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Mechanical Selection

A project log for 3D Printer

Attempt to dive into 3D printing

willbadenwillbaden 01/28/2015 at 03:170 Comments

Looking through the parts I have on hand, I am narrowing down the candidates for the mechanical/motor selection. There are three scanner beds pulled from copy machines that I am trying to decide between. Two have stepper motors and the third does not have a motor attached anymore.

To find the resolution of the scanner beds, the motors are spun (manually) and the number of revolutions are counted. The overall distance moved is then divided by the number of revolutions. This is then divided again by an assumed stepper step resolution of 200 steps per revolution. The following was found:

Scanner bed 1:

23.75 revolutions = 19.25 (both approximates)

19.25 inches/23.75 revolutions = .8105 inches/revolution

Assuming 200 step stepper:

1/200 * .8105 = .0041"/step (this is all approximate)

Scanner bed 2:

29 revolutions = 19.25 inches (approximately)

19.25 inches/29 revolutions = .663793 inches/revolution

Assuming 200 step stepper:

1/200 * .663793 = .0033"/step (this is all approximate)

Scanner bed 3:

Due to not having a motor mounted this was passed as a candidate.

From the above tests, I am leaning towards Scanner bed 2 to pick up some resolution with full stepping. Here is a picture of the candidate:

The Z axis will utilize a rack and pinion of mechanism that was used on the output of a copier machine for paper selection. This will take some modification to allow for the Y axis and table sit rigid enough to not cause issues with printing. Here is a picture:

The drive is a DC motor that will raise and lower the tray. This will end up being converted to a stepper motor:

The X axis is being kicked around to use the same of printer that was used for the claw machine. It has a long travel (more than is needed) but it already has a stepper motor to drive it. There is an old dot matrix printer that is begging to be torn apart. . . That will be explored before the decision is made.

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