Circle shape is oval

#1

Hello,

When I print object with circle shape (example a hole), I have noticed that my circle is oval.
It is clearly visible with small object.

Does anyone have this problem ?

ps : I did a ticket, I will post Zeepro’s answer.

Distortion of my 3D prints
#2

What orientation is the circle in? I have printed several circular objects with the circle laying flat on the bed and they came out fine. An example of what I have printed is here.

I haven’t tried printing a circle perpendicular to the bed so I don’t know if that will cause problems.

#3

circle flat on bed.

#4

I suspect you have issues with backlash on the Y-axis. Lucky for you I have already gone through this and worked up a fix. I will attach a message that links the problem as I explained it to Zeepro and the fix that I implemented. If you have access to a milling machine, or CNC router, the fix is pretty quick to make. I bit of a PITA to install since you have to disassemble the Zim to get access to the Y-axis motor holder. A quick check to see if you have backlash is to place your finger on the moving belt for the Y-Axis (looking at the machine, it is the belt on the left). If the belt tension changes when the belt reverses direction (your finger will more easily push the belt down) you have the same backlash problem I did.
Cheers,
Ryan

#5


Here are video links of the problem belt. note how in the one video the belt “hops” a little bit when it changes direction.

#6

I took my support ticket and copied it all into a word document so that it would have the entire exchange with all the photos. I created a pdf of this but apparently you cannot attach a pdf to this forum. I then created 24 .jpg’s, one for each page in the pdf, but I guess I am too new of a forum user to be allowed to attach photos. If you want the document describing my issues, and the fix, email me at 716skis@gmail.com
Cheers,
Ryan

#7

Thank you very much Ryan. (I sent you a email)
I will wait Zeepro answer before repair it myself… I’m not very good to repair thing :slight_smile:

I did your test and I confirm, I have the backlash problem.
Tension is clearly not the same on left belt between normal / reverse direction…

#9

FYI: I bumped everyone in this thread up to Member rank. When I just checked, you all were at a Basic level that should have allowed most of the basics like pics and attachments. It just takes a few posts, or reading a handful of posts to do that. Just makes sure you’re not a bot or hit and run spammer. Thanks for contributing guys and I hope you are working out your Zim issues ok. I’ve been so busy with work I haven’t had time to get back to fixing mine yet.

#10

Here are the jpg’s of the pdf I created of that outlines my conversation with Zim support on my backlash issue. It outlines the fix that I modeled and then machined on a CNC mill after hours at work, The design is real close to finalized, but I should maybe look at moving the top bearing stack down about 0.5 mm from where I moved it to. This will give a little extra clearance with the limit switch, yet still allow the belt to clear the top of the drive gear. However, the design as it stands works and I just have not had the desire to tear my Zim apart again to swap out some parts.























1 Like
#11

All of this looks very familiar… I would be interested in what the fix entails. I don’t have access to a mill, but I know someone else that also owns a zim and has a shop with milling machine and lathe. Any chance of making your adapter part with a manual mill?

#12

Sure you can make it on a manual mill. I’ll try and get a print generated soon of the part I made and post it on here.

#13

Hi, I am also having this problem but I do not have a mill or lathe. I am really not too good at this sort of stuff and feel like I would break my machine. Is there a simple / easy solution to this?

#14

@andrewxue
Sorry I haven’t been on the forum lately. Winter is a busy time for me with my ski race coaching schedule. If there is interest I’ve thought about machining up some kits for the modification I did to fix peoples backlash. Unfortunately, it still involves some hand cutting of plastic with a dremel rotary tool on the Y-axis motor holder to create clearance for the drive belt. I passed my modification design back to Zeepro (I want to think it was in January?) and they were going to do some further testing on their end. Maybe they have a solution in the works?

#15

I am having the same issue and expect all Zim users to have the same.
This should be fixed by Zeepro Team.
Is there any reply on your ticket what the fix is?

#16

Thank to Ryan, I tried something cheap and easy for backlash issue.
It is a temporary fix because it not works 100% well. So I’m still waiting Zeepro official solution or if there is no official solution, I will do Ryan’s solution.

So for my temp solution, if I well understand our backlash issue, it is because of tension of belt.
There should be no contact between top a belt and pulley to avoid backlash issue.

I put an ikea furniture wheel to avoid contact between pulley and belt.
It works most of time when print is in plate center.
Circles shapes are a little bit better, Corners are sharper and there is less gaps around holes.

#17

TortureTest Before : High Quality Preset

TortureTest After : Normal Quality Prest

Even if I printed with normal quality preset (instead of high quality preset, It looked better than before fix)

#18

Nice interim solution and congrats that you have better results.

I thought I had the same problem, but seem to be wrong.
I am having difficulties with the rear belt. The tension on top side is good but the tension on lower side is loose.
So every time head motion changes from left to right through the lost lower tension the head is missing some movement.

Your solution does not work for the rear belt.
Any ideas what can be done there?

#19

Can’t we just adjust lenght of belt to get right number of belt’s teeth in relation to pulley’s teeth ?

#20

Of course you can for the left and right belt and the front belt as well…but not the rear belt.
You can just remove the little bolt with the spring keeping the tension on the belt and with the srew fix the belt to the length you like.
But the rear belt is upside down so you cannot access it.

#21

@rnordell that’s super impressive work! The results speak for themselves. Have you heard anything further from Zeepro on an official fix? I’d very much like to get rid of my little gaps that make an otherwise perfect part, imperfect :wink: