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Guerrilla guide to CNC machining, mold making, and resin casting (2015)

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Re: Guerrilla guide to CNC machining, mold making, and resin casting (2015)

#31

Post by kube-system »

eightysixfour wrote: post #23
rspeele wrote: post #19

Earlier quoted context omitted.

Another problem is that really good CAD software is expensive. I have used FreeCAD. Its instability frustrated me. Not very rewarding to work on a part that needs a moderately complex feature like a loft, only to find out that after adding the loft FC crashes every few minutes so the part is essentially impossible to edit further. SolveSpace is much more stable but it doesn't have those complex features at all. You c…

> You can use Fusion 360 for hobby stuff, but if you're attached to your work (as any creator would be), it's disquieting to have it hosted in a cloud that you're just being given permission to access. You're one corporate decision away from losing your files. I can export things locally in any format I want from Fusion, is that not the case with certain licenses or something?

You can export it... either in a non-source format, or in a format that only opens in said cloud.

Re: Guerrilla guide to CNC machining, mold making, and resin casting (2015)

#32

Post by dragontamer »

digdugdirk wrote: post #18
throwaway4aday wrote: post #8

I think CNC machining is primed for developments that make it much easier to use for the home hobbyist. The tech is very close to what's needed for 3D printing but it has a few added requirements like the need for a sturdier frame and accommodations for a fairly large and powerful motor. Both are solvable with the right materials and the motor can be anything from a DC spindle to a repurposed wood router. The biggest…

I love your optimism, and would absolutely love to have this capability in a garage. But as someone who designs physical products (and deals with all of the manufacturing techniques you mentioned above on a regular basis) I can't say I agree. There's a huge amount of knowledge and skill required to make machined/cast/extruded metal components, and a very steep learning curve before someone can do so safely. Gamechang…

I've often considered a CNC Mill though. A huge variety of plastics are readily available from McMaster-Carr of varying machining qualities (Acrylics are best for Laser cutters, but you can get extruded Nylon, Cast Nylon, extruded ABS, etc. etc.). There's also a wide variety of cheap woods available.

This guide focuses on Urethane Casting, which is yet another set of plastics you can work with.

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I've worked with all of these plastic technologies and materials, not necessarily in my lab but in various Makerspaces. Its all easy enough, and "safe enough" to work with.

Obviously, even woodworking equipment can chop off your limbs. So you should go in with a degree of woodworking training and/or study. But there's plenty of woodworking classes available at community colleges everywhere. Take one of those and you _should_ be set for wood/plastic level cutting tools (like a CNC Mill).

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Taking the next step into metalworking... ugggh. I know people who take that step, but it is another level of safety / study above and beyond wood/plastics. I'm happy with my woodworking level of knowledge (and its incredibly practical, especially if you're a homeowner).

Re: Guerrilla guide to CNC machining, mold making, and resin casting (2015)

#33

Post by DalekBaldwin »

As somebody trying to get into mechanical engineering while living in a small urban apartment, this has been an incredible resource... not that I've made much progress along the lines it describes though.

It's tough to plan a path toward growth in these skills without sustaining inordinate expenses at each step. I can't afford to become afflicted with Gear Acquisition Syndrome. I've come close to dropping huge sums of cash on tools before discovering, at the last minute, critical reasons that they could not do what I need for the designs I have in mind. Maybe I'll visit a makerspace? Ah, but every one in my area appears to have gone defunct since Covid year zero.

So the journey up to this point has been:

- A lot of reading: not just faffing around with hobbyist blogspam -- full-on MechE textbooks, learning what really goes into engineering schematic diagrams, all that good stuff

- Getting back up to speed with the pencil-on-paper geometry and math skills I've lost after years of doing all my intellectual work in digital form (at least I can still draw a freehand circle)

- Proto-proto-prototyping: just making some physical objects roughly of the same geometry as what I've designed -- whittling them out of wood, sculpting them out of polymer clay

- Hacking together janky tools: trying to make a crappy mini lathe out of Meccano-clone parts, trying to make a crappy mini lathe out of an electric drill, just to get a basic feel for what's involved

- Apologizing to my wife for all this weird scary stuff in the corner of the apartment

I was a CS major. The only hands-on physical engineering I did in college was cooking a single-transistor chip in a freshman applied physics lab. Basically I feel like someone who has studied everything about the physics of bicycles but has never ridden one. I'm really struggling on how to proceed.

Re: Guerrilla guide to CNC machining, mold making, and resin casting (2015)

#34

Post by giantg2 »

legitster wrote: post #6

Semi-related: As an average consumer I'm disappointed that nearly a decade of the "makerspace" has seemingly failed to produce any sort of meaningful Renaissance in small-scale US manufacturing. I've purchased the odd 3D printed or resin cast tchotchke from small operations a few times at this point. But it's still disappointing that if you need professional quality products, you still either need to pay out the nose…

The domestic production problems/advancement have almost nothing to do with the ease of production itself. The costs still tend to be high because of the high overhead and cost of living. Unless you have huge scale (at which point other manufacturing methods may be more economical) or do it as a side hobby, you have to charge a lot. For a hobbyist, most equipment would be too expensive and take up a lot of room if only using it for a couple projects.

