No I hadn't, but I suspect that it will be mainly Windows based, and I am a Mac user. I'll set a d/l off later and check it out.

Cheers
Geoff

Hi James,

I doubt we're experiencing the same problem. My extruder stepper steps fine, it is the filament that jams in the hotend after a few centimeters of filament being printed. As we discussed off this forum, it is probably due to the fact that the hotend was not re-drilled after I had to tighten it up as Camile mentioned in his blog.

My current status is that I'm still waiting for a response on a request I sent out for the 'extra long 2mm drill' to re-drill the hotend. If it takes too long I will accept your offer to order one for me and mail it to me.

I have been working with the mendel-parts version of pronterface, Marlin v0.9.3 and this combined with the latest SFACT (github master branch).

Attached is a test cilinder that seems to works fine on my printer (until the filament jams...)

Good luck,
Hollie.

Hey Hollie,

Have you figured out why your filament jams? I am having the same problem. It seems to occur independently of the feed rate and I have also played around with many other parameters without any luck.

Best,
Troels

Hello Troels,

I'm eagerly awaiting the drill that is on its way to me through regular mail. Expecting it somewhere mid-next week. So no progress yet...

I'm quite convinced that the problem is due to the fact that I had to tighten the hotend further. As I stated in previous messages, I notice extra resistance when I try to hand-feed filament that was in the melt chamber before (so it is slightly wider than the original filament). This extra resistance occurs when the tip of the filament is around the PEEK part of the hotend. I assume that not all sections of the hotend are aligned any more (because I could turn it about 3/4 of a turn more than the state in which it was delivered to me). I hope/expect that this causes the problem, and that it will be fixed by re-drilling the hotend.

Only issue: how to get hold of the required drill bit? My local metal-worker had drills up to 10 cm, but only from 3 mm on (had I known this, I would have opted for a 3mm hotend). 2mm drills that are readily available are too short to fix the hotend. The 2mm drill that is now on its way was shipped by a friendly reprap enthousiast to me from the UK, as the ebay seller only ships them to the UK. (Sidenote: if the hotends are delivered in this shape, it would make sense that Camiel ships a drill together with the hotends...)

Did you also have to re-tighten your hotend after you received it form Mendel-Parts? If you did, it would increase the plausibility that the problem is related to the re-tightening of the hotend.

Best regards,
Hollie.

PS: the long drills on ebay are here: http://www.ebay.co.uk/itm/EXTRA-LONG-HSS-DRILL-BITS-2mm-2-5mm-3mm-4mm-5mm-6mm-SET-/120683678951#ht_2734wt_1163

Hey again,

After rereading the thread I am not sure that it is the same problem anymore.

I have not had the hotend apart. Also I have had semi-successful prints of http://www.thingiverse.com/thing:477, i.e. I have managed to write half of the cube before the filament got stuck. Therefore I do not believe that my problem is related to the hotend as the problem would have occured earlier then.

I have spent a great deal of time on reassembling the feeding mechanism with no luck. I have also changed the filament from the orange PLA to the blue PLA which is a bit different in consistency and I have noted the problem occurs earlier with the blue one. Finally my problem also seems to occur faster at high feed rates than at low feed rates and at extremely low rates it does not occur.

In conclusion I am quite confused about the behaviour of my extruder.

- Troels

Hmm, depending on when you received your hotend, it might need to be tightened. There was a notice on the blog of Camiel that for some hotends the brass parts were not tightened enough in the PEEK part.

My hotend had this problem and I fixed it before I first used it. It was sent on 07/10.

If you don't tighten it enough, PLA can get stuck before it enters the hot part of the hotend. So maybe you do need to tighten it...

Regarding the assembly of the hotend: http://www.heyjameshowdoi.com/2011/11/how-to-assemble-the-mendel-parts-v9-hot-end/

Good luck!
Hollie.

After sleeping over it, I think your problem is that the hot part of the hotend doesn't get enough heat transferred from the heating resistor. This would result in the problems that you describe: if you feed the filament fast the hotend needs more heating energy. If this process fails the temperature will drop and the filament will jam in the end. If you feed slowly it doesn't jam because there is time enough to transfer the heat to the hotend tip and the temperature stays high enough.

Could you check that:

• if you enable the 'monitor printer' checkbox in pronterface, does the temperature remain at the setpoint during the print. This ensures that the thermal contact between the resistor and the heater block is fine.
• if it is fine, then I assume the thermal connection between the heater block and the hotend hot part (brass threaded part+nozzle) is not good enough. Check that everything is tightened OK, if possible add some 'thermal cooling paste' (used to fit heat sinks to chips) so that there is a good thermal contact between both parts.
• Is the heater block block enough to the nozzle part of the hotend, if possible lower it a bit on the threaded rod

Just my 2 cents of course, I'm not printing myself yet. Just passing on some tips I received from other people on #reprap. So no success guaranteed

Yesyesyes. Problem solved!!

I had to redrill the hotend after re-tightening it. Now I'm printing smoothly

A very big thanks to James for helping me out and sending the drill to me.

I have to go now to print another item

Glad to hear Hopefully this will solve my problem as well.

Unfortunately I broke a drill in side the tube so I am currently waiting for spare parts from mendel-parts.com

Best,
Troels

OK, got over all my problems in this area.

1) Enable PID control in configuration.h in the firmware. It's brilliant: can't imagine why it's optional.

2) Never, EVER retract PLA when shutting down the machine. It just draws molten plastic into the cool part of the hot end, where it solidifies, and you're stuck forever. If you HAVE done this, then you'll have to strip down the hot end, and drill out the plastic (very carefully: one time I did it I snapped the drill off inside the brass tube! I'd like to order a spare from Camiel, but he's not talking to me, so I'll have to find a way of making a spare, maybe using an Afghan lathe and a brass M6 bolt:

http://staff.bath.ac.uk/ensab/replicator/Downloads/Afghan_lathe/Afghan_Lathe.html

I've ordered this drill bench clamp: http://www.axminster.co.uk/axminster-universal-drill-clamp-prod21094/