Handling long, multi-spool print jobs  

RE: Handling long, multi-spool print jobs

you didn't say which printer you have but generally, if you have the filament sensor enabled, it'll prompt you to unload the filament, then load the new filament spool.
now if you have the multi-tool XL, then you can just enable spool join and you wouldn't have to do anything.

Experiment with a couple of short lengths cut from a spare spool ... you will find that the printer pauses, bleeps and prompts for a normal filament change.

Or: use the spooljoin function. Load two or more filaments and at the start of the print when setting/confirming the toolhead assignments on the LCD tool mapping screen choose which one(s) to switch to:

https://help.prusa3d.com/article/tools-mapping-xl_668277

Cheerio,

RE: Handling long, multi-spool print jobs

I have the 2-head version but one of the tools has been set with a narrower nozzle so I'd like to find an alternative to the spooljoin function. Is it possible to set an alternative gcode to park the toolhead whenever the sensor has detected there's no more filament?

RE: Handling long, multi-spool print jobs

I have XL 5T and have used Spool Join on several occasions. Most recently a ~ 7 hour print that needed about 200 g of PETG Black Matte. I had a large 2 kg spool with 100 g remaining and newish 750 gram spool. I loaded the 100g of filament ("Spool 1" ) for Tool 1 and loaded the 750 gram "Spool 2" for Tool 2. Used Connect and loaded the gcode and let it run. Have a cam with live feed to monitor remotely and the job proceeded as planned. When the primary filament detector (on side of XL) detected the feed from Spool 1 was exhausted it parked Tool 1 and finished the job with Tool2 using filament from Spool 2. I had two concerns when setting this up... would the filament on Spool 2 run out cleanly? Yes the pigtail of filament at the core of the Spool1 detached from the core of Spool1 and fed into and thru the Primary Filament Detector for Tool1.  Second concern was the strength of the "joint". The printed model has tall and narrow. About 250mm tall (Z), 150 wide (Y) and thin 4 mm (X). I examined the "joint" carefully after the print completed and found that the joint was weak. 15% fill. The "joint" Snapped cleanly under moderate pressure bending across the narrow X axis. I used CA to rejoin the parts and moved on. 

I examined the print history by expanding the time line (from the Telemetry data) and found that  Tool 1 had stopped according to plan, docked and then cooled off. It seems this began once the primary filament detector reported  that Spool 1 was exhausted. Tool 2 appears to have immediately loaded and started to heat up. I did not have time lapse photos of the routine for Tool 2 but the data shows it took say 10-12 minutes for Tool 2 to begin printing. This seems to be the typical time it takes the XL to start printing. If the data (and my interpretation) is reasonably accurate, with a tall narrow model the top edge of the model would have cooled considerably before  Tool 2 started printing. It seems that this considerable cooling of the top edge of the model would be the cause of the weak joint between the last layer laid down by Tool 1 and the first layer laid down by Tool 2. 

Soooo.... Did I need to invoke something I overlooked in order to have Tool 2 start printing earlier or ???? Seems that somehow Tool 2 needs to heat up and start quickly once Tool 1 stops printing. Or somehow have Tool1 print a closed last layer (100% fill?) to increase the bonding area for Tool 2 to print on?  Or use Spool Join where the joint is kept warm on the heated plate and avoid Spool Join for tall narrow edge models where the joint area is not on the heated plate? Or just accept that frankly the Spool Join feature is amazing the way it works (it is!) and if a weak joint breaks then using CA to rejoin is a workable solution (for now?) 

RE: Handling long, multi-spool print jobs

i have a 5TH version and the spooljoin works UNLESS your main nozzle TH1 has worn and due to how it only calibrates TH1 on the print bed (or the primary TH) and then relies on stored calibration data it either crashes into itself or the bed, or has a large gap. prusa needs to change the way it claibrates Z distance 

As nozzles wear (or are changed) you need to revisit:  https://help.prusa3d.com/guide/7-first-run_512915#513527

Start from Step 21.

Cheerio,

RE: Handling long, multi-spool print jobs

That's what im saying. It would be simpler if the nozzles z calibrated themselves instead of relying on old data or the need to wait 20 mins to recalibrate. Afterall the center line of the nozzle hasn't changed just the z offset 

Afterall the center line of the nozzle hasn't changed just the z offset

... and possibly the external diameter if a different type of nozzle has been fitted or enough has worn away from the tip.

Just fit the fit the Calibration pin, start the process and walk away for a while.

Cheerio,

RE: Handling long, multi-spool print jobs

Im strictly speaking about z offset not external diameter.  How would you know when to use the calibration pin for nozzle wear ? 30 hours into a print where the spool join fails ? Or would it not be better the printer also z calibrates all print heads being used ? As it removes the guessing 

I generally run calibrations when I do my routine maintenance; roughly once a month, plus whenever I change a nozzle. No need to guess if you keep on top of it.
Cheerio,