Filament stops feeding during printing - extruder leaving marks on filament every 14mm

Hi,

I am very much new to 3d printing. Just built a Fisher Delta and am amazed at the potential it has. However I am having problems with the feeding of the filament.

I start a print and watch as it prints the first ten or so layers and then leave it to it's own devices. On several occasions I have found that there are about 25 to 30 layers printed and then the extruder stops extruding. I can retract but not extract. I have slackened the extruder tension right off and increased it until the filament feeds well (can't pull through fingers as per instructions).

I am getting frustrated that I leave the print to happen and then come back to see it 'air printing'. I have extracted my filament and have found these marks on the filament at intervals of 14mm.



Can anyone help me solve thesis I have a little doing his nut for a 3d printed Batarang!

Your help would be very much appreciated.

I have just posted a reply to your similar post on the Ormerod forum,

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Many thanks for your reply.

I didn't realise my first post went into the ormerod section until after I had posted it.

I have the Fisher Delta 1.0.

I found that the inside of the bowden (at the extruder end) had a step in it where I initially drilled it. I have now re-drilled the end of the ptfe in the bowden (having altered the cutting edge to a steeper angle). It now seems to feed better. Would this "snagging" be enough to cause it to stop feeding?

How do I adjust the motor current? If it skips a step does this do any harm anywhere?

Many thanks for you help.

I read the Omerod post, but I'll reply here.

I get this a lot, actually I get deep divots where it makes a big hole. I have to take the extruder apart regularly and clean the hobbed insert. I have the Beta and it grinds filament quite happily when it can't extrude.

I don't have the latest firmware yet which is supposed to be better about setting the height. Most of my problems can be tracked back to the starting height. If it starts a bit low it can't extrude well enough against the bed, gumms up the hobbed insert grinding filament, and the print fails later. The other issue is probably temperature. A few deg C makes a big difference, and I suspect that the thermistor isn't that great so if it drifts a few deg C it can cause extrusion problems.

Skipping a step when the nozzle is temporarily obstructed is better than grinding an indentation into the filament. The extruder motor current is set by the E parameter in the M906 command in config.g. I don't have a Fisher, so I don't know what the optimum current is. But I did need to reduce the extruder motor current on a Mini Kossel that had a similar problem.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks a lot.

This has given me some things to look at.

I will try the various options and report back when I can.

Cheers

Hi,

I have tried the suggestions given to me before xmas to solve my filament feed problem.

I adjusted a drill bit to cut at a shallower angle. This smoothed out the inside of the ptfe tubing and the filament moves through with ease now. I also adjusted the motor current to 80% of its initial value.

This seems to have solved the problem for me at the moment.

Many thanks to all that replied to my initial post. Your help has been invaluable.

A belated happy new year to you all.