Tec4 problems with levelling

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Beta
Posts: 19
Joined: Sat Mar 03, 2018 6:23 am

Tec4 problems with levelling

Post by Beta »

So I thought I was doing fine until I noticed the first layers of my prints were off depending upon where they were positioned on the print bed.

Layers on the left side of the bed (furthest from the Z screw) printed fine. The ones on the right had visible gaps between the lines. Using Simplify3D, Felix Tec4 profile with PLA.

Notes:
  • I got rid of the Kapton tape which shipped with the kit, as nothing would stick to it: Not PLA, not PETG. Using 3M blue painters tape now.
  • I had to set the global z-offset to -0.18 to get PLA to stick. Z-probe has been calibrated according to the Quick Start manual procedure using a 0.4mm brass feeler gauge instead of the paper calibration card.
  • Bed was leveled and bump-mapped before printing.
  • PLA diameter was measured 5 times, with the top and bottom values ignored and the rest averaged. Set settings in S3D to 1.73mm

This seems to me that the build plate is thus not levelled by some small amount. It was my understanding the levelling procedure and bump-mapping done before the print would compensate for this. Doesn't seem to be.

Please help me understand what I'm missing here.
Attachments
5 squares, each 0.2mm thick (1 layer)
5 squares, each 0.2mm thick (1 layer)

Beta
Posts: 19
Joined: Sat Mar 03, 2018 6:23 am

Post by Beta »

The Z deviation on a freshly levelled build plate between X:200 - Y:100 and X"10 - Y:100 looks to be around 0.152mm. This was measured with the Z-axis set to a reported 10mm using a calibrated 10mm bar and calibrated brass feeler gauges between the bed and the nozzle. This is roughly 23% of the nozzle diameter, which would certainly explain the differences in the first layer I'm seeing.

Beta
Posts: 19
Joined: Sat Mar 03, 2018 6:23 am

Post by Beta »

Spent a few more hours trying to track down the inconsistencies in this machine, and it feels like I'm just going in circles. I've gone back to the basics: Uploaded the firmware and run the reset g-code, and started from the end of the Assembly manual to reset the height of the Z-probe in relation to the build plate (step 107), then started following the Quick Start guide in the order listed there: Level the plate (again), Z-probe calibration (again), followed by XY calibration (dual heads). I get as far as the XY calibration and all it does it print PLA that doesn't stick to the build plate.

I'm going in circles and getting very frustrated, so I need some guidance please.

Beta
Posts: 19
Joined: Sat Mar 03, 2018 6:23 am

Post by Beta »

And spent even more hours on this. I'm not at all convinced the distortion correction being measured at print-bed levelling time is being applied at print time. In digging through the source code for the Tec4 dual head firmware, I discovered a g-code command; M323. With no parameters, this simply reports whether distortion correction is enabled or disabled. I added this to just after the G28 (home) command in the start script (Simplify3d).

Log shows "Distortion correction disabled"

So why would the firmware go through bed-levelling and distortion correction measurements and NOT apply it to an actual print job ? Someone please help me understand.

Notes:
- Started from scratch again. Flashed the firmware and ran the reset g-code
- Levelled the bed as per the Quick Start instructions
- Calibrated the Z-probe as per the Quick Start instructions
- Calibrated the height right hot-end relative to the left hot-end (which is at a fixed height).
- COULD NOT get through the XY dual head calibration, as PLA filament would not stick to the blue painters tape I'm using as a bed coating.

Right away this is telling me something is wrong. Would someone kindly offer some guidance. I've been struggling with this for days now.

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gfeliksdal
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Post by gfeliksdal »

Hi Beta,

Leveling problems are usually caused by the following.
- Not using the latest firmware
- Please double check if the set-screw is properly fixed of the spindle onto the z-axis.
- Make sure the nut of the spindle is properly placed into the z-axis bracket.
- Is the rest of the mechanical parts properly fastened? Set-screw of the pulley's belts, the y-axis linear rail onto the z-axis bracket.

