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Rostock Max v2 Jamming

Posted: Fri May 19, 2017 1:09 pm
by Waycer
Hi,

I have a Rostock Max v2 with some upgrades: E3D v6 and Duet + FSR. I have some trouble with my E3D v6 that keeps jamming. Almost everyone of my prints occur under extrusion. The extruder has some hard time pushing the filament through the nozzle and grinds the filament. It is hard to push the filament through the nozzle by hand too. I have to print with temperature way higher than it should be (240°C for regular PLA)

I previously changed my old E3D v6 with the HE280 with little success. I then came back to the E3D v6 and have this problem. I tried changing the heatbreak, then the nozzle, but the problem was the same. I recently tried to put thermal past on the heatbreak to make the heat transition better but it didn't work.

Is the problem coming from the PTFE tube (which seems tu be pushed all the way in the hotend) or by the cooling fan ?
I had to change the peek fan wires with the blue and orange one coming from the HE280 whip. As I changed the hotend back to the E3D, I didn't changed the orange and blue wires back to the regular wires (I don't know if it changes anything).

I bought a new PTFE in order to see if it was the problem. What is the regular length of the PTFE tube ?

Re: Rostock Max v2 Jamming

Posted: Mon Jun 05, 2017 1:55 pm
by hectori
You need a good fan 40mmX40mmx10mm.
the 30x30 Does not have enough power.
DSC_0292.JPG
E3D V6.png

Here is STL:
Fan40x40.stl
(4.36 MiB) Downloaded 10 times

Re: Rostock Max v2 Jamming

Posted: Mon Jun 05, 2017 6:16 pm
by IMBoring25
Plenty of people run v6s with the stock fan without this problem. I have been one of them and I have not been one of them. The difference for me was being completely OCD about seating the Bowden tube. Push it in and, while holding the tube in, pull up the PTC fitting.

First, though, is it a genuine E3D? Are you running a short and slow retract (usually 2 mm at something less than 20 mm/s)?

Re: Rostock Max v2 Jamming

Posted: Sun Jun 11, 2017 4:49 am
by Waycer
Hi,
Yes I have a qenuine E3d and I always run my prints with 2 mm of retraction at 40mm/s, it seems to me that the Bowden tube is pushed all the way in, or atleast I can't push it further.

Re: Rostock Max v2 Jamming

Posted: Sun Jun 11, 2017 4:53 am
by Waycer
hectori wrote:You need a good fan 40mmX40mmx10mm.
the 30x30 Does not have enough power.


The problem with 40mmX40mmx10mm fans is that they usually don't fit the mount. That means I'll have to put my hotend below the platform and I don't really want to change my setup. Will a 24v 30x30 fan do the job ?

Re: Rostock Max v2 Jamming

Posted: Sun Jun 11, 2017 5:43 am
by DeltaCon
The stock fan works just fine if nothing is obstructing the airflow besides the heatsink of the E3D. Mostly 2mm retracts work fine, but maybe there is some specific circumstance where you would want to try 1.5mm. If you push in the PTFE tube, usually you will find a first barrier 1 or 2 mm before the definite end of the heatbreak. You must push beyond that! "Sharpening" the end of the PTFE a little with a pencil sharpener makes that a lot easier. Try that! If you do that, also take a look at the roundness of the PTFE, are there any leftovers from cutting it? Maybe if you used scissors, you pushed it "unround" a bit? Do not use scissors, use a sharp razorblade or Stanley knife instead and roll the tube when you cut I us a sharp HSS drill to remove any cutting brims.

Also when you have had a jam, it is best to dismantle the hot-end and make sure there are no leftovers (that could keep you from pushing the PTFE in completely!). I know it is not the best way, but I use a torch and burn everything clean.

How old is your nozzle and is it original E3D? In some past Michael Hackney discovered that nozzles had a too long bore and caused a lot of jamming. E3D decided to adapt their design and made the bore less long. You can measure that by zeroing the length of a 2mm drill, shove it into the nozzle and remeasure like this:
NozzleBoreMeasure.png

I am sure Michael will comment when he reads this ;-)

I believe in the past we found some reaching 2mm and the PLA got cold before it left the nozzle.
Hope to shine some new light on your problem.

Re: Rostock Max v2 Jamming

Posted: Sun Jun 11, 2017 1:47 pm
by Waycer
Then I'll try "Sharpening" my PTFE tube and see if it works better.

I still doubt that the problem comes from the tube not being completly pushed in the hotend, because even if I push the filament by hand in the hotend, I feel some pressure and it's hard to push the filament through. That means maybe it has nothing to do with the tube and with the retraction settings. Because even with a cleaned hotend and without doing any print, I can't push the filament through the nozzle. It's not like I did a print with too much retraction or with the bowden tube not fully seated and after that it's jammed. It happends even if the hotend is clean.

