layer alignment on multiple parts print fail

[gestalt73]

So, what would you change to solve for this? Jerk? Move Acceleration? Top mounted abs spool holder wobble?

So, a client wanted a rush job on four parts, so I tried running them all on the same plate overnight, to see if anything had changed since the last time I tried.
I'm going to run them individually over the next day or two, but it would be nice if I could reliably run multiple parts without this issue in the future.

What I'm finding is that my layer alignment is terrible when printing multiple objects simultaneously.
I also see it in single parts, when there are feature changes in a layer, but it's not so pronounced.

- This is printed at 20mm/s perimeter, 30mm/s infill, 40mm/s sparse infill
- Jerk set to 20, print acceleration set to 1000, move acceleration set to 2000
- Heated build plate is nice and secure, and glass plate is firmly affixed with 6 clips.

Belts are nice and taught, and printing single objects renders beautifully.

What's confusing is that it's not overshoot, I'm not seeing any type of bounce back to alignment in an individual layer, it's as if the entire layer gets shifted over for the duration of the layer.

[img]http://i.imgur.com/ogqi6g7.jpg[/img]

[Eaglezsoar]

I would suspect some binding going on. If you are using the original arms, the "rollers" the arms attach to could be sticking to the axle.

[Tinyhead]

Is it only in one axis? Just wondering if this was maybe an example of skipping steps from the Rambo being too hot.

As Eagle mentioned though, I would definitely check those joints if it's the stock arms.

[gestalt73]

These are all great suggestions.

I'm not sure that it would be the RAMBO overheating, as single parts have much better layer alignment than with multiple parts.

I'm also using xnaron's mag arms, so binding shouldn't be an issue, and single parts don't show the same variance.

I suspect the next step would have been to slow down travel & travel acceleration, reduce jerk and try again.

Now I'm curious about if the smoothieboard shows the same issues. The current travel values are sane, and slow, so it will be interesting to see how it handles multiple parts on the same plate.

Alan

[Mac The Knife]

I'm new to 3D printing, But I have converted a Harbor Freight mini mill to cnc a few years back. This magnetic arm stuff, to me, seemed to be a fix for the "Delta arms blues". Supposedly the latest version of arms took care of that problem, however it is still the responsibility of th owner to do preventative maintenance. With that said, unless your magnetic ends are levitating, the balls are rolling around on the surface of the magnet, and at extreme travel, they then slip and reposition themselves.

But, since I haven't tried them yet,,, I'm kinda talking out of my lower orifice.

[McSlappy]

I'll echo Eagle and suggest it's a universal joint binding. I had almost the identical issue and it was just a single Universal joint. Pull of all the arms and move the joints till you find it. Clean that bad boy off and lube it back up.