Off the drawing board

New printer creates 3-D models of objects

New printer creates 3-D models of objects

October 24, 2005|by KAREN HANNA


The $29,000 printer in Alan Zube's office at Washington County Technical High School would look at home in a college dorm room surrounded by pizza boxes and posters of musicians.

Though it might resemble a miniature microwave/refrigerator combo, the machine cooks up more than soup from a can. Students are using it to see how their ideas stack up in 3-D.

The Dimension SST, which uses material similar to glue from a hot-glue gun, creates plastic models of objects designed on computer screens, said Zube, who plans to offset some of the cost of the machine and the material it uses by fabricating parts for outside companies.


For students, the machine presents the opportunity to see a model of the images they created on-screen.

"That's one of the values of this ... it gives them a chance to actually touch it and look at it without going into the lab and trying to fabricate it," Zube said as students in his junior-level introduction to engineering design class plotted designs for chess pieces.

Most of the students will go on to four-year engineering schools, Zube said.

Domingo Mencia, a 15-year-old South Hagerstown High School student, showed off intricate white plastic models of chess pieces he and a partner built based on pictures of swords. Domingo said he was excited to hold the model he made because, "it makes you think, and it makes you want to do more things. It really amps you up."

Domingo and his classmates used pictures and sketches of objects like the Eiffel Tower, the mushroom in the Super Mario Bros. video games and "Nightmare before Christmas"-type characters as the inspiration to begin work on the computer. A computer program allows them to draw on a variety of planes, creating objects on-screen that can be rotated in all directions.

Once that's done - the process can take several hours per piece, students said - the designs are sent to the Dimension SST, a rapid prototype printer the school system bought on sale this year, Zube said.

As students worked in the classroom, a screen on the front of the machine in Zube's office showed it heating up to nearly 300 degrees in preparation for printing three-dimensional models. The interior lit up like a microwave oven, and an arm inside traced out streams of molten plastic, putting down one layer on another, according to the dimensions of students' drawings.

The machine also uses a brittle brown filler material to provide support between the layers, Zube said. That material dissolves in a chemical bath in a separate unit in the process' last step.

The printer has exposed the weaknesses of some students' drawings. If part of the drawing is too thin, the plastic can snap.

"You kind of realize what you can do and what you can't do, because it might look cool on a piece of paper, but sometimes you have to realize that's not really going to work," said Christine McMaster, a North Hagerstown High School student who worried the thin jaw of a skull she drew in three dimensions might break once it's embodied in plastic.

Some students, including a Clear Spring middle-schooler who has elaborate drawings for a model of a Star Wars ship, have gone back to the drawing board to figure out ways to make hinges and pins to create moving parts or to make pieces that can fit together. The printer is limited to making one-piece objects that are 8 cubic inches or smaller, Zube said.

The material the machine uses costs about $5 per cubic inch, Zube said.

As a class, students are only printing a few of the pieces they make, but Zube has given them the option of buying their entire chess sets.

James Harvey, a 17-year-old South Hagerstown High School junior, said owning a chess set would be the payoff for hard work.

"I'm probably gonna buy all of it," James said. "I mean, it's something you actually created, You can look at it and say, 'Yeah, I made that.'"

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