Trajectory Planner for 3D printing - A axis blending issues

tommylight wrote:

There is a working printer i linked to using axis U (or A ) for Z, and Z axis for driving the extrude.
On FDM printers Z axis moves only on layer shift so not blending or anything required as all other motion is stopped while the Z is moving.

On cartesian FDM printers the Z axis only moves on layer shifts and possibly on retractions but on delta FDM printers X Y and Z are coordinated and part of what makes them so fast.

Yes, Deltas are ...  interesting with all those moving parts, up/down/sideways/sideways from sideways ....

yup and with far fewer parts than a Cartesian and those parts are in triplicate so easier to assemble. My first experience with 3D printing AND LinuxCNC was with Mini Kossel deltas. Well, the early fork of LinuxCNC called Machinekit on a Beaglebone Black. ~2014

A little update,

I installed and tried the uvw-blending-dev of 2015 github.com/LinuxCNC/linuxcnc/tree/feature/uvw-blending-dev . It's not the latest version, but it's the first one that I was able to install.

With this version, the blending with 4-axis is improved against the 1 segment lookahead, but the motion is not smooth as the lookahead with only 3-axis XYZ.

I wonder if it's possible and how difficult is to hack the tp telling him to blend also if the 4th axis is inside the gcode.