Hey all, been searching the web in every manner I can and posting on MB forums around the place and still haven’t gotten a solid answer, so want to pick all of your brains.

Recently started seeing bad roof gapping and cateye issues. Come to find the tension spindle had worn through the plastic Y carriage, so replaced it and now have great tension back on all the belts. Went and did a test print, and sure enough I am still getting cat eye effect on circles (which makes it VERY hard to print more precise pieces). I’m starting to wonder if I have a bent rod. Any thoughts? Below is a picture of where the cat eye-ing is occuring…your thoughts guys and girls?
printexamp.png

Try other brands of pla to see if it’s hardware or filament issue

Have tried a few different brands now. Something I started witnessing last night, is there is a shutter, about mid way on the axis rod. I’m stArting to suspect that my x axis carriage is indeed causing too much tension and bending the rods slightly.

As well, I am pretty sure the firmware is pretty outdated so going to update that as well.

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What’s “cat-eye” mean. Listen, normally a picture is worth 1000 words, but you’ve already pasted a picture and all I’m hearing is “blah blah blah”. Can you post a picture of the print? Also, what type of Makerbot are you using?

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There are better ways to offer your input than being smug about it… Also, if you are unfamiliar with what a CATEYE effect from Backlash is, then you haven’t been printing nearly as long as I have.

SO… Backlash, being when your belts don’t have enough tension and reversing jog on the extruder creates SLACK on the belt and essentially stops the extruder from moving momentarily. Attached, is an effect of BACKLASH which is known as a cat’s eye effect. Notice the bulges on the sides.

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I’m sorry you though I was being smug. I just didn’t know what the term “cateye” means. But it is possible you’ve been at this longer than I. You’re only coming here asking for help. Sorry I wanted you to be clear about it.

I’ve seen corner ringing from backlash, those sort of echos that occur when a head doesn’t stop or change direction fast enough and wobbles around corners. but that doesn’t sound at all like what you’re talking about. This is literally the first time I’ve seen this sort of distortion you show in this picture in the 5 years and thousands of hours I’ve been 3D printing. So thank you for showing me something new. I’ll keep an eye on this so I can find out what to do about it, just in case I ever run across it in the future.

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Well, I generally take “all im hearing is ‘blah blah blah’” as a generic “I don’t have the time to care” mentality. So, thank you, and I appreciate your input. I am getting good fill, but like I stated…I’m seeing (more so hearing) a shudder in the middle of the x axis rods when the extruder assembly carriage passes over it… this to me is indicating that its meeting resistance and could possibly be the tension on the rods… we’ll see when I replace that x-end housing tonight…

Well, I was trying for clever. Picture is worth 1000 words, but the words were just “blah blah blah”. Get it? I was saying the picture didn’t convey what it needed to. Sometimes I’m not as clever as I think I am.

I’ve apparently never experienced a bent rod causing drag before. But you say it’s offset on the X. I’m curious to keep my eyes on it.

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Yeah, theorizing here, as the near end X Chassis (marked Green) has too much tension, it will essentially make the rods bow as shown below (rod bending in blue). The red arrow signfies where the peak of the bowing occurs, which is why I theorize the shudder is coming from the middle of the rods. The extruder assembly is getting to the point and the steppers are essentially FORCING it past the bulge where we get the low THWAHTHWAHTHWAH sound…

Doctors, do you concur?

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So got the new carriages on, and its now to the point that all the belts are nice and tight…I also calibrated the steppers and got the alignment back in sync…

But I am still getting a tiny bit of the cat eye effect still…anyone have any ideas to what it might be? Firmware is up to date too, so I dont THINK it’s the issue. Any other thoughts as to what could be the culprit?