What is 3D Printing?

Matt Donley 3D Printing, Fabrication, News Leave a Comment

Since getting into 3D modeling, I have always been fascinated with the idea of being able to create real-life objects from my digital models. I haven’t had a chance to try it out, but I recently attended a local 3D printing meeting at AS220 Labs, in Providence, RI. It was my first time ever seeing a 3D printer in real life, and I learned so much in one night I thought I’d share my experience.

The Local “Hackerspace”

When I walked in to the AS220 Labs, I could tell I was in the right place. I saw a miniature laser cut wooden trebuchet sitting on a table, loaded with mini tennis balls. There was a shiny new shop bot in the back of the space, getting ready to be set up. And there was the crowd of people, circled around a table, watching some kind of contraption whizzing away.

It was a 3D printer. The first 3D printer I’ve ever seen in person. And it was printing away at multiple copies of “mustache rings” (More on that later).

As people scooted aside to invite me into the circle, I watched in amazement as this little machine was “printing” out a 3D object. It’s really quite mesmerizing to watch it in action.

I found out about the 3D printer meeting organized by Matt Stultz from 3DPPVD on the Make website. It’s a blog/magazine that’s all about making things. It’s a really great resource for anyone who is into personal fabrication, DIY, electronics, etc. They also host the Maker Faire, which is an event that encourages the creativity within everyone to make things. There are a number of “mini” Maker Faires all over the world so you’re likely to find one near you.

Matt Stultz is a 3D printer fanatic, and actually used to work for MakerBot, a company that designs and sells personal 3D printers. He started 3dPPVD to create a thriving 3D printing community in Providence, and to share his knowledge and passion for 3D printing technology.

AS220 Labs

The AS220 Labs is a “Fab Lab” located in Providence, RI. They are one, of many, around the world. It’s a place where people can have access to many resources to help them create things for fun. At AS220 Labs, they have a CNC machine, a laser cutter, a vacuum forming machine, a 3D printer, and many other tools and equipment that I don’t even know what they’re called.

As a member, you can rent time on different machines to create your own personal projects. Most of the members are artists, and use the equipment to help them create unique art. You also become part of a community of like-minded makers, who love to share their experiences and knowledge.

They also have the Fab Academy, a Digital Fabrication Program that teaches people how to use different technologies to create things. It’s a 6-month part-time course that is directed towards any skill level.

The MakerBot Replicator (3D Printer)

The 3D printer that was set up was called the Makerbot Replicator. It “prints” out objects by melting and extruding a plastic onto a small platform in multiple layers, forming an object. The machine can by purchased, fully assembled, for a price tag of around $1,700 bucks.

This model had an upgraded option, allowing a second roll of filament to feed through the printer head, allowing it to print in dual-colors. The dual printer head is a $250 upgrade. The plastic filament is 1.75mm – 3mm thick and comes in a roll. The spool unrolls as it feeds the printer head with filament as the printer is working.

This Makerbot was busy spitting out a handful of mustache rings. You basically put it on your finger and hold it up to your face to make it look like you have a mustache, lol. It was printing out 10 copies at once. It took about an hour and a half to complete the task. (One of the rings didn’t stick to the platform and ended up being pulled out of position by the printer head.)

This type of 3D printing is called Fused Deposition Modeling. It is an additive manufacturing technology, and has some disadvantages over some other types of 3D printing. Mainly, the model must be designed so that it is self supporting as the model is printed. Each layer that is printed depends on the layer underneath to support it as it is being extruded.

Other popular 3D printing technologies include Stereolithography, and Selective Laser Sintering. Check out my post on the Solar Sinter, a solar powered 3D printer that uses desert sand as a medium. Because of the higher cost for equipment to use these technologies, it is more practical to look for companies like Ponoko or Shapeways to produce models for you using these methods.

How 3D printing works

The printer head is mounted to multiple rails that are attached to motors. The motors are controlled by the processor and move the print head along an X and Y axis. So the print head can move left to right, and front to back. The platform in which the object gets printed to is also on a motor controlled rail that allows controlled movement on the Z axis. So after one layer of the object is printed, the platform is lowered by a fraction of an inch, and the printer begins printing the next layer.

The processor tells the motors how to position the printer head based off of instructions prepared by special software. It imports your model and compiles it into a program for the printer to follow.


ReplicatorG Software

One of my biggest questions was “How do you take a model from Sketchup, and end up with a plastic model in your hands?” What happens in between? Is there a lot of work involved “setting up” the model to be printed?

It’s actually quite simple. To prepare a model for the MakerBot Replicator, you have to process the model using the open source ReplicatorG. What this program does, is create the instructions for the bot to print the model. It optimizes your model and plans out a “path” for the printer head to travel while it is extruding the melted plastic. This software does that for you automatically. You don’t have to worry about manually defining the path.

You also don’t even need to know how to use Sketchup. There are many other free and paid modeling programs out there. But there is also a resource, much like the 3D warehouse, called Thingiverse. It’s a website where people can upload their models and allow other people to download them for free to print out on their own 3D printers. So you don’t even need to know how to 3D model in order to use a 3D printer.

There are a few options in ReplicatorG that you can define. While most of the time you can just use a preset configuration, a lot of people tend to define the amount of “infill” they want printed.

In order to save material, most models are printed hollow. But a hollow shell isn’t going to be very strong. So ReplicatorG has an automated way of creating an internal “cell structure” to add strength to your model, without wasting material. You can set the amount of infill by defining a percentage. 100% infill would be a completely solid model, while 0% would be completely hollow. A common infill setting is around 20%.

The bot interfaces with a computer via USB cable, or you can upload your model to the bot using an SD card. There is a built in LCD screen with controls for you to operate the printer. Because of the option to use an SD card, the printer is completely mobile, and can be taken with you anywhere.

The Result

3D printed object

Click to enlarge for details

They passed around a few examples of models that have been made by this printer. There was a frog, a camera mount adapter, a gear, and a few other things. Each item was no bigger than 3″-4″ in any direction.

You could clearly see each layer that was printed. The surface is left with a unique ribbed texture. You can feel each ridge on the model with your finger nail almost like a metal file. At the same time, there is an impressive amount of detail that’s achieved using this type of 3D printer. The ridges appear more pronounced on more horizontal surfaces, and less pronounced on vertical surfaces. The bottom is noticeably smooth, from being melted on the flat platform plate. You can see the rows of filament clearly, along with any imperfections.

Close up Bottom

Click to enlarge for details

The objects were pretty light, almost like a wiffle ball. You could tell they were mostly hollow. If you dropped one on the floor, it would probably bounce around a bit because of the hard plastic material. The plastic is ABS, the same stuff Lego bricks are made of. They are very durable. For some reason, I had always imagined 3D printed models to be extremely fragile. But they seem very strong.

I can’t wait to start doing some 3D printing of my own. I’ll probably be heading back up to AS220 Labs for these 3D printing meetings to learn more about it. In the meantime, I have to figure out what I should print. Any ideas? Mustache ring?

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