Well here goes... Aluminium frame router design

[CharlieRam]

So I stripped the carriage, 119 ball bearings, measured quite a few of them and they were 3,975-3,988 ish so my measurement last night was good, still notchy :-(

Would the lack of one ball really cause this issue? degreased and checked all ball tracks, checked the end plastic things by pushing the balls back and forth and they seem ok? Could the plastic cage thing be chafing?

Just out of interest I got some digital kitchen scales on the end of each rail and pushed on it until the rails started to move, the good one started to move at about 400g of pressure, the notchy one was just over 1000g, for info the rails are 375mm long.

BTW, the brand is PDF and model is DFH20A

[sinnsvak]

I also have a set of 600mm PDF 20mm profile rails, which dont run smooth at all. I will change them out with hiwin down the road when I get some leftover money to do so. For now Im gonna keep it as it is until it proves to be a huge problem.

[CharlieRam]

I also have a set of 600mm PDF 20mm profile rails, which dont run smooth at all. I will change them out with hiwin down the road when I get some leftover money to do so. For now Im gonna keep it as it is until it proves to be a huge problem.

Lee Roberts is sending me some ball bearings, I'll see if it makes a difference and if not I will fettle the carriage a little......Now wheres that bastard file ;-)

[Lee Roberts]

So I stripped the carriage, 119 ball bearings, measured quite a few of them and they were 3,975-3,988 ish so my measurement last night was good, still notchy :-(

I would think they are to the closest standard size of 5/32in then, your in luck as well because I've got some that size, PM me if you want me to send you some, call it the postage cost...

Lee

[CharlieRam]

Well I've been busy doing the electronics and control cabinet and familiarizing myself with the AXBB motion controller, its my first one so can't compare with any others but i must say I'm impressed with it. I have completed almost all of the electronics but before I fit the motors to the machine I want to make sure the limits are fitted just in case! Is 5mm from a hard limit a good distance or do i need more? I think I may of gone a bit overkill with the cable chain too!

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[routercnc]

5mm distance from the hard stop will function fine as the motors stop very quickly. If it was a home switch you might want a bit more as the machine over travels a bit.
Only thing to think about is if you can get your finger trapped.

[CharlieRam]

So I had some issues with my AXBB charge pump output but that has now been resolved thanks to some helpful people on here .
This means that I have finally been able to make some movement on my machine however I'm not entirely happy with it.
What kind of rapid speeds would you expect on nema 23 and 70v driver/psu?
I may have to go for twin motors on the X axis or a higher power nema 34 as that seems to bind if I go above 12000 units per minute(I am running at 10000 to be safe) whereas y axis goes upto 17000 units before binding(running at 14000). The z axis is only around 8000 but I assume that's because of the ballscrew pitch.
Anyway, it's looking promising but there may be room for improvement.

The y axis is smooth one way but seems to have a judder when rapid in the opposite direction...any ideas?

The X axis sounds gratey in both directions ! I'm thinking it may be sounding worse because it runs on the steel box section and that may be amplifying the sound?

https://youtu.be/Jv9x7rc4N-8

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[JAZZCNC]

Hi Charlie, don't know anything about your setup so might be way off here.
If you are using a Single nema23 with 70v to drive 2 x 10mm pitch screws then you're doing well to get 10M/min. Or if you're using single Nema34 with only 70V you still won't get much more than 10Mtr/min. You'll need more Volts for Nema34 to get higher rpm.

Now 2 x 23 will get you little more speed but my question would be WHY.? You can't cut many materials higher than 10mtr/min, woods etc will be much lower feeds and the machine isn't massive so 10mtr/min rapids will still get you end to end quick enough.

[CharlieRam]

Hmm...well I suppose the need for speed is more down to seeing the rapids from the machines at work! Yes I know they cost more like 1 mill each but y'know
I suppose the real answer is I'd of liked the X and Z to run at the same speed....not a deal breaker and maybe in the future ill upgrade the X axis but I'm happy with it for now. I tweaked the speeds and acceleration values today and it's a pretty speedy little thing soon be making a cut.

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[JAZZCNC]

I suppose the real answer is I'd of liked the X and Z to run at the same speed...

Doesn't really matter because if both axis are moving together the feed will be calculated so they both arrive at the same time so you are unlikely to hit the max velocity anyway.