New Rostock MAX V2 prints 5% small in X and Y

regillmore · Post by **regillmore** » Fri Nov 20, 2015 9:56 pm

Hi, all!

I just finished putting together a Rostock MAX V2 kit that I bought back in September, and so far everything I've printed has come out just a hair over five percent small in X and Y. A 40mm calibration square I printed came to 37.8 x 37.8 mm, and the 20mm square I printed came to 18.9 x 18.9 mm. Consistency, at least? My Z heights are dead on as long as I get a clean first layer.

Here's a borrowed hot end shroud next to mine. Mine's in red. http://i.imgur.com/HG6KZU1.jpg

I couldn't get either the fan into my shroud, nor my shroud into the effector platform. His works great, though. (Shoutout to gchristopher!)

Any ideas? I've been using the current SeeMeCNC guide throughout the build, and everything is stock Repetier 0915 as prescribed. I'm running MatterControl 1.4, and I'm printing with Matterhackers pro ABS. Diagonal rod length is 290.8, steps per mm is still 80. My kit doesn't have the newest style arms, but it does have the newer cheapskates, if that narrows it down enough which kit I have.

Thanks!

Earthbound · Post by **Earthbound** » Sat Nov 21, 2015 2:44 am

The new ball link arms use the new longer arm length value of ~290mm. If you have the u-joint style arms, the correct arm length vale is 269mm. Change that setting and print size should improve. You may need to recalibrate. You'll definitely need to reset height for Z=0.

regillmore · Post by **regillmore** » Sat Nov 21, 2015 3:36 am

Thanks! That certainly isn't clear in the instructions, but it would explain the current situation. I'll give it a try and come back when I have some new results.

Post by **geneb** » Sat Nov 21, 2015 8:00 am

It IS clear in the instructions - if you're using the version of the manual that matches the revision of the kit you have.

If you've got the u-joint arms, you should be using the 3rd Ed. If you have the ball-joint arms AND the new power supply, you should be using the 4th.

g.

regillmore · Post by **regillmore** » Sat Nov 21, 2015 12:52 pm

Ah! You're right. I see that now. It had looked like all the version differences had been carried forward through manual revisions, so I had just been following whatever manual was current.

Spinning up now for a new calibration print after tuning in new Z heights, along with setting the diagonal rod length back to the default 269mm. Crossin' my fingers!

Update: Good fun, now my prints are 2.5% oversize. 40x40 calibration square came to 41.0 x 41.0 mm. Closer, at least.

regillmore · Post by **regillmore** » Sat Nov 21, 2015 4:36 pm

By plotting the diagonal length values I've tried so far along with their resulting print dimensions, I came up with a new diagonal length of 275.7mm. After plugging that in to the EEProm settings and retuning my Z heights again, the first calibration print was dead on 40.0 x 40.0 mm in X and Y.

That'll work! Thanks for the help. I'm sure I'll be around.

gchristopher · Post by **gchristopher** » Sat Nov 21, 2015 4:54 pm

geneb wrote:It IS clear in the instructions - if you're using the version of the manual that matches the revision of the kit you have. If you've got the u-joint arms, you should be using the 3rd Ed. If you have the ball-joint arms AND the new power supply, you should be using the 4th.

I was trying to help regillmore figure that out, too. That bit of information is fairly low-profile on the SeeMeCNC webpage, compared to the big, prominent "Rostock Max V2 Assembly Manual" link on the Downloads tab.

I have the 1st and 4th edition manuals handy, but had no idea there were kits that required the 2nd or 3rd ed, mostly because my 1st edition manual seems to so comprehensively cover options for past versions. Might be worth a mention either more prominently on the web page, or in the manual, in 0 - Introduction and Acknowledgments section? It's pretty common to say something like "This is the 4th edition, appropriate for kits shipped after 10/2015. If your kit may have been shipped earlier, please see the SeeMeCNC website to download an earlier version of this manual."

Post by **Eaglezsoar** » Sat Nov 21, 2015 9:45 pm

regillmore, good job in calculating that value. The normal for your arms is 269 but if your numbers work, then use them.

Earthbound · Post by **Earthbound** » Sun Nov 22, 2015 12:51 am

regillmore wrote:By plotting the diagonal length values I've tried so far along with their resulting print dimensions, I came up with a new diagonal length of 275.7mm. After plugging that in to the EEProm settings and retuning my Z heights again, the first calibration print was dead on 40.0 x 40.0 mm in X and Y.

Arm length is not a dimension that you should alter to tune the printer. It is the physical length of the arms between pivot centers. The arms you have are 269mm.

The extra 1mm in X & Y you found on your 40mm nominal test print is likely due to other factors. Try a different size test print (60 or 80mm) and see if 275.7 still works. I'll bet it doesn't. Then try same larger print after going back to 269mm. You'll likely find it to be a similar 1mm oversize.

JFettig · Post by **JFettig** » Sun Nov 22, 2015 11:23 am

Sadly that is the only way to adjust horizontal size. You'll find that you don't print a percentage off, but more like a numerical value off. For me it was .015-.020" off regardless of the size. My diagonal rod length is much shorter than stock in the firmware even though my rods are 269mm exactly.

regillmore · Post by **regillmore** » Sun Nov 22, 2015 6:20 pm

I printed a 70 mm ring with the 275.7 mm diagonal length setting, and it came within .1 mm all the way around. If there are finer tolerances to be gained than that, then I haven't got the tools to measure it anyways.

Success!

BuckeyeVolunteer · Post by **BuckeyeVolunteer** » Tue Nov 24, 2015 3:45 pm

I have the new arms and was told they were 290.8 it does seem to work. I was also told not to sand the plastic balls, picky picky picky. Now I have grease zerks on them for the long runs.....

Post by **geneb** » Tue Nov 24, 2015 3:54 pm

The ball and socket joints do NOT require lubrication.

g.

BuckeyeVolunteer · Post by **BuckeyeVolunteer** » Tue Nov 24, 2015 3:59 pm

It was a joke lighten up

BuckeyeVolunteer · Post by **BuckeyeVolunteer** » Tue Nov 24, 2015 4:02 pm

I also grease the belts increases the speed and stability

bot · Post by **bot** » Tue Nov 24, 2015 5:48 pm

I grease my heated bed to allow the nozzle to glide smoothly across it.

Post by **geneb** » Wed Nov 25, 2015 9:12 am

I swear you guys are the root cause of alcoholism among nerds.

g.

BuckeyeVolunteer · Post by **BuckeyeVolunteer** » Wed Nov 25, 2015 10:26 am

I also do datalogging so I can print better it has an amazing effect on the smoothness of the prints.

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New Rostock MAX V2 prints 5% small in X and Y

New Rostock MAX V2 prints 5% small in X and Y

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Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y

Re: New Rostock MAX V2 prints 5% small in X and Y