X-axis shift? Or S3D settings?

[Steven Colgan]

Hello Everyone,

I'm new to 3D printing and I'm not sure how to solve my problem. I'm using S3D 1.1.2. My models are printing perfectly, then all of a sudden they start leaning/slanting along the x-axis for about 25mm (see attached pics).The Y=axis and Z-axis are printing fine.

Usually they start leaning for the last 25mm of the model. In the attached pics I was printing two models. It started leaning along the x-axis for the last 25mm of the smaller model, and shifted for the corresponding 25mm of the larger model. When the smaller model finished printing the printer corrected its self and printed that last 25mm of the bigger model correctly. I've attached photos because I know my explanation is difficult to follow!

I'm printing using natural PLA

Extruder is set to 190

Bed temp is 75 for first layer, and 65 for all other layers.

I'm using tomlombardi's profile.

Models were drawn in SolidWorks but I've checked them in S3D for errors.

Any help is appreciated!

[Eric U.]

Looks like the print shift described in the threads at  https://groups.google.com/forum/?fromgroups=#!searchin/makergear/print$20shift/makergear/LNgNbltdGeI/D9CP10lFB-kJ and https://groups.google.com/forum/?fromgroups=#!searchin/makergear/y-skip/makergear/6LK70qx_YoE/Uv80PndoHa8J.  If you haven't got the upgraded bushings or bearings, they might fix it.  You can also try lowering your max acceleration/jerk as I described in the second thread above.

[Steven Colgan]

Thanks Eric,

I think this might not be a hardware issue. My M2 is only 2 week old and cam pre-assembled. I tried to reprint the models today and the same thing happened at the exact same position! I printed another model that this x shift happened to yesterday. This time I printed it on its side and it printed perfectly! I wonder is it a bug with my slicer (S3D), my slicer settings or the model its-self? I'm at a compete loss!!!!

[Joshua Wills]

Steven, could you email me your .stl and .gcode files for that part?  I may be able to look at them and see if there's an issue - my current thought is that, at the faulty location, you have the normals inverted somehow.

[Steven Colgan]

Thanks a million Josh,

Please find attached the gcode files and the .stl files. These files are the ones the created the models shown in the pictures on my post. I imported these two .stl files into S3D and then sliced them.

Thanks a million for this.

On Mon, May 13, 2013 at 11:10 PM, Joshua Wills <joshe...@gmail.com> wrote:

Steven, could you email me your .stl and .gcode files for that part?  I may be able to look at them and see if there's an issue - my current thought is that, at the faulty location, you have the normals inverted somehow.

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[Steven Colgan]

I have been playing around with my m2 over the weekend trying to figure out why I keep getting x shift, but I still cannot solve the problem.

I checked to see if any connections had come loose, but everyting is perfect. The machine is only two weeks old, and I bought it pre-assembled.

I reprinted to the models for a third time and the x-shift occurred in exactly the same position. 

I then rotated the models 90 degrees. The x-shift still occurred, but it wasn't as pronounced. 

I then tried printing the models individually (I was trying to print two models at once) and the both printed perfectly.

I thought trying to print two models at once was the problem. I then started to print my next model individually but the x-shift returned. What I've noticed is the the x-shift does not occur at a specific height, but rather at a specific "feature" of the model. The models I'm printing are simple block shapes. The problem occurs on the top feature /block when I am printing an individual file.

When I am printing two models at once the shift occurs at the top feature of the smallest model, but it effects both models. Once the smallest model is finished printing the shift corrects its self on the biggest model.

Any thoughts?

[Charles]

On Sunday, May 19, 2013 11:15:13 AM UTC-6, Steven Colgan wrote:

I have been playing around with my m2 over the weekend trying to figure out why I keep getting x shift, but I still cannot solve the problem.

Download Slic3r any newer version, and slice and print your model and see what happens if it prints o.k. you will at least know it is not a hardware

problem. Good Luck.

[Ketil Froyn]

Use a gcode viewer to inspect the generated gcode. Or share one of your bad print gcodes here, and perhaps someone will have a look.

I've used tatlin (from github) to view gcode, but there are definitely better viewers available.

-Ketil

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[Steven Colgan]

Thanks Charles and ketil,

I took both your advice and I've downloaded slic3r and printrun. I ran the model through both S3D and printrun and it came out perfectly with printrun! I compared the g code from both files and I noticed the S3D g code adds a blueish colour to the top feature of the model. I dont know what this colour means (is it extruder movement? an increase in speed?) but this is where my x shift problems are occurring. 

Simplify 3D

Slic3r

I'm attaching the gcode also if anyone wants to take a look and let me know whats happening here.

