I recently bought an UP plus 3D printer from Denford and after about two prints it started making a knocking noise as the table moves in and out.
Having spoken to a Graham Bradley he suggested I remove the cover so I could see if something was catching.
On checking I found nothing cattching but that the knock occured at four points in the movement at exactly the same rotational position on the stepper motor. This I reported back and was told they would check with the manufacturer but have received nothing since and that was 20 days ago.
Now the head drive has developed the same knock in 4 positions and although I havent checked inside I am fairly sure it is the same fault on that axis.
Has anyone else experienced this problem it almost seems as though there is a fault in the stepper motor bearing but for two to go suggests it may be a more common problem.

Hi Pete,

I thought you were going to report back to me (Graham Bradley) by phone, what your findings were when you had inspected the axes?

I did ring you back and explained what I had found and you asked me to put it all down in an email which you would foward to the manufacturer.
This I did on the 10/06/13 and enclosed a short video on which the sound could be heard.
The next day I saw your email address was @denford.ltd.uk not @denford.co.uk so I fowarded it to that address just to be sure.
Here is the text of the email

As stated above the same knock has now developed on the head axes which again happens at four positions along the travel.
Looking back at the email I notice that the enclosed video was 42Mb long so may be your system does not allow such large emails.
Just added
I have just shot a new video to demonstrate the problem unfortunately the head didn't go far enough left and the table didn't come far enough forward
for the 4th click but you can get the idea.
http://youtu.be/yHJZ7S_IZVw

Hi Pete,

Unfortunately i never got the e mail and video, wonder if our Spam / AV stopped it coming through to me? If you drop me an e mail (gbradley@denford.co.uk) with your contact details, i will send you out 4 new timing belt pulleys. I think this will cure the problem, it did on our demo unit, but we only tried it to see if it was the pulley causing the clicking but we could nod see how it was. As you stated and confirmed by the manufacturer the "Clicking" does not effect the quality of the product being built. Sorry for the problem.

While you were replying I added a video link to my last post.

Hi Pete,

Thanks for the video, it is repeatable on both the X and Y axes but does not seem to effect the quality, i think the way forward may be to try new pulleys.

Thanks I will certainly try that.
Looking over this thread it seems to paint a depressing picture but when all is considered the machine is really working well.
I have been particually impressed by the way the software generates all the support structures required for some very complex parts.
I build small combat robots called Antweights as per Robot Wars but 150 gms instead of 100 kgms and here are a few of the bits I have produced already on my UP Plus.




The high gloss finish is achieved by treating the final item in an Acetone Vapour Bath which seems to greatly increase the inherent strength.

Thank you for the feedback and pictures of the models you are producing.

I have replaced the belt drive gears on the stepper motors for the X and Y drives and it appears to have silenced it at least winding it about using the maintenance function I haven't done any actual printing yet. I still cannot see anything wrong with the old gears and wonder if it is more to do with the position on the shaft than the gear itself. First I replaced the table drive one and check it had worked before I did the slightly harder to get to (well More screws) head drive. After doing the head drive I found I could just about detect a faint noise on the table drive again so I removed that and checked the positioning of the gear and found I had pushed it fully on. I pulled it back a fraction and found it was again silent but I cant see any reason why that should have any effect. Any way for the moment it is all OK and I could detect no problem with the stepper motor bearings which was my main concern.
So thanks for the parts and help and I look forward to many hours 3D printing.

Hi Pete, sorry for the problems, glad you are sorted. i could see no reason for the "Clicking" noise, especially as it occurred once per revolution. Only thing i could think of was a molding fault on the gear.