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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)

#151

Post by dekhn »

mmaunder wrote: post #144
takk309 wrote: post #139

Earlier quoted context omitted.

I watched a good video on the subject of adaptive clearing taking too long to calculate and it helped me to improve the processing and machining time of complex geometry. https://youtu.be/osNPQr5-EpM Another thing I found with topographic stuff is to simplify the mesh after importing it. It makes very little difference to the final project depending on your scale.

Makes a big difference in quality in my experience and the conversions generally run overnight. Same applies to M1 architecture and high end gaming PCs. I am for example carving the entire state of Colorado on 24” X 24” oak 2.5 inches deep. But I’ve see the same loss on quality on eg a VW beetle relief that I carved that was 24x12”. Aspire has blown me away with the end result and speed of computation.

This is interesting to me; I carved a large model of California elevation using Fusion 360 and an X-Carve. It definitely pushed the limits of Fusion 360, the final model that I CAMmed was 5M (million!) facets and 2.8M vertices and it's just barely usable (rendering, operations, etc all take ~minutes after a change). Are you saying I can replace F360 with Aspire and it will just do STL meshes faster? Good to know.

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

#152

Post by HeyLaughingBoy »

mbustamanter wrote: post #61
totemandtoken wrote: post #48

Earlier quoted context omitted.

I was a mechanical engineer before I shifted to software development (so kind of the opposite of you) and I think you need actual, full on college level schooling to be a mechanical engineer in most cases. The stuff you're focusing on - basically manufacturing techniques - is a very small part of engineering in general. I didn't see any mention of CAD or FEA work, but even assuming you do know some of that or can acc…

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

There's an MIT course on OpenCourseware that's called (roughly) "How to make (almost) anything" and also "FUNdamentals of Machine Design." (or something like that!) I think they're by Richard (?) Slocum. I started a long time ago and cherry picked the parts I cared about. Slocum's writing is very entertaining and he's easy to follow along with.

As you can tell, my memory isn't that great :-)

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

#153

Post by Rokid »

totemandtoken wrote: post #135
Rokid wrote: post #85

Earlier quoted context omitted.

> The biggest difference I see between software developers and mechanical engineers is a way of thinking. Can you give an example? Myself being a mechanical engineer who also turned to software development, the people I talk to from SW are used to dealing with large matrices and semi-complex math. Sure they don't know about modal analysis or Navier–Stokes equations, but the lack of a certain way of thinking I cannot…

As the other comment and a few others have iterated, software guys don't have as much of a "measure twice, cut once" mentality. It's not so much about the math or technical knowledge, it's more of a mentality. Let me put it this way - I've seen many times software engineers laugh when they encounter a funny bug or an output they didn't expect. I don't think I've ever seen an ME laugh when something breaks.

Ah now I see what you mean, and I fully agree :)

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

#154

Post by HeyLaughingBoy »

jononor wrote: post #147
tgsovlerkhgsel wrote: post #65

Earlier quoted context omitted.

One major difference between 3D printing and CNC is that 3D printing is standardized and simple enough that the steps from a 3D model to a printout are mostly automated. The workpiece is held by sticking to the print bed, print paths are autogenerated and layer by layer. With CNC, you have to figure out how to hold the workpiece, often with multiple setups (which have to be done precisely), machining strategy (toolpa…

These are all things that I believe can be improved by better software and machines that are designed to teach people how to do it. Current software is still mostly designed for the experts, assuming a whole lot of knowledge exists from before or is built up separately.

Sure, but now you're talking about what could be vs what's available right now! And what "could be possible" will always be a lot better.

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

#155

Post by HeyLaughingBoy »

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…

I sympathize with your disappointment, but I'm honestly not surprised by what happened. I never expected much to come from it except for introducing a few more people to light manufacturing.

The reason is that the people who were already going to do this (actual mechanical engineers and machinists) had a path forward: buying used CNC machinery and starting up in their garages. And many of them did/are doing this, but it's not the kind of thing that's discussed unless you are on a manufacturing forum, which HN definitely is not.

Part of the problem is that if you're going to make a living doing it, you need professional quality tools that can run all day, every day. "Maker" level tooling won't do that.

