Many come to Pulaski County school board meetings for updates on the school system; few come to witness a medieval siege engine display. Those who attended Thursday night’s meeting were given both.
As part of the meeting’s instructional focus segment, school board members and onlookers were treated to a demonstration of what can be made with a 3D printer and exactly how a trebuchet works. There was a 3D printer in the meeting room that worked on one of the presenter’s projects throughout the evening.
This past summer, Pulaski Middle School math teacher Georgeanne Lavery and Pulaski County High School technology education teacher Christian Miller spent time at Virginia Tech, working on different projects through a fellowship from the National Science Foundation. Their efforts, which Lavery described as “an inquiry-based learning curriculum,” provided the university with some research information and helped Lavery and Miller work on this year’s class planning. Eleven area teachers participated in the fellowship.
Lavery explained that her work involved testing the durability and breaking point of plastic objects that were 42 microns thick and made by a 3D printer. “My job was to figure out at what point do the specimens break, how strong the materials were, each of the different types,” she said.
Such printers have been around since 1984 but are getting more attention lately; they create three-dimensional objects from plastic polymers and other materials. The process is somewhat akin to traditional manufacturing, although objects are created by fabricating materials, rather than subtracting (stamping, cutting, lathing) them as in traditional manufacturing or machining.
“I worked with the Object Connex 350,” said Lavery of the particular 3D printer she was assigned. “It’s a huge machine that deals with micron-sized outlets of photopolymers.” Of the materials the printer made, she said, “It’s plastics that have to be cured by UV light.”
She showed slides of different things manufactured by the printer, including an object made of white plastic, black rubber and monofilament wire, which she said was created all by the same printer at the same time. “There was no assembly,” Lavery told the school board. “That’s the promise of 3D printing. That you can get higher-quality parts with no assembly needed.” CAD software was used in some of the research, she said.
For her own students, she said that she was teaching a curriculum called “Transformations” this year, using a 3D printer. “It shows the students how, if you put in something wrong, something wrong is going to be printed,” she said. Her example on one slide was a plastic snowflake designed to look like a series of Darth Vader helmets.
“Is it true what they say? No two Darth Vader snowflakes are alike?” quipped board member Joe Guthrie to Lavery later in her presentation.
Lavery passed around items made from the 3D printer to the board, including two types of gears and a small “minion” figurine from the “Despicable Me” movie series.
“And you’re able to print it and give the spacing between the gears?” asked Vice Chairman Jeff Bain. “Because the way these gears interlock, the spacing on these gears, that is amazing.”
Guthrie asked, “Mr. Miller, we’re understanding that because of your participation and Ms. Lavery’s participation, we have this 3D printer now for the high school?
“Yes sir, we both received a 3D printer. This is not the one we received. It’s very similar to that.” Miller said two had already been bought for the high school. Miller went on to thank the board, saying, “I want to thank you all for letting me run this noisy machine during your meeting.”
He took the floor and said that he teaches STEM classes. “I often tell my students, ‘This isn’t your dad’s shop (class),’” he said. Miller indicated the 3D printer and informed the board, “It is currently printing out the frame for a remote-controlled quad copter. The goal of that project is to deliver a payload, which I think is going to be a leaflet, to a predetermined location. We’re keeping our fingers crossed that we can get that done by the end of the first semester.”
Miller then allowed Sam Norris, 17 and a senior at PCHS, to demonstrate their second-semester project: a functioning trebuchet, which is in the family of catapult-type weapons.
“We have decided that is going to be the class project,” said Norris. “The goal is to throw a lemon the length of a football field.” Norris had a one-quarter scale model of the trebuchet the class intends to make, though this one was wooden. To demonstrate it, he loaded it with a red rubber ball and proposed to shoot it into the corner of the room, which happened to be near Bain’s seat.
Bain laughed and asked Director of Operations Ronnie Nichols, “Ronnie, do you have replacement ceiling tiles?”
Nichols replied with a straight face, “Yes, we do.”
After its launch, the ball flew a short upward distance before bouncing off the ceiling, though both tiles and onlookers were spared. Norris, who said he is interested in the Middle Ages, continued his presentation.
“Most of that was just made from looking at pictures of trebuchets; I didn’t use any formal design plans,” he explained to the board. “A lot of it was trial and error. I’d say the hardest thing to calculate was probably trying to figure out when to get the ball to release. I have to get the release hooked at a very specific angle. Three or four angles too far forward, it would shoot into the ground; too far back, it’ll just go straight up and come back down. A lot of hard math is involved.”
He continued, to laughter, “The big scale that I’m working on now is 6’6” tall by 8’ long. Maybe we want to get that and bring it into the next board meeting.”