Otherwise it could be that the z-sensor is not functioning correctly. If you have an older version main board (Pre felix 3.0) it could be that he voltage of the z-sensor is not consistent giving bad z-values

Hope these points give you better results.

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gfeliksdal
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Post by gfeliksdal »

Also forgot to tell you regarding the kapton. Before anything want to stick onto it, it needs to be completely grease free. Also finger grease is killing print-adhesion. Please use methylated spirit, 99% alcohol or acetone.

Beta
Posts: 19
Joined: Sat Mar 03, 2018 6:23 am

Post by Beta »

Thanks for the kind response. I've triple checked everything on all 3 axis over the last several days: Set screws are properly affixed as much as a tiny hex-key will allow. As far as I can tell, mechanically the device is solid.

I'm using the latest firmware as downloaded from your site, including the reset g-code. Have flashed the board and reset the settings many times. Shows up as "1.0.0 - FELIX TEC 4 - Dual - V08"

Kapton: Cleaned with 99% isopropyl alcohol before each attempt at printing. Never got PETG to stick. PLA had real troubles as well, so I switched to a material known to stick to both. Now that I've gotten this far, it is probable the root cause may be levelling.

As for the controller board: This printer was a Tec4 kit and seemed to conform to the complete description in the Tec4 assembly instructions.

Inductive Z-sensor: How might I confirm/deny correct function and accuracy? Following all the assembly instructions, it seems to trigger in proximity to metal (LED turns off). Of course, that's just a rough measurement.

What is my next step? I can completely disassemble the unit and go through the assembly again. I have the source code for the firmware, I can easily compile and flash if there's some debug output we can turn on. I'm open to anything, but I'm spending a great deal of time on this. Also, why would I be getting "Distortion correction disabled" as I previously mentioned?

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gfeliksdal
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Post by gfeliksdal »

If all is mechanically ok, we can double check how unflat the bed is.

Manually check flatness of the bed. Do the bed leveling routine and after that move the bed close to the print-head. then manually move the head and table and check if the distance between nozzle and bed is varying a lot over the whole surface.

To check if the z-probe is measuring consistently you can do this in an easy way by turning the leveling knobs one turn, so the leveling is off. Then do the leveling routine and let the printer measure about 5 times. What is the deviation in measurement what you get? It should be about max +/- 5deg

Distortion correction should be on after homing. When you start printing, do you see the spindle turning back and forth when the bed and head are moving? Otherwise if the bed leveling has failed to complete, the bed leveling will be disabled.

Another check we can do is if the leveling is completed, then do the same flatness test which we did manually, but now do it via the interface of the printer. Press home all, then move z-axis to about 0.2mm or less and start moving the x-axis and y-axis and check what the distance between the bed and nozzle is while moving over the whole surface. While doing this, the z-axis should be moving up and down and the distance should be consistent.

Beta
Posts: 19
Joined: Sat Mar 03, 2018 6:23 am

Post by Beta »

Hand levelled build plate, distortion corrections cleared

> G33 R0
> G33 L0
READ: G33 X10.00 Y40.00 Z0.000
READ: G33 X10.00 Y78.74 Z0.000
READ: G33 X10.00 Y117.48 Z0.000
READ: G33 X10.00 Y156.22 Z0.000
READ: G33 X10.00 Y194.96 Z0.000
READ: G33 X66.25 Y40.00 Z0.000
READ: G33 X66.25 Y78.74 Z0.000
READ: G33 X66.25 Y117.48 Z0.000
READ: G33 X66.25 Y156.22 Z0.000
READ: G33 X66.25 Y194.96 Z0.000
READ: G33 X122.49 Y40.00 Z0.000
READ: G33 X122.49 Y78.74 Z0.000
READ: G33 X122.49 Y117.48 Z0.000
READ: G33 X122.49 Y156.22 Z0.000
READ: G33 X122.49 Y194.96 Z0.000
READ: G33 X178.74 Y40.00 Z0.000
READ: G33 X178.74 Y78.74 Z0.000
READ: G33 X178.74 Y117.48 Z0.000
READ: G33 X178.74 Y156.22 Z0.000
READ: G33 X178.74 Y194.96 Z0.000
READ: G33 X234.99 Y40.00 Z0.000
READ: G33 X234.99 Y78.74 Z0.000
READ: G33 X234.99 Y117.48 Z0.000
READ: G33 X234.99 Y156.22 Z0.000
READ: G33 X234.99 Y194.96 Z0.000

