Skip to main content

3D Printer Nozzle Cleaning - Cold Pull Method

3D Printer Nozzle Clearing - 

3D Printer Cold Pull Method

Found this awesome info on http://bukobot.com/nozzle-cleaning!! 
Reposted here with CC Attribution-Share Alike 3.0 Unported

A clean nozzle is a happy nozzle
There are several reasons you may need to clean out your nozzle. Foreign particles, filament contaminants, accumulated dust, overheated and scorched plastic can all become lodged in your nozzle and prevent smooth extrusion. Scorched plastic can also stick to the sides, creating resistance for the plastic traveling past without actually blocking the nozzle. This procedure for clearing your nozzle should be performed any time you are unable to extrude plastic, and periodic cleaning by this method is not a bad idea.
In the early days of home 3d printing, it was much more difficult to clear nozzles. It often required disassembling them and heating with a torch to remove plastic to get obstructions out, but this results in more scorched plastic and risks damaging some of the parts if improper force is applied (stripped threads, nozzles breaking at the narrow point between the threads and the inner bore, etc.) or nozzles being reinstalled without a proper seal. Some people also soak their nozzles in a solvent, but it can take some time for solvents to completely penetrate the plastic inside the nozzle, and even once saturated with a solvent, the plastic can be viscous and difficult to remove entirely.
The safest and most effective way to completely clear the plastic from a nozzle, taking any contaminants with it, is what I call a “cold pull”. The idea behind the cold pull is to pull the filament out of a nozzle at a temperature cool enough to keep it in one piece (rather than leaving molten plastic in the hot zone), but still warm enough to allow the plastic to stretch enough to pull away from the sides of the barrel so that it doesn’t seize up entirely. This is easiest to perform with a polished-smooth stainless steel barrel, with those that have a PTFE liner all the way to the end coming in second, because nozzle pressure can slightly compress the softer PTFE and create a plug that will be difficult to pull out.
The cold pull technique has been successfully done with both ABS (this was the best material to use for a long time, with a cold-pull temperature of about 160-180C) and PLA (much more difficult due to its thermal transition properties, but a cold-pull temperature of 80-100C will sometimes work), but Nylon 618 from Taulman (pull temperature of 140C) is far easier and more reliable to use for this purpose due to its strength, flexibility, and low friction. These are generally maximum temperatures (temperatures above which the plastic is unlikely to come out solid). For best results, you should always pull the plastic at the lowest possible temperature, and it may help to cool the nozzle well below this temperature and then continually attempt to pull it as the nozzle heats up again.
Successful cold-pull with ABSSuccessful cold-pull with PLASuccessful cold-pull with nylon
Successful cold-pull with ABS. Air was pulled in through the tip leaving the sample hollow and likely to break while being pulled.Successful cold-pull with PLA. Air entered around the filament as it stretched. Too much stretching leaves the filament too thin, and the stretching concentrates at the (weaker) thin section until it breaks.Successful cold-pulls with 618. The strength and low friction allow it to be pulled at a temperature low enough to prevent deformation that will cause the filament to break.

How to clear your nozzle with Nylon 618:

The first thing you want to do is remove as much of the plastic that you’ve been using as possible. To do this, you can attempt a cold pull with ABS or PLA with the temperatures listed above. Next, you will want to heat your nozzle to 240C so that it can thoroughly melt the nylon and push the nylon filament in. Attempt to extrude the Nylon slowly. Most clogs (especially those caused by accumulated dust) will not actually block the nozzle entirely, but will be pushed into the nozzle and stop it when the nozzle pressure increases, then float up out of the way when left to sit. If you don’t have a hard clog (usually a solid foreign particle lodged in the nozzle) a slow, pausing extrusion should allow you to purge the old printing material. Once nylon starts coming out of the tip, you can begin cooling your nozzle to the pull temperature.
Not completely purged.
A tip that is rough and or colored indicates that the old plastic wasn’t completely purged, and you may want to try again to make sure the nozzle is completely clear.
If you have a hard clog that prevents you from extruding at all, you will have to dislodge it before proceeding. The best way to do this is to find a thin steel or brass wire (electrical wires like aluminum and copper are usually too soft) that will fit up through the nozzle (bristles pulled from small wire brushes work well, thin wire works too - You can buy our Extruder Floss here: http://www.makergeeks.com/exflsehounmu.html ). Push the wire up through the nozzle to dislodge the clog, then continue attempting to extrude. Really nasty foreign particles may need to be dislodged repeatedly. Once the clog is dislodged, you can push the nylon in to try to purge the old material.
Wire pulled from brushPushing wire into nozzleClog embedded in nylon
Wire pulled from wire brush.Pushing wire into the nozzle to dislodge a hard clog.Nylon pulled with hard foreign particles visible in the tip.
If you pull the nylon out and the surface is rough, dark/discolored, or has black spots around the sides, this indicates that there is residue of overheated or carbonized burnt plastic in the nozzle, usually from sitting hot for extended periods without flowing (Deezmaker printers use a feature called “extruder runnout prevention” to avoid this by periodically extruding a few millimeters of filament if the machine is idling with the nozzle hot, but a clogged nozzle will prevent it from working) or from attempting to clear a clog using fire. If you see this, you should clip off the end and repeat the process until all of this residue is removed and the nylon comes out smooth, clean and mostly white.
Nylon with residue from overheatingNylon with redisue from burned plastic
Nylon with residue from overheated plastic.Nylon with residue of carbonized plastic comes out cleaner with each successive pull.
Found this awesome info on http://bukobot.com/nozzle-cleaning!! 
Reposted here with CC Attribution-Share Alike 3.0 Unported

