@T3P3Tony This thread can of course be joined to the very similar sticky thread about configs and macros. I didn’t want to high jack that thread.
I think the best way is to make the first message moderated/“ wiki like” so that all relevant info is mentioned first. The rest of the conversation can be suggestions and discussions.
@o_lampe my bad! I thought you criticized something I wrote about segmentation.
@o_lampe I think there are examples macros available. It’s no problems to program pauses for ramp up/down in macros.
Hi
I would like to have a moderated sticky post where all suggested configurations are placed in the first message. We have the https://docs.duet3d.com/User_manual/Machine_configuration/Configuration_CNC but it is not really updated and does not mentions configurations that needs to be done for a working CNC.
None trivial things I have noticed that needs to be configured for a Cartesian CNC in Duet Wifi firmware 3.4.6:
M203 RRF has a default minimum movement speed of 0.5mm/sec. This is way to high. I crashed my CNC while trying to drill a hole. Very BAD. A warning should appear in the DWC when it replaces speeds lower than 0.5mm/s for 0.5mm/s.
M350 Interpolation should not be used. The lowest speed limit for Interpolation to always work good is to high for my CNC it created wobbly lines while turning a cone.
M669 Segmentation is good to have if you need to stop the motion in a predictable manner.
Looking forward to learn more things that should be configured.
Thanks
//P
The point is that the mounting arrangement is not good. Just because it is done doesn't mean its good and life time of a bearing is not until it ceases to function or exist as a ball bearing. I know that 100N is in the high tension for most people and 2000 RPM is the upper speed for many steppers. Slower speed and repeated short back and forth motion can be really bad for bearings since the grease has problems forming a good film inside it at lower speeds.
Here is what happens if you do as I told you earlier and center the load between the ball bearings. All else the same. You can run with much harder tension and lower friction. That reduces ringing since the extra load due to the accelerated mass is smaller compared to the tension in the cord. This should be extra important for you since you have a very long thin free cord and hence a relatively elastic setup.
Loading a deep grove ball bearing axially is not that bad since it distribute the load on all included balls.
Depends on how fast you want to drive the system. If you go slow it can be open. Your Z is going slow.
//P
Congratulations! Looks really nice.
Just as a quick calculation of the life time of a high quality motor bearing mounted as you have it and a 200N load sideways. This means 100N cord tension @2000RPM.
//P
I want more videos 
Perhaps have rolling side supports instead of fixed ones.
Yes motors can be that bad, some are better than others. Even full steps can vary in size by up to 5%. Changing to 0.9deg motors helped me a lot, but didn't completely solve it.
Good to know
I also have issues with how all drive pulleys are attached to the motors. This is a common fault on almost all machines. The front bearings of the motors are not designed to take up torque and that is how they are mounted now. To be 100% correct you should have bearings above and under the pulley and a somewhat flexible shaft to the motor. That can be simplified on almost all machines to the front bearing of the motor and a bearing above the pulley. Technical that constitutes an overrefined system but should be ok. On your machine I would go for a separate bearing above and under since the pulley is to high. Benefit is higher belt tension with less resistance.
An issue that might create ripples would be if your pulley is not fitting 100% to the shaft and rocks in the direction of the load. My guess is that it would be less repeating but it could still be the fault.
//P
Hi
After reading this post it becomes clear to me that a great feature on the wiki is a list of features that the senior members of this forum recommend us less senior to implement. This is a great feature I never heard of before.
Thanks!
You have an unusually low steps/mm.
HTH David
Yes, the spools are very big. But are motors that bad? It would have to be approx. a full 16th microstep out of sync. @David did it solve your issue?
By running the machine faster you introduce more randomness to what the cords are doing and the speed makes jerks less impacting. I am still 90% convinced that there is some sort of concentrically issue. It is not easy to get artifacts as repeating as you have managed in other ways. The ball bearings should be good. And If mounted correctly, by fixating the centerpiece down to the base of the mount, there can't be any movement to them. If the bearings can't be bolted down add a shim above, middle and under.
Do you have the same bands on you pulleys? That can explain the problem. I think that if you spend the money on nice rails you should try to get the pulleys turned in a lathe or minimum put a metal sleeve above your printed part.
Can it be the patterns on the cords from how it is woven? I would say you have to many contact points with the cord to make it the most likely scenario.
You might also want to have some air in between the cords on the pulley. If the new cord clings to it's neighbor the effective diameter increases. but it would most likely not give this repeatability to your pattern.
The satisfaction once you solve this will be good
Hi
I'm no expert in this type of printer but do mechanical designs 2000h a year and will try to help.
Since the pattern is so uniform the extruder can be excluded. It's not over under extrusion.
