FIRST Robotics Team 'Slight Malfunction' 3D Prints Robot for Competition

Hidden in the woods of Southwest Mississippi is the duo of robot builders known as FTC Team 14236, Slight Malfunction. Nine-year FIRST veteran Nick and Rookie Jake have been working hard this year to design, build, program, and drive a very unique robot.

A FIRST Tech Challenge team can consist of up to 15 team members but, due to little local interest in robotics, we have two. Funding for robotics is also very hard to come by in our area. That being the case, we must be creative in our use of materials.

Many different factors guided us to our unique design this year: a small team, which limited our available man-hours for the design/build process, and a minuscule budget. This season, a majority of our robot is 3D printed.

FIRST Robotics team Slight Malfunction use 3D printing to make sturdy components for their competition robots.

Many FTC teams base their chassis design on one or two kits of parts. There are a few off-the-shelf chassis kits that are very well-designed, and we have used them in the past. Last season, we used one such kit to help us achieve top scores in the state, and with the help of our finalist alliance partners at the state championship, the Bogue Chitto Technocats were able to secure a position to represent the state of Mississippi at the world championships in Houston, Texas where we competed with 160 other teams from around the world.

Last season’s robot game featured choke points that favored a small chassis. This season’s game includes even more obstacles that a robot must maneuver around and through. We quickly realized that, if our robot had a smaller footprint than the last, it would give us an advantage in that we could traverse the field faster than our opponents. An off-the-shelf frame was quickly ruled out in favor of custom aluminum parts.

A nearby business was willing to CNC cut custom parts for us, but we did not have the means to purchase the aluminum plate needed. As we were working out a way to fundraise, we decided to 3D print prototypes in PETG filament to see how well our design would work, if at all. The side panels of our chasses were a little too big to fit on the build plate of our printer, so we printed them as two parts and assembled them afterward. Heat set inserts and 4mm bolts hold the halves together and allow motors to be installed within the side rails, saving precious space inside the robot, yet keep everything rigid.

Slight Malfunction's compact, well-engineered robot and MatterHackers' mascot 3D Phil A. Ment

The game-scoring elements are smooth plastic cones, which proved to be a challenge to move around the field. After some time spent researching and designing, we decided to carry the cones using an expanding gripper that is inserted into the top. We were able to quickly design and test several iterations of this grabber thanks to 3D printing. Printing in our lab allowed us to test ideas almost immediately without needing to wait for parts to come back from a machine shop. Cost was also only a few cents per part, as opposed to being a large expense for every design version produced. This allowed us to test parts and modify them several times in a single day until everything was just right. We ran several tests with our printed chassis in our lab, including crash tests where we intentionally tried to break it, and were pleased to find out that it was quite durable. As we were still unable to acquire the aluminum in time to build a metal chassis for our first competition, we decided to compete using the PETG version.

Tournaments consist of two parts; an interview with a panel of judges, and the robot game itself. At our first qualifier, the judges were impressed enough with our team to award us the Connect Award and Inspire 2nd place, which secured us a position in the upcoming Mississippi State Championship. We were also picked to compete as a part of the finalist alliance in the robot game.

We have used MatterHackers’ filaments in the past and have been very pleased with the results we get whenever we print with them. Our PETG chassis was even printed with their black filament. We reached out to MatterHackers for a sponsorship prior to our first competition. MatterHackers happily agreed to sponsor us and supply our filament needs. After several emails back and forth explaining what exactly we were doing, the team at MatterHackers suggested that we use their NylonX or NylonG filaments. We opted for NylonG so we could make use of their orange and black colors to keep with our team's branding.

MatterHackers' NylonG comes in a lot of different colors, so we were able to match our team's branding easily.

After our first tournament, we started printing with the NylonG filament and quickly realized that we now had a material that would much better suit our needs. As we changed our old PETG frame parts out for the new NylonG, we found that we had cracked one of the pieces original while competing. With the new parts in place, we again tested the robot’s durability. Even crashing into the field walls at full speed, we have not been able to damage the new parts!

Printing with NylonG and NylonX gives Slight Malfuntion's parts the strength needed to compete.

Printing parts with NylonG has been relatively easy, thanks to the advice we’ve received from MatterHackers, both through emails with the MatterHackers' pros, and from the articles and videos on the product pages. If your printer is capable of running higher temperatures up to 260°C, and has a heated bed capable of 70°C, you should be able to print NylonX and NylonG with just a couple of upgrades. A hardened nozzle is necessary as the glass and carbon fiber additives to these filaments are abrasive and will quickly wear away a brass nozzle. Adding a Garolite print surface will ensure that your prints will stick, though we found that roughing up the surface with the supplied sandpaper and adding a skirt around the part has been necessary to prevent warping as the part cools. We have found that printing at 50-60mm/s with a .36mm layer height creates usable parts, but slowing down to 20mm/s with a .20mm layer heigh will leave a pristine surface and almost no print lines visible at all. Cooling fans are typically not used, but we have used them on occasion for small items, like a hollow tube to hold an antenna support that projected above the top of the part.

We are so appreciative of MatterHackers and their willingness to partner with our team this season. We can’t wait to see how far we are able to reach together!

FIRST Robotics Team 'Slight Malfunction' 3D Prints Robot for Competition

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