Comments

Post a Comment

Popular posts from this blog

Comparison of Flexible 3D Printer Filament - Ninja Flex vs Maker Flex

Comparison of Flexible 3D Printer Filament - Ninja Flex vs Maker FlexMAKER FLEX
FLEXIBLE 3D PRINTER FILAMENT FINALLY AN ALTERNATIVE TO NINJAFLEX THAT'S MADE IN THE USA! 
THE MAKER FLEX DIFFERENCE: Trade-marked high-strength engineering grade flexible resinShore Hardness of 40 (Rubber Band Soft feel)Polyester-based thermoplastic elastomer (TPEE)UV StableWater tight and stable for underwater applicationsStyrene-freeBPA FreeFDA Compliant for Food contact1KG Spool (2.20lbs)(Dimensional Accuracy +/- 0.05mm)Low to NO odorNear zero warp-age or shrinkageVacuumed Sealed With DesiccantLow moisture absorption Sourced and Manufactured in the USAAffordable - we make it, you save big!! Spool Diameter: 7.94" - Spool Width: 2.50" - Spool Hub Hole Diameter: 2" Maker Flex series of 3D printing filaments are a polyester-based thermoplastic elastomer (TPEE). Maker Flex is an engineering elastomer combining the properties of rubbers and engineering plastics, thus bridging the gap between …

News from the Maker Desk

News from the Maker Desk
Happy Monday to you... hope you are doing great today; wanted to share something that was on my heart this morning about MakerGeeks and what’s going on and what the next steps are for us.

Almost 3 years ago we started selling 3D Printer filament(all of it from China) and over the next 2 years saw a booming business come out of those items; reselling filaments from China, Germany and the Netherlands. About a year and a half ago we started with a single extruder and a dream to start making 3D printer filament in bulk scale here on US soil… back then I thought that 1 extruder and me working part time would make more filament than I could sell in a life-time. Well, within just a few months we had bought another extrusion line and hired our first full time operator just to keep up with demand.

Now, surly we would have enough filament to last a life-time; NOPE… in just a few more months we added another extrusion line and lots and lots of overtime and weekends. Now we…

How to Use Ninja Flex PLA on a MakerBot Replicator 3D Printer

How to Use Ninja Flex PLA on a MakerBot Replicator 3D Printer

NinjaFlex's unique flexibility and smooth feeding characteristics enable you to create in ways you never thought possible. Open a world of possibilities, limited only by your imagination. NinjaFlex, a cutting-edge filament for 3D printers, is a specially formulated thermoplastic elastomer (TPE) that produces flexible prints with elastic properties. Patent pending technology allows for smooth feeding and clean, high-quality printed parts. Features: Filament shore hardness of approximately 85AConsistent diameter and material properties provide reliable, high quality printsPatent pending technology allows for smooth feedingLow tack, low CoF exterior allows smooth feed through filament guidesHigh elasticity and excellent abrasion resistanceExcellent build platform adhesion and bonding between layersREACH and RoHS 2002/95/EC Directive Compliant1.75mm filament spool = .50 kg3.00mm filament spool = .75 kgProcessing Guidelines: Re…