I then printed a set of 1-layer squares (Results are attached). While my manual print height was a touch high, the important point is the results at all four corners of the build plate were consistent. This seems to indicate my hand-levelled build plate was in fact level relative to the XY axis.

Now lets do a few build plate levels using the Felix UI (Control | Level Build Plate)
READ: busy:heating...

READ: Z-probe:2.681 X:132.00 Y:98.00
READ: busy:processing
READ: busy:processing
READ: Z-probe:2.651 X:25.50 Y:40.00
READ: busy:processing
READ: busy:processing
READ: Z-probe:2.610 X:25.50 Y:170.00
READ: plane: a = 0.0004 b = -0.0003 c = 2.6524

UI shows the following adjustments:
Rear: 80R
Front: 124R

Without changing anything, I'm going to press "measure again" on the control panel

READ: Z-probe:2.731 X:132.00 Y:98.00
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
READ: Z-probe:2.665 X:25.50 Y:40.00
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
READ: Z-probe:2.629 X:25.50 Y:170.00
READ: plane: a = 0.0008 b = -0.0003 c = 2.6566

UI shows the following adjustments:
Rear: 100R
Front: 138R

Without changing anything, I'm going to press "measure again" on the control panel again (second time)

READ: Z-probe:2.715 X:132.00 Y:98.00
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
READ: Z-probe:2.647 X:25.50 Y:40.00
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
READ: Z-probe:2.610 X:25.50 Y:170.00
READ: plane: a = 0.0008 b = -0.0003 c = 2.6381

UI shows the following adjustments:
Rear: 101R
Front: 140R

Without changing anything, I'm going to press "measure again" on the control panel again (third time)

READ: Z-probe:2.707 X:132.00 Y:98.00
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
READ: Z-probe:2.639 X:25.50 Y:40.00
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
READ: Z-probe:2.602 X:25.50 Y:170.00
READ: plane: a = 0.0008 b = -0.0003 c = 2.6308

UI shows the following adjustments:
Rear: 100R
Front: 140R

Without changing anything, I'm going to press "measure again" on the control panel again (fourth time)

READ: Z-probe:2.744 X:132.00 Y:98.00
READ: busy:processing
READ: busy:processing
READ: busy:processing
READ: Z-probe:2.679 X:25.50 Y:40.00
READ: busy:processing
READ: busy:processing
READ: Z-probe:2.644 X:25.50 Y:170.00
READ: plane: a = 0.0008 b = -0.0003 c = 2.6700

UI shows the following adjustments:
Rear: 100R
Front: 137R

Without changing anything, I'm going to press "measure again" on the control panel again (fifth time)

READ: Z-probe:2.739 X:132.00 Y:98.00
READ: busy:processing
READ: busy:processing
READ: Z-probe:2.666 X:25.50 Y:40.00
READ: busy:processing
READ: busy:processing
READ: Z-probe:2.630 X:25.50 Y:170.00
READ: plane: a = 0.0008 b = -0.0003 c = 2.6556

UI shows the following adjustments:
Rear: 104R
Front: 141R

Without changing anything, I'm going to press "measure again" on the control panel again (last time)

