Draft nozzle drippi...
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Draft nozzle dripping  




My single filament Robox print head is having some issues: whenever fine nozzle is used (print quality 'normal' or 'fine', first layers of 'draft' print) there is a slight drip from the draft nozzle that deposits on top of existing layers and forming blobs. It is causing future problems - layers are not smooth due to bits of a filament sticking in random places. 

Slowing down the printing and changing the temperature won't fix the issue. My suspicions are:

1. heat block seal is failing,

2. draft nozzle needle malfunctioning.

I can't finish the nozzle opening calibration due to material coming though the draft nozzle.

I've disconnected the printer head and found out traces of decomposing filament in the secondary feed, deep in the inlet nozzle. That makes me thinking the previous user must have feed the printer using 2nd slot and possibly had an issue with snapped or jammed filament (hence traces of red filament I've never used in 2nd entry path at the back of the printer head).

Can you advise if manual purge instructions would fix the issue? ( removed link )

I know it's recommended for single filament printers only. 

Is the malfunction caused by particles of decomposing filament preventing the draft needle form closing down completely?







2 Answers

@thistle-ost If you have a fine and a coarse nozzle you have a single material print head. These heads have a black housing and are recognized as a QuickFill or QuickFill V2 head in AutoMaker. The second material feed, on the right when you are looking at the back of the head with the fan on top and the gold contacts facing you, is not used on this nozzle and will have a blockage of red filament that occurs the first time the print head is used. This should not be purged out. Removing it may cause the second inlet to leak filament. This is not the cause of your issue. 

The valve on the large nozzle not working may be caused by debris, but in that case a normal purge will solve the issue. A manual purge is used only if the filament won't go all the way into the print head. You can try using the nozzle cleaning feature found under the Maintenance tab in AutoMaker. This only cleans the inside path of the nozzle, not the outside surfaces of the nozzle. 

If the automatic purge and the nozzle cleaning routine does not resolve the issue you will need to open a support ticket; it is likely that your guess #1 is correct. It may be that your head can be repaired, but it may also be that your head will need to be replaced. A support representative can tell you in better detail on your support ticket. You can open a support ticket at www.cel-robox.com/support Please make sure you fill in as much information as possible so that your ticket is routed to the correct support provider for your region. Please use your region of residence when filling out the support ticket and not the region where you bought the printer, if they are different. 

If you look at the X-Carriage, where the print head mounts, you will see the white Bowden tube coming out of the back. If you have one Bowden tube, you have a single material printer. If you have two Bowden tubes, you have dual material capability. In the first case, only material entry #1 is used. In the second case, you can use either material entry and assign the model to the material in which you want the material printed in during your project setup in AutoMaker. 

While you are looking, check to see if the Bowden tube is in a mesh sleeve with the red and black power cable or if the Bowden tube runs on its own and the power cable is in a black cable chain. In the first instance you may want to have the printer upgraded as the mesh sleeve can sometimes catch on the corners of tall prints. 



Thanks a lot for your answer and explanation why the second material feed is blocked off.

I'll try to open a support ticket but the machine and the print head warranties expired some time ago.

I've been trying automatic purge and nozzle cleaning procedures multiple times with no effect, so it's possibly the time to save up and buy a new print head.



Even if you are out of warranty you can still open a support ticket and get assistance. Assistance is available to all customers. The repair just won't be covered under warranty.


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