It's begun....

[Washout]

Thanks Fivetide - wish I had bought a self-reversing tapping chuck for my pillar drill - hand tapping all that profile was tiresome..

[meerkat]

Hi.
First pic looks like a mechanical beast,but good!
A little tip for tapping holes. I use my B&d pivot driver saves a lot of work and no aching hands!
meerkat.

[Washout]

Hi Meerkat,

Thanks - "beast" is the target after Dean' comments further back :-)

I made a little progress last night after putting a bracing structure and bearing onto the 2nd ballscrew extension - this has cut down flex considerably (i.e. hardly any movement even when leaning into it) and I did a test by jacking my motors up to 4000mm/min in MACH3 and had no stalling on full speed jogs. So a step in the right direction methinks. I'll likely push the speeds up again tonight and see where the stalling starts, but I'm quite happy with 4m/min, as in its original guise the machine wouldn't go above 2.5m/min reliably with the single ballscrew configuration.

To do tonight will be to put the belt tensioning pulley on and take the slack out of that (the bracing has improved that also anyway). Then run some more tests to see if there's been improvements.

I'll then think about plan b dependant on the results of that.

Chris

[m.marino]

Just for giggles I set up my machine to where it stalled and then backed it off. Now this is a rough set up and I have NOT gone back and tuned the drives so that would change things as well. Given that I was able to get x(x/c) axis up to 17m/min V with 450mm/sec^2 A; Y axis was gotten to 11m/min V with 350mm/sec^2 A and Z to 7.5m/min V with 250mm/sec^2 A. Let's just say that is a bit scary in speed.
-Michael

[Washout]

Wow - effective limit switches are a must at those speeds I expect ;)

Even 4m/min was hairy compared to what I've been used to previously when I tested it last night.

Oh and a quick question or two: I'm running the same test job "cutting air" to see what progress I'm making as I make mods etc. to the machine and I notice that whatever max speed I set the motors to is what the test run seems to use as its rapids - I'm assuming that's normal behaviour?

The other thing is when I first power up and load MACH3 the motors always seem to need one axis setting up in MACH before they "remember" the settings from the last session?

[Washout]

Hi All,

Quick update (no pics or vids yet).

Last night I completed the mechanical option for running two ballscrews (I still have parts for plan b if needed), by adding some extrusion bracing and additional bearing to the long "bendy" extension on the back of the 2nd ballscrew. Alignment was surprisingly easy, as it was a case of using the already aligned ballscrew and using a transfer punch to mark, drill and tap the new bearing mounting holes. Things are much more sturdy there now.

I have also added a 3rd pulley mounted on more extrusion and an axle, which I can adjust up and down to increase or decrease tension on the belt (better than what my car engine uses methinks :) ).

So ran some tests - 4,000mm/min was no problem at all, so upped it to 6,000 mm/min and its still fine, but getting quite scary at that speed (I'm wondering if I should back off of 500mm/s/s acceleration?).

I'm going to start some cutting jobs, once I have solved my VFD issue (see other thread in Electronics section) and then its back to the feeds and speeds learning curve :)

Cheers


Chris

[Jonathan]

(I'm wondering if I should back off of 500mm/s/s acceleration?).

No, you want to increase the acceleration if anything. I run my machine at around 1m/s^2, so twice what you've set. Part of the reason m.marino got such high feeddrates in post #91 is that the acceleration was set very low, and it's a compromise between high acceleration and speed.

For example, in this video I set the acceleration lower and put a bigger pulley on the motor, and got 60m/min:
https://www.youtube.com/watch?v=k3MG7ww49A8
... but it's not terribly useful.