READ: Z-probe:2.745 X:132.00 Y:98.00
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
READ: Z-probe:2.674 X:25.50 Y:40.00
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
SENT: M105
READ: busy:processing
READ: Z-probe:2.643 X:25.50 Y:170.00
READ: plane: a = 0.0008 b = -0.0002 c = 2.6637

UI shows the following adjustments:
Rear: 104R
Front: 138R

So, all of these adjustments would swing the left side of the build plate up while depressing the right side -- exactly the symptoms I've been observing in the print results when I let the machine carry out the build plate levelling.
Attachments
IMG_E2626.JPG

Beta
Posts: 19
Joined: Sat Mar 03, 2018 6:23 am

Post by Beta »

The next stage is to actually let the machine determine the level then look at the reported distortion maps. I did this many times without otherwise touching the bed - just let the machine tell me what to do then proceed on its own. Here are the results.

Results 1:
<-G33 X10.00 Y40.00 Z0.416
<-G33 X10.00 Y78.74 Z0.407
<-G33 X10.00 Y117.48 Z0.396
<-G33 X10.00 Y156.22 Z0.416
<-G33 X10.00 Y194.96 Z0.474
<-G33 X66.25 Y40.00 Z0.417
<-G33 X66.25 Y78.74 Z0.407
<-G33 X66.25 Y117.48 Z0.389
<-G33 X66.25 Y156.22 Z0.424
<-G33 X66.25 Y194.96 Z0.500
<-G33 X122.49 Y40.00 Z0.386
<-G33 X122.49 Y78.74 Z0.398
<-G33 X122.49 Y117.48 Z0.472
<-G33 X122.49 Y156.22 Z0.482
<-G33 X122.49 Y194.96 Z0.573
<-G33 X178.74 Y40.00 Z0.533
<-G33 X178.74 Y78.74 Z0.538
<-G33 X178.74 Y117.48 Z0.514
<-G33 X178.74 Y156.22 Z0.545
<-G33 X178.74 Y194.96 Z0.611
<-G33 X234.99 Y40.00 Z0.543
<-G33 X234.99 Y78.74 Z0.525
<-G33 X234.99 Y117.48 Z0.497
<-G33 X234.99 Y156.22 Z0.515
<-G33 X234.99 Y194.96 Z0.516

Results 2:
<-G33 X10.00 Y40.00 Z-0.062
<-G33 X10.00 Y78.74 Z-0.083
<-G33 X10.00 Y117.48 Z-0.104
<-G33 X10.00 Y156.22 Z-0.098
<-G33 X10.00 Y194.96 Z-0.061
<-G33 X66.25 Y40.00 Z-0.054
<-G33 X66.25 Y78.74 Z-0.072
<-G33 X66.25 Y117.48 Z-0.095
<-G33 X66.25 Y156.22 Z-0.074
<-G33 X66.25 Y194.96 Z-0.023
<-G33 X122.49 Y40.00 Z-0.082
<-G33 X122.49 Y78.74 Z-0.075
<-G33 X122.49 Y117.48 Z-0.006
<-G33 X122.49 Y156.22 Z-0.009
<-G33 X122.49 Y194.96 Z0.063
<-G33 X178.74 Y40.00 Z0.079
<-G33 X178.74 Y78.74 Z0.081
<-G33 X178.74 Y117.48 Z0.048
<-G33 X178.74 Y156.22 Z0.066
<-G33 X178.74 Y194.96 Z0.096
<-G33 X234.99 Y40.00 Z0.094
<-G33 X234.99 Y78.74 Z0.074
<-G33 X234.99 Y117.48 Z0.049
<-G33 X234.99 Y156.22 Z0.042
<-G33 X234.99 Y194.96 Z0.016

