Both the solid rods and lead screws are supported at the top and measure the same top and bottom… And they are well cleaned and oiled.
the leadscrew should not be supported at the top. There is a reason that so many cartesian bots leave the top of the leadscrew free. But people are free to make their own descions. a few links for your review http://forums.reprap.org/read.php?4,431977 http://www.buildlog.net/forum/viewtopic.php?f=33&t=1496&start=10. This one in particular has great insight to this https://groups.google.com/forum/?hl=en#!topic/3dprintertipstricksreviews/DTISGbOYnTQ[1-25-false].
The top of the leadscrew moving around is what causes the z platform to remain stable. Its just the physics of the situation.
30mms is rather slow. You may think slower is better but I think you may be overheating the print because the head is moving slow. Can you try a print at 45mm without slowing for the small perimeter and external. If your printer doesn’t like faster print a few things on the buildplate so the head moves more giving parts time to cool more. Not expecting anything other than results to troubleshoot. Incedently I don’t support the top of my threaded rods either
I will bump it up to 45 for the next print and see how it goes… Many thanks for all of the advice.
@Keith_Applegarth Why the spring tensioner? Wouldn’t that cause your belt to vary in length with a varying load? And the load is always variable, unless everything is super super perfect.
@Rien_Stouten Early on someone mentioned that I should use them. So I did and just never removed them.
@Keith_Applegarth Yes, early on I read somewhere that your first layer should be very thin, so it has cost me months of despair to see what good advise that was. Think about it. Do you want a variable length of belt on any axis?
@Rien_Stouten I just want it tight I will remove it when I redo the belt on the X axis. And what would you recommend for a 1st layer height with a .4mm nozzle printing at .2mm?
@Keith_Applegarth 0.3 mm. first layer extrusion width 150% minimum. depends a bit on the type of filament. I’m having good results with 200% using PETG.
@Rien_Stouten I found Slic3r 's recommendations after I read your post. I made some adjustments and need to test.
I had a massive failure yesterday towards the end of a 3 hour print job… my right Z axis motor just started grinding. I swapped the motor leads on the Ramps board and the problem went away… go figure. I suspect that the connection to the Ramps board was a little loose… Now when I run up and down, they are spot on… Time to run a taller test…
you should take that as a sign. Link your two leadscrews to one motor using gt2 belt. 1 motor is better then 2.
@adam_paul I finally got it sorted. The right hand stepper connector was loose. I swapped the connections on the Ramps board and the problem went away. One doen.
Always the little things that cause the biggest headaches.
I agree… next thing is to change out the flexible couplers for solid.