Bed compensation

I have a strange problem with my bed compensation. Manualy the bed is flat yet my Auto bed leveling says :
G32
Bed equation fits points [60.0, 0.0, -0.097] [60.0, 180.0, 0.046] [218.0, 180.0, -0.817] [218.0, 0.0, -0.843]
the last 2 points are lower by 0.8 mm yet when i try a peice of paper at 0.1mm it just bearly touching it

Here are a couple of possibilities:

1. Are you certain that the coordinates you have chosen place the sensor head over the centre of the white squares?

2. There may be a slight anticlockwise twist in your X plate as viewed from the +X end, due to the weight of the head. This will cause the head to sag slightly at X=218 compared to X=60. The stock IR sensor is offset from the nozzle in the X direction, so this sag will increased the height difference between the sensor face and the nozzle, causing an error of the sort you observe. You could check this by using a feeler gauge to measure the height of the edge of the sensor board above the bed at various places, when the nozzle is just gripping the paper.

If this is happening, there are a few potential remedies:

- The height sensing board that I sell has the sensitive area in line with the nozzle in the X direction, so as to reduce the sensitivity of the reading to varying amounts of head sag.

- Fitting DaveK's aluminium X arm kit will reduce the sag.

- RepRapPro's new X carriage design (with the X runner underneath the X plate instead of on the right hand side of it) may also reduce the sag.

- I did a mod a long time ago to mount the original proximity sensor on the print head so that it is in line with the nozzle in the X direction.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

1. it is directly in the middle of the white paper area.

2.this might be it then ,i have plan to buy the aluminum arm as soon as i have the money for it and your sensor. atm i am a bit short on budget tho

Thanks for the answer

Where can the new x caridge design be found?

Edited 1 time(s). Last edit at 04/19/2015 11:01AM by Darathy.

Quote
Darathy
Where can the new x caridge design be found?

See [github.com]. I'm assuming it is compatible with the old nozzle mount, I haven't checked.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Is there any way to set the bed comp table manually? atm I'm printing on plain glass and the RRP IR sensor needs the targets, planning on trying out a white coating soon to see if the probe will work on it. If not I might just live with manual bed comp.

I'll have to upgrade eventually to DC42's I think.


Also, DC42 if I had 2 hotends (0.5mm and 0.3mm) would I need to swap your custom board each time I switch hot ends (or have two of them)? It looks like it attaches to the hot end instead of the carriage.

Quote
shadow651
Is there any way to set the bed comp table manually? atm I'm printing on plain glass and the RRP IR sensor needs the targets, planning on trying out a white coating soon to see if the probe will work on it. If not I might just live with manual bed comp.

Yes you can, see [reprappro.com].

Quote
shadow651
Also, DC42 if I had 2 hotends (0.5mm and 0.3mm) would I need to swap your custom board each time I switch hot ends (or have two of them)? It looks like it attaches to the hot end instead of the carriage.

Unfortunately, yes.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

so could I use 5 points for that then?

like:

G30 P0 X5 Y10 Z-0
G30 P1 X5 Y195 Z0
G30 P2 X195 Y195 Z0
G30 P3 X195 Y10 Z0
G30 p4 x100 y100 Z0 S