HTMAA 2024 - Week 10

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This week, we learned about CNC machining. I've always wanted to use the CNC machine in the makerspace but never felt courageous enough to try so I'm glad I was able to take this opportunity to finally learn it.

I started by reading the documentation for the Shapeoko 5 that we used in the makerspace.

Then I downloaded Carbide Create onto my home desktop.

The UI looked rather simple and clean, and it was easy to find documentation on how to use it.

I set the job setup parameters to the ones we were given on the onboarding document. We were working with 4'x4' sheets of 5/8" OSB.

I played around with the built-in design tools and made a circle to see how long a big circle would take to cut, since apparently people's designs took a long time.

After making the circle, I edited the toolpath.

They sent out an email with a few clarifications, so I made sure to follow them as I was working.

I set the max depth to 0.655, which would have been 5/8" + 0.03, which is what they specified, but I would later learn to bring this down to 0.64.

I chose the end mills we were given in the documentation, the #205 1/4" end mill, and the #102 1/8" end mill.

I saw the toolpaths once generated allowed me to see the amount of time a job would take, and Joe told us to add ~20% to that run time..

Now that I was familiar with the design space, I decided to start making my own design. I looked for inspiration online. I wanted to do something I could only uniquely make with a large format CNC, so not something like a table. Then I came up with the idea of a rocking chair, and looking into CNC rocking chairs I found this design which I was inspired by.

First I drew a rudimentary design in Solidworks to see generally how long it would take on the CNC router.

After I put it into the design space, I found that it took about 40 minutes to cut the general profile, so if I multiplied this by 2-3 for all the design features of the chair, it would be within the 2 hour time slot I was alotted..

I got to work making the chair in solidworks. I started with a nice organic design, but realized that it would be difficult to scale.

I added a lot of dimensions to make the design more replicable, and then got to incorporating the widthwise planks into the design by creating dogbones.

The holes needed to be rectangular to accommodate 1x4s, which had dimensions of .75"x3.5", but the router doesn't cut straight corners, so I had to add a little divet at each side to allow the 1x4s to fit.

These holes needed to be machined from the inside while the outer profile needed to be machined from the outside.

Here's the final at-home design!

It took about an hour and a half according to the estimation, so I was good to machine it. To give me more time I decided to have my print ready before coming to the makerspace by setting all the parameters beforehand.

Here's the simulated toolpath!

At the makerspace, Jeff and Joe helped me clarify some design parameters, adjusting the depth per pass to 0.1 and the max depth to 0.64, both of which would decrease the amount of time spent machining.

Due to the time saved (nearly cut down to 50%!), I decided to add some machined text using the 1/8" bit, which I originally didn't use to the loss of time due to swithcing the bit out, but now that I had time, I wanted to learn how to switch the bits out in the middle of a job.

TBC.

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