The other thing I noticed that might be a factor was the huge time difference between S3D and Slic3r. This model took nearly twice as long to print when I used slic3r and print run. (Nearly four hours vs 1.79 in S3D ). What default speeds would you recommend? I think I'm using the S3D defaults, unless I edited them by accident.

Thanks for the help

[Ketil Froyn]

I opened both gcode files in tatlin and flipped through all the layers while zoomed in on different corners (in 2D mode), and I couldn't see any shift there. So if the gcode looks fine in a viewer, that leaves some possibilities:

1. a hardware issue on your printer

2. some gcode that fails on the printer but looks fine in theory (ie. a move with faster speed than the printer can handle)

(3. something in the gcode that triggers a bug in the firmware)

I'd say 3 is the least likely. The only difference I see in the included file from layer 181 and up (that's the top feature) is different speeds, presumably it's slowing down to allow each layer to cool. Maybe that's what the blue means? Anyway, that certainly shouldn't affect X offset, but maybe it triggers something else? Can you see if the shifts usually happen where the speed changes?

The current slic3r doesn't have an optimal algorithm for choosing which line to print next, that's probably part of the reason for the different print times. I usually print at a base speed of 60mm/s or 80mm/s, depending on the parts, but I've done up to 120mm/s in tests. Looks like you used 80mm/s.

Cheers, Ketil

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-Ketil

[Steven Colgan]

Thanks Ketil I appreciate you going out of your way to help me. I think your right and I'm going to try to rule out the possibilities one by one.

I'm trying out slic3r and printrun instead of Simplfy to see if i can get consistently good prints. If i can then I can eliminate the hardware issue. If you use slic3r could you send me on a copy of your config settings? Im finding adjusting the speeds to be a very hit and miss process! 

Cheers,

Steve

[5sgte]

I highly doubt it's software.  I recently purchased the Creator software from Makergear and am still having consistent Y-axis shift issues on every single layer.  I haven't had a single good print and my M2 has essentially been a $1500 paperweight from the day I purchased it.

[Dean Piper]

You need to slow down your printing speed, or you are having 1 of 2 other problems. Your motors are being told to move faster than they can with the motor controller current and thus are under powered and skip steps, or they are turned up too high and are overheating. When they overheat they intermittently cut out and cause the skips you see. 

I think you are all on RAMBO boards so you will need to change your motor controller current via firmware.

Once you get the print speed and motor current setting dialed in, the skipping will stop.

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[Steven Colgan]

Sorry to hear that 5sgte, If i have any luck with mine Ill let you know and hopefully it will help solve your problem

[Steven Colgan]

Thanks for the reply Dean. 

I varied the speeds from 30mm/sec, 60m/sec to 80mm/sec and I have had the exact same result with all three models. Th x shift occurs in the exact same location, and the shift is identical in all three models, so I think I've eliminated the speed aspect. I am just going to slice the model using slic3r and run with printrun, it will be interesting to see if I get the same result for a fourth time today.

My board is indeed a RAMBO. How do I go about correcting the motor controller current? I bought my makergear pre-assembled so I am very unsure of how to go about this. I am a complete noob to 3D printing and my background is in woodwork, not engineering or electronics. I'm very nervous about going at board so pointing me in the direction of fool proof instructions would be great! 

[5sgte]

I am not sure that this is the case, as I've run a print at 15mm/s with the E0_Current increased to 200 with the same results; consistent Y-axis shift producing a build that is "leaned" over by quite a bit

[Dean Piper]

Considering you have tried slowing down, it is likely overheating or you have a bind in your linear motion somewhere in certain situations. I've had some prints in my past that are problematic like this but I have always gotten through it by slowing down or adjusting my motor controllers, or by finding a broken bearing or over-tight/loose belt.

I'm sorry I'm not sure if there is an easy way to adjust the motor controller current without writing and uploading a new firmware. Maybe someone else can answer that one for you.

Best of luck!

-Dean

[Charles]

5sgte I know very little about messing with firmware but could you explain why you increased E0_Current? I can't think how that would do

anything for Y-shift other than possibly getting more response from the extruder stepper motor.

[Dean Piper]

Charles is correct, I failed to notice you said you increased E current. You need to slow down and/or increase current on the axis that is skipping. If your extrusion is working reliably then there is no reason to adjust E current.

[Steven Colgan]

Hello everyone,

Sorry I haven't posted my progress in so long, and thanks for all the help! Turns out it was 99% human error and & 1% mechanical error! 

The gear/pully drive for the x axis pulley belt wasn't fully tightened and it had slipped down and was resting flush with the motor. I have since realigned and tightened it and I've had no x shift problems. I feel like a dope for missing it originally.

Thanks for all the help, I'm new to 3D printing and using forms and it was amazing to see so many people give their time and share their expertise while trying to help me. 

Thank you all again!