G28 isn't reliably homing all axis on my delta printer.

3D Printing
,
1

G28 isn’t reliably homing all axis on my delta printer. I can immediately do another G28 and it will find home on all three towers just fine. What should I look for?

I just flashed Umikaze last night and brought forward my Redeem settings from the prior Kamikaze 2.0.8.

Sample Log:
Send: G28
Recv: End stop Z2 hit!
Recv: End stop Z2 hit!
Recv: End stop Z1 hit!
Recv: Homing done.
Recv: ok
[…]
Send: G28
Recv: End stop Z1 hit!
Recv: End stop Y1 hit!
Recv: Homing done.
Recv: End stop X1 hit!
Recv: ok

Even here the X1 hit was late.

2

Can you post your local.cfg?

3

It concerns me that Z2 is firing off, I assume that’s a probe?

4

@Alex_Carlson Here’s my config.
[System]
machine_type = Folger Tech Kossel 2020

[Geometry]
axis_config = 3
offset_x = 0.0
offset_y = 0.0
offset_z = 0.0

[Steppers]
microstepping_x = 3
microstepping_y = 3
microstepping_z = 3
microstepping_e = 3
current_x = 0.5
current_y = 0.5
current_z = 0.5
current_e = 0.5
steps_pr_mm_x = 5.0
steps_pr_mm_y = 5.0
steps_pr_mm_z = 5.0
steps_pr_mm_e = 6.0
backlash_x = 0.0
backlash_y = 0.0
backlash_z = 0.0
backlash_e = 0.0
in_use_x = True
in_use_y = True
in_use_z = True
in_use_e = True
in_use_h = False
in_use_a = False
in_use_b = False
in_use_c = False
direction_x = 1
direction_y = 1
direction_z = 1
direction_e = -1
direction_h = 1
direction_a = 1
direction_b = 1
direction_c = 1
slow_decay_x = 0
slow_decay_y = 0
slow_decay_z = 0
slow_decay_e = 0
use_timeout = True
timeout_seconds = 500

[Endstops]
has_x = True
has_y = True
has_z = True
invert_x1 = True
invert_y1 = True
invert_z1 = True
invert_z2 = True
end_stop_x1_stops = x_pos
end_stop_y1_stops = y_pos
end_stop_z1_stops = z_pos
end_stop_x2_stops =
end_stop_y2_stops =
end_stop_z2_stops = x_neg, y_neg, z_neg
soft_end_stop_min_x = -0.210
soft_end_stop_min_y = -0.220
soft_end_stop_min_z = -0.5
soft_end_stop_max_x = 0.210
soft_end_stop_max_y = 0.220
soft_end_stop_max_z = 0.5

[Homing]
home_x = 0.0
home_y = 0.0
home_z = 0.3055
home_e = 0.0
home_speed_e = 0.01

[Macros]
g32 =
M574 Z2 x_neg,y_neg,z_neg ; Enable the Z2 endstop (z-min)
g31 =
M574 Z2 x_neg,y_neg,z_neg ; Disable the Z2 endstop (z-min). Don’t jack with them for now.

[Delta]
l = 0.24
r = 0.15
a_radial = 0.0
b_radial = 0.0
c_radial = 0.0

[Cold-ends]
connect-therm-e-fan-0 = False
connect-therm-e-fan-1 = True
add-fan-0-to-m106 = False
add-fan-1-to-m106 = True
cooler_0_target_temp = 60

[Heaters]
pid_kp_e = 0.0172202991985
pid_ti_e = 88.0257707596
pid_td_e = 6.35106571137

5

And yes, I’ve got a z-min probe that I leave enabled until I’m sure G28 doesn’t go slamming the extruder into the bed. It likes to go about 100 - 150 mm in the negative direction before going up to try to find the endstops.

6

@Nathan_Reichenberger I’ve just added

The total length each axis can travel

This affects the homing endstop searching length.

travel_x = 0.5
travel_y = 0.5
travel_z = 0.5

to the geometry section. Now it travels all the way down to the bed and heads back up, falling short. Putting those back to a smaller value.

7

As a side-note, it’d be cool if the local.cfg editor could do git commits. I don’t have the discipline to do it by hand yet and it’d be cool to be able to roll back.

8

Changing the offset parameters in the geometry section fixed that issue.

offset_x = 0.3
offset_y = 0.3
offset_z = 0.3

9

Ok so it should never travel down for a home, only up

10

Make your travel negative, and your offset negative, have the offsets be close to the height of the nozzle from your bed.

11

Home z will need to be a bit less than the offsets, but positive, otherwise the carriages will hit the end stops and stay there, not do the second homing

12

This seems to have done the trick. With my config set as:

[Geometry]
axis_config = 3
offset_x = -0.3055
offset_y = -0.3055
offset_z = -0.3055
travel_x = -0.320
travel_y = -0.320
travel_z = -0.320

…snip…
[Homing]
home_x = 0.0
home_y = 0.0
home_z = 0.300
home_e = 0.0

It now only moves upward and settles down just shy of the endstops and still goes to the print bed with G1 Z0.

Thanks!

13

Cool :slight_smile: I suggest increasing your travel though. If you were to run g28 when your nozzle is off to the side, it wouldn’t home right the first time. (Travel is basically the actual length of the possible travel on a tower.) total travel length is roughly home_z height +sin(60) x rod length , or -0.503

14

I found that out when checking level and adjusting my R value. I measured my towers to be 600 and used that value.