Week 7 - Computer-Controlled Machining

objectives >

link to Incite Focus Computer Controlled Machining page

hero shot >

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concept >

I did quite a bit of brainstorming for this one. Initially, I had an idea for a suit of armor that would double as armor, or a chair. I dubbed it arm(or) chair.

However, I quickly realized that it might be too daunting for a hello world, applying CNC machining principles.

Previously, before fabacademy, I spent time making 2x4 furniture to make my spaces more usable. These included workbenches and “modular” coffee tables.

I’m overdue for some more furniture, so I started off with a basic lack-like table.

safety >

shopbot is only machine that could seriously injure or kill someone in MSI fablab. MSI follows industrial “lockout/tagout” procedure that complies with OSHA.

design >

basic >

The idea was to make a table that assembled w/o fasteners, and ideally had flexible surfaces. I started with the fasteners criteria.

TODO: transform images into montage

2ft x 2ft top, which matches a lot of my other furniture cnc

side profile for el-leg. cnc cnc cnc

joint between top and el-leg. cnc cnc

circular pattern to repeat feature for all 4 corners. cnc cnc cnc cnc cnc

another joint to constrain el-legs to each other. Assembly might behave in a zipper-like fashion, may need to add a chamfer to the edge here for easier insertion. cnc cnc cnc cnc cnc cnc

nesting >

TODO: gif of settings

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I had been meaning to use deepnest for the laser assignment, but didn’t find the time to. It’s only fitting that I used parts from the laser cutting assignment to test out deepnest, in preperation for this assignment.

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one of my motivations for my 1x1 table hello-world was to create a design that was easily nestable and optimized space usage. I still need to design the table to optimize for standard stock sizes, but it seems to do a pretty good job compared to a more traditional pattern, such as the One to Several Table from AtFab. I used that table for reference during design.

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more design >

added an additional leg piece to further constrain table.

TODO: gif?

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model is not very parametric and I didn’t account for an extra part initially. cnc

corrected by measuring offset and adjusting the sketch plane. cnc cnc

rebuild errors, on making cuts to fit joints together, removed some edges being used for reference in sketch. cnc cnc cnc

using design checker to identify problems. cnc

as far as I am aware, dxf export must be manually done to each individual part. Wonder if there is a more automated workflow in SolidWorks. If not, maybe export as step file and pass it through freecad? mods?

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dogbones >

I tried to use the mods plugin for dogbones but fell short… mods is sorely in need of more easy to access documentation. I did however learn a bit about the history of mods.

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scalemodel >

a common practice that I’ve picked up to get around SolidWorks assembly feature limitations is to save an assembly as a part. I scaled the entire assembly down for prototyping purposes, which Dan, Kyle-Pierre, or Blair mentioned.


stacked >


using Easel for my CAM software, per Dan’s recommendation.

imported nested file, doesn’t fit stock. cam

resized stock. cam

unfortunately, simulation space appears to be constrained to tiny box. cam

adjusted cut depth to match design. cam


turns out, constrained simulation space is due to a tiling feature in the settings. cam

on turning it off, simulation space is no longer constrained. cam

unfortunately, I don’t have access to a large format CNC (that isn’t the shaper origin) at the moment, so we’ve opted to kick the can down the road until I can find a large format CNC to complete this assignment.

machining >

Kyle-Pierre graciously offered his large CNC (Forest Scientific) to help complete the machining portion of this assignment.

picking plywood >

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the machine >


fixturing, impact driver >

the impact driver is a nice tool for installing fixturing fasteners, since the screw + impact driver make for a self-tapping combo. This means I don’t need to drill a pilot hole prior to screwing.

Kyle-Pierre has this DeWalt 20V impact driver.

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indexing >

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air compressor, cleanup >

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loading my 11/32” stock >

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my gf Fong, helping me document :)

checking index >

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impact driver, fixturing >

searching for “bubbles”, to smooth out the sheet. Similar to squeegee’ing a new screen protector onto a phone, want to force the air out in a single direction to avoid creating trapped air bubbles. kp kp kp kp kp kp kp kp kp kp

CAD -> CAM >

I initially ran all of my CAM through Inventables Easel, but in an effort to streamline the process, I ran the CAD through the Fusion360 CAM process, which Kyle-Pierre is familiar with wrt his Forest Scientific machine.

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vacuum >

Kyle-Pierre has a large air compressor hidden in the corner of the room. Neat trick: He uses a piece of cardboard as an adapter between the two sizes of tubes.

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changing endmill >

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machining time >

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fit >


filing >

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hammering >

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final assembly >

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hero shot >

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