don’t make me clamp you, part 3

Oh, the fun.  After a few fails, I managed to print out several C-shaped clamps in carbon fiber—infused PLA, finally getting the temperature right.  I then spent several more hours in Autodesk Fusion 360 to further tweak/finalize the bottom of the chassis for the Raspberry Pi 3 supercomputer and sent that off for a 56-hour print job.  Whoa.

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Four of these clamps then were employed during last night’s printout while it was still going.

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Unfortunately, the pause feature that I’d asked for in the slicing software went rogue upon resume and tried to bury the extruder into the plastic, forcing me to abort at 4am this morning.  <_<

At least there’s much less part curling at the base versus last time. So I think I’ll redesign the clamps to have an even lower top profile and clamp right after the first four layers of the raft are down.

 

don’t make me clamp you… (part 2)

You wouldn’t believe the difficulty I just had getting Autodesk Fusion 360 to do what I’d thought would be trivial: I wanted to cut down an existing part from Thingiverse to meet my needs.

Thingiverse ≠ OpenSource

The first thing I learned yesterday from this is that—even though Thingiverse seems like a wonderfully collaborative place—it isn’t actually open-source. If this were open-source, then in addition to the mesh (STL) files that are shared, each author would also include their project file as well (DWG, for example).

Don’t get me wrong, Thingiverse allows people to share their work. And yet, it isn’t the same as github which allows someone to take 100% of what you worked on, tweak it and then share that as well. It’s this iterative modification that makes open-source so powerful. And the reason behind that is that each new person doesn’t have to start from scratch.

CAD Project File

A typical computer-aided design file will include a variety of information. Most, though, are built around the concept of an initial sketch in two dimensions with a variety of measured constraints, for example. One then brings that 2D sketch into the third dimension and suddenly you have a part.

If you’d like to then edit the sketch or change the height of the sketch in that third dimension, you’d need to have that project file. (Thingiverse does not share project files.)

Mesh File

At the end of a design session, it would be necessary then to export that part into a 3D model which is usually a collection of points and triangular faces. The sum of these describes a solid in 3D space. (These STL files are shared on Thingiverse.)

Toolpaths File

Once you’ve exported your own design to an STL file (or you’ve downloaded one from someplace like Thingiverse), the file is taken into software like Cura if you’re trying to print to a 3D printer. This is known as “slicing” since it’s Cura’s job to know your printer well enough that it may slice your part from the bottom, up. Each layer then is converted into a number of instructions called G-code which tells the printer exactly what to do at every step of the way. (Thingiverse does not share these files either.)

Autodesk Wants You to Design in Autodesk

It was clear from my initial interaction with Autodesk’s support that they don’t want you to work using other software. They want you to start over and redesign your part in their software. Given that they charge $40/month to use the software, it’s easy to see why.

They actually do support the conversion of a mesh file into your project file in such a way that you can cut it, for example. They just hide the feature as an Easter Egg; only after turning off project journaling (Time Line) can you see the Mesh-to-BRep option. Granted, the program became painfully slow using this feature since it was grappling with about 50,000 triangular faces. Eventually, though, it processed the mesh file and I was able to apply the cutting action to remove some of the clamp from Thingiverse.

Progress So Far

Knowing that I could further modify the C part of the clamp should I need to, I then set the first of two prints into motion.

With the standard white PLA filament in the printer, I was able to print this in just over twelve hours last night. It’s a collection of eight screws plus their respective protector caps for the ends of those ball points. And tonight, I’ll print the C-shaped parts in black carbon fiber PLA for its added strength. (I’ll need to break them away from the adhesion raft, of course.)

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In case you’re wondering, I had to laboriously place each of the sixteen individual parts into Cura’s workplace, carefully including enough space between them. The tighter you bunch them, the less movement the printer will have to do and the faster it will print. Get them too close and the extruder might bump into one of the other parts or perhaps merge two parts together.

As you can see from the slight bit of raft curl on the right side in the second photo, these clamps in theory will do a nice job of holding the raft down into the bed for the first inch or so of the part’s printing. In some cases, they should save what would otherwise be a failed printout.

