Filament feed stops half way through prints problem

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.

Try posting this the Fisher forum, and in your post say whether you have the Fisher beta or the Fisher 1, because they have different extruders. But here is my take. The teeth marks on the filament are normal. However, if there are marks where the hobbed insert has ground through the filament leaving an indentation, this suggests that you had an obstruction but the motor current was too high to allow the motor to skip steps. If the obstruction was temporary (as can easily occur as a result of over-extrusion), reducing the motor current will help, because extrusion will start again when the obstruction is removed. I doubt that you will have this problem with the Fisher bets because it's extruder is not very powerful, but you might on the Fisher 1.

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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].