Bizarre Ripples in the plastic

[limor]

I noticed these odd "ripples" in the plastic print. what could possibly cause these ripple effects common in more fluids?


Ripples in the plastic by RoboSavvy, on Flickr



Ripples in the plastic by RoboSavvy, on Flickr


Answers: vibrations in the Makerbot Replicator. The horizontal layer containing a slice of that hole has the extruder doing a horizontal motion in the hold side and then a long vertical motion along the side of the structure. The horizontal motion causes the Replicator structure to vibrate which is then seen in the vertical motion extrusion.

[tempusmaster]

I noticed these odd "ripples" in the plastic print. what could possibly cause these ripple effects common in more fluids?

Answers: vibrations in the Makerbot Replicator. The horizontal layer containing a slice of that hole has the extruder doing a horizontal motion in the hold side and then a long vertical motion along the side of the structure. The horizontal motion causes the Replicator structure to vibrate which is then seen in the vertical motion extrusion.

That's some of the worst ghosting I've ever seen. How big is the part?

That seems to occur more with machines that have a lot of mass to move. The Replicator, with its dual extruders, is an extreme case. The Bowden tube based systems, like Tantillus, don't seem to have the problem at all since the only moving mass is the hotend/printhead. Of course they have other short-comings.

[limor]

That's some of the worst ghosting I've ever seen. How big is the part?

The distance between two adjacened holes in that part is about 11mm

[tempusmaster]

That's some of the worst ghosting I've ever seen. How big is the part?

The distance between two adjacened holes in that part is about 11mm

The ghosting may be caused by the heavy carriage resonating. Here's an example:

http://d2oadd98wnjs7n.cloudfront.net/medias/243498/pictures/full/20120519005225-Resonance.resized.JPG?1337413967

Adjusting the speed might help. Sometimes just a 10% change in the speed is enough to eliminate or at least minimize the problem.

You might also try rotating the part on an angle so that the part major axes aren't directly on the printer x/y axes.