press ahead with plans to manufacture a couple of dozen and see if anyone enjoys these things as much as I do.

Puzzle Prototyping with 3D Printing

The summer was way too busy but I nonetheless was able to design and prototype my first mechanical puzzle. It even works!

Building a working prototype turned out to be much easier than I expected now that 3D printing has become so affordable and so widespread. All I had to do was create .STL files (I used OpenSCAD) and take them to a local outfit called Einstein’s Workshop whose fantastically helpful staff (thank you Katy and Matt!) printed them for me.

I tried prototyping a puzzle about twenty years ago by taking my design to a machine shop and that cost me a couple of hundred dollars. The 3D printed prototype, on the other hand, was about a twentieth the cost and took a quarter the time, thanks to the amazing march of technology. Also, even though I made a mistake in the first version of my design it only cost me the wasted 3D print, not the cost of a machine shop’s time and materials.

So here is a picture (the pen is there for scale):

3dproto

As you can see, the surface finish is pretty rough since it was made using FDM (Fused Deposition Modeling). I’m currently waiting to get back a higher tolerance version that was made using SLS (Selective Laser Sintering) and hopefully that will compare favorably with the smooth finish of machined aluminum. My plan is to iterate my design with 3D printed prototypes until the puzzle is working perfectly; then I will decide whether it’s worth the extra cost of having them machined from aluminum or delrin or something.

Most important is that the puzzle mechanism is working dependably and as it was designed to. I’ve shown it to a couple of friends and the feedback has been positive: it’s very hard to solve but not unfairly so. (At some point I want to write an opinion piece about puzzle “fairness” but that’s a post for another day.) For some reason I’ve always liked dovetail joints on puzzles – I guess that’s why I have all three (1, 2, and 3) of Wil Strijbos’ beautiful cube puzzles (great review here) – and so I couldn’t resist the temptation of using them for my first puzzle.

So anyhow, I have reached the prototype milestone and hopefully I will be able to finish the puzzle design and put it into production before the end of the year. Feel free to comment or email me at kay en oh see kay at-sign pea why are eye gee aye en dot see oh em.