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Tried 3D printing a simple box-thing for a project yesterday. A 5 hour job. Box-like structures always take forever to print.

It didn't fit quite right.

Dammit!

Slight redesign, printed it again over night.

It still didn't fit quite right.

ARGH!

(I am not an engineer.)

in reply to Sean Heber

Monty Hayter
Monty Hayter
• •

When I went to college (technically CEGEP, the system in Quebec is a little different) I was in a Mechanical Engineering Technology program — there was a fair bit of time spent on allowances for machining tolerances, shrinkage when casting, thermal expansion…

No idea how much of that would apply to 3D printing, because I’ve (so far) resisted getting one — I know it would be an enormous time sink for me.

in reply to Monty Hayter

Sean Heber
Sean Heber
• •
@montyhayter there's imprecision in the 3D printer, for sure. I think maybe less so with a resin printer, but I don't have one of those. Sometimes the problems occur because of roughness with overhangs or bridging which I usually forget about.
@Monty Hayter
in reply to Sean Heber

Sean Heber
Sean Heber
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@montyhayter mostly, though, I'm just not used to thinking about stuff in 3D so I end up forgetting that when I'm going to attach a plate to a thing, I have to consider how thick the plate is too. Or that nuts are bigger when you measure them from point-to-point instead of edge-to-edge. Oops. Or that if the hole for the nut is big enough, but too small to fit my fingers or a tool in there, I can't very well tighten it, can I? Stuff like that. 😛
@Monty Hayter
in reply to Sean Heber

Monty Hayter
Monty Hayter
• •

Given that it was the late 80’s we didn’t have much in the way of computer rendering, so we were kind of forced to get practice in visualizing/thinking about things in 3D.

A prof might give us a part to machine with only an orthographic drawing, not even an isometric view… and then (in part) grade us on how well it mated with another part we’d never even seen.

“Fun”

in reply to Monty Hayter

Sean Heber
Sean Heber
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@montyhayter I did a tiny bit of early CAD stuff in a highschool class in the late 90s. There wasn’t any manufacturing though. Was a (presumably early) version of AutoCAD that ran on DOS machines so while there was some visualization, it wasn’t exactly… good. 😛
@Monty Hayter
in reply to Sean Heber

Monty Hayter
Monty Hayter
• •

It’s all changed so much. I had a summer job in ‘88 working for a CAD software company, and man it was rough. It would actually do a shaded render rather than just a wireframe, but the rendering times were in the hours and even days.

Everyone was pretty excited about the then-brand-new PS/2 model 70 towers that had just arrived, with “fast” 386’s in them…

And now you can do more in free software on Raspberry Pi.

…man that makes me feel old 😜

This entry was edited (1 month ago)
in reply to Monty Hayter

Sean Heber
Sean Heber
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@montyhayter haha - yeah, it's amazing how much it's all changed! What's weird is how quickly we get used to those changes. I was watching some retro computer YouTube thing a few days ago and they had a program bouncing "balls" written in BASIC on a C64 or something. And it was like, they could only bounce maybe 6 of them and could double that if they used assembly language. (Or maybe more - I already forgot the details.) Now we can do thousands on a web canvas with javascript. 😛
@Monty Hayter
in reply to Sean Heber

Monty Hayter
Monty Hayter
• •

I distinctly remember the Amiga bouncing ball demo, which was mind-blowing at the time: real-time, shaded, animated, 3D rendering?!?! Never mind that it was fairly low res by today’s standards, and tied up most of the machine including the custom chips.

And now… as you said, thousands of instances on a web canvas.

(I really need to dig out my Amiga and see if it still works)

in reply to Monty Hayter

Sean Heber
Sean Heber
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@montyhayter that bouncing ball demo was legendary. I remember reading about it in magazines and stuff, even. I never had an Amiga. Was a long time before I ever got to see it in person, but even when I did finally it was still impressive at the time.

Then Wolfenstein 3D came out and suddenly everything else looked terrible by comparison and then Doom was dropped a year later, I think, and wow... What a fun time that era was. Stuff got exponentially better almost every year for like a decade.

