Welcome to the SeeMeCNC Community

Hi Everyone,

I need some help here. I am having a problem where a straight part will narrow or taper in within its length. The 2 photos show 2 different orientations . The first where the "spokes" each point to a tower. In this orientation the width, which should be 20mm, is a little wide but consistent. The second photo shows the model printed with the
spokes between the towers (60° from the tower). The one facing "south or down" is a full mm skinnier at the tip.
The third photo shows some of the same wonky stuff.


While this doesn't seem much it causes problem when I want squared parts. The model is only 1 mm high. It is the
same regardless of how tall I print. It is printed in pla @200. bed @ 50.

The printer also cannot do circles worth damn. They are squished or out of round.

Here is what I've done or checked

1, The cheapskates are nice and smooth and belts are good. I even removed the belts and checked each wheel on the cheapskates and adjusted them to a nice light roll. No shimmy or shake.

2, I am using Trick laser arms. The effector is pretty solid. I have checked the arm length in the eeprom and it is set to 269. I played with that setting a bit but the problem followed.

3, I cleared the firmware and reloaded and recalibrated with a dial indicator to within .001 inch. The effector tracks nicely.

I've had an Orion since last winter and built the Max this summer so I am pretty familiar with the workings. I get good prints just not accurate. I have got to do some rectangular prints for work but the wider the print the more pronounced. I need rectangles not wedges. I understand about shrinkage but this is not the problem.

Any help would surely be appreciated.
Please excuse the poor representation on the photos. Not my strong suit.

Thanks
Tony

Here's an example of another person talking about the circles issue and why that sometimes can be an issue with the slicing and the way the RAMBo interprets and interpolates the gcode. In your case it appears to also be a result of your irregular build shapes...

As far as your scaling issues, many members here suggest checking your steps per mm on each motor in the Repetier firmware. Tweaking those just right can usually get your arms to cooperate more in sync with eachother.

lightninjay wrote:Here's an example of another person talking about the circles issue and why that sometimes can be an issue with the slicing and the way the RAMBo interprets and interpolates the gcode. In your case it appears to also be a result of your irregular build shapes...

As far as your scaling issues, many members here suggest checking your steps per mm on each motor in the Repetier firmware. Tweaking those just right can usually get your arms to cooperate more in sync with eachother.

Thanks for the reply. I should mention I have used 3 different slicers to the same result. I'm not sure my build shape is irregular, a 3d printer is capable of the oddest of shapes.

I am not worried about circles coming out undersized, more that they are not round.

How would one go about changing the steps per mm for an individual motor? I've looked through the configuration h file and there seems to be only one general spot to change this for all the motors not just one.

Ya know, come to think of it, is your effector platform tightened all the way down? This includes the hotend and nozzle itself.

It seems like nozzle wobble could cause some of the scaling issues to me...

lightninjay wrote:Ya know, come to think of it, is your effector platform tightened all the way down? This includes the hotend and nozzle itself.

It seems like nozzle wobble could cause some of the scaling issues to me...

Yes, for sure

Wow, then I'm flush out of ideas for now.

I guess the last thing I should ask is, what speeds are you printing at?

You mention your head tracks fine after calibration, I just wonder if some sort of speed acceleration settings have gone awry because of print speeds.

I'm grasping at straws at this point. :/

lightninjay wrote:Wow, then I'm flush out of ideas for now.

I guess the last thing I should ask is, what speeds are you printing at?

You mention your head tracks fine after calibration, I just wonder if some sort of speed acceleration settings have gone awry because of print speeds.

I'm grasping at straws at this point. :/

I usually print slow 30mm/s. It makes no difference. I would say by the silence from everyone else that no one else has any ideas. I'm getting ready to chuck this thing out the window and buy a cartesion style.

I guess, what are your layer heights and nozzle settings looking like?

If you could post up your KISSlicer and Cura configs, I might be able to diagnose a bit better.

