Weird Looking Infill

[Matthew Meyer]

I have a Replicator2, and I have noticed that every now and then my infill comes out looking very ragged. I was wondering if anyone else had this problem or knew what was causing it. 

Normally, the infill is a smooth honeycomb-like shape, but I've noticed that fairly often, the infill appears ragged, almost like a spiderweb instead of a honeycomb.

I am attaching a photo of a print in progress to show what I mean.

[Ryan Carlyle]

You're getting stringing, either from printing temp too high or retraction settings too low. You might try dropping your print temp by 5-15 degrees. It doesn't really matter if it's inside your print though.

It also looks like you have a lot of Y backlash. Are all your belts tight? Specifically the one on the Y stepper at the back right corner of the bot.

[Matthew Meyer]

Thank you. I will try dropping the print temperature and see what that does.

Looking at the belts, it seems the one you mentioned, the back right corner, has a little bit of slack. The others are fairly tight. I can't believe you saw that from my print! I will look up how to fix that.

[Ryan Carlyle]

Your infill has gaps that indicate backlash... basically when the extruder reverses direction on an axis, it doesn't travel as far as it's supposed to. That's leaving gaps in your honeycomb. It's pretty simple when you've seen it a few times. But with that kind of picture resolution, I wouldn't have been surprised if I were wrong.

Use a long 5.5mm socket or needle-nose vise grips or something to loosen the two little ny-lock nuts holding the stepper bracket to the frame. Push down the stepper hard and re-tighten the nuts. The belt should make a middle-pitch sound when you pluck it.

This is a very difficult operation if you don't have the right tools, sorry.

[Matthew Meyer]

Thank you! I should be able to find the tools. I believe this explains the problem completely.

[Jon Wong]

The belt on my Rep 2 broke within the first 2 months of owning it last year. I temporarily fixed it by pulling the belt and sliding it into the grooves. I don't think I did it right, as there is some slack. It prints just fine though, so I've never bothered fixing it. MakerBot did send me a new pulley, but I have no idea on how to install it. I took off the body and took screws off to get at the pulley, but could not figure out how to get past that step without screwing everything up. I'll post pics later, but I guess my question is:

Are there any tutorials (I looked and didn't see anything) for this? (replacing the belt on the right side). Thanks!