Results 3:
<-G33 X10.00 Y40.00 Z0.050
<-G33 X10.00 Y78.74 Z0.037
<-G33 X10.00 Y117.48 Z0.014
<-G33 X10.00 Y156.22 Z0.026
<-G33 X10.00 Y194.96 Z0.064
<-G33 X66.25 Y40.00 Z0.056
<-G33 X66.25 Y78.74 Z0.042
<-G33 X66.25 Y117.48 Z0.019
<-G33 X66.25 Y156.22 Z0.049
<-G33 X66.25 Y194.96 Z0.104
<-G33 X122.49 Y40.00 Z0.029
<-G33 X122.49 Y78.74 Z0.037
<-G33 X122.49 Y117.48 Z0.107
<-G33 X122.49 Y156.22 Z0.116
<-G33 X122.49 Y194.96 Z0.196
<-G33 X178.74 Y40.00 Z0.192
<-G33 X178.74 Y78.74 Z0.191
<-G33 X178.74 Y117.48 Z0.160
<-G33 X178.74 Y156.22 Z0.191
<-G33 X178.74 Y194.96 Z0.237
<-G33 X234.99 Y40.00 Z0.216
<-G33 X234.99 Y78.74 Z0.190
<-G33 X234.99 Y117.48 Z0.163
<-G33 X234.99 Y156.22 Z0.175
<-G33 X234.99 Y194.96 Z0.152

Results 4:
<-G33 X10.00 Y40.00 Z0.014
<-G33 X10.00 Y78.74 Z-0.007
<-G33 X10.00 Y117.48 Z-0.039
<-G33 X10.00 Y156.22 Z-0.037
<-G33 X10.00 Y194.96 Z-0.010
<-G33 X66.25 Y40.00 Z0.039
<-G33 X66.25 Y78.74 Z0.017
<-G33 X66.25 Y117.48 Z-0.016
<-G33 X66.25 Y156.22 Z0.003
<-G33 X66.25 Y194.96 Z0.043
<-G33 X122.49 Y40.00 Z0.030
<-G33 X122.49 Y78.74 Z0.031
<-G33 X122.49 Y117.48 Z0.093
<-G33 X122.49 Y156.22 Z0.086
<-G33 X122.49 Y194.96 Z0.143
<-G33 X178.74 Y40.00 Z0.209
<-G33 X178.74 Y78.74 Z0.199
<-G33 X178.74 Y117.48 Z0.164
<-G33 X178.74 Y156.22 Z0.177
<-G33 X178.74 Y194.96 Z0.201
<-G33 X234.99 Y40.00 Z0.254
<-G33 X234.99 Y78.74 Z0.221
<-G33 X234.99 Y117.48 Z0.191
<-G33 X234.99 Y156.22 Z0.180
<-G33 X234.99 Y194.96 Z0.133

Results 5:
<-G33 X10.00 Y40.00 Z0.099
<-G33 X10.00 Y78.74 Z0.072
<-G33 X10.00 Y117.48 Z0.034
<-G33 X10.00 Y156.22 Z0.034
<-G33 X10.00 Y194.96 Z0.044
<-G33 X66.25 Y40.00 Z0.121
<-G33 X66.25 Y78.74 Z0.097
<-G33 X66.25 Y117.48 Z0.061
<-G33 X66.25 Y156.22 Z0.071
<-G33 X66.25 Y194.96 Z0.097
<-G33 X122.49 Y40.00 Z0.111
<-G33 X122.49 Y78.74 Z0.116
<-G33 X122.49 Y117.48 Z0.167
<-G33 X122.49 Y156.22 Z0.154
<-G33 X122.49 Y194.96 Z0.209
<-G33 X178.74 Y40.00 Z0.280
<-G33 X178.74 Y78.74 Z0.273
<-G33 X178.74 Y117.48 Z0.237
<-G33 X178.74 Y156.22 Z0.243
<-G33 X178.74 Y194.96 Z0.249
<-G33 X234.99 Y40.00 Z0.312
<-G33 X234.99 Y78.74 Z0.282
<-G33 X234.99 Y117.48 Z0.255
<-G33 X234.99 Y156.22 Z0.244
<-G33 X234.99 Y194.96 Z0.195

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