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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)

#111

Post by bsder »

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…

> It seems to me the industry is very good at serving hobbyists and prototypers.

Sorta. Prototyping has gotten a LOT better thanks to the resin printers.

Extrusion continues to suck like always, though.

> But I think there is a huge market being missed out on easy-to-use, introductory products for mold tooling, plastic injection, and general manufacturing automation.

Sadly, I simply do not believe that there is a huge market being missed out. I'd love to know what you think isn't being served.

However, in the end, customer service is THE drag on small volume production.

There is a reason why there is nothing in the gap between $100 Chinese electronics things with no customer service (see: NanoVNA) or $10K lab equipment with mediocre support.

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

#112

Post by kragen »

s1artibartfast wrote: post #84
mbustamanter wrote: post #61

Earlier quoted context omitted.

Can I ask you a couple of questions? I am in a patricular situation, I'm a mathematician who does FEM and I think my training has been too abstract. My most recent work involves programming custom code in C++ for the study of buckling of thin shells (finite element method, continuum mechanics, differential geometry of shells, and all under the umbrella of functional analysis). Still the region I live in has virtually…

>Regarding manufacturing and machines/machining, any book or resources that stood out? I'm most familiar with the Machinery's Handbook. I went to a top tier school for MechE and Materials, and would recommend two intro books: Engineering Mechanics Statics by Meriam and Kriage and Shigley's Mechanical engineering Design in that order . If you fully understand the contents of these book, it probably puts you in the top…

Kraige?

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

#113

Post by s1artibartfast »

kragen wrote: post #112
s1artibartfast wrote: post #84

Earlier quoted context omitted.

>Regarding manufacturing and machines/machining, any book or resources that stood out? I'm most familiar with the Machinery's Handbook. I went to a top tier school for MechE and Materials, and would recommend two intro books: Engineering Mechanics Statics by Meriam and Kriage and Shigley's Mechanical engineering Design in that order . If you fully understand the contents of these book, it probably puts you in the top…

Kraige?

It is a really simple book and not particularly academic, but you have to start somewhere.

It is basically the equivalent of a picture book, with 200 pages of free body diagrams, which may be helpful to someone if they aren't used to thinking in terms of beams, forces, and moments.

The entire books' contents is probably covered in pages of Shigley's, and perhaps for some people that is enough..

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

#114

Post by gaze »

naasking wrote: post #88
gaze wrote: post #76

Earlier quoted context omitted.

The problem is that once you start adding up the cost of the components to make a capable CNC mill, you get really close to the price of existing ones. Ball screws, good linear rails, etc. are no joke. Big heavy castings (cast iron or polymer concrete) are no joke. The most "disruptive" maker-style machine is the Tormach and it's not well liked.

Lots of open source designs that can route steel, like PrintNC [1] and OpenBuilds [2]. If all you need is Aluminium, then you can make do with something like the RS-CNC32 [3] or MultiBot [4]. [1] https://wiki.printnc.info/en/about [2] https://openbuilds.com/builds/category-list [3] https://www.makerfr.com/en/cnc/rs-cnc32/ [4] https://hackaday.io/project/176110-multibot-cnc-v2

They don’t hold great tolerances, but if that’s ok then they’re fine.

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

#115

Post by kragen »

s1artibartfast wrote: post #113
kragen wrote: post #112

Earlier quoted context omitted.

Kraige?

It is a really simple book and not particularly academic, but you have to start somewhere. It is basically the equivalent of a picture book, with 200 pages of free body diagrams, which may be helpful to someone if they aren't used to thinking in terms of beams, forces, and moments. The entire books' contents is probably covered in pages of Shigley's, and perhaps for some people that is enough..

I mean, you meant "Kraige" rather than "Kriage", right? I wasn't deprecating the book.

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

#116

Post by s1artibartfast »

kragen wrote: post #115
s1artibartfast wrote: post #113

Earlier quoted context omitted.

It is a really simple book and not particularly academic, but you have to start somewhere. It is basically the equivalent of a picture book, with 200 pages of free body diagrams, which may be helpful to someone if they aren't used to thinking in terms of beams, forces, and moments. The entire books' contents is probably covered in pages of Shigley's, and perhaps for some people that is enough..

I mean, you meant "Kraige" rather than "Kriage", right? I wasn't deprecating the book.

Ah yes, it was hard for me to tell the difference even reading the spellings side by side.

That said, it is definitely the weakest of the suggestions. The rest are serious books that a professional might refer back to. On the other hand you should really never need to refer back to a statics text, and it could be switched out for any number of options.

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

#118

Post by UncleEntity »

michaelt wrote: post #64
bsder wrote: post #50

Earlier quoted context omitted.

> Gamechanger? Yes. But likely mostly for the ambulance industry. While I laughed, I don't find this to be very true at all for working in metal. Working on metal seems to have WAY fewer injuries than people who work on wood. Metal working is almost always in a vise and your hands are on levers/cranks--away from the cutting surface. Whereas, with woodworking, your hands are almost always the motive force and directly…

I don't know, I'd have thought the angle grinder - signature tool of the metalworker - is probably one of the most dangerous tools you'll find in the average DIYer's garage.

Pretty much everyone I watch on YouTube calls them some permutation of “the wheel of death”.

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

#119

Post by toss1 »

krschultz wrote: post #81
jalk wrote: post #73

Earlier quoted context omitted.

I imagine a circular saw with 1 inch teeth will do far more damage to human flesh than a grinding disc

The grinding discs shatter. Wear a full face shield.

Yup. I've seen several stories about such incidents, one of the good things about the internet is the ability to spread info on these things.

Safety specs saved this guy's eye from an exploding angle grinder disc.

https://www.reddit.com/r/pics/comments/4npyfu/safety_specs_s...

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

#120

Post by toss1 »

prova_modena wrote: post #29

I skipped right to the section on CNC machining because that's what I have some expertise in. A couple pieces of feedback: - In section 2.1.1 there is a note that states "CAM applications are designed to fail safely; that is, if any of the features of the model cannot be reached without plowing through another essential section of the geometry, the problematic region simply won't be machined at all." This is really,…

>> First paragraph on article stating "CAM applications are designed to fail safely"...

1000% !!!

That jumped pout in the article. I've gto 15 years doing CAD/CAM/CNC as part of what my shop does for a living have no idea what software he's thinking of.

You MUST be extremely careful with EVERY new toolpath, even after checking the simulation. I verify the zero point, pause and single-step every initial part of each sub-toolpath to ensure it is engaging where I want. After over a decade, I got to pretty much hand-specifying every path and entry, and having an idea of where to check in every new program, and it has been a long time since I've broken a tool or gouged a part.

But the idea that new toolpaths are somehow inherently safe is, well, dangerous.

Wear your safety glasses always and keep your distance. Seeing a half-inch razor-sharp diamond-coated carbide tool break off at 22000 RPM and fly across the shop is not cool (and the $200 lost is not even close to the uncool part).

That said, once fully debugged and I trust a toolpath, I can leave the machine running in the quieter next room for a half hour+ and just listen if any potential issues start happening and intervene then.

This is absolutely NOT 'move fast and break things'. The things you'll break are your expensive machine, expensive tools, expensive materials, and your irreplaceable body parts. It is measure thrice, check twice, cut carefully, and you'll make some very cool and amazing stuff.

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