Comment by DavidPeiffer | Hacker News Reader

Comment by DavidPeiffer | Hacker News Reader

Industrial engineer here. I love seeing people get into manufacturing!

I agree with the other points, injection molding would be difficult to get into and is designed for moderately big runs. That being said, I know of a guy who was in a similar position as you with a couple inventions he wanted to bring to market. The quote for plastic injection molds was coming out to low 6 figures, and there wasn't a guarantee they would work the first try, so he bought a 3-axis CNC mill and a plastic injection molding machine for the same cost and could iterate faster and cheaper. He now runs a decent size contract manufacturer in Iowa.

Depending on your designs and interests, I'd suggest checking if your nearby community college has welding classes. They're typically very cheap and professional guidance with a skill like that is invaluable. They may have other classes for other manufacturing skills which you could learn on YouTube, but again professional guidance can be invaluable for learning fast and avoiding poor habits that will hold you back later.

Take a look at the hobby offerings for Inventor and Autodesk if you feel at all limited. I recently tried using Fusion 360 but found the interface confusing coming from using Autodesk in school.

If you have more specific examples of things you're looking to make, we could give more tailored advice. There are tons of manufacturing processes available, each with a range of units and product features they're optimal for.

Back in school the manufacturing professors would have us bring in products if we couldn't determine the manufacturing method and they would help us figure it out.

> The quote for plastic injection molds was coming out to low 6 figures, and there wasn't a guarantee they would work the first try, so he bought a 3-axis CNC mill and a plastic injection molding machine for the same cost and could iterate faster and cheaper.

For small parts, it’s now possible to buy reasonably priced injection molding machines (under $10K) that take 3D-printed (resin, not FDM) molds.

This is the way to learn and iterate. Mold making is not as easy as it sounds, but it can be learned. Once the mold is working well you can CNC machine a soft or hard tool.

Although I have to admit that even in the large scale manufacturing space we have no desire to do injection molding in house. Working with a trusted Chinese injection molding company is extremely cheap these days.

Would you recommend any particular brand of said injection molding machines?

I can't recommend anything personally because I haven't used them.

They're also very new, so they're not as mature as old machines. Older machines are massive and poorly documented, though.

This is one of the more polished micro injection machines: https://www.micro-molder.com/

This one is more industrial but seems better for continuous runs: https://www.apsx.com/desktop-injection-molding-machine

There are also several Chinese vendors offering reasonably priced injection molding machines now, but unless you're well-versed in the art of dealing with these vendors and DIYing your own support, they're not a great place to start.

If you just want to experiment, you can build or buy a manual lever-operated machine for under $500: https://busterbeagle3d.square.site/product/buster-beagle-3d-... These won't be powering any production runs, but if you're only interested in prototyping then they can be surprisingly effective.

I don't know Autodesk but recently have been playing with Fusion 360 (like OP, for stuff for my farm) and coming from a software engineering mindset I can't believe how annoying these tools are... so much fiddling with the mouse and camera angles and positioning and switching modes, to do something that requires precision. Like, I know exactly where my holes need to be, why am I dragging them and stretching them and all this nonsense? I felt like I was using Photoshop or Illustrator.

FWIW I found the same nonsense when doing schematic and PCB layout with e.g. Eagle. I'm running a data bus from one component to another. This is a standard thing since the 70s. Why is the tool making me drag lines and manually connect them and individually label them? In Eagle get the exact mouse end point wrong and it doesn't even connect the components and you don't find out until much later in the process when you move something or try to switch to PCB layout and nothing hooks up. Yes, there's some aggregate bus routing stuff but it's the exception rather than the rule.

I don't understand how hardware and manufacturing engineers can stand these tools. So manual and finicky.

I tried some of the programmatic CAD tooling, too but they also didn't really click with me. But I did notice a plugin for Fusion 360 that adds python scripting, so I might give that a try.

Are you using constraints to position and dimension your holes? (If you know the sizes and locations, you should be.)

I find F360 to be quite efficient and precise at these things.

Make a sketch; make a rectangle. Constrain it until it all turns black (do this by reference to the origin). Drop a circle on the sketch. Click the circumference. Press d. Place the dimension tag. Enter the diameter. Press d again, click the center of the circle. Click the left edge of the rect, drag the mouse up to place the tag someplace nice. Type in the distance from the edge to the center of the circle. Do the same for the Y location.

It shouldn’t feel like you’re dragging and sizing anything manually unless it’s just a decorative part.

I need to follow some better tutorials, apparently.

I looked briefly to try to find the ones I watched as intros, but couldn’t.

I will say that I learned a lot by watching James at clough42 do some designs, but I think I’d learned the very basics before that.

Briefly, for functional parts: “blue lines on the sketch are bad” Add constraints until they turn black (fully constrained). If you aren’t sure why a line is blue, drag it and see which degree(s) of freedom it still has and add constraints to those.

Once you have that down and made a drawing, I’d then look at “modify user parameters” to make sketches more easily tweakable (especially if you’re 3D printing or trying to match a bolt pattern that’s somewhat “random”). Almost every drawing I start now starts with defining the user parameters (and then using those as the dimension entries).

This might not be the best “first video” to watch, but it’s topically relevant to help you here: https://clough42.com/2020/07/04/tap-guide-block-ii-fusion-36...

I've found the Product Design Online's "Learn Autodesk Fusion 360 in 30 Days for Complete Beginners!" youtube playlist quite helpful -- though skip the intro videos to Day #1 if you already have experience: https://www.youtube.com/playlist?list=PLrZ2zKOtC_-DR2ZkMaK3Y...

I use Fusion 360 exactly how you say you want to. Just slap some shit on there and then use dimensions and constraints to actually precisely position everything to match my measurements.

I don’t want to judge here, but, as someone who was well versed in fabrication before I used fusion, I found the model of sketch/constrain/extrude to match well with what I do when I physically make things. It is well suited to the mindset that thinks about the manufacturing method while designing.

Parametric modeling is a godsend for woodworking.

Have a look at OpenSCAD, fully scripted CAD. Worked for me coming from programming. But to create more organic forms I've recently used Shapr3D, especially nice on iPad with the pencil. Easy to use with good tutorials.

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