You have rails all around the machine so you know that the linear motion is without the pattern. You also know that the patterns are exactly straight in the Z direction –> the fault is in your XY plane. The carriage needs to wobble in the Y direction along the X linear rail. The pattern is very tight and I find it a bit strange because my guess would been that there is a pulley or two that are not concentric. But to get such a tight pattern means that the pulley is small or it has several high spots. I don't know exactly how an eccentric pulley would effect the print but I'm guessing exactly like your fault. The harder you tighten the wires the more motion is created by the elongation of the path.
It is very unlikely that it has to do with the card. It runs smooth as silk and even if it didn't the error is no were near enough to create such a pattern. It would require microsteps out of sync pulsating back and forth.
How have you made all the pulleys?
//P
Hi
I was playing around with the z probe and built a mount that sits 30mm from the nozzle. When I added the probe offset in G31 and ran the bed compensation my nozzle collided with the fixation of the bed. I had the coordinate at Y15 so my nozzle hit the nut at Y-15.
It might be good to look in to how that function is handled. The Mesh Comp removes the non accessible points.
//P
Good call! Have you considered a nano cryptocurrency wallet to accept small donations? After all you saved me endless of frustrating hours and did so on a Satuarday.
Thanks a million!
1. Run the following commands without any parameters, and check that the values they report match the values you specified in config.g:
M669 Kinematics is Cartesian
M574 X: low end active high switch, Y: low end active high switch, Z: low end Z probe
M208 Axis limits - X: 0.0 min, 260.0 max, Y: 0.0 min, 240.0 max, Z: 0.0 min, 180.0 max
M92 Steps/mm: X: 66.667, Y: 66.667, Z: 960.000, E: 120.000:120.000
M584 Driver assignments: X0 Y2 Z1 E3:4, 3 axes visible
All good
2. Restart the Duet and connect DWC. What X and Y head positions does DWC display?
X9999.9 Y9999.9
3. Press the Home X button. When it finishes, what X and Y positions does DWC display?
X9999.9 Y9999.9
4. Press the Home Y button. When it finishes, what X and Y positions does DWC display?
X9999.9 Y9999.9
5. Repeat #1 again.
M669 Kinematics is Cartesian
M574 X: low end active high switch, Y: low end active high switch, Z: low end Z probe
M208 Axis limits - X: 0.0 min, 260.0 max, Y: 0.0 min, 240.0 max, Z: 0.0 min, 180.0 max
M92 Steps/mm: X: 66.667, Y: 66.667, Z: 960.000, E: 120.000:120.000
M584 Driver assignments: X0 Y2 Z1 E3:4, 3 axes visible
All good
The homing macros also need to have S1 in them to create motion. So the macro halts half way thru since the later G1 commands does not have S1 or S2 in them.
I can run Z with G1 S0 Z100 F100 commands but it runs 100mm in less than one second so the motor naturally stalls with a short scream.
G92 X Y Z does not clear the X and Y pos error
When G28 Z is called I get errors from deploying the probe. That is a routine not used in my macros.
When refreshing the web interface with X and Y in the 0 pos i got this error.
Yes, the axes move correctly
; homex.g
; called to home the X axis
;
; generated by RepRapFirmware Configuration Tool on Sat Feb 24 2018 04:09:19 GMT+0100 (Västeuropa, normaltid)
G91 ; relative positioning
G1 S1 Z5 F1000 ; lift Z relative to current position
G1 S1 X-265 F1000 ; move quickly to X axis endstop and stop there (first pass)
G1 X5 F1000 ; go back a few mm
G1 S1 X-265 F360 ; move slowly to X axis endstop once more (second pass)
G1 Z-5 F1000 ; lower Z again
G90 ; absolute positioning
; homey.g
; called to home the Y axis
;
; generated by RepRapFirmware Configuration Tool on Sat Feb 24 2018 04:09:19 GMT+0100 (Västeuropa, normaltid)
G91 ; relative positioning
G1 S1 Z5 F1000 ; lift Z relative to current position
G1 S1 Y-245 F1000 ; move quickly to Y axis endstop and stop there (first pass)
G1 Y5 F1000 ; go back a few mm
G1 S1 Y-245 F360 ; move slowly to Y axis endstop once more (second pass)
G1 Z-5 F1000 ; lower Z again
G90 ; absolute positioning
; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool on Sat Feb 24 2018 04:09:19 GMT+0100 (Västeuropa, normaltid)
G91 ; relative positioning
G1 S1 Z5 F1000 ; lift Z relative to current position
G90 ; absolute positioning
G1 X15 Y15 F1000 ; go to first probe point
G30 ; home Z by probing the bed
; Uncomment the following lines to lift Z after probing
;G91 ; relative positioning
;G1 Z5 F100 ; lift Z relative to current position
;G90 ; absolute positioning
Firmware Name: RepRapFirmware for Duet WiFi
Firmware Electronics: Duet WiFi 1.0
Firmware Version: 1.20 (2017-12-23)
WiFi Server Version: 1.20
Web Interface Version: 1.20
Web Interface by Christian Hammacher
Licensed under the terms of the GPL v3