Checkmate!

Introduction

Sometimes it's nice to take a break from the electronic world! My kids and I used to play a lot of the classics like Uno, Clue, BattleShip and the ultimate classic, Chess! Since getting a 3D printer, I've wanted to print my own chess set. The recent publicity of AlphaZero learning to play chess on its own decided it!

After printing the pieces, my son and I were so happy with the way the pieces came out, we decided to 3D print a board as well!

Thingiverse

The search for the perfect chess pieces began with a search on Thingiverse. In fact, it is the place I go most often whenever I want to explore 3D printing projects!

There are so many chess different designs available, you could spend hours trying to find just the right set. My favorite chess pieces are the Lewis Chessmen. The beauty and history of these pieces is fascinating. They are enchanting works of art. However I couldn't find a ready made set that I really liked. and I am not an artist enough to create my own. Additionally, my feeling is that for regular play the simple, elegant Stauton style pieces are the best. To me they express the role and power of each piece without distracting attention from the game itself.

After a few hours of searching and a few more of test prints, we decided on two different projects for our chess set:

• Pieces, OpenSCAD Chess by TimEdwards, published Dec 9, 2014

• Board, Chess pieces with board by Winslow, published Jun 29, 2017

Thanks to the generous work of these two makers and artists, and their willingness to share their work, we were able to make this project!

3D Printing - lulzbot mini

Our 3D printer is the lulzbot mini. It was our first and so far only printer. We have been using the same printer with almost no troubles for over 2 years now! Any project on our accounts here on Hackster.io has been printed with it and we are very happy with it.

My only significant problem to date was with the extra print head we purchased to print flexible filaments, such as ninjaflex or semiflex. We made a handful of prints with it, <5, and then the flexible filament began jamming in the "cold" part of the extruder. I tried many of the suggestions on the forum and used the suggestions from technical help but nothing worked. Unfortunately we discovered this problem after the warranty period on the head had expired, and Aleph was not interested in sending me a replacement. In defense of Aleph, after asking a few people at some Maker faires, I have not found anyone with the same problem! Just my luck.

So for rigid type filaments such as ABS, PLA, HIPS, tGlase and some semi-rigid such as PCTPE I can highly recommend the lulzbot mini. I have printed with all of them with great success and minimal to no problems. However, I would look elsewhere if I wanted to print flexible materials. Once bitten, twice shy.

For the filament we used red, white and black 3mm HIPS(high impact polystyrene) from Gizmo Dorks. It prints with an hot end extruder temperature of 240 and a bed temperature of 110. So you can see that the heated bed of a lulzbot mini is essential.

To PEI or not to PEI

Originally the lulzbot mini's glass bed comes with a covering of a material called PEI. This material helps with filament adhesion and cooling. Unfortunately, due to my not properly cleaning the hot end extruder, the head bed leveled incorrectly prior to a print and tore into the PEI sheet. We never replaced at the sheet as we found out that either applying glue from a glue stick or blue painters tape gave the same results!

After this write-up was originally posted, I had received some very complimentary feedback and a concern they had in printing without PEI:

Great writeup! Are you still printing on bare glass? If so, give replacing your PEI sheet more consideration. You'll find, like we've found, that over time due to part adhesion parts can lift portions of the borosilicate glass bed out, or even crack it. Here's the replacement PEI sheet with adhesive: https://www.lulzbot.com/store/parts/lulzbot-mini-pei-sheet …

We also have a new two part modular bed system, that makes printing on PEI or bare borosilicate glass (say for flexibles) easy: https://www.lulzbot.com/store/parts/lulzbot-mini-glass-pei-print-surface …https://www.lulzbot.com/store/parts/lulzbot-mini-modular-print-bed-heater …

I have not experienced this with my glass bed, but I tend to wait to remove my HIPS print until the bed has cooled. They simply lift off without any effort, but I could see that certain filaments, especially if using glue, might cause this to happen. So out of respect for your printer and their experience, I thought it important to update this post!

However, in the case of HIPS, nothing is needed on the glass bed! At 110 degrees, the HIPS adheres directly to the glass and comes off the bed easily after cooling! We love HIPS!

Overhangs

The open scad chess pieces come divided in the middle to avoid the problem with overhangs, especially with the knight. In 3D printing, with a single head, print overhangs are a constant problem. This is melted plastic, so after a certain length, it will sag if it not supported before it cools.

