PLA stuck in Bowden Tube

[Tom Gidden @gid My Robox is a Green Kickstarter Beta Portishead, UK]

Good news! The hot needle trick worked! Back to printing nice, reliable, curly ABS.

[Omega64 @omega64 My Robox is a Blue Commercial Version]

What is the hot needle trick?

 

[Tom Gidden @gid My Robox is a Green Kickstarter Beta Portishead, UK]

I’m not sure who originally posted it, but if there’s filament stuck in the head with not enough exposed to get a grip on it, then try this:

Take a sewing pin or similar, and heat it up really hot. Quickly force it into the end of the blocked filament and let it cool without moving. This does risk enlarging the PLA more, so the thinner the needle the better. Once cooled, it’s fixed well enough to be able to pull out the ~2 inch length of PLA still in the head.

I’m still not sure why this happened. It sounds like the problem @bhudson has. It definitely went through a completely normal print followed by a completely normal eject attempt without any power-downs or crashes before the jam occurred, so there must be another thing causing the PLA to swell up.

@pete, any ideas? I closed the ticket, but it’d still be good to try to figure out why it happens.

[Omega64 @omega64 My Robox is a Blue Commercial Version]

Just a thought: wouldn’t it have worked too to make several manual purges in order to “consume” the filament that had remained inside?

 

[Tom Gidden @gid My Robox is a Green Kickstarter Beta Portishead, UK]

Unfortunately not. It was the metal channel into the melt chamber that was blocked… while it does get warm, it doesn’t get hot enough to melt the filament (intentionally). As a result, no amount of force would result in pressure in the melt chamber.

[Omega64 @omega64 My Robox is a Blue Commercial Version]

@gid: Thanks, I understand it now. And it’s something that can happen only with PLA, due to the very low melting temperature.

[Tom Gidden @gid My Robox is a Green Kickstarter Beta Portishead, UK]

I think it’s more to do with this apparent property of PLA that it expands in certain cooling regimes. I don’t really know what’s going on… just that PLA always seems to jam in my printer, and each time it’s where the filament has expanded somewhere in the cooler part of the system.

[Bert Haverkamp @brjhaverkamp My Robox is a Blue Commercial Version]

Hi all,

Sofar I printed with both PLA (indeed polar white:-) and black ABS. I was happy with the print results for both.

Untill I realised that the nozzle clogging I now experienced three times always occured when I was printing white objects:

The fill nozzle had clogged on the second day of usage already and I sort of had given up on it since then, only printing in normal or fine modemode.

The fine nozzle had clogged up 2 or 3 times over the past 2 weeks, always with white PLA.

Today the clogging was so severe I that I had to perform a manual purge. But even that didn’t help. Untill I realised the PLA- clogging correlation. I put in the black ABS and voilla, the first purge worked, and even the fill nozzle is working again.

Robox team: could you comment on the above PLA issues? How is your experience, do you recognize the above experiences? are you working on improved settings, hardware modifications, etc?

 

Kind regards,

 

Bert

 

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