# How can I avoid jamming in the feeder?

Recently, at work we bought a Guider II printer from FlashForge. When we try to print models using a high resolution or models with a too high printing time, the feeder gets clogged. And the feeder is too hot. We have concluded that the feeder is getting clogged because the high temperature softens the PLA.

We check the feeder fan and is working fine. How can I avoid the jamming? Pausing the 3D printer and wait a few minutes is not working for us. I don't know if it is a common problem for this 3D printer model.

Edit:

The hotend is an all metal hot end. I can't find more information about the hot end.

In the manual of the guider II flashforge recommend a temperature of 210°C for the head and 30°C for the bed. I have tried different temperatures. The most common temperature I've used is 190°C for the head and 55°C for the bed (I obtain the best results with this temperature).

This is the Hotend used by this 3d printer.

• Welcome to 3dPrinting.SE! Feb 2, 2019 at 1:02
• This is really odd. I've printed 6 hour prints on my Finder with no problems like what you're mentioning. It sounds like maybe there's a disconnect, like the extruder is pushing out more filament than it needs. Maybe return it? Feb 3, 2019 at 21:49
• Finder is a different printer than the Guider II. Feb 3, 2019 at 23:44
• @Trish In this moment, I can't open the 3D printer and take a picture. But I added a picture of the hotend that I obtain in flashforge web. Feb 5, 2019 at 15:52
• That looks in the base relative similar to an e3D v6, but with a very short heatbreak and a proprietary top. Feb 5, 2019 at 18:24

The symptoms you describe hint to heat creep. Heat creep is the gradual increase in temperature of the cold end assembly (cooling fins and heat break). This gradual temperature increase leads to too high filament temperatures and as such premature filament softening. In combination with (large) retraction settings, this can lead to clogging of the nozzle. All-metal hotend assemblies are more prone experiencing these problems; lined hotends have a PTFE lining that also insulates the filament so that it does not soften prematurely like in all-metal hotends can happen. Heat creep is best remedied by properly cooling the hotend (good quality fan, no obstructions or large ducts) and reducing the retraction length (and possibly lowering the print temperature, but you already tried that). You could also contact the manufacturer for advice.

• also an exchange of the heatbreak can help Feb 5, 2019 at 19:02
• @Trish Yes totally true, hence the hint to lined hotends, but, lined hotends limit the maximum temperature to about 250 ℃, this might be enough for many materials, but poses a problem printing Nylon, high temperature co-polyesters, etc. Good that you pointed it out!
– 0scar
Feb 5, 2019 at 19:10
• I was thinking a necked down one (E3D style), but a lined one does the trick too Feb 5, 2019 at 20:56
• @Trish Thanks. I'm not sure why the Guider II doesn't have an appropiate hotend. Is there another method to cooling the hotend? Feb 7, 2019 at 17:36
• @MauroRivera an all metal hotend is an appropriate hotend, but it needs to be used correctly, that is with lower retraction. Feb 7, 2019 at 20:03

If the temperature is too high it can charr the plastic, causing jams. There are many reasons for that. If the temperature you have selected is not too high (<200C), then it might be the thermistor not correctly reading the temperature. If you can measure the hot end temperature, that will give definitive answer to that question.

Additionally, some filament contains additives that can get burned even at lower temperatures. I find it every difficult to print with woodfill if it takes very long to print. Some wood chips gets burned and causes jamming.

• That is very unlikely, a more plausible explanation would be heat creep.
– 0scar
Feb 2, 2019 at 16:55

Don't know about your specific printer model, but I encountered late print fails with clogged systems due to plastic molten above the heat break due to excessive use of retracts. Retracting hot material transports heat up into the normally cooled down heat break part. If you set up a very long retract or retract very often, the amount of heat can surpass what the fan is able to push off and soften the filament above the heat break.

Try adjusting the retraction settings in your slicer and see if it helps on longer prints.

• Im using the slicer Flashprint by Flashforge. In the settings I can't configure the retracts. Feb 5, 2019 at 15:54

As Oscar pointed out, this seems to be heat-creep.

## What is Heat Creep

Hear Creep happens if the thermal energy deposited in the hotend works up through the heat break and out of the dedicated melt zone, resulting in filament clogging up in the coolend.

## Where does Heat Creep come from

Heat Creep is usually a sign of having chosen the settings for the print incorrectly.

The biggest culprit is by having a too high printing temperature. I personally have not yet encountered any PLA that demands to be printed at above 200 °C.

In an all-metal hotend, the flow of filament down the path is a serious contributor or keeping heat-creep in check. So as a result, very low extrusion speeds have to be avoided to allow to keep the melting happening only in the meltzone. As the speed of extruded filament is related to the diameter of the extrusion, it is usually better to stay away from very small nozzle diameters.

The anatomy of the heatbreak is also a factor. Take a look at your heatbreak and then at for example the e3D v6 heatbreak below. As you see, it is necked down between the coolend section (the long part) and the part that screws into the heater block (the short part). This reduces the capability of heat to transfer up through the heatbreak, as $$I\propto A =(R_a^2-R_i^2)\times\pi$$. If $$R_a$$, the outer radius, shrinks by necking down the heatbreak, then the whole flow of thermal energy is reduced, counteracting heat-creep. But that has to be designed for.

Another factor that can result in heat creep is insufficient cooling of the cool end. Make sure that the fan that is mounted on the cooling fins spins always and gets 100% of its supply voltage power. Then make sure that it can draw in the maximum amount of air and push it out an unobstructed path.