Exercise 06 > 1:1 Machining

This exercise was based on machining (milling, bending, etc) a functional part for our 1D CNC machine.

 

SKETCHES

Our original idea was to use the wire bender to make a cross plane crank for our machine, as we had started thinking about this concept back in Exercise 03. (Thanks @ cars for the inspiration!)

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MODELING PROTOTYPES

Well, no wire bending for us. The machine was making an AWFUL noise. The head was over rotating and running into the machine housing — over and over and over again. We had to scrap our original plan, which was this line, rotated 90 degrees after every 4 turns.

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We decided to just make a flat plane crank instead. Since we were now laser cutting this mechanism from masonite instead of specifically designing it as a single wire, we decided to give ourselves some leeway and create a part that we could test out different placements of attachment in the actual building process. This resulted in a sort of peg-board. We also constructed files to laser cut a base for our machine along with the new flat crank.

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Now, we needed a part to machine for our machine. So we decided to mill gears to convert the linear motion from our gantry to rotational force to swing the crank.

We were using this online gear generator, as it has a rack and pinion option, but it doesn’t allow you to download the gears.

So, we switched to this one. (The graphics are also way nicer.)

TIP: Pitch Diameter (D) x Diametral Pitch (P) = Number of Teeth (N)

The site seems to choose one of the other two to change randomly when you adjust one, so you may have to edit all three if you have particular specifications in mind.

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We had to flatten out the gears for the straight part and set the length equal to the travel range of the 1D CNC.

 

 

PHYSICAL CONSTRUCTION

We were going to mill the gear out of 3/4 inch acrylic sheets that we had, but we realized that it was going to be really heavy for the gantry to move, and rather unforgiving.

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So we milled the gear on the Roland out of blue foam.

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Watch the gear being milled here.

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But…… They don’t actually match up. We milled them at the wrong scale, and not matching scales, rendering them essentially useless with one another.

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So we skipped the gears for now and finished the rest.

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We forgot about the pipes sticking out of the backside of the 1D CNC — so we drilled a hole in the masonite after laser cutting. Our Arduino still won’t stick to the cardboard!

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Since we didn’t have the gear to attach to the plane, we added washers so that we could manipulate it by hand, for now.

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Watch the machine (sort of?) work here.