Diy cnc

[Meta358]

Im looking at building a cnc router/laster. Looking online all i can really find are build guides to build what someone else made, or guides on the software. Is there any places that i can find alot of good info l on building one that not some random guys 1hr building guide on YouTube.

[James Evens]

budget?

[Meta358]

Dont really have one in mind, kinda hoping not to go over 1000 i guess. At the moment im more looking for a place to find out why id want this motor over that one and such

[James Evens]

With CNC mills the budget dictates what you can get.

How big it should be and what material.

For example my 20x20x10cm is roughly $1000 and has no problem with aluminium or steel (e.g. 8.8 bolts) but with the same budget you could build like 100x500x15cm if is for MDF or wood.

 

Also the accessories drastically change: with metal you want at least a fog buster/lubrication system, slow spindle with high torque. With a wood CNC you can't use this but instead want a dust collector and high rpm spindle not needing the high torque at low RPM. With composites like carbon fibre or FR4/fibreglass the requirements change again. Here would be dust collection crucial to ensure a safe workplace. For stone? flood cooling and dust collection combined with a high power spindle.

 

Btw. How much money can you spend on a ongoing basis for consumable's? The number depends but $1-2 per machine hour would be a rough number if you use value optimized milling bits in aluminium. With carbon steel the cost goes up as tools get more expensive while the lifetime decreases. With wood it would be cheaper.

[Meta358]

6 hours ago, James Evens said:

With CNC mills the budget dictates what you can get.

How big it should be and what material.

For example my 20x20x10cm is roughly $1000 and has no problem with aluminium or steel (e.g. 8.8 bolts) but with the same budget you could build like 100x500x15cm if is for MDF or wood.

 

Also the accessories drastically change: with metal you want at least a fog buster/lubrication system, slow spindle with high torque. With a wood CNC you can't use this but instead want a dust collector and high rpm spindle not needing the high torque at low RPM. With composites like carbon fibre or FR4/fibreglass the requirements change again. Here would be dust collection crucial to ensure a safe workplace. For stone? flood cooling and dust collection combined with a high power spindle.

 

Btw. How much money can you spend on a ongoing basis for consumable's? The number depends but $1-2 per machine hour would be a rough number if you use value optimized milling bits in aluminium. With carbon steel the cost goes up as tools get more expensive while the lifetime decreases. With wood it would be cheaper.

Well this would be a cnc for wood and would hook up to my current dust collector (1.5h). I plan on using one of my wood routers as the spindle. Ive found kits with all the mototrs and break out boards needed online however idk if they are good motors or will be under powered. Was hoping to have its cutting bed be like 4ft x4t (1.3m x1.3m in metric i think)

[James Evens]

There are a lot of points to consider. If you aren't into tinkering start with one of the well known diy cnc wood router projects. Feel free to post the one you decided to get additional feedback. A lot of those projects have at some point boneheaded decision where you could improve on. Often this is in the electronics/wiring.

 

1. do you want or need 1.3 by 1.3m? Building for example 3m by 0.5m (same area) is a lot easier as the gantry is shorter.

2. generic/3nm NEMA24 with TB660 is good enough and those cheap USB controller board are also good enough (e.g. GRBL compatible)

3. No linear rails, no ball screws: they would blow your budget at this size. SBR-16 or so and genuine Gates GT2 belt could work (if the Gates doesn't fit your budget buy the "high". quality china option. Don't buy the cheap china belt).

4. 3D-printed parts are fine for a router like this

5. material of choice will be aluminium extrusion and MDF beside printed parts.

6. gantry stability will be the major challenge.

7. Don't cheap out on cables, use strain relief and select the matching drag chain. 

8. Use shielded cables for everything (within the electronics box/enclosure none shielded is fine). No exception to this rule at any cost.

9. Leave some budget for fixes/upgrades or mishaps (with $1000 total I would say $100-200).

10. Before buying any part do the entire planning and spreadsheet. Once you get to order these parts first check everything is still the same price. If not and blows the budget go back to planning.

11. Do the calibration after building (squaring and trimming).

12.Use 36V for the motors. This gives you more torque out of the same motor at no extra cost.

13. You might want to dissemble the TB660 driver and check for thermal paste. There are at least 3 different designs going around: one with thermal pad and different parts, 1 without thermal paste, 1 with thermal paste

14. Use drag chains with the largest bending radius you can fit (cheaper cables)

15. Buy a drag chain larger than it needs to be/empty compartment. This allows adding new cables later on. e.g. airblast cooling, camera, ringlight, etc.

16. Leave at least 5-10 cm per side on each cable as a service loop.