16mm or 20mm , DIY CNC 60cmx50cm

[nquantum]

Wow! Very nice info. Thank!

My design will be start 10mm pitch then. Since it my first and like you say. I'm not access to more accurate tools yet. Even need to buy drill-press. Or tap-hole. Etc.

I choose hand-held router coz. My house electric not sure to handle 2kw or 20A spinder or not. As I remember meter for my house is maybe 20A top. But 500watt+ no problem. It begining I will upgrade soon. Not so difficult I can see z-axis mouth plate can easily change.

Beside I think hand held shold handle wood 5mm to 1cm, acrylic 5mm to 1cm, am I right? I will not use for commercial like whole day but coupler of hours should be okay!? If not I may upgrade to bigger spindle later.

And from you say the gantry beam look interesting! will look more on it. Even maybe adapt design to that.

[wizard]

wizard I come from a land down under where power is 240VAC and the lowest available is 10A so that makes for 2400w.

Yes but you end up with the same problems in that you have additional power being used by the rest of the machine and you end up too close to the trip point on the breaker. So you have to either upgrade the feeder to the machine or lower the expectation on the power you can get out of the spindle. You will have to lower the power output expectation anyways if you run the spindle at a lower than rated RPM.

Beyond all of that I think my main point is that power ratings in hand held router motors are optimistic. It certainly doesn't reflect the continuous duty at lowered speeds common in a CNC router.

You can also get 15A and 20A here and 3 phase but it's not the norm, you need an electrician to do specialty wiring for it.

We supposedly "officially" went 230VAC decades ago, but it was never really implemented.Typical voltage here is more like 250VAC.

Frankly it sounds like your hows is a lot like mine. Built a long time ago with a grand total of 4 breakers for the entire house. It might be time for a service upgrade.

[Bad Wolf]

Yes but you end up with the same problems in that you have additional power being used by the rest of the machine and you end up too close to the trip point on the breaker. So you have to either upgrade the feeder to the machine or lower the expectation on the power you can get out of the spindle. You will have to lower the power output expectation anyways if you run the spindle at a lower than rated RPM.

Beyond all of that I think my main point is that power ratings in hand held router motors are optimistic. It certainly doesn't reflect the continuous duty at lowered speeds common in a CNC router.


Frankly it sounds like your hows is a lot like mine. Built a long time ago with a grand total of 4 breakers for the entire house. It might be time for a service upgrade.

The new house when it gets built will have 50A 415v 3 phase We have a lot of schools / colleges in the area where the new house is going, so the whole area has been up-specced for power delivery.

[nquantum]

I've done quick draft cnc plan but still long way to go. Plan to have working area 60x90x10 or smaller.
Still concern about:
- distance between block along x-axis rail (15cm),
- distance between rod y-axis rail (15cm), distance between block y-axis rail (15cm)
- distance between rod z-axis rail (10cm), distance between block y-axis rail (10cm)

Those distance not from calculate , just copy from other and/or estimate on screen.
Actually I look for spreadsheet for aid design, found a few in forum but like it long time ago. Seem not active no one talk about it for long time. You guy not use it in design?

Should I still post about plan design in this topic or open another post?

[Bad Wolf]

If you put the Y axis linear rails on top / bottom (like I did) or behind the Y axis extrusion, you would move the Z axis back closer toward the Y axis and move the spindle back. Every bit matters if you can't get the bearing wider apart.

Also I would use one piece over two pieces on the Y axis. Remember if the Y axis is twisted the cutter won't be square to the job you are cutting, and cause all sorts of chatter / cutting problems. Why have you gone away from the idea of doing the angled end plates to centre the spindle on the Y axis?

[nquantum]

If you put the Y axis linear rails on top / bottom (like I did) or behind the Y axis extrusion, you would move the Z axis back closer toward the Y axis and move the spindle back. Every bit matters if you can't get the bearing wider apart.

Those are good if I can't get bearing wider, the A u mean then. It seem easier to put it in front or top/bottom than in back I think. If put on top don't you think the top linear rail will get more weight-load than normal?

Also I would use one piece over two pieces on the Y axis. Remember if the Y axis is twisted the cutter won't be square to the job you are cutting, and cause all sorts of chatter / cutting problems. Why have you gone away from the idea of doing the angled end plates to centre the spindle on the Y axis?

Of course I still do have the idea. In CAD I just put it like that at the time to see how far stuff z-axis to tend forward. Later I will lean backward.

Those two pieces on y-axis is aluminum extrusion 4x8mm, one for each rail. It no good put it like this? It is not better for less flex? If change to aluminum 20mm plate, a long 1 piece but thinner than 4mm of 2-extrusion. It do more good?

[Bad Wolf]

Note how the one closest sticks out further than the others. Which pushes it closer to the front bearing. Load wise the one in the middle keeps the weight closer to the bearings,not only making it more stable but puts the load directly over the Y axis gantry.