3d cover for the pi noir camera

Using the (included) industrial-grade Autodesk Fusion 360 software, I was able to design a part for my Robo C2 printer. It’s a cover and mount for the Raspberry Pi NoIR v2 camera (8MP resolution @ $27). I picked up several cheap suction cups (@ $0.99) from Ace Hardware yesterday and used a digital caliper to carefully measure the distances all around. I’ll sand it a little to make it smooth; the photos below is what it looks like after removing the raft and supports (throw-away extras to make everything print correctly). The jaggies inside the suction cup slot I’ll leave since they’ll grip tightly. I’ll likely also keep some of the jaggies in the fitting between lid and base for the same reason.

I’ll still need to receive the longer cable from Adafruit for this to work so I haven’t snapped down the parts firmly yet. In the meantime, I might create a ribbon clip with a second suction cup (editing the money clip from an earlier post).

If you’d like the STL files for the part now, let me know and I can shoot you the URL for those but I’ll eventually write up a step-by-step tutorial on the full upgrade to adding the video feed capability.

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100posts

autodesk fusion 360

The new Robo C2 comes with a one-year trial of CAD software which appears to be none other than the probably-expensive Autodesk Fusion 360.  It looks like it allows you to design a part, engineer & simulate forces as well as to create tool paths (slice) a part for 3D printing, for example.  I’ve been attempting to use the open-sourced FreeCAD but the learning curve has been slow for me and I’ve run into some Mac-related bugs when attempting to create a screw thread, unfortunately.  So I hope to give this trial software some of my attention to see if I can design some parts.

AutodeskFusion360

First Thoughts

Wow.  It’s just a beautiful interface.  It starts things up with a clean working space set in a useful 3D perspective.

Because of the barren space they’re trying to create, Autodesk has pushed the typical  File -> Open commands off into a hidden panel.  It’s that tic-tac-toe menu icon in the upper left.  Opening this, I’m guessing that there is some kind of change control software running since they have indicators for “master” (branch), View Project History, Branch / Merge Options, Upload files from your desktop.  So perhaps they store all your files in a cloud-based repository, if I’m guessing correctly.  Additionally, there is built-in support for team members.

From what I’m seeing, there are no example files typical of a design program.  Still within the Data Panel, pressing what I thought was a “back” triangle, I’m now seeing a different collection of options:  My Recent Data, Demo Project, My First Project and then under Samples, Basic Training, CAM Samples, Design Samples, Simulation Samples and finally, Workshops & Events.  So I was wrong in suggesting that there are no samples, they’re just an Easter Egg within the interface.  Double-clicking Design Samples includes three very-sexy designs:  bike frame, lamp and utility knife.  I’m bringing in the lamp.

Viewing a Part

It takes a bit to learn Autodesk’s methods of changing viewpoint but I think I’ve got it.  By interacting with that cube in the upper-right corner, this is how you can quickly move around your part.  Note that clicking the little home symbol returns to the original perspective.  Click a labelled face of the cube, go to that perspective.  Grab and move the corner of the cube and you have the usual behavior in most 3D programs when you grab-and-move the part itself.  It feels like they only want you to click on the part when doing a selection process, so that’s probably a good idea to separate the two activities.

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Selecting Something (a Sketch) to Modify

Looks like their basic building block is a Sketch (a 2D drawing) so when I click on the top of the lamp’s base, this sketch is selected.  Now that it’s highlighted, I’m clicking the Modify icon in the Toolbar.

Modify

Attempting to do a Physical Material replace didn’t seem to work for me.  The method appears to be to click on the top of the base, then shift-click each of the other two parts, then right-click to bring up a contextual menu, choosing Appearance from there.  I then changed the material to a gray aluminum.

Aluminum

A mere ten minutes into it and without reverting to Google searches for answers, I’ve managed to do something in here.  That’s seriously better than my results from FreeCAD.

Price

Okay, so I just had to know how much this would cost me after the trial period.  It’s $40/month as a month-to-month subscription or $25/month if paid up-front annually ($300/year).  That’s probably worth it if you do this for a living.  Is it worth it for a standard hobbyist/maker?  That’s a tough call.  You usually end up spending your money on the hardware and consumables, to be honest.

I think Autodesk needs a notch in their software for the new world of amateurs who need to design parts.  Certainly, their three-year trial for students is awesome but that doesn’t help the rest of us who aren’t commercial.

Overall Thoughts

I guess I’ll need to go into crunch mode this year and to produce most of the 3D designs that I had in mind.  But I will circle back after one project and see if it exports nicely for other (free) softwares out there.  Otherwise, you’d be stuck in Autodesk’s business model and that sounds a bit expensive in the long haul.