Re: Guerrilla guide to CNC machining, mold making, and resin casting (2015)

#35

Post by dragontamer »

DalekBaldwin wrote: post #33

As somebody trying to get into mechanical engineering while living in a small urban apartment, this has been an incredible resource... not that I've made much progress along the lines it describes though. It's tough to plan a path toward growth in these skills without sustaining inordinate expenses at each step. I can't afford to become afflicted with Gear Acquisition Syndrome. I've come close to dropping huge sums o…

Take a woodworking class at your community college.

Focus on the serious fundamentals first. I mean like how to hammer a nail into a thing, how to screw things together. Learn the difference between nut+bolt, Truss Head screws, and pan-head screws. Learn when to use each of these things.

Visit Home Depot. Build a damn coffee table.

Focus on the fundamentals. CNC Mill comes after all this IMO on the hierarchy of knowledge. You really should be extremely familiar with fasteners (Glue vs Nuts+Bolts vs Screws vs Nails) before you start designing things that get glued/screwed/snapped together.

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Most things are left unsaid because just building a damn coffee table (or similarly simple / small object) is everything you need to know about beginner level mechanical engineering.

Finding a class (community college) with this basic level of skills really is the bulk of it. Once you've accomplished the basics, it becomes obvious how to use a CNC Mill or 3d printer or whatever these electronic tools are.

Re: Guerrilla guide to CNC machining, mold making, and resin casting (2015)

#36

Post by prova_modena »

digdugdirk wrote: post #18
throwaway4aday wrote: post #8

I think CNC machining is primed for developments that make it much easier to use for the home hobbyist. The tech is very close to what's needed for 3D printing but it has a few added requirements like the need for a sturdier frame and accommodations for a fairly large and powerful motor. Both are solvable with the right materials and the motor can be anything from a DC spindle to a repurposed wood router. The biggest…

I love your optimism, and would absolutely love to have this capability in a garage. But as someone who designs physical products (and deals with all of the manufacturing techniques you mentioned above on a regular basis) I can't say I agree. There's a huge amount of knowledge and skill required to make machined/cast/extruded metal components, and a very steep learning curve before someone can do so safely. Gamechang…

Agreed. I've seen a lot of people coming from 3D printing become interested in CNC and assume the complexity, risk and investment are similar. They hit a wall pretty quickly when they realize all these things are much higher when machining metal. There are a lot of hobby mill companies willing to perpetuate this assumption by selling cheap benchtop mills. But to do produce anything with "industrial" precision, strength and surface finish at a decent rate, the physical size of the equipment alone is more than what most garage shops are willing to accommodate.

Re: Guerrilla guide to CNC machining, mold making, and resin casting (2015)

#37

Post by prova_modena »

dragontamer wrote: post #35
DalekBaldwin wrote: post #33

As somebody trying to get into mechanical engineering while living in a small urban apartment, this has been an incredible resource... not that I've made much progress along the lines it describes though. It's tough to plan a path toward growth in these skills without sustaining inordinate expenses at each step. I can't afford to become afflicted with Gear Acquisition Syndrome. I've come close to dropping huge sums o…

Take a woodworking class at your community college. Focus on the serious fundamentals first. I mean like how to hammer a nail into a thing, how to screw things together. Learn the difference between nut+bolt, Truss Head screws, and pan-head screws. Learn when to use each of these things. Visit Home Depot. Build a damn coffee table. Focus on the fundamentals. CNC Mill comes after all this IMO on the hierarchy of knowl…

Woodworking was also my gateway into CNC and machining metal. The most important lesson it taught me was that every manufacturing process has a system of tools around it. One tool is almost never enough to build anything of quality. Early on, I was very interested in the charm and ingenuity of individual tools. After learning more and working in the field, I realized that building sophisticated things is all about the integration of tool systems into stable, predictable processes. A holistic approach is necessary.

Re: Guerrilla guide to CNC machining, mold making, and resin casting (2015)

#38

Post by dekhn »

kube-system wrote: post #31
eightysixfour wrote: post #23

Earlier quoted context omitted.

> You can use Fusion 360 for hobby stuff, but if you're attached to your work (as any creator would be), it's disquieting to have it hosted in a cloud that you're just being given permission to access. You're one corporate decision away from losing your files. I can export things locally in any format I want from Fusion, is that not the case with certain licenses or something?

You can export it... either in a non-source format, or in a format that only opens in said cloud.

No, you can export STEP to local files, or f3d's. f3d's open from the filesystem, so you can send that to another person.

Re: Guerrilla guide to CNC machining, mold making, and resin casting (2015)

#39

Post by marmetio »

DalekBaldwin wrote: post #33

As somebody trying to get into mechanical engineering while living in a small urban apartment, this has been an incredible resource... not that I've made much progress along the lines it describes though. It's tough to plan a path toward growth in these skills without sustaining inordinate expenses at each step. I can't afford to become afflicted with Gear Acquisition Syndrome. I've come close to dropping huge sums o…

> As somebody trying to get into mechanical engineering

As a career? I'll assume "yes".

Go to college for ME. Not one of the big brand-name schools. The local one that services the regional mechanical engineering industry. Tell them you want a career change. If you're serious about it, they'll bend over backwards to make it as feasible as they can. They'll also be brutally honest about whether you've collectively reached the point of feasibility yet.

I'm saying this as someone who is very outspokenly critical of universities as unnecessary gatekeepers.

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