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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)

#91

Post by bluGill »

mvidal01 wrote: post #68
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…

The Millennium Machines Milo does look interesting. I wish there was an inexpensive cast iron or epoxy granite equivalent to aluminum extrusion.

You pretty much have to DIY epoxy granite. You probably get a better machine that aluminum extrusion (which are not meant for machine parts). You can DIY cast iron as well, but the high temperatures scare me away (and I done al casting in my backyard)

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

#92

Post by bluGill »

Animats wrote: post #50
sottol wrote: post #43

Earlier quoted context omitted.

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.

I like to think of wood CNC as a step in the kit to something better. If you do your operations rights errors can cancel each other out and so you get better results by having a few extra steps. Make the wood CNC, then use that to cut the molds to make a epoxy-granite frame, then transfer the electronics to the new frame.

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

#93

Post by WillAdams »

alnwlsn wrote: post #71
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…

Any time I see a guide like this, everyone will go on and on about the types of cutters, toolpaths, speeds & feeds, etc. but will always gloss over work holding. For every action, there is an equal and opposite reaction. Without reaction forces, the best cutter in the world is useless. A sizeable chunk of your tooling will just be clamps and indexing tools needed to align and secure the thing you're CNCing, while als…

There are entire books on workholding:

https://www.goodreads.com/book/show/53168863-jigs-and-fixtur...

https://www.goodreads.com/book/show/5042096-jig-and-fixture-...

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

#94

Post by jwr »

syntaxing wrote: post #85
jwr wrote: post #73

Earlier quoted context omitted.

I have the Carvera (not Air) and it's a very good machine mechanically, the software leaves a lot to be desired. It isn't even close to being the Bambu Lab of the CNC world, unfortunately, but I'd say only because of the software. If they open-source their controller, things might improve quickly.

Oh bummed to hear that, how’s the ATC? The ATC was always the most fascinating part for me for the original Carvera. The Air does not have this feature but it’s expected given the price difference.

The ATC works really well, better than I expected. Although without software support it is pretty much useless — I have no idea how people can recommend that I renumber my tools to 1-6 in Fusion CAM for every job.

What I did was write a post-post-processor of sorts that takes the .nc output, watches for tool changes, and using the tool library information automatically assigns ATC slots, renumbers tools, and generates pauses if collet changes are required (e.g. changing from a 6mm shank to 4mm or to 3.175mm).

That means I can now look at a list of assigned ATC slots, put in the correct tools, and let the machine rip, only pausing for collet changes. Pretty nice and how it should be.

However, I have to say, while the ATC is nice to have, I would not consider it to be the primary factor when buying a CNC machine. Those tool changes don't take long and are not difficult to do manually. It's much more important to get a rigid machine with limited backlash.

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

#95

Post by riiii »

eth0up wrote: post #58

To the machinist/s here: For nearly a year, I've been contacting local machinists for a small[*] project which involves 1) an accurate cut on both ends of a 17" billet of T6061, 2) two crescent cuts, 3) up to 8 threaded holes, but probably, 4) a wee bit o end shaping. All the aesthetic contours, shaping and weight reduction I'd do manually - I hand machine bronze, aluminum and wood archer's thumb-rings, so can wangle…

Do you have a complete technical drawing?

My guess form rejection is either:

1. No drawing and vague specs.

2. Too time consuming and they don't want to quote the crazy price it'd take.

Machine shop time is very expensive.

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

#96

Post by Animats »

sottol wrote: post #82
Animats wrote: post #50

Earlier quoted context omitted.

> plywood design. Coolant and plywood do not play well together.

The bottom panel is hdpe currently and "trayed", but you wouldn't run this machine with flood coolant anyway. mql might work but the idea was to cut dry, suck away chips and rely on coated end mills. I've seen people experiment with diesel heater pumps for mql, might try that some time. coolant always ends up very messy. even mql lubricated chips can be a relative mess compared to dry cutting.

> but the idea was to cut dry, suck away chips and rely on coated end mills.

You can go through a lot of end mills cutting dry. This is less of an issue for hobbyists who aren't turning large volumes of metal into chips and aren't using high-powered milling machines. The main limit on milling speed is getting rid of the heat. If you're willing to run slow, dry cutting works. Or if you only cut materials softer than steel.

At some point, you get Machinery's Handbook.[1] For most of a century, machinists' toolboxes had a built-in space for a copy of that book. Now it's available as an app.

[1] https://books.industrialpress.com/machinery-handbook/

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

#97

Post by throwaway81523 »

WillAdams wrote: post #65
throwaway81523 wrote: post #54

Earlier quoted context omitted.

Sure, knife forging is one thing, but the idea of making replacement blades for folding knives sounds like it takes machining, because of the weird shapes needed at the pivot end, especially for weird locking mechanisms. It would be nice to be able to do that at a semi-commercial level if one were to get into it at all. Victorinox is on a completely different scale, making millions of units of whatever. But forging i…

We (ob. discl., I work for Carbide 3D) have a video series on doing this: https://www.youtube.com/watch?v=G5TYla5x-Nk

Thanks! That looks like just what I want. I looked at the first few seconds just now, and will watch the whole thing later.

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

#98

Post by syntaxing »

jwr wrote: post #94
syntaxing wrote: post #85

Earlier quoted context omitted.

Oh bummed to hear that, how’s the ATC? The ATC was always the most fascinating part for me for the original Carvera. The Air does not have this feature but it’s expected given the price difference.

The ATC works really well, better than I expected. Although without software support it is pretty much useless — I have no idea how people can recommend that I renumber my tools to 1-6 in Fusion CAM for every job. What I did was write a post-post-processor of sorts that takes the .nc output, watches for tool changes, and using the tool library information automatically assigns ATC slots, renumbers tools, and generate…

Kinda crazy, I know post processors cost money for CAM software like masterCAM but didn’t expect you needed to write one for a hobby CNC too. I know fusion360 had a post processing functionality but I think they moved that into the paid version. I miss the fusion360 of 5 years ago.

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

#99

Post by eth0up »

riiii wrote: post #95
eth0up wrote: post #58

To the machinist/s here: For nearly a year, I've been contacting local machinists for a small[*] project which involves 1) an accurate cut on both ends of a 17" billet of T6061, 2) two crescent cuts, 3) up to 8 threaded holes, but probably, 4) a wee bit o end shaping. All the aesthetic contours, shaping and weight reduction I'd do manually - I hand machine bronze, aluminum and wood archer's thumb-rings, so can wangle…

Do you have a complete technical drawing? My guess form rejection is either: 1. No drawing and vague specs. 2. Too time consuming and they don't want to quote the crazy price it'd take. Machine shop time is very expensive.

I have another riser to copy the connectors. I have a not so technical drawing of the stringer and a wood/Al prototype.

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

#100

Post by eth0up »

WillAdams wrote: post #77
eth0up wrote: post #58

To the machinist/s here: For nearly a year, I've been contacting local machinists for a small[*] project which involves 1) an accurate cut on both ends of a 17" billet of T6061, 2) two crescent cuts, 3) up to 8 threaded holes, but probably, 4) a wee bit o end shaping. All the aesthetic contours, shaping and weight reduction I'd do manually - I hand machine bronze, aluminum and wood archer's thumb-rings, so can wangle…

Have you looked at Shapeways or sendcutsend or xometry or 100k Garages? That said, I have an especial interest in archery and multiple machines. Contact me at: https://community.carbide3d.com/u/willadams and we can at least work out doing a couple of prototypes.

Thanks for the help. I will see what shapeways says too.
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