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Hobby CAD, CNC machining, and resin casting (2015)

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Re: Hobby CAD, CNC machining, and resin casting (2015)

#41

Post by sgnelson »

sottol wrote: post #33
sottol wrote: post #5

Shameless plug if anyone is interested - I'm working on a $600-ish open-source, reasonably capable, but small and somewhat "tidy" hobby CNC machine with BOM cost around $600 that requires some DIYing. It's meant to be an alternative to the Desktop CNCs like Nomad, Carvera, Bantam, ... moreso than a PCNC or other proper entry-level CNC. The ultimate goal is to make it hobbyist-friendly, capable of easily cutting alumi…

I uploaded a quick video of it cutting some alu recently if anyone's interested: https://youtube.com/shorts/XUsj06iMbb0

At first I was skeptical, but that's an impressive demo for such a small machine.

The documentation on your github is a tad lacking however. :)

But good luck on your machine, I like your CPAP fan idea.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#42

Post by sottol »

sgnelson wrote: post #41
sottol wrote: post #33

Earlier quoted context omitted.

I uploaded a quick video of it cutting some alu recently if anyone's interested: https://youtube.com/shorts/XUsj06iMbb0

At first I was skeptical, but that's an impressive demo for such a small machine. The documentation on your github is a tad lacking however. :) But good luck on your machine, I like your CPAP fan idea.

Documentation is definitely lacking - I just got the design to a point where I'm pretty happy with it. So far only 1 machine exists and the build has a few bits that are... less than ideal.

The plan was to build a second machine and optimize some of the assembly, take notes and document the build.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#43

Post by sottol »

Animats wrote: post #36
sottol wrote: post #5

Shameless plug if anyone is interested - I'm working on a $600-ish open-source, reasonably capable, but small and somewhat "tidy" hobby CNC machine with BOM cost around $600 that requires some DIYing. It's meant to be an alternative to the Desktop CNCs like Nomad, Carvera, Bantam, ... moreso than a PCNC or other proper entry-level CNC. The ultimate goal is to make it hobbyist-friendly, capable of easily cutting alumi…

Fully enclosed with a chip vac is good. Chips all over the place is no fun. Especially with coolant. Don't expect people to precision-cut wood for the frame. The Liteplacer people tried that for their pick and place machine, and most people never got a working machine. If it needs plates with holes in them, make them in bulk and sell them. Waterjets are good for that. The holes will be where they are supposed to be.…

Good point - there is a provision for laser-cut steel or alu plates that sit inside pockets inside the enclosure panels as I figured many would be turned off by a full plywood design.

The metal parts are symmetric so you can cut 2x of each - that is way cheaper on send-cut-send (afair only 25% extra for 2nd part).

Re: Hobby CAD, CNC machining, and resin casting (2015)

#44

Post by Animats »

aaronblohowiak wrote: post #38
Animats wrote: post #36

Earlier quoted context omitted.

Fully enclosed with a chip vac is good. Chips all over the place is no fun. Especially with coolant. Don't expect people to precision-cut wood for the frame. The Liteplacer people tried that for their pick and place machine, and most people never got a working machine. If it needs plates with holes in them, make them in bulk and sell them. Waterjets are good for that. The holes will be where they are supposed to be.…

What about the lumen from opulo?

That's neat, but it's meant to get its parts from feeders. It's a small-volume production machine.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#45

Post by sottol »

syntaxing wrote: post #17
sottol wrote: post #11

Earlier quoted context omitted.

It is definitely more expensive than 3d printing in terms of consumables but china/aliexpress has really good hobby-quality equipment now - if you don't mind the country of origin. Many of their coated end-mills are decent and Maybe not stuff you would want to run professionally but it works quite well in a hobbyist setting and a mistake won't cost you $50. I also looked into the Millenium Milo, only downside for me…

Have you seen the Carvera Air? Not gonna lie, I'm equally tempted but that price point is tough to swallow. Its about $7-800 more than the Milo but has a bunch of things built in that you would probably would enjoy like touch probe leveling and camera zeroing. Its the "Bambulab" of the CNC world.

I designed a little machine that's smaller than the Carvera with a 300W spindle at a lower price-point but requiring DIY (my build is probably around $550-600 now), I kept it smaller for a couple of reasons but stiffness was one of them.

The Carvera has an excellent work-volume to machine size ratio. Afaict it's not the stiffest machine but quite decent. The spindle power looks about right for it's level of stiffness judging by the YT videos I've seen.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#46

Post by throwaway81523 »

Animats wrote: post #40
throwaway81523 wrote: post #29

Earlier quoted context omitted.

