Nozzle hitting the print/ under extraction

[mariem 0]

Hi guys! I've been getting some weird issue on my latest prints!

I printed 3 heartstone key before without any issue >>

I had to print couple of them for a tournement, unfortunatly I also start to print them a little late aaaand...

I started getting trouble with the print.

I had 3 prints in a row fail on me

I dont have the picture of them all but the first one unstick to the print bed,

I redid my calibration and it seems like it was better.

My second and third print both failed for the same reason,

It seems like something happens (not too sure why) wich makes that at some point my nozzle start hitting my print (like if my print was a layer too high or something)

then after a little while of the nozzle kind of stressing/hitting the print while printing, of course the print unstick from the bed and hop, huge tangly mess!

My third print seem like it was doing fine, went way higher than my two last attempt.

Then at a certain high I got a understruded later (allright?) but it continued and I though it would be okay,

a litle while after another unde-extruded layer.

Then it started slowly messing up and I was going to loose the print once again.

The head start hitting the print once again, I taped the print and the support together and tape the bottom of it to the print bed in the hope of saving the print.

Anyone had this issue before...?

 

[yellowshark 153]

Hi Mariem, could you answer a couple of questions please.

1. Extruder temp., print speed, layer depth, fan setting.

2. The 2nd picture suggests you are printing 3 copies simultaneously, were the previous attempts printed with 3 copies also?

3. Being curious, do you print the key element separately and then stick it to the shaft?

 

[gr5 2,265]

If you look carefully you can see sh prints the key with the part you normall hold down and the shaft pointing upwards. Plus she has a support column going all the way up to the top to support the locking portion of the key.

First of all - you have "raised edges" which are common on overhangs. Just above the hexagon key grip you have two sections that come together at a steep overhang. Once these connect the printer slowly recovers but until thin you get raised edges that the printer can hit. Hard! The solution is to have the part stick to the glass. Hard!

So I recommend you:

1) clean your glass well. It probably has some oils from your fingers.

2) Use PVA glue - the glue stick that comes with the UM2 is pretty good. You can smear that out with some water and paper towels maybe and let it try. Or what I do: mix normal Elmer's wood glue with 10 parts water. Shake it up in a jar and paint on the glass with a paint brush. Heat up the glass until it dries out and becomes invisible.

3) Use brim (you did already of course).

4) Fans at 100%. Fans are very important for overhangs. The more fan the better. Add extra fans. Also maybe lower your printing temp for these overhangs. What temp are you printing at? Maybe go down another 10C?

5) You can push down on the lifting edges *while it prints* if you want. I use a putty knife. You have to be quick.

Once the print gets to the shaft of the key I think you are safe.

 

[mariem 0]

Sorry for the delay in my response, i've been super busy!

Yellowshark, I was printing at 30mm/sec, 190C, 60microns, fan 100%

I was printing one only and all in one piece

gr5, thanks for the tip to make the print stick better.

I always used the glue but never smear it out or anything, I just basically applied a thin layer straight up with the tupe.

I think the fan are always a 100% by default right? when I click on ''tune'' on my printer it always says 100% but do I have to manually ajust it somewhere else?

I was printing a 190C I'm not sure If I can go any lower?

In my last two prints I started getting under extrusion like this

I've never had issue like this before, and in my last two print, lines line that happens a couple time through the print.

sometimes it almost looks like those lines are shifted. Like one layer a little bit too much on one side and then another one on the opposiite direction, then thing go back to normal ..

How can I prevent this from happening, what is the cause?