Low Speed for 3d Printing application

Thanks, I was thinking of moving the extruder to Z and coordinate Z to A, ie swapping current Z/A to get the extruder in the 50 segment look-ahead and blending but why W instead of A?

This will really throw a wrench in getting this setup(LinuxCNC/Remora) generally accepted as a 3DP platform since all the 3DP slicers generate XYZA gcode for LinuxCNC/Machinekit and for all others it's XYZE.

I don't know how the look-ahead and blending was implemented but dang, it would have fit well had it been coded to take in the 3 axis to blend. But I get it, CNC standars are XYZ=linear motion, ABC=rotary motion.

Thanks for explaining. I will look up how to create an input filter since that would be great and hide the work-arounds.

Should I create a new thread as I try to configure my machine this way and hit problems? ex: LinuxCNC is complaining about my joint_2/W axis having a MAX_LIMIT of 230 and wants +1e99

IIRC things are messing up for 3D printing because using the A axis(a rotary axis in CNC world) reverts to a 1 segment look-ahead and disables blending capabilities.

So, would the segment look-ahead still drop to 1 segment if I move my extruder(A axis) to one of the 3 linear axis( UVW ) leaving standard coordinate system setup of X Y and Z motion?

Thanks for the reply Andy and unfortunately PathPilot nor Machinekit will work at the moment as I'm running LinuxCNC on the rPi. Tormach is doubtfully supporting rPi and Machinekit has been all about the Beaglebone Black and derivatives. I have one of my detla 3D printers running Charles Steinkuehler's CRAMPs board on the BBB. But the GUI stuff is tough on the BBB so I used the Machinekit remote VCP but that's a Machinekit thing..

So here I am with Scott Alford's Remora firmware on SKR v1.4 controller board in a Creality Ender3 3D printer with LinuxCNC on a Raspberry Pi and finding out there's no look-ahead path blending because I have an extruder motor on the A axis.

It works but it seems like it's being held back greatly because of the 1 segment fallback. So it'll be a tough road to get people excited about using LinuxCNC on 3D printers even though it can be done for less than $100 and the rPi box is tiny compared to the big gray PC box typically needed for LinuxCNC.

Sounds like it's going to need an on-the-fly file filter and swapping the extruder axis(A) for the motion axis(Z) and getting Z away from ABC and over to linear U, V or W axis.

should extruder even be an axis? couldnt it be some kind of spindle? using some kind remap of G33/G33.1 so that it isnt on at all times. what happens to the look ahead when you do synchronized spindle motions? or just use a synced move for z

tommylight wrote:

Sorry to hijack the topic, but what are the chances of having a 3D printing section of the forum and is anyone here interested in it?

Yes, I think there should be, because it is a good potential use case for linuxcnc (best option for 3d printing but not the easiest) also, because it can hopefully centralize discussion related to 3dprinting into fewer sections, making it easier to find information for setup and about problems that might not exist in normal cnc operations. the extruder axis/tp lookahead being a good example.

tommylight wrote:

not LinuxCNC related but it takes an afternoon to switch one to it !

not yet it isnt. Octoprint is great and all, but it seems kinda backwards way of doing it, now that the rpi4 is out and has some guts to it. With the increased availability of linuxcnc on a small, cheap platform, and the excellent work everyone has done from the rpi images, to the other embedded platforms like H3, to scott alfords work with the rpi and existing 3d printer boards, the shift is on its way, that much can be seen with how many more rpi4 related threads there have been in the past few years.