Printrbot Front

by tolomea on September 2, 2012

Printrbot Front
GXR A12, 50mm (35equiv), ISO 200, 1/111s, f/2.5, 2012-09-02

This is as good a shot as any for doing a brief overview.
The heart of the system is the extruder, this pulls in ABS filament, melts it and squirts it out the hot end (kinda like an automated hot glue gun). In the picture the gears in the top left are for pulling the filament in, the bright red bit is the hot end and the black bit is a fan. The fan is something I added, it helps the molten filament set faster so another layer can be added on top.
The extruder is positioned and moved so that the extruded plastic builds up into the desired object. This requires moving it along 3 axis.
X, left to right. The extruder is on a carriage that slides along the two horizontal rods, it’s driven by a motor and belt on the other side, you can see them better in the next photo.
Y, forward and backward. Instead of moving the extruder we move the object being printed by moving the bed it is resting on. This is driven by a motor and belt underneath, the white bit center front holds one end of the belt, you can see the motor just to the right of it.
Z, up and down. The entire extruder and X axis assembly is raised and lowered along rods at the sides. Looking at the right, the inner rod is the guide while the outer rod is threaded and transmits the motive force from the motor bottom right. The left side is the same.
Additionally the bed on which the object is constructed is heated, this is necessary because ABS, our material of choice, expands as it heats. Since it is extruded hot we need to keep it hot during the printing to prevent it from warping.
The heaters and motors are controller by a small computer, this is mounted below the bed, you can see some of the connectors and plugs, bottom center.
The only other component of note is a standard PC power supply that isn’t visible in this shot.

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