Problems printing fan duct

My Chinese J-head clone works halfway decently, but the heater block is a bit larger than a "real" j-head (to allow for the set screws holding the heater cartridge in place) and slightly melted the edge of my fan duct. I have been trying to print another in white ABS to use with my real j-head Mk.V-BV. It starts out okay, but eventually the inner ring of the duct becomes detached from the bed, ruining the print. My hotend is set at 240 degrees and the bed is set at 115 degrees. I am using hair spray on the bed which seems to work well for the rest of the print. Any suggestions?

Hi Rich,

I suggest ABS juice (slurry). Using that I have printed a fan duct at 220C (bed at 125C) without an enclosure. I tried hairspray but it did not work for me.

Addenda: There is a bit of a trick to the fan duct. It is intended to be printed with a 0.35mm layer height and, like a lot of the Mendel90 parts, a line width of 0.6mm.

Regards,
Neil Darlow

Edited 1 time(s). Last edit at 11/27/2014 02:44AM by neildarlow.

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

I print ABS on PET tape at 130C.

The line width I use is 1.5 * 0.35 for those. I also set the infill start direction to 0 so that the first layer of the roof goes width ways.

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nophead
The line width I use is 1.5 * 0.35 for those. I also set the infill start direction to 0 so that the first layer of the roof goes width ways.

Good point about changing the infill direction, I had done that but forgot to mention it.

I thought that you specified the wall thickness in conf/scad/config.scad but having studied x-carriage.scad I now see that you have hard-coded the wall thickness for the duct separately.

Regards,
Neil Darlow

Edited 1 time(s). Last edit at 11/27/2014 08:54AM by neildarlow.

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.