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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)

#71

Post by Prcmaker »

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…

If you can get access to student or lite versions of some FEA software, start using them. I've found few places have cared about my software certifications, and more than I can adjust to their software package of choice. Some places will have higher requirements, but not all.

Machinery handbook rocks, but it is far from perfect. It's great for machining, it doesn't cover all of mechanical engineering. I've leaned hard on Roarks formula handbook through my career. A materials reference book goes a long way too. More recently referring frequently to degarmos manufacturing book.

I've used a cheap-ish Windows laptop for almost all of my research and design. CAD can suffer as assemblies get large, I turn fancy rendering off as it is mechanical engineering, not making prettying renders. FEA can eat resources fast. I've pushed to a beefier desktop as required. I've done some CAD on a tablet, but I hate the form factor for it.

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

#72

Post by DanTheManPR »

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…

> The biggest difference I see between software developers and mechanical engineers is a way of thinking. I realize that sounds very woo, but it's very obvious to me and to other mechanical engineers I've spoken to.

As a fellow trained ME, yes, it seems obvious to me as well. A good school and program will have you spending several years in intensive study and thought about the fundamentals and wider implications of the physical principles and mathematics of machines and systems. If you can then follow that up with a few years of good hands-on professional experience with the subject of your study, it's going to give you a level of insight into the workings of the physical world that is difficult to achieve just through direct experience.

Which is not to say that you can't succeed in manufacturing without an engineering degree. It's pretty common for experienced machinists/welders/etc. to break out of a career cul-de-sac and go into business for themselves and engage in some effective and knowledgeable engineering in the process.

But there's no shortcut. You either do the schooling, or you earn the experience. Otherwise, you're not even going to be realizing the mistakes you're making.

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

#73

Post by jalk »

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.

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

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

#74

Post by iancmceachern »

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…

For #2 check out the YouTube series "the secret life of components"

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

#75

Post by Prcmaker »

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,…

Mech eng here as well. This advice is great. I work in a high tech firm, prototyping through in-house production. Stuff breaks and we fix it. We make prototypes with the wrong parts, the wrong tools. We do our design, send out parts for machining, and often end up fixing stuff by hand because of a design oversight (it happens, it's prototyping, not production).

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

#76

Post by gaze »

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…

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.

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

#77

Post by pessimizer »

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…

> nearly a decade of the "makerspace" has seemingly failed to produce any sort of meaningful Renaissance in small-scale US manufacturing.

I think the problem is the constant declaration of the end of manufacturing economies of scale. "Maker" culture should have been focused on rapid prototyping, instead of pretending that the expensive output of 3D printers is sturdy enough to be a final product. "Makers" should be educated about how normal manufacturing processes work, so they can translate their experiments into things that factories could easily and cheaply make.

For me it was a sign that when maker culture was arising, resources for independent engineers (who weren't making kits) actually started to disappear around the edges. The end of the Small Parts* catalog was the worst. Also, instead of using 25¢ micros, people were using $20 full Linux systems to do insignificant things. It seemed like everything was moving backwards.

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

I don't think it's good for serving prototypers because prototypers should be ultimately thinking about manufacturing as a goal. I don't think that small scale manufacturing is being held back by anything, it's just not efficient and nothing has changed that would make it so.

-----

[*] https://web.archive.org/web/20190221190826/http://smallparts...

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

#78

Post by dicknuckle »

legitster wrote: post #46
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…

> I only sell replacement brake cable guides for 1980's powersport machines Haha! Doing the Lord's work. Although, it should be noted that while I buy lots of hard to find car parts this way, as a buyer I almost universally prefer actual molded plastic parts in almost every situation. In some cases I have even requested my money back because the seller deceitfully tried to make their parts look OEM.

I'm actually expanding to Fork Guard Guides in the near future and can appreciate the design differences, all of my stuff is blocky and minimalistic for the most part, and cannot be mistaken for OEM, moreso because the metal brackets are something I simply can't supply with my tiny operation.

I've actually started recommending alternative parts that operate the same, but came from different machines, or even competing manufacturers (like a Suzuki brake cable guide that bolts directly on to a Yamaha but looks nothing like the original).

In the end, this is a product of my frustrations with obsolete parts that become impossible to find. I'm also trying to stay cheaper than the OEM costs of 5 years ago to promote my alternatives ending up on machines that see dirt and rocks on the regular while NOS parts are more likely to end up on pristine restorations. Buying NOS parts for some rough examples never sat well.

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

#79

Post by stu_ »

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…

Similar position here. CS major who went to work software / FAANG pretty much for my 30 year career.

Something about mechanical engineering feels amazing, unlike software getting real tangible /physical/ results from your work. I feel the CS experience gives a very distinct advantage as well here. Software and CAD isn't scary for a CS brain. CnC (additive and subtractive) seems like logical way to do everything, which is what makes cool parts for projects.

I've acquired a few cheap Harbor Freight welders and oxy/acetylene cutting tools, started with small CnC routers to carve soft metals for parts. 3d print what I can't do in metal.

One really easy area to get into for a software dev is robots, look into RoS, an open source robotics OS based on Linux, order some parts from the RoS wiki. And you can get to your own advanced little r2d2 pretty quickly (real-time 3d mapping of your house, arm with gripper control, voice control, image recognition in real time) - most of the software pieces that ME might struggle with are not so difficult for CS folks, and it enables some really cool results!

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

#80

Post by Animats »

pyb wrote: post #10
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 also hold this unpopular opinion : the maker movement has ultimately failed. I am not fully certain why, but think social factors are partly to blame. What I saw (in the UK) was that the new generation of middle-class, hobbyist makers weren't interested in engaging with and learning from the historical, working-class manufacturing sector.

> the maker movement has ultimately failed.

I know. I went to the wake. After the TechShop failure, the TheShop failure, and the Maker Faire failure, there was a meeting in Sunnyvale where some of the people responsible made excuses. There was a speaker who'd bought the remnants of Heathkit. But they'd gone retro, re-issuing old kits.[1]

TechShop used the business mode of a gym - people sign up, pay a fixed monthly fee, and show up occasionally or not at all. It didn't work. Gyms can get away with way overselling memberships. Most people come a few times a week, max. Usually less. Gym equipment is rugged and not complicated.

None of this is true of a workshop. The people who will pay $100-$200 a month want to use the shop. For some, it's their primary workplace. Machine tools are maintenance-intensive and have many consumables. So the operating costs per customer are far higher.

TechShop, as we customers found out in the bankruptcy, was never profitable. The San Francisco location was said to be, but that's because it was assigned the revenue for the other two bay area locations. The business model was very Silicon Valley - lose money while growing, plan to dominate the industry and eventually make a profit. Didn't work.

It's not impossible to do this, but you need cheap land. This usually means some kind of subsidy, often being part of some publicly-funded facility such as a library or school.

[1] https://shop.heathkit.com/shop

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