@Monty Hayter
in reply to Sean Heber

Sarah Brown
Sarah Brown
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@Sean Heber @Monty Hayter When i saw Doom I realised that the world had changed, quite profoundly.
@Sean Heber @Monty Hayter
in reply to Monty Hayter

Monty Hayter
Monty Hayter
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In all seriousness though, while it certainly wasn’t all wine and roses, and some of the profs were tough — one knocked 1% of your final grade every time you were late, either at start of class or from coffee breaks (5 hour class) — I really enjoyed it.

There’s a refreshing simplicity (compared to code) to a lot of it, and actually making physical things is pretty satisfying.

in reply to Monty Hayter

Sean Heber
Sean Heber
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@montyhayter yeah I really am growing a bit tired of the non-physical aspect of software. And how abstract it is. That of course is also a huge source of its power, but… often it is not satisfying.
@Monty Hayter
in reply to Sean Heber

Monty Hayter
Monty Hayter
• •

The fact that it’s been getting progressively more abstract every year makes it worse, too.

I think that’s why I love the Pi Pico: it’s software, and you can use a higher level language like Python, but it’s such a thin layer between that and the hardware: poke a memory location, something happens on the I/O pins.

in reply to Monty Hayter

Sean Heber
Sean Heber
• •
@montyhayter I'm tempted to get into that stuff just because it seems so much more powerful and probably easier, but I worry that my projects might get unreasonably bigger (and more expensive). 😛
@Monty Hayter
in reply to Sean Heber

Monty Hayter
Monty Hayter
• •

There is that temptation haha

The picos themselves are cheap, but displays, individually addressable LED strips, etc add up fast. On the plus side, you already have a 3D printer you can use for mounts, small enclosures, etc…

But it’s probably better to stay the course on the discrete stuff until you’ve reached the limit of what you want/are practically able to accomplish.

in reply to Sean Heber

GadgetGav
GadgetGav
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@montyhayter When I was learning (on a manual drawing board) there were guides for how big any given nut was in both directions and how much space you needed to leave to get the wrench on and be able to turn to the next flat. (Kids these days, etc, etc)
@Monty Hayter
in reply to Sean Heber

Chris Wagner
Chris Wagner
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tolerances are hard. OnShape makes this a lot easier to adjust with its constraints based design system.
in reply to Chris Wagner

Sean Heber
Sean Heber
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@cwagdev I really need to figure out how to use a proper CAD tool. Every time I try I get confused by how they work, what constraints I need, what things are called, etc. and I fall back to TinkerCAD - lol. There's something I like about just adding and subtracting shapes. It somehow seems to fit how I think, maybe?

Of course the problem is, changes to anything *sucks* because you end up having to redo everything everywhere because there aren't any real smarts there. No constraints, etc.

@Chris Wagner
in reply to Sean Heber

GadgetGav
GadgetGav
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@cwagdev Parametric solid modeling CAD can save you from having to redo everything if you can think ahead about how you define features when you make them. If the feature needs to be offset from a wall for instance, you can define it like that and then if the wall changes the feature follows it. Or vice versa, you could define a feature relative to the global origin and then the wall could move and the feature would remain.
@Chris Wagner
in reply to Sean Heber

Chris Wagner
Chris Wagner
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I love that TinkerCad is a thing but it’s not for me. Waaaay too “loose” for me. Our kid likes it though! He’s done some neat stuff that we have printed.
in reply to Sean Heber

Eric Gustafson ☑️
Eric Gustafson ☑️
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you also have to be part material scientist because there will also be some kind of shrink or size differential because of the materials properties .. once you fail enough times, you will start to kinda know to add a degree of compensation to your objects, but yea I often have to print things many times to just get it right (sometimes I section out the area to its own new test part to reduce printing time and not print the whole object). if the test part works then im good.
in reply to Sean Heber

GadgetGav
GadgetGav
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I am an engineer and have 25+ years of SolidWoks experience but I still 3D print stuff too small, especially when trying to design mounting bosses for PCB mounts.
in reply to Sean Heber

Nick Foster
Nick Foster
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as an engineer who regularly has to reprint things for this reason, the only tip I’ve learned is to print facsimiles for testing. If it’s a box, cut it off after like four layers and you can at least test two of the three dimensions with that flat thing
in reply to Sean Heber

Christian Selig
Christian Selig
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This is where parametric CAD like Fusion 360 is so awesome, you can just add like an “allowance” variable of 0.1 mm and if it doesn’t quite fit change the variable, the entire design reflows, and print again!
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