Shear rate of syringe tips while Discov3ry extrusion


#1

Hi all,

I’ve received Discov3ry last month and having fun time optimizing and getting used to it.

I’m using Discov3ry with Seemecnc Orion delta and trying to test print few materials by researching their viscosity and their printability.

But I’ve found that a viscosity of a material changes with applied shear strains due to thixotropic behavior. So I noticed that the shear rate of Discov3ry’s syringe tips must be studied as well in order to find out clear relationships between viscosity and printability.

Would anyone studied about the shear rate when paste materials are being extruded through “cone-shaped” syringe tips as the ones provided with Discov3ry?

This would be very good starting point to match up viscosity and paste printability of the materials and give basic idea to people when they want to 3d print pastes with Discov3ry.

Thanks all!
Jason


#2

Don’t think this is due to the tip so much as separation of fluids under pressure, first thing i noticed printing nuetella was when the nozzle was plugged and pressure was built up in the tubing, the palm oil was separating from the coco and other ingredients, also noticed this very bad and made printing with a fine concrete powder mix impossible due to water separating in the same manner.

don’t really know about shear rate’s or anything but its all going to depend on the materials consistency with the way discov3ry works.

I use to make donuts at a job i had, and the machine used to fill them was very neat and would fill 2 with jelly or cream or w/e at an extremely fast rate, had to be careful. was an really old machine.
it was a bunch of worm gears and stuff and i keep thinking about it and wish i had one.