3D printer & CNC design

[Trakyan]

While i know you said you didnt want people saying stuff like the above, he has a point. Cnc machines and 3d printers have totally different needs and opposing design philosophies. For a 3d printer you usually want fairly quick speeds, this means a light as possible gantry that only needs to resist forces from accelerations. Cnc cutters on the other hand want a rock solid (read:heavy) gantry that can resist cutting forces. The speed of your motion system is not a limiting factor.

At best you get a printer that doubles as a light duty mill that will do wood and maybe aluminium if you go super slow. Or a cnc that doubles as a slow printer. Dont get me wrong, id love a good two in one machine, but it wont be the best of both worlds.

If i were to make thr machine, i'd go for a replicator, ultimaker, corexy or other similar 'cube' form factor. Steer clear of prusa style gantries as the cutting forces when cutting in the y direction will do horrors to the vertical part of the frame with the torques they'll exert on it. Build it out of aluminium as a compromise between weight and rigidity, and use nema 23 where possible. And don't cantilever the bed.

[KrYpTOCiD]

While i know you said you didnt want people saying stuff like the above, he has a point. Cnc machines and 3d printers have totally different needs and opposing design philosophies. For a 3d printer you usually want fairly quick speeds, this means a light as possible gantry that only needs to resist forces from accelerations. Cnc cutters on the other hand want a rock solid (read:heavy) gantry that can resist cutting forces. The speed of your motion system is not a limiting factor.

At best you get a printer that doubles as a light duty mill that will do wood and maybe aluminium if you go super slow. Or a cnc that doubles as a slow printer. Dont get me wrong, id love a good two in one machine, but it wont be the best of both worlds.

If i were to make thr machine, i'd go for a replicator, ultimaker, corexy or other similar 'cube' form factor. Steer clear of prusa style gantries as the cutting forces when cutting in the y direction will do horrors to the vertical part of the frame with the torques they'll exert on it. Build it out of aluminium as a compromise between weight and rigidity, and use nema 23 where possible. And don't cantilever the bed.

Be sure that I didn't wanted to make something like prusa. I don't like the their performance even at 3D printing mostly because that bed...... But I think that I'll go for laser engraving ( it was something like a backup option. until now) as you said

Thanks for reply

[Trakyan]

Be sure that I didn't wanted to make something like prusa. I don't like the their performance even at 3D printing mostly because that bed...... But I think that I'll go for laser engraving ( it was something like a backup option. until now) as you said

Thanks for reply

The laser was CAs idea, so I can't take credit. But now that you've mentiomed you only want to work with a few mm thick wood, I would say something like a 5w diodr laser mounted instead of an extruder would be your best bet as laser cutting and 3d print both dont need to endure cutting forces, and would work fine on the same machine. Be sure to enclose the printer though to protect yourself from the laser, it's dangerous and its an invisible threat if it reflects off something.

[Don McLean]

I wrote a big long post with responses to a number of quotes but then realized that it was overkill.

We really don't know what it is you want to cut with the CNC router part of this.

You could do some very nice wood carvings at a very slow speed with a hybrid machine, but forget about aluminum.

If you could give some more details and perhaps some pics of the cad files of what you want to make and what you want to cut exactly, the advice would be more relevant.

Trakyan, you are overly optomistic. Also, when you bump up to a router, things cost alot more. The speed of a filament printer is slow compared to a proper CNC router and very very slow compared to a commercial laser. IMO, filament printers are not made as spartan as they are in order to increase speed, they are made this way to reduce cost, and because beefier components aren't necessary to achieve the goals.

Unless you are talking about an XY area that is very large, I don't see an advantage in combining the two machines, and I think you would be better off to keep them separate.

[Trakyan]

I wrote a big long post with responses to a number of quotes but then realized that it was overkill.

We really don't know what it is you want to cut with the CNC router part of this.

You could do some very nice wood carvings at a very slow speed with a hybrid machine, but forget about aluminum.

If you could give some more details and perhaps some pics of the cad files of what you want to make and what you want to cut exactly, the advice would be more relevant.

Trakyan, you are overly optomistic. Also, when you bump up to a router, things cost alot more. The speed of a filament printer is slow compared to a proper CNC router and very very slow compared to a commercial laser. IMO, filament printers are not made as spartan as they are in order to increase speed, they are made this way to reduce cost, and because beefier components aren't necessary to achieve the goals.

Unless you are talking about an XY area that is very large, I don't see an advantage in combining the two machines, and I think you would be better off to keep them separate.

People can and have milled aluminium with converted 3d printers. I'm not saying it was ideal, I'm just saying it's doable. Check out thomas sanlader's video where he converted his mendelmax to a cnc. The "router" was the bit that gave out in the end, since he was using a rotary tool not proper router. That being said, you can do better than a mendel style frame for milling. And I don't know what sort of desktop routers you're thinking of that have higher travel speeds than 3d printers, they usually go a fair bit slower as they have to cut through material as they move, 3d printers don't face any noticeable resistance when they move. That aside, a lot of them are powered by lead screws of some sort (acme, ballscrew) which limits their speed compared to belts.