Re: Rostock Max v2 Jamming

Posted: Sun Jun 11, 2017 6:14 pm
by DeltaCon
Hmm, that still leaves the bore length as a possible cause. Another option would be that your hotend temp is way below what the thermistor guesses. Have you checked that against a thermo couple?

Re: Rostock Max v2 Jamming

Posted: Mon Jun 12, 2017 9:16 am
by IMBoring25
As I read the description I don't follow how that excludes the Bowden tube either.

Re: Rostock Max v2 Jamming

Posted: Thu Jun 15, 2017 8:25 am
by Waycer
The hotend temp being below what it shows can be a cause of my problem, I'll get a thermo couple then.

Re: Rostock Max v2 Jamming

Posted: Thu Jun 15, 2017 11:35 pm
by Dionysus480
I was having horrible problems with my E3D v6 jamming with PLA. I did isolate it to a heat creep problem. I lowered my temp a lot and it helped quite a bit. Then I disassembled and replaced the thermal paste with some stuff I had around. I intentionally wanted a bunch of squeeze out which was messy. Now PLA prints fine and reliably.

Re: Rostock Max v2 Jamming

Posted: Fri Jun 16, 2017 4:03 am
by DeltaCon
Yes, I recently re-assembled my older E3D and adapted to the newer thermister cartridge and the sock. I saw that in the manual they advised about thermal paste too. I never did that in the past. I used ordinary thermal paste that is used for computer CPU fans. I hope that it has a large enough temperature range ;-)

Now I think of it, that could indeed be the reason for my prints coming out with a bit less of stringing. But I did not have issues with jamming before.

Re: Rostock Max v2 Jamming

Posted: Sun Jun 18, 2017 11:29 am
by Waycer
I tried to apply some thermal paste (artic silver) on the heatbreak but it didn't work. I thought that the cause could maybe come the connection from the hotend to the Duet. I made some pigtails as Mhackney showed in his guide. I didn't use the green and white wires, maybe I should have ?

Re: Rostock Max v2 Jamming

Posted: Thu Jun 22, 2017 3:08 am
by Waycer
Well, I don't know what to do. I bought a whole new E3D v6, I applied some thermal paste on the heatbreak, I sharpened the PTFE Tube, but I still have the exact same problem... The first print I did was okay and I could push the filament through the nozzle really easily (as it should be) and then as soon as I tried to do my second print, the problem came back. I ran my print with 2mm retraction. Any ideas ?

Thank you

Re: Rostock Max v2 Jamming

Posted: Sat Jun 24, 2017 9:52 am
by Dionysus480
Have you tried mhackney's filament profiling? It was very eye opening for me.

You'll find it in his A Strategy for Successful (and Great) Prints.

So I was experiencing consistent jams until I rebuilt and re-profiled my PLA filaments. I now print consistently and with good results at 185C. The only step I add to his profile process is to print a single walled hollow tube. I then pull the layers apart to test adhesion. I do figure out the absolute lowest temp, but I usually end up printing slightly higher.

It might be some interference with the temperature sensor wires (or perhaps you've removed some interference) and its just changed things enough that the end is hotter than being reported, or it may be that some other factor affects the PID tune.

So at this point I would be really frustrated, so I don't blame you if you are. But I'd clear the hotend and try extruding PLA at 190 ish. If it works, then drop to 185. Its counterintuitive, and I don't really know how your system changed to warrant such a overhaul, but in my experience 240C is too hot for PLA and is likely contributing to the problem.

Re: Rostock Max v2 Jamming

Posted: Sat Jun 24, 2017 10:40 am
by Tincho85
Hi, PLA at 240ºc seems very hot for me too.
Did you update the firmware with the new thermistor? The one from E3D is different than the HE280.
Either way, you should check that temperature with a thermocouple and make sure that there is no resistance when pushing the filament by hand.

When assembling the v6, did you leave a little slop between the nozzle and the heater block? Because if you tighten the nozzle against the heater block insted of the heatbreak, it will jam. Be sure to check that.

ALso, are you usign a heated chamber? High ambient temperature could make the v6 fan not to properly cool the heatsink.
Touch the heatsink while printing, it should be cold. If not, measure the voltage going to the fan. Maybe it's not working at 100%.

Agree, I would also try slow retracts.


Best of luck.

Re: Rostock Max v2 Jamming

Posted: Mon Jun 26, 2017 10:48 am
by Waycer
I updated my firmware with the new thermistor and my problem seems to be resolved !

Thank you all for you help ! :D