Ripples on edges of prints

[orionthunter]

Hi, I just finished building and callibrating my i3v 10" and I am getting ridges along the sides of my prints. The spacing seems regular and has a period of about 1 mm, see the attached picture. Any idea what is causing this and how to fix it?
Thanks
2014-09-11 13.58.18.jpg

[gmay3]

Hi orionthunter! Firstly, welcome to forums!

Hmm, can't say I've ever seen that before (not that I've seen a lot) but here are a few things to try:

1. Make sure the belts on your x and y axes didn't loosen up. They should be tight enough to pluck.
2. Try to gently rotate your y bed and make sure it is solid both where the delrin idlers press against the y rails. If they are loose tighten them up so the y bed only moves in the y direction and has no play in any other directions. Also do this with the x carriage.
3. Look under the z carriage and make sure that the two nuts that are on the threaded rods are still seated in their laser cut slots.
4. Make sure your hotend is rigidly mounted to the base of your extruder/x carriage.
5. Verify that the clipped down glass is securely fastened.
6. Verify that your seatbelt is securely fastened and your tray table is in it's upright position

I wonder if there could be a print defect on your large gregs extruder gear that could lead to this periodic type error. If there is a defect in there maybe it over extrudes slightly to create those ridges in your print. Take the filament out and double check that the large gear is completely perpendicular to the hobbed bolt when you rotate it.

Keep us posted!

[MiniMadRyan]

I would also check to see what the gcode output looks like in your print software. I remember from my Printrbot days, but in some cases, your layer height settings in repeater can cause those edges as well. Your Z steps value can also affect the ribbing that you are seeing. This was a common error on my first printer. The following thread has a great write up on the science behind it

http://www.printrbottalk.com/forum/v...hp?f=20&t=2653

[orionthunter]

Solved it! It turns out I had somehow put 3 washers between the large gear of my extruder and the extruder body, rather than 2. This was causing the gear to rub up against one of the bolts on the x carriage that hold the idlers in place. After removing the extra washer I got a very nice looking cube. That Z step issue is interesting, not something I would have thought of but it makes sense once its explained. Its good to know about even if it isn't the cause of this issue. Thank you guys for your advice. Now to try a real print!

[gmay3]

Woo hoo! Good job fixing it!

[orionthunter]

More problems. My wooden bed has warped to the point where there is no longer enough adjustment in the idlers to keep them pressed against the aluminum extrusions. Colin is sending me a new one, but now I have to wait for it to arrive before I can print anything.

[printbus]

More problems. My wooden bed has warped to the point where there is no longer enough adjustment in the idlers to keep them pressed against the aluminum extrusions. Colin is sending me a new one, but now I have to wait for it to arrive before I can print anything.

I don't think anyone has had that problem before. Some questions so we can understand this - How hot have you ran the heat bed? What are you using for an insulator between the heater and the wood? Did you use the wood material as-is or was it painted or anything?

[orionthunter]

I've been using my heat bed at 110, with double corrugated cardboard, which had been squished to make it fit between the heat bed and the wood. I was using the wood as is, no paint or sealant. Do most people typically paint theirs first? What had happened is that the center of the wooden bed sagged, so that the edges are at an angle, causing the idlers to be tilted outward.

[printbus]

Nah, I'd guess that some people paint, and most do not. The 10-inch hasn't been out long. It'll be interesting to see if this becomes a common problem.

[orionthunter]

I found one person posting on the Reprap forum about a year ago, who had issues with the bed warping on the regular 8" i3, like me it was shortly after he got it , and he got a replacement. There were no further posts about it so I assume the replacement worked fine. Probably the occasional batch of plywood has some issues. It would seem surprising if going from 8" to 10" increased the strain by enough to cause significant extra warping.