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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)

#101

Post by imtringued »

the_cat_kittles wrote: post #94
donkeyofd00m wrote: post #51

Earlier quoted context omitted.

Hey man, actual Mech-E here. Also general mechanical hobbyist and handyman; not just one of those CAD guys Just some quick things that may help you point you in the right direction. This is coming the "small scale hobbyist", not indusdrual profesional viewpoint: -getting better and making actual projects come to fruition is actually a lot like CS. A lot. Somebody can spend all their time reading CS theory, textbooks,…

fixing stuff will teach you everything! i didnt even mean to learn so much about so many topics, but knowing that i could fix it just kinda made it happen. and its mostly fun, when its not incredibly rage inducing lol

I have to get this out of my system. No, your YLOD on your PS3 is most likely not caused by the tokins capacitors, it is the solder bumps on your RSX GPU silicon die. You can't fix those cost effectively, just get a replacement RSX.

Also, reballing the BGA solder balls doesn't fix the solder bumps inside the RSX.

Screw you NVIDIA!

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

#102

Post by digdugdirk »

totemandtoken wrote: post #48
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…

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…

I'd actually suggest a slightly different tact. The initial commenter seemed to want to learn how to make things. To me, that sounds like they want to be a skilled machinist (in the general sense) instead of a ME.

Some of the most brilliant people I've ever met are gruff old dudes in a machine shop. They don't use CAD because they can hold an entire design in their head. You ask them about a change to a part, and they tell you why three other parts need to be modified if you want to make that change.

These "old school" types (in my experience) actually have a deeper understanding for the interplay of physical phenomena in a design. They might not know the specifics of the underlying reasoning for said phenomena, but they can absolutely tell you what the outcome will be and how to avoid it.

How'd they get started? Apprenticeships, usually. But how did they get good? They made stuff. A lot of stuff. Eventually you'll get good at it.

Just keep doing what you're doing. And wear your PPE. And try not to chop any fingers off.

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

#103

Post by buildsjets »

legitster wrote: post #17
thepasswordis wrote: post #9

Earlier quoted context omitted.

You're wrong. There are massive 3D printing farms that are producing consumer products at scale in the united states now, and that is a direct result of the work that the maker community (both here and especially in China) has done on 3D printing.

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…

3D printing is great for prototyping, and for small production runs, but economies of scale are not in favor of 3D printing for mass production. The material deposition rate is too slow, and the machine cost is too high, compared to traditional manufacturing methods. I have one part that I designed several years ago which is part of the APU installation on a certified aircraft. The part we flew during flight test was 3D printed aluminum (AlSi10Mg). The turnaround time from completing the design, to having a completed, inspected part ready to be installed, was about a week. For a machined part, the turnaround would have been about 6 weeks, and about 6 months for a cast part. But then when we looked at manufacturing methods for the production part. 3D printing directly in metal was the most economical method for up to 10 parts, because there is no up-front tooling cost, but the recurring cost of both the raw material and the machine time is very high. For 10 to a hundred or so parts, the most economical method was investment casting using a 3D printed wax preform, and for more than 100 or so parts, the most economical method was to buy traditional permanent closed-die tooling for the casting.

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

#104

Post by jacquesm »

This is a great guide. One word of warning: it's not the shop tools that will cost you real money over the longer term, it is the tooling. It isn't rare at all to spend double or more on tooling than you did on your CNC machine, especially if you bought it second hand. So keep a sharp eye out for local machine shops going out of business and ebay to score tooling in quantity, sort out what you think you'll need and sell the remainder. That's going to cost a very small fraction of what you would spend otherwise.

To give you just one example, a pretty common 1/2" dia 3" long quality endmill will easily set you back $40 or more.

And you never have enough clamps and hold down gear.

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

#105

Post by digdugdirk »

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…

Excellent overview. I'd also add "Marks' Standard Handbook for Mechanical Engineers" to the front of the list. Its a great way to dip your toe into the breadth of the field and will serve as a nice reference book on your shelf later if you keep going with it.

