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owen

Big blobs on short layer, fast prints.

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When printing the cylinder for Netfabb Calibration, printing just the outer skin so basically a single wall tube, I get a big blob when the Z goes up one layer.

For the following half of the layer it is very uneven and thick and then returns to smooth again for the next half before it reaches the next Z move.

It doesn't start till about 6 layers in to the print.

If I print slower it doesn't happen.

Initially I thought it was communication so I printed direct from Netfabb on a different faster machine with the same result.

So I printed a cube with the same circumference (15.7mm sides). Same result.

If I print the same thing slow it's OK.

If I print the cylinder scaled up 3 times in the X and Y it's OK.

So basically it seems to happen if the Z is doing many moves in a given time.

The Z motor feels warm, not hot.

I get a slight change in behaviour if I adjust the pot on the Pololu stepper driver board.

I think the stepper driver board or the Z motor is crook.

I have a spare of each so I will try them tonight.

Just thought I'd put it up here in case someone knows what it is or comes up with the same problem.

Owen

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I think the stepper driver board or the Z motor is crook.

I have a spare of each so I will try them tonight.

Owen

I put in a new stepper driver and Z motor and no change.

I'm using the latest Marlin firmware with no configuration changes.

I notice that when it happens the X and Y motors stutter as the Z motor steps.

I'm thinking of electronics now. The bottom fan is going and this happens straight after turning on so it doesn't seem heat related.

Anybody got any ideas?

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Hi Owen!

Your Problem reminds me at a problem that I had. I visited Florian (floush) and we came across a problem that NetFabb made Blobs at every? layer at the same position. He told me the solution for MY problem!

First, I have Marlin from github g9f57cdd from the october 16th.

In the firmware the default-Acceleration for z-Axis is set to 150 (DEFAULT_MAX_ACCELERATION).

We raised this value to 300!

You should set the new value with the M203 and store them into EEPROM.

The above mentioned github version has a Bug however -> it doesn't report back the EEPROM-Values, so you should use a later version that is known to work;-))

Then in NetFabb under Ulitmaker/machine settings/General settings you can enter the max z-acceleration of netfab: we changed it from 0.?? to 10m/2^2!!

This solved MY problem of z-Axis-Blobbing.....

Hope this helps a little bit ;-)

Best regards,

Toni

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Hi Owen!

Your Problem reminds me at a problem that I had. I visited Florian (floush) and we came across a