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

#156

Post by HeyLaughingBoy »

dicknuckle wrote: post #25
legitster wrote: post #17

Earlier quoted context omitted.

Sure. But the vast majority of products are not ever going to be 3D printed. Most of the things you are going to touch today are going to be injection-molded. Keyboards, keychains, car parts, cups, computer cases, etc. There's a 3d print shop that sells at my local farmer's market. But they only sell tchotchkes. I am imagining a world where the same size business could also phone cases or mugs or even supply a local…

We're not at farmers markets, because our niches are too focused. One guy I follow on YouTube pretty much only sells tool trays for cannabis products and I only sell replacement brake cable guides for 1980's powersport machines. We've been at the very beginning of what you're describing for about 3-4 years now. I only started selling by request of the communities I'm part of because none of them knew anyone to print…

Hmmm.

There's a (non-critical) switch for my 2000 Honda Foreman that I can't find anywhere except direct from Honda or a dealer and I don't think it's worth the $100+ they want from it. For other model years, I can find it from $20 - $60 which is more reasonable.

I've been thinking of making my own for a while but now you have me thinking of making them for resale. I can't be the only person in this situation.

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

#157

Post by jononor »

HeyLaughingBoy wrote: post #154
jononor wrote: post #147

Earlier quoted context omitted.

These are all things that I believe can be improved by better software and machines that are designed to teach people how to do it. Current software is still mostly designed for the experts, assuming a whole lot of knowledge exists from before or is built up separately.

Sure, but now you're talking about what could be vs what's available right now! And what "could be possible" will always be a lot better.

Sure, it is aspirational - but at least doable. Others in sibling threads are claiming that CNC machining will never be safe, affordable or approachable due to fundamental reasons. Which I do not agree with.

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

#158

Post by buescher »

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…

I started down the path to be a materials scientist and wound up in embedded hardware, so take my opinions with a big grain of salt.

For self-learning, I don't know if anyone would work through the problems in a statics textbook. Shigley looks good. Thanks for that recommendation.

For heat transfer, I eventually wound up on the bibliography from Hot Air Rises and Heat Sinks by Tony Kordyban, which is more focused on cooling electronics. I have Holman's Heat Transfer on my shelf as a result and I can recommend it for self-learning. One big advantage to Holman: he shows how to set up common thermal problems in Excel in an appendix. I would consider recommending a good continuum mechanics book in the place of a fluid mechanics book - I liked Yuan-Cheng Fung's First Course in Continuum Mechanics but I haven't looked at it or anything else in its domain for a while.

Ogata is a good controls text. I don't know if any of them are good for self-learning. I tried and had to take a class to wrap my head around feedback control. Tongue looks interesting. Thanks for the recommendation.

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

#159

Post by dicknuckle »

HeyLaughingBoy wrote: post #156
dicknuckle wrote: post #25

Earlier quoted context omitted.

We're not at farmers markets, because our niches are too focused. One guy I follow on YouTube pretty much only sells tool trays for cannabis products and I only sell replacement brake cable guides for 1980's powersport machines. We've been at the very beginning of what you're describing for about 3-4 years now. I only started selling by request of the communities I'm part of because none of them knew anyone to print…

Hmmm. There's a (non-critical) switch for my 2000 Honda Foreman that I can't find anywhere except direct from Honda or a dealer and I don't think it's worth the $100+ they want from it. For other model years, I can find it from $20 - $60 which is more reasonable. I've been thinking of making my own for a while but now you have me thinking of making them for resale. I can't be the only person in this situation.

Ideally you'd print it in PETG, and this can be done on a $100 Ender 2 clone with a $20 spool of filament, but if all you want is a few small parts and maybe a few batches for other people, you could find a local 3d printing service on FB market.

I'm selling a pair of brake cable guides for $10 including shipping to the lower 48. I'll make more money if I find a cheaper way to ship, but I'm not really doing it to make money.

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

#160

Post by gaze »

rfrey wrote: post #131
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.

What you say is correct, except that a hobbyist can source parts from Ebay and the like. Which you could never do for a production machine. That can bring the cost WAY down.

you can also buy an old fadal or some other thing and just run it or retrofit it, and this is pretty cost effective.
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