z lift not working

[callel]

Hi All,

I have had some success and mostly failure that I have troubleshot down to a z lift problem. I can replicate this with MatterControl using both slicing engines (Matterslice and Slic3r) where I set the Z lift as noted below but the head still drags across the print. The z lift seems to be in place on most of the big movements but some times it doesn't lift and drags across the print. The motors loose track of their steps and things go all wacky.

I can also replicate this using the stand alone Slic3r with the same z lift settings. I simply generate the gcode and use mattercontrole to print the G code.

attached is the .gcode file for anyone to look at. There are a few places where you can see that the z lift is not being issued if you look at the tool paths. How can I manually or programatically force a z lift if the head is going to move more than 2mm without extruding?

Nozzle Diameter: 0.5mm
Length: 3mm
Lift Z: 5mm
Speed: 40mm/s
Extra length on restart: 0mm
Minimum travel after retraction: 2mm
Retract on layer change: yes
Speed for non-print moves: 280mm/s

[Earthbound]

Speed for non-print moves is likely too high. The slicer speed values are in terms of cartesian movement. The carriage movement rate of a delta printer gets much higher as the effector moves away from a tower. A speed of 150mm/s in the slicer is generally safe for the entire build area. You can go a bit higher if you aren't printing near the edge of the build area.

[mhackney]

+1 sounds like you are over driving the steppers. What are your X Y Z speed and acceleration values in the siicer?

The alternative is that you have some mechanical binding with reasonable speeds and accelerations. The way to diagnose this is to find the speeds and accelerations in the EEPROM and divide them by 2 and see if the problem goes away. If not, divide by 2 again. If so, increase in increments until you find the sweet spot.

[callel]

ok, both replies make a lot of sense. I thought that the stock movement speed was high. I'll chop it way down to 25% of what it is now, say 75mm/s as I think the stock is 300mm/s.

Tensioning the belts; I put just enough tension that the carriages didn't wiggle from slack but still loose enough that the motors seemed to move easily by hand. The tone of the sound increases and decreases as the load/tension is increased. I used that tone and the feel of the carriages to set them. Could they be too loose? How tight is too tight? (that's a tough one to answer via text)

[callel]

I'll use MatterControl with MatterSlice for now to not complicate with other programs.

You mentioned x,y,z speeds specifically and I don't see them in MatterControl/Slice with Advanced view enabled. Where are these settings?

For this I am using ABS and a standard printing quality. Below is my config with some modifications. I also included other settings that might be worth review.
....as I type this I am thinking that a profile file would be nice, that way I could use a super tested config rather than the default settings.....

QUALITY: Standard
MATERIAL: ABS

General:
Layers/Surface;
Layer Height 0.2mm
First Layer Height 0.3mm
Bottom Clip 0mm
Perimeters 2
Avoid Crossing Perimeters yes
Spiral Vase no
External Permimeters First no
Top Solid Layers 1mm
Bottom Solid Layers 1mm
Infill
Infill Density 25%
Infill Type Triangles
Starting Angle 0mm
Infill Overlap 0.06mm
Speed
Infill 40mm/s
Raft 100%
Inside Perimeters 40mm/s
Outside Perimeter 35mm/s
Bridges 60mm/s
Non Print Moves 75mm/s
First Layer Speed 12mm/s
Filament:
Diameter: 1.75mm
Extrusion Multiplier 0.9
Extruder Temp 228
Bed Temp 80
Retraction length on Move 6.9mm
Retraction Length on Tool Change 10mm
Retraction Speed 110mm/s
Z Lift 5mm
Extra Length on Restart 0.1mm
Min Travel requiring Retract 9mm
Min Extrusion requiring Retract 1mm
First Layer Width 110%
Support Material 0.6
The rest is stock and not relevant, I think.....

[mhackney]

In the post at the top of the page you have:Speed for non-print moves: 280mm/s

change that to 50mm/s to test. If the problem goes away, try 75, then 100, 125, etc until you find the max that doesn't miss steps on your zlift.

[callel]

I set it to 75mm/s and started a small print that has a 25% success rate so far.

fingers crossed xxxxx

[mhackney]

Ok, that explains the 75 mm/s setting in your previous post! I was hoping that was the case.

[callel]

SUCCESS!!!! .... so far.....

one print done, 100%. It looks much better even printing at the same 0.2mm layer thickness. Just that one setting to slow the non print head speed down from 300mm/s to 75mm/s is drastic.

I am now getting ready to print a larger ABS piece for the enclosure. Trying 85mm/s on this one.