To overcome this, printer software like Cura, for the lulzbot, can put supports in locations where overhangs exist. This solves the problem of sagging, but leaves a leave support material that need to be removed. This not only can cause damage to the print but also leaves marks and scars after removal. A dual head printer could be used to print the original in one type of filament, and supports in a water soluble filament for superior prints! If I were getting a new printer today, I would seriously consider any printer with this capability.

"Handcrafted" Chess Pieces

By cutting the chess pieces in half, overhangs are avoided but each piece must be printed in two individual pieces then glued together. The surface of the print adhered to the glass bed comes off incredibly smooth and does not take as well to gluing.

We recommend filing and scoring each of these surfaces and keeping the "dust" from the filing on the surfaces. This will cause the glue to cure very quickly.

Be prepared, especially for the pawns, it only takes a few seconds for the pieces to firmly and permanently adhere to one another!

Acetone Vapor Finishing

If you were attracted to the smooth and glossy appearance of these pieces and want to do this with your prints, you need an acetone vapor finish! All this is nail polish remover in a covered jar! We purchased a large can of acetone at Walmart and use this. We never warm or heat the acetone and we always use it in a well ventilated area! It does not work for all filaments, but as you can see from the final results, it works well for HIPS! Regular pieces took about 2 hours and the pawns only 1 1/2 hours. We did not vapor finish the board, but you could if you wanted to.

This process does not work for all filament types. I tried in on tGlase because I thought a smooth finish on the translucent tGlase would look amazing. Well, after 2 hours, nothing! So back to the HIPS. However, I used this property of the tGlase filament to print a support base for pieces in the acetone vapor chamber.

You don't want HIPS in direct contact with acetone for any length of time as it will rapidly "melt" You want the nice, even, slow effect of acetone vapors for your finish. We designed the acetone vapor platform in Fusion 360 and printed it on the lulzbot with standard settings.

We recommend printing several of them so you can use multiple jars. They tend to stick to the tGlase platform after coming out of the chamber. Having a few allows you treat one piece after another. Again allow the pieces to off-gas in a well ventilated area and viola, beautiful, smooth and glossy prints!

The Board

A chess board has 64 squares on it. The print we used has four squares per interlocking tile. Each interlocking tile has 2 raised squares on it and 2 recesses. The base tile is printed in white and the separate squares are printed in black. These black squares are then glued into the white base tile with the same super glue that we glued the chess pieces with.

We printed the tiles on the quickest print setting. If we had done otherwise, we might still be printing the board! The time estimates from Cura for printing a single tile with HIPS are:

• Standard: 2 hrs 33 mins

• High Speed: 1 hr 32 mins

• High Detail: 4 hrs 34 minutes.

Let's do the calculation on that for a high detail print of the tiles alone:

• 4 hrs 34 mins = 274 mins

• 274 mins * 1 hr/60 mins = 4.57 hrs/tile

• 4.57 hrs/tile * 16 tiles = 73 hrs

• 73 hrs * 1 day / 24 hrs = 3 whole days of printing time

The same calculation for high speed settings comes out to about 1 day, which makes a big difference. These estimates are calculated using the default settings. Cura allows you to modify these settings which can lead significant time savings.

Unfortunately, using the high speed settings probably led to the result that our tiles did not interlock well enough to be glued together directly. To solve this problem we went to a hardware store and bought a thin plywood board, cut it to size and sanded the edges smooth. We then glued the tiles in place one by one. Make sure you pre-place all the pieces prior to gluing them to understand how they fit together(if you do make a mistake, you could use a regular screwdriver and a hammer to wedge the tiles off, not recommended).

After you glue all the tiles in place, place the board on a flat surface and load it up with books to weigh it down and ensure the tiles cure/dry to the board without warping it.

Conclusion

You're now ready to play a game. Turn the cell phone to mute, get off Twitter, turn the computer off and spend some quality time with your loved ones . . . checkmate!

Bonus Pics

This last picture is of some test prints. The blue pieces were printed with tGlase filament. The red pieces are from a set by Joe Warren on Thingiverse. One of us(Phil) liked them, the other thought they were a bit too fancy and distracting.

Yes that's an elephant you see there, and was the "bishop" of the original game of chess, chatranj from India.