This would be a lot more interesting if it could cut steel and titanium. I guess that is more difficult. Added: a dumb question, if the main cutting device is a router with a spinning bit, how do you cut angles? One thing I'd like to make is a 4mm hexagonal hole in a piece of steel, to turn little hex drive screwdriver bits and the like. Is it even possible to make that with a mill, or do you need a different machine…

That's usually done with something called a rotary broach.[1] This is a clever trick. You first make a round hole. The rotary broach is a hex-shaped cutting tool. Both workpiece and tool are clamped in a lathe. But the center of the tool is slightly offset from the rotational center of the workpiece. Both spin, but the eccentricity makes it cut a hexagonal hole. Here's the process.[1] A milling machine can cut a hexa…

Thanks, yeah, a separate 4mm socket with a handle is certainly a possibility, but I liked the idea of a 4mm hex hole in something like this, to accompany the holes that are already there:

https://knifeworks.com/crkt-9100kc-eatn-tool-black-oxide-fin...

I'll look at the rotary broach video. Yes the hole would go all the way through, so a punch sounds ok. Anyway it's not about making this one hole. It's more an example of the kind of stuff I'd like to do with metalworking gear if I had access to it and knew how to use it.

It does sound like hard materials are an obstacle as well. Aluminum is a start though.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#47

Post by blackeyeblitzar »

syntaxing wrote: post #7

Former MechE for a decade and I owned personal CNC routers and on my 6th 3D printer. The biggest issue with CNC is the cost for consumables and accessories. Need a special bit? $$$ Need stock to cut? $$$ Want a nice ER11 or R2 collet set? $$$. A nice vise? $$$ Cut something wrong with a carbide bit? Shrapnel explosion. 3D printing has a bunch of limitations but is a way better machine for hobbyist. But I have been ey…

Have you tried metal 3D printing? Is that a thing for home hobbyists?

Re: Hobby CAD, CNC machining, and resin casting (2015)

#48

Post by mionhe »

blackeyeblitzar wrote: post #47
syntaxing wrote: post #7

Former MechE for a decade and I owned personal CNC routers and on my 6th 3D printer. The biggest issue with CNC is the cost for consumables and accessories. Need a special bit? $$$ Need stock to cut? $$$ Want a nice ER11 or R2 collet set? $$$. A nice vise? $$$ Cut something wrong with a carbide bit? Shrapnel explosion. 3D printing has a bunch of limitations but is a way better machine for hobbyist. But I have been ey…

Have you tried metal 3D printing? Is that a thing for home hobbyists?

Those machines are still really expensive, and I haven't seen any versions that aren't a giant pain in the rear to setup and run. (spent several years setting up and rubbing prints on metal 3d printers.)

Re: Hobby CAD, CNC machining, and resin casting (2015)

#49

Post by Animats »

throwaway81523 wrote: post #46
Animats wrote: post #40

Earlier quoted context omitted.

That's usually done with something called a rotary broach.[1] This is a clever trick. You first make a round hole. The rotary broach is a hex-shaped cutting tool. Both workpiece and tool are clamped in a lathe. But the center of the tool is slightly offset from the rotational center of the workpiece. Both spin, but the eccentricity makes it cut a hexagonal hole. Here's the process.[1] A milling machine can cut a hexa…

Thanks, yeah, a separate 4mm socket with a handle is certainly a possibility, but I liked the idea of a 4mm hex hole in something like this, to accompany the holes that are already there: https://knifeworks.com/crkt-9100kc-eatn-tool-black-oxide-fin... I'll look at the rotary broach video. Yes the hole would go all the way through, so a punch sounds ok. Anyway it's not about making this one hole. It's more an example…

Ah. Here's the tool for that job - a Roper-Whitney hand punch.[1] This is like a hand paper punch, but stronger. Costs $85. Made in USA. With a punch and die, you get clean edges on the hole on the exit side. Scroll down for how to order the specific punch and die you need. Hex punches are not common, but are available. If you fill out their form, and tell them you need to punch 3CR13 stainless, they'll tell you what to order. Might need something with more leverage than the small hand punch. Lubrication helps.

Most machine shops will have such a punch, but they won't have a 4mm hex die in stock.

Or you could drill an undersized round hole and file it out to a hex hole. Maybe use the existing round carabiner hole.

There are touch-up kits for guns, called "gun bluing", to make your shiny new hole black.

This is all do-able but way more trouble than it is worth.

[1] https://www.roperwhitney.com/our-products/no-5-jr-hand-punch...

Re: Hobby CAD, CNC machining, and resin casting (2015)

#50

Post by Animats »

sottol wrote: post #43
Animats wrote: post #36

Earlier quoted context omitted.

Fully enclosed with a chip vac is good. Chips all over the place is no fun. Especially with coolant. Don't expect people to precision-cut wood for the frame. The Liteplacer people tried that for their pick and place machine, and most people never got a working machine. If it needs plates with holes in them, make them in bulk and sell them. Waterjets are good for that. The holes will be where they are supposed to be.…

Good point - there is a provision for laser-cut steel or alu plates that sit inside pockets inside the enclosure panels as I figured many would be turned off by a full plywood design. The metal parts are symmetric so you can cut 2x of each - that is way cheaper on send-cut-send (afair only 25% extra for 2nd part).

> plywood design.

Coolant and plywood do not play well together.

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