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

#106

Post by digdugdirk »

donkeyofd00m wrote: post #95
Prcmaker wrote: post #91

Earlier quoted context omitted.

High voltage and radiation equipment here. Our products are sleek, or prototypes you literally would not touch with a 10ft pole. Jank is part of the game. If we can run a bunch of sketchy tests for $100s to find a path forward, and do pre production on the order of $1k to $10k, we might justify that $100k purchase down the track. On the other hand, we might find our own method that means the $100k solution is never r…

Lol sweet... so even you guys with highly dangerous stuff too Hey, my favourite jank tip: an O ring blew but you don't have a replacement? Bubble gum works pretty well for a few days

Okay, but maybe lets not share that particular tip with the dude who works on radiation equipment?

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

#107

Post by bsder »

Animats wrote: post #63
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…

> Maybe I'll visit a makerspace? Ah, but every one in my area appears to have gone defunct since Covid year zero. Yes. I miss TechShop, where I did CNC machining. It's not all that difficult. Maybe 100-200 hours to minimal competence. What's left of the maker movement seems to have been taken over by little old ladies into crafting. Gluing construction paper and macrame, not machining and welding. Activities classes…

Some makerspaces are still around, for example:

Austin, TX: https://asmbly.org/

Worcester, MA: https://technocopia.org/

Irvine, CA: https://urbanworkshop.net/

The problem is that none of them are what I would call "cheap" anymore.

> Activities classes for middle schoolers where they assemble kits, not original work.

Don't look down on this. Assembling an electronics kit is what got a LOT of us greybeards into electronics. Debugging something you put together is non-trivial.

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

#108

Post by digdugdirk »

donkeyofd00m wrote: post #51
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…

Hey man, actual Mech-E here. Also general mechanical hobbyist and handyman; not just one of those CAD guys Just some quick things that may help you point you in the right direction. This is coming the "small scale hobbyist", not indusdrual profesional viewpoint: -getting better and making actual projects come to fruition is actually a lot like CS. A lot. Somebody can spend all their time reading CS theory, textbooks,…

This. 1000x this.

Also, to add on to the reading comment - keep an eye out for old (40's->70's in particular) technical books and manuals on topics that interest you. I find they had a way of conveying information that was somewhat lost once video became commonplace.

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

#109

Post by Prcmaker »

donkeyofd00m wrote: post #95
Prcmaker wrote: post #91

Earlier quoted context omitted.

High voltage and radiation equipment here. Our products are sleek, or prototypes you literally would not touch with a 10ft pole. Jank is part of the game. If we can run a bunch of sketchy tests for $100s to find a path forward, and do pre production on the order of $1k to $10k, we might justify that $100k purchase down the track. On the other hand, we might find our own method that means the $100k solution is never r…

Lol sweet... so even you guys with highly dangerous stuff too Hey, my favourite jank tip: an O ring blew but you don't have a replacement? Bubble gum works pretty well for a few days

If it gets it through the test, it did its job.

Ratchet straps can be a good insulator, when clean and used properly, to higher voltages than you'd suspect.

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

#110

Post by DalekBaldwin »

switchbak wrote: post #67
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…

I read this as the OP was wanting to dip their toe into "making", not to do some self-directed learning such that they'd call themselves a MechE. Schooling would be great of course, but if your goals are very modest, I think what the OP has in mind might be fine too. It'd be like telling someone fooling with Python that they need to take a full CS degree otherwise they'll fail to appreciate the beautiful mathematical…

Yes, I was implying "to do stuff like the author of the article does" ( https://lcamtuf.coredump.cx/rstory/ ), coming from a very similar situation as him -- as a software engineer with an already broad general scientific and technical background, in a small apartment, getting into the concrete particulars of designing and building cool mechanical projects on a small scale and budget.
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