Straight line curves down at top of the sheet (solved)

No, the only limits are the feed rate ones.

It is not directly calculated, but is incorporated into the chainSagCorrection value in an inverse-squared manner. Also incorporated into this value are aspects such as the chain weight, bed lean angle, as well as a variety of scaling parameters, so directly pulling the weight from this value would either require that other data be input or guessed.

I do think it gives a close-enough relationship to sled weight however that it could be used to create some sort of maximum speed setting based on sled weight though.

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there is a speed limit, we also have code to detect that we are exceeding the
max speed the machine is able to do (will be in next week’s update)

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That would be the software feed rate,

and this would be the physical/electrical limitations of the equipment. The software doesn’t look to current limiting or shield protection.
Another variable to check along with voltage on the motor would be temperature of the H-bridges. They don’t have protection, and could have reduced performance at high temperatures, which would also show up as reduced voltage at the board end of the motor cables.

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i’m pretty sure we don’t have temp monitoring of the drivers in the hardware

You’re right, it would take some form of remote sensing.

Given the kind of singularity of this cuts, don’t bother to much. Working on it.

Thank you all for all the support, suggestions, clues, hints and inspirations.
This amazing combined community effort put a list for me together to test, that pushes me in the background for a moment. Don’t think I will not be reading!

What I really would love to read is, a combined task force of min. 10 Maslows testing 1.08 thoroughly from all sides.
Starting as if you just opened the kit.
By the time the new kits arrive at their destinations, the support from our side will get everyone from unpacking to cutting.

It was suggested to open a post, but sadly my current powers do not allow me to create a spark strong enough to ignite. Volunteers?

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you have shown a weakness in the system, and figuring out what’s happening will
make everyone’s machines better.

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Only 2 things that I’ve changed solved the issue.

  • I replaced the 5A power supply with a 10A one.
  • I tested 1.09

And the WINNER is (for now until proven otherwise) @Robert!
With a new power supply and 1.09 (please join us on the mission Let’s make v1.09 the most stable release yet) the cut seem to be straight. A restricted feed rate might have contributed, there is more to find out.
That I’m able to continue testing in the ‘Heavy Weight’ category is good news.
Thank you all.

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Based on this outcome; for those outside the US who need to source their own power supply anyway is it worth going straight for a 12v DC 10A over the recommended 5A to be on the safe side?

Cheers!

I would vote for YES. The price should not be much different I hope and it’s good to have a solid reserve.

There is also a chance that a future motor shield will have stronger chips, allowing for heavy load :relaxed:

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What is the risk of burning out the motor shield by providing it up to 10A of current? Would it be prudent to go to active cooling (i.e., heatsink w/fan) if you up the available current?

I failed to provide the proof it was the power supply.
The version was changed from 1.07 to 1.09 that decreased the max feedrate from 1000 to 750 and perhaps some other changes. But with 1.07 I had to go down to feed 200 to get a straight line.
All speculation till now.

Active cooling is never a bad idea. As far as I know we are running the shield within, but close to upper limits (with a heavy sled and/or short vertical hight, top of the sheet, motors are pulling against each other)

Under normal operation the motors and shield should not pull more A then needed. If a chip shortens, the amount of magic smoke might increase. I like to make my power supplies ~30% stronger then I calculated. I don’t remember why, perhaps to compensate for errors in the math or from old transistors those days, that had the best performance around 70%.

Currently running this china 12V/10A without magic smoke.



Kindly ignore the Bedouin style mounting :grin:
I live in a country under (not so active) development, plus the window AC is blowing sideways over the electronics.

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My thought was that if the power supply wasn’t providing enough current at the upper limits to cause an accuracy issue, then it was limited on the amount of heat it could produce. Giving it the possibility to pull more power also gives it the possibility to generate more heat. But its good to know that your 12V/10A doesn’t let out the magic smoke.

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I like the jack to adjust tilt (I assume). I had suggested at one point putting a scissor lift in between the legs and the top beam to adjust the “height” of the top beam. But there’d be too much slop since the force is acting in a different direction than the scissor lift is designed for.

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The far future new frame will have 2 jacks with an old motor turning them :slight_smile:
1 jack in the middle makes the strongest frame flimsy at the low corners.

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One more statement about the power supply:
I was running the original 5A for more then 1 year and fried at least 1 shield with it, at same weight and steeper angels.
If it has anything to with my cut, then it could not supply the 5A or even less any more (weekend somehow). LOL, yes, tomoorow weekend, weakened…

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@bar Any thoughts on using a 12v 10A power supply in lieu of the recommended 12v 5A?

It certainly can’t hurt! It does sound like that fixed the issue for some. The motor driver board is really only rated for about 5 amps, but there is a new driver board in the works which will remove that limitation also.

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