nylon problem

[saksophone 0]

 

Hello!

 

On the first layer the machine was proceeding I heard clicking noises coming from the nozzle, I reduced the operating temperature from 255°c to 220°c therefore the clicking noise has stopped but in return that messed up the quality of the material (Nylon polyamide) as the piece came out in a form of layers easy to peal instead of one solid piece as shown on the photo joined.

 

Best Regards & Thanks in advance. TUNI-PACK.Co.

 

 

 

Note:

Printer: Ultimaker 2+ Extended

Material used: Nylon Polymide 2,85mm

Printing Temperature: 240°c - 260°c

Build Plate: Glue + Raft (60°c)

[geert_2 557]

On my UM2 (=non-plus) the clicking noise is when the feeder tries to feed more material than the nozzle can eject. This is a sort of protection against overloading, I don't know the official name.

 

Not sure if that is still the same on an UM2+?

 

So, could it be that you are printing too fast, too cold, or in too thick layers? Or a bit of all, so that the nozzle can't melt it in time?

 

Try a small testpiece and print a bit slower, hotter, thinner layers (whatever you think might be the cause)?

 

But apart from the poor layer bonding, it seems the gear teeth come out quite well?

[Torgeir 242]

Hi @saksophone,

 

Welcome in here.

 

What you explain here is named stepper skipping, -or stalling. Simply, -there is not enough magnetic "force" to do the next step forward, so it's stepping back to the same step it is tried to leave..

 

The first layer is very thin, so here the feeder will need to make very high pressure to extrude the filament (because of very limited space for extruding first layer)! This is the reason for the stepper is clicking -"stepping back or slipping".

 

Actually by reducing the temperature making the issue worse, cause the density of the filament increase and making the problem worse.

 

In your case, -I'll think the first layer just finished and resolve itself due to lo pressure demand after first layer finish.

All this make sense and confirm -a known issue.

In order to reduce force needed for filament drive, increase first layer height -or decrease first layer horizontal expansion.

 

This is a very critical parameter to select, so do some test to find the sweet spot..

 

Just go for the print temperature you selected and you'll have good addition between layers..

 

Also consider using the "draft shield" (found in experimental setting in Cura), this will reduce warping -(keep your object from cold draft)..

 

Also, cover up the front of your printer to keep the temperature steady.

 

You need to keep the temperature at default around (250-260) deg. Celsius, -typical temp for Nylon.

 

Doing so, your layer addition will stay good as the rest of your printing with nylon!

 

Good luck

 

Thanks

Torgeir

 

 

 

 

 

 

[saksophone 0]

                thanks guys for your advises,

     I have done an other printing test with this parameter :

Nosel : 255°c

Bildplate : 60°c 

Speed machine : 90%

Ventillation : off

and the problem has been solved , but the quality of the print has not been as good as the first print.

          I faced an other problem this time wich is : 

My piece is 48h duration with NYLON materiel , when it still 14h to go,something really bad happen , the nosel went crazy and start drowing rectangulaire  , and some other forms i didn't know what was doing outside the piece space , it went worse the buildplate went high very fast and hit the nosel  so i stoped the printer very quickly to reduce the damage , I can't find out why it did that ?

I have faced this probleme last time with CPE materiel .

could you have something in mind and help me ?THANKS

[saksophone 0]

this picture represent the damage  

[Torgeir 242]

Sorry to hear about this problem.

This could be caused by several issues, -however there have been reported in here that the SD card can be faulty and send erratic data during printing.

So first thing, try a brand new SD card, also check that the SD-slot in the printer is clean.

The SD card and the reader is very important in an UM2 series printers..

 

Can you show the difference between the two printed model you made (a picture side by side).

 

Good luck

Thanks

Torgeir

 

 

Edited November 6, 2020 by Torgeir
Text

[geert_2 557]

First check if that random movement is not in the layer preview in Cura. Most likely not, but there could be model problems or software bugs too. If okay, indeed clean the SC-card slot as Torgeir says: human hairs (I had that once), dust and filament hairs can get into it, causing poor contacts. If you have compressed air, blow it out. Or try a new SD-card. Try to write a long video to the old card, until full, and see if that plays well. Or run a disk check program on it.

 

Something else I just come to think about: nylon can absorb too much moisture from the air in a few hours, degrading print quality. So when printing nylon, do it in a very dry climate, or put the nylon spool in a dryer box, even while printing, and route filament from there to the printer.