Unable to swap print cores

[Ytzen_PLTW 1]

I've had my U3 for about 8 months now, but I've mostly just been running dual extrusion PLA prints. I haven't printed with PVA in about 6 months. I went to swap out print cores today so that I could to a print with some PVA and I am unable to remove the core. 

 

I remember it being tough to pull out before, but both myself and a number of students have been unsuccessful this time. I'm wondering, does it have anything to do with the different heights of the cores (seen in attached pictures). Printcore 1 is held higher as if it was going to be printing from printcore 2. 

[Job_van_gennip 23]

are you squeezing the print core a little bit when you try to take it out? there is a spring in there that is supposed to keep everything in place. The reason printcore 2 is lower is because when it is the the heightened position the print core is blocked. 

[Nicolinux 288]

Looking at the picture, the second print core might have been inserted in a wrong way at first. The cores should be at the same height. Here is a picture of my print head:

[Ytzen_PLTW 1]

Yes, I've been squeezing as much as the printcore would allow

[Job_van_gennip 23]

59 minutes ago, Nicolinux said:

Looking at the picture, the second print core might have been inserted in a wrong way at first. The cores should be at the same height. Here is a picture of my print head:

 

@Nicolinux Do you think it could be in wrong but still make contact well enough for the printcore to connect? Cause i assumed that was not possible and that is why i ignored the position of the print core. 

Edited April 25, 2018 by Job_van_gennip

[Ytzen_PLTW 1]

I don't believe it is set incorrectly. I just reloaded the PLA material and am successfully printing a part with that core right now.

[Job_van_gennip 23]

Have you taken out the material before trying to take out the print core? sometime the material has not retracted enough and is still stuck in the print core.

[gr5 2,210]

In the photo I can see some orange pla sticking into the core.  That material must be pulled out far enough so the core can slide out.  It's easy to do - just squeeze the lever on the feeder and pull down on the filament just below the feeder.

[Ytzen_PLTW 1]

1 minute ago, gr5 said:

In the photo I can see some orange pla sticking into the core.  That material must be pulled out far enough so the core can slide out.  It's easy to do - just squeeze the lever on the feeder and pull down on the filament just below the feeder.

That's not mine. Mine's the one with the blue filament that has been pulled out

[gr5 2,210]

Well there are 4 things that can hold the core in from most common issue to least common issue:

1) Filament at the top

2) Not squeezing enough - you need to lift that steel part up and above the anodized aluminum part inside the head

3) The clear part has two holes in it that catch on two wedges in the head.  You might have to push down a bit on the clear part.  Without squeezing the "trigger" you can explore this by pushing the clear part into the head and listening for a snap.  push down and pull out on the clear part such that it moves out and repeat until you know how much to push down on the clear part to get it past those two wedge/bumps.

4) The pcb on the core can slide down too much and get behind the rear of the anodized aluminum part in the head that holds the cores in place.  The best solution to this issue is to remove the swinging door cover of the head (takes 3 seconds - squeeze it off the hinge) so you can get your fingers under the core better.  Then push up on the rear of the core while trying to slide it out the normal way.

 

There may be a fifth issue that I don't know of and have not experienced.

 

[gr5 2,210]

By the way you can always just take the whole head apart.   But you should talk with your reseller before doing that to avoid voiding warranty.

[fbrc8-erin 296]

Are the 4 screws that hold the printhead together tightened throughly? If any of them are loose you could have difficulty remove the Print Core. 

[Ytzen_PLTW 1]

Thanks everyone... I'll have to check out some of the suggested solutions in the future.

 

I've got a backlog of parts to print and since those will work with just PLA, I'm running those first. It'll be at least a day or two before I make another attempted swap