Problem with Nozzle replacement

ufodoctor3

Type

Hello IGaurora Team
I have the JGaurora5 since Nov 2018 and wanted to replace the nozzle according the IGaurora Instructions
All was correct with the instructions up to the moment by twisting out the old nozzle
Now I see two wires, formerly connected somwhere, see attachment
What shall I do with these wires?
Thank you for your kind advice
Peter

your message

Der_Muck

Hi Peter,
as I can see you didnt change the nozzle, you change the whole hotend?
I dont wanna bring bad news but your thermistor is now broke, you have a lose wire.

You can find the original here:
https://www.aliexpress.com/item/JGAURORA-3d-printer-A3S-A5-3pcs-bag-thermistor-cable-temperature-resistance-1K-1000K/32849606493.html

But there are also cheaper once in the web.

Good luck!

Ah and please be aware! On the heater, there are 2 wires to. Please get sure every time that they are ok and dont touch each other or the heater itself or the hotend. That would be fatal!
On that work you might want to change the PTFE inlay of the throat to or minimum check if it is still ok and usable.

ufodoctor3

Dear Der_Muck
Thank you very much for your quick answer. 
I have orderd now two thermistors at Ali Express according your proposal.
The extruder gets durty after long use and both heater cell and sensor are hard to get out (and in later, too)
Best regards and many thanks
Peter

ufodoctor3

Dear Der_Muck
My principle error was that I misunderstood the JGaurora instruction about nozzle disassembly. In fact, I wanted to change the old nozzle only!

Since I have to wait for receiving the NTC temperature sensor I started to exchange the ball bearing.

First I dissembled the base unit with the y-axis. After hard work I found out at the very end, that the best ball bearings are already installed, exactly the same as ordered by Ali Express as JGaurora replacement bearings!

When I have looked at the x-bearings: the some type as ordered for replacement!

A present, I need to clean and lubricate the x-rods before any new printing session, else rattle and x-offset of the next layers

Does it make sense to replace the x-bearings ? The ordered long upper bearings shows quite a lot of friction (in the order of 50 Grams)tested on a precise steel axis.

The SKF expert in Switzerland checked the new replacement bearing and is not happy with it. Better bearings from Switzerland are only available with larger outer diameter

Please give me an advice, thank you
Greetings
Peter

Der_Muck

Ah ok thats a problem yes, it always can happen that a wire breaks away.

Yes the bearings are not always so bad as some say, I also found out that even fushi bearings are the same as others. Seems that they only produce only some own bearings and the others are from different companys.
I had some bearings and tested them, only used the once that fit perfect to my wishes.
Ofcause it makes sense to change the X bearings, they have to go very smoooth. I dont think that it has to be SKF, they also produce in china they are not that good as they where. In Austria I didnt ask localy for bearings, I just ordered enough from Aliexpress. 

ufodoctor3

Dear Der_Muck

Thank you for your comments!

From Ali Express I got a pack with 6 bearings, 4 for the y-axis and 2 for the x-axis. The new upper long x-bearing shows the same friction of about 50 grams as the old installed original, so replacing makes no sense.

With a well cleaned rod the upper bearing works fine, but with a little bit of dirt the very small spheres in the longitudinal channels in the bearing get blocked.

The expensive NBR stripper washers “Schmutz-Abstreifer” ASOB 8-16-4/7 by my SKF-expert shows a friction of about 500 gram, with and without lubrication, thus not suited for our application with stepper motors delivering about 1500 gram!

Periodic cleaning and lubrication is required. 

Proposal for Cleaning Alert:

Monitor the current of the x-stepper motor! If the current exceeds 70 % of maximum, a beeper will be activated telling the user “Clean the rod now!”.

I think you know where on the PCB is a terminal for picking the current value!

Waiting for your comment! 

By the way: I cannot activate the Thank button above your Post: I see April 4 and Unthank (with underscore)

Kind regards
Peter

ufodoctor3

Dear Forum
Here my tutorial about the inspection of the Base of the JGaurora5
I hope that this help you in case of problems
Regards
Peter