Waviness or not...That is the question

i used to have this issue very badly and managed to get it to calm down alot but not get rid of it. The most effective thing i have done was i disassembled the whole x and z carriage. remove the threaded rods and removed the smoothed rods to. i tightened all the screws. removed the pulleys and made sure everything was perfectly on right and tight. sadly the issue is still here but looks abit better.

 

My hobbed bolt did not have even recess cut. It was off centered while getting cut so it ended up wobbly.
Looks much better after replacing it. Almost perfect.

 

Waviness yes... when I print a huge flat area like a circle, I get diagonal ripples, like a pond has disturbed the water. I have yet to figure out how to fix this.

 

Jan 2014. Waviness YES, but not as bad as some of the reports I think. I've noticed that the top of the threaded Z rod moves in a circular fashion rather than holding vertical. My assumption is it's either an issue with the couples or the rod not being straight. Have just looked at the couples and only 1 threaded Z rod has plumbers tape wrapped around the bitten where it connects to the couple. Check later if it's both or only that rod that circles.

 

Just to make sure we're all on the same page for the discussion:




The lines occurring a approximately 1.5mm intervals along the z-axis is what we're referring to.

(Ignore the other defects in this print. I was playing with different temperatures at the time of this print to see if they had any effect.)

 

No. Dec 2013.

 

Yes Jan 2014. But not bad at all like the picture montravont showed. Just in the surface finish.

 

No, Oct 13

 

Nope! October 29

 

Got my printer today. Everything works great and I am amazed by the result. Especially considering I'm totally new at this! No problem with sticking to the bed or warping. I do however, have some really bad waves. Se the picture below. My Z-axis wobbles like crazy!! I plan on printing the stabilizers tomorrow, maybe that will help a little bit.

 

My first print looked as bad as Kadows. The biggest cause of the waves was the couplers for the z axis screws. The screws were bent and the z smooth rod mounts were cracked. I replaced the z mounts with ones I printed. Then replaced the z screws with M8x1.25 screws that are much better than the stock ones. I made my own screw couplers that are perfectly true. Also replaced all the 5/16" bearing rods with case hardened and ground 8mm rods. That removed a lot of slop from all the bearings. All the screws that hold the motors were loose. They were too long so I added a flat washer under each one so now the motors do not float all over the place. Also the head was loose in its mount. Replaced the screws that held the head in place with longer ones. That fixed that.

Now after a month of messing around it prints just good enough to make parts. Still wouldn't bother trying to print a figure like the tree frog. It just isn't good enough of a machine for that kind of work. Maybe after I replace the y axis drawer slides with nice rod bearings it will be a great machine. It was a long road fixing everything up but now at least I can load a program and print. Great for my quad copter project.

 

How'd you make your own screw couplers?

 

I made them out of aluminum on a lathe. They are the same size as the original ones but the hole through them is the same size as the motor shaft on each end. This makes it easier to be sure that the hole is true on each end. Then I machined 12 inch long 8mm x 1.25 threaded rod on one end to the same size as the motor shaft. This insures that the threads will run true with the motor shaft. I also turned up the threaded rods in the lathe and checked over and over to make sure they run true. Now I no longer have wobbly threaded rods on my machine.

Even with all the things I have done it is not the best printer I have owned. I'm pretty sure that replacing the y axis drawer slides with nice rod bearings will improve things to a useful level.

I hope that robo 3d improves their printer with all the ideas they are getting from everyone on these forums. But with that said it's a shame that they just do not seem to have the knolage to figure it out themselves.