Bowed Gantry?

Ask the MakerGear community for assistance...
Post Reply
Quark
Posts: 79
Joined: Sat May 23, 2015 6:21 am

Bowed Gantry?

Post by Quark » Wed Nov 02, 2016 11:21 am

Hey guys, who has bowed down gantry's? I'm talking the x-rail here where the print head sits on.

I've been chasing a level build plate for a few days now, and thought I had a bowed glass, always high in the center, but I busted out my straight edge rule I use in my garage for checking engine block and head warp, and verified the glass plate is flat. Method of checking is you put a known straight edge on a surface, bust out the feeler gauges and see which and where it slides in between. Glass was less than .001" very good if you ask me. The gantry, not so much, I get about .006" (.152mm) of space in the middle of the gantry at the aluminum plate and on top the x-rail. Searching turned up to be belt tension, so I loosed the belt completely, and it was still showing .006" gap. I loosed all the bolts to the x-rail and tighten it back up again, still have a gap. Is it possible that over time, the gantry got flexed permanently? This is the first time I've touched the belt tension since I got the M2 shipped to me about a year ago. Always seemed fine when I checked.

What's the fix for this? shims? if so where? under the x-rail, the aluminum plate? or the plate and the steel frame? Logic says between the rail and the aluminum plate? I'm going to do more measuring and taking the x-rail off later this week and see what I can come up with here.

Let me know, thanks!

ksevcik
Posts: 56
Joined: Fri Oct 21, 2016 1:07 am
Location: Houston, TX

Re: Bowed Gantry?

Post by ksevcik » Wed Nov 02, 2016 11:39 pm

I had something similar. Diagnosed it with a taper gauge between the nozzle and a pretty flat MIC6 plate. I just shimmed the middle of the X rail by however much the bed was "high" and that got everything flat. I tried not to loosen all the hardware, though. Left a screw on each end mostly tight so I didn't have to worry about messing with the squareness of the rails. It sounds like you're past that point now, so I'm not sure what that's gonna do to ya. I've been thinking about making a print up to check and calibrate squareness, but I'm temporarily printerless, so that'll have to wait a bit.

User avatar
jimc
Posts: 2888
Joined: Wed Apr 09, 2014 11:30 pm
Location: mullica, nj
Contact:

Re: Bowed Gantry?

Post by jimc » Sat Nov 05, 2016 2:36 am

yes the rail needs a couple shims under it. goes directly under the rail. very common issue

Quark
Posts: 79
Joined: Sat May 23, 2015 6:21 am

Re: Bowed Gantry?

Post by Quark » Sat Nov 05, 2016 9:40 am

alright. I think I got it all squared away, not sure if it was the best, but I put a a .006" shim in the center and had to progressively put smaller shims going out. Putting a single shim in the center gave me almost like a "W" shaped rail when the screws where all tightened up. I'm down to .0015" in one spot now, and perfectly okay. Leveling on the borosilicate glass is WAY better now. Anyone care to share how they are shimming? Just the middle section? or throughout till its flat? Perhaps just screw in the two end screws and one in the middle? or less torque on the screws in between? Just throwing out ideas in my head. Let me know, thanks!

User avatar
rpollack
Posts: 494
Joined: Wed Apr 09, 2014 9:01 pm
Location: Beachwood, OH
Contact:

Re: Bowed Gantry?

Post by rpollack » Sat Nov 05, 2016 1:56 pm

If you think there is a problem, please contact support. We have a jig that we can send out that you can use to reset the axis.

Rick

Quark
Posts: 79
Joined: Sat May 23, 2015 6:21 am

Re: Bowed Gantry?

Post by Quark » Sat Nov 05, 2016 8:32 pm

Huh, ok, I'm printing fine right now, not too concerned about squareness yet, but I'll give you guys a call just in case I missed something. Thanks Rick.

Post Reply