Everything is stock on the hotend. .50 nozzle. 2mm height. I have tried matterhacker, cura and S3d. I use S3d mostly and with exception of diameter I use the models on the Orion and Max equally. The Orion has no issues with the models so I doubt its a slicer issue. Yes, I could print them on the Orion but I need the extra width. Its a good machine, the Orion, has over 30 days on it.
Thanks lightninjay.

.05mm nozzle...is it typo i think...

Khalid Khattak wrote:.05mm nozzle...is it typo i think...

Thanks but that was not helpful.

I am still stuck. Patience and moral at an all time low.

I had a bit of this type trouble along with overshoot on corners and looked at a lot of things with no result. In the process of moving the effector I notice that while the skates and arms were tight, I could wiggle the nozzle a bit. Apparently the black plastic "springs" that go over the u-joints (mine are aluminum) could be a little stronger. I placed sever taunt rubber band across the arm pair and positioned these at the center of the arms. It is amazing how much tighter and stiffer than made the nozzle and effector plate.

My problem largely went away maybe because this worked, maybe because I wanted it to. I still find holes a little undersize but this is due to the polygon effect. When measured across the "flats" or "corners" they look pretty good.

Good luck with your frustrations!

nitewatchman wrote:I had a bit of this type trouble along with overshoot on corners and looked at a lot of things with no result. In the process of moving the effector I notice that while the skates and arms were tight, I could wiggle the nozzle a bit. Apparently the black plastic "springs" that go over the u-joints (mine are aluminum) could be a little stronger. I placed sever taunt rubber band across the arm pair and positioned these at the center of the arms. It is amazing how much tighter and stiffer than made the nozzle and effector plate.

My problem largely went away maybe because this worked, maybe because I wanted it to. I still find holes a little undersize but this is due to the polygon effect. When measured across the "flats" or "corners" they look pretty good.

Good luck with your frustrations!

Thanks nitewatchman. It's a good thing I am bald because I would have no hair left if I wasn't!! I still feel is is a mechanical problem so I am going to dismantle the whole thing and start from scratch.

Are all 3 axis motors the same brand? And are your motor currents set up correctly in the firmware?

I'm wondering if perhaps for some reason, your motors aren't strong enough to move the effector exactly where it needs to be. The 3 culprits I could think of might be firmware, overheating, or power supply.

Seems like overheating might not be it since you seem to get this problem immediately at the start of a print (presumably).
Also seems like power supply might not be it since that would tend to affect hotend temperature first.

You've mentioned repeatedly how stiff and well-calibrated your machine is. One would think if that were the case, stepper motor weakness might be the next logical cause for something like this?

I'd also take a second look at those belts. Even if the tension is correct right now, if they warped at all at some point in their lifetime, that might also cause this. Maybe lay them out side-by-side and make sure you can get the teeth to align across all 3 belts along their entire length.

BenTheRighteous wrote:Are all 3 axis motors the same brand? And are your motor currents set up correctly in the firmware?

I'm wondering if perhaps for some reason, your motors aren't strong enough to move the effector exactly where it needs to be. The 3 culprits I could think of might be firmware, overheating, or power supply.

Seems like overheating might not be it since you seem to get this problem immediately at the start of a print (presumably).
Also seems like power supply might not be it since that would tend to affect hotend temperature first.

You've mentioned repeatedly how stiff and well-calibrated your machine is. One would think if that were the case, stepper motor weakness might be the next logical cause for something like this?

I'd also take a second look at those belts. Even if the tension is correct right now, if they warped at all at some point in their lifetime, that might also cause this. Maybe lay them out side-by-side and make sure you can get the teeth to align across all 3 belts along their entire length.

Thanks, I'll be sure to check the belts. I've got them out already anyway. Good tip! The power supply is new (700watt). The motors are the same and the currents in the firmware has been triple checked.

Solved!

Great! What wound up being the issue...?

Wonderful, I assume you will let us know what the problem was.

Holy1, You have left us in limbo!
What was the problem?