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Will changing the outer probe points mess up the calibration?


What I'm running into is that outer Y probe point is too close to the tower and the white tension piece is getting forced up against the hot end fan enough to stop the fan. I was hoping that moving the points in a little wouldn't completely mess up the auto-calibration.

I've included the G-Code.

; Auto calibration routine for SeeMeCNC Rostock MAX V2
;
; About the G30 S parameter
; Used to specify what calibration computation to perform.
;
; S=-1 Don't adjust anything, just print the height error at each probe point
; S=0 Equivalent to S=<number_of_points_probed>
; S=3 Adjust homing switch corrections only
; S=4 Adjust homing switch corrections and delta radius
; S=6 Adjust homing switch corrections, delta radius, and X and Y tower position offsets
; S=7 Adjust homing switch corrections, delta radius, X and Y tower position offsets, and diagonal rod length

M561 ; clear any bed transform, otherwise homing may be at the wrong height
G28 ; home the printer

G1 X0.00 Y135.00 Z10 F15000 ; move to just above the first probe point (from the list below)

; bed.g file for RepRapFirmware, generated by Escher3D calculator
; 13 points, 6 factors, probing radius: 135, probe offset (0, 0)
G30 P0 X0.00 Y135.00 Z-99999 H0
G30 P1 X116.91 Y67.50 Z-99999 H0
G30 P2 X116.91 Y-67.50 Z-99999 H0
G30 P3 X0.00 Y-135.00 Z-99999 H0
G30 P4 X-116.91 Y-67.50 Z-99999 H0
G30 P5 X-116.91 Y67.50 Z-99999 H0
G30 P6 X0.00 Y67.50 Z-99999 H0
G30 P7 X58.46 Y33.75 Z-99999 H0
G30 P8 X58.46 Y-33.75 Z-99999 H0
G30 P9 X0.00 Y-67.50 Z-99999 H0
G30 P10 X-58.46 Y-33.75 Z-99999 H0
G30 P11 X-58.46 Y33.75 Z-99999 H0
G30 P12 X0 Y0 Z-99999 S6


G1 X0 Y0 Z150 F15000 ; get the head out of the way of the bed

A related request for those of us who have built enclosures that are fairly close to the bed diameter... doing a G29 can crash the head into the enclosure wall. So if we don't mind a smaller build diameter, is there an easy way of telling the auto calibration to use a smaller area of the build plate?

TwoTone wrote:Will changing the outer probe points mess up the calibration?

What I'm running into is that outer Y probe point is too close to the tower and the white tension piece is getting forced up against the hot end fan enough to stop the fan. I was hoping that moving the points in a little wouldn't completely mess up the auto-calibration.

I've included the G-Code.

; Auto calibration routine for SeeMeCNC Rostock MAX V2
;
; About the G30 S parameter
; Used to specify what calibration computation to perform.
;
; S=-1 Don't adjust anything, just print the height error at each probe point
; S=0 Equivalent to S=<number_of_points_probed>
; S=3 Adjust homing switch corrections only
; S=4 Adjust homing switch corrections and delta radius
; S=6 Adjust homing switch corrections, delta radius, and X and Y tower position offsets
; S=7 Adjust homing switch corrections, delta radius, X and Y tower position offsets, and diagonal rod length

M561 ; clear any bed transform, otherwise homing may be at the wrong height
G28 ; home the printer

G1 X0.00 Y135.00 Z10 F15000 ; move to just above the first probe point (from the list below)

; bed.g file for RepRapFirmware, generated by Escher3D calculator
; 13 points, 6 factors, probing radius: 135, probe offset (0, 0)
G30 P0 X0.00 Y135.00 Z-99999 H0
G30 P1 X116.91 Y67.50 Z-99999 H0
G30 P2 X116.91 Y-67.50 Z-99999 H0
G30 P3 X0.00 Y-135.00 Z-99999 H0
G30 P4 X-116.91 Y-67.50 Z-99999 H0
G30 P5 X-116.91 Y67.50 Z-99999 H0
G30 P6 X0.00 Y67.50 Z-99999 H0
G30 P7 X58.46 Y33.75 Z-99999 H0
G30 P8 X58.46 Y-33.75 Z-99999 H0
G30 P9 X0.00 Y-67.50 Z-99999 H0
G30 P10 X-58.46 Y-33.75 Z-99999 H0
G30 P11 X-58.46 Y33.75 Z-99999 H0
G30 P12 X0 Y0 Z-99999 S6


G1 X0 Y0 Z150 F15000 ; get the head out of the way of the bed

You can have the auto calibration points wherever you want, as long as they cover all areas of the bed, especially around the periphery of the printable area. Moving one or two points to avoid fouling the fan will not cause a problem. You are using 6 factor calibration, but if you ever want to use 7-factor then you should include points opposite the towers that are as far out as possible.

...and then understand that your scaling will be off after it screws with the length of the arms.

g.

Thanks for the replies. I'm still chasing issues after the upgrade, I I took apart the hotend and put it all back together and low and behold it's no longer a problem. Go Figure.

geneb wrote:...and then understand that your scaling will be off after it screws with the length of the arms.

g.

If you have points sufficiently far out opposite the towers, then auto calibration is will do much better at working out the length of the arms - or more precisely, the products of arm length and carriage steps/mm. But most deltas don't have a print bed that goes out far enough, or the arm joints don't have enough range to let the head move out far enough between towers.

How far is "far enough"?

g.

geneb wrote:How far is "far enough"?

g.

This http://forums.reprap.org/read.php?178,5 ... msg-554531 may give you some idea.

David- is it an issue if I keep getting a much higher Z than your range? Mine is 2.88.

To calibrate the sensor for Z homing and bed probing, home X and Y, then position the head over the centre of the bed. With the nozzle at operating temperature, lower the head so that it is just touching the bed or just gripping a sheet of paper, then send G92 Z0 to define that position as Z=0. Raise the head 5mm and remove the paper. Then send command G30 S-1 to probe the bed at that point without adjusting the Z height setting. Read off the Z height in the “Head Position” box in Duet Web Control, or from the Z coordinate shown on the Control page of PanelDue, or send M114 to retrieve the head position if using a USB host program on a PC. It should be in the range 0.5 to 2.5mm.

I presume you are using my IR sensor then. 2.88mm may be within tolerance depending on how high the bottom edge of the sensor board is above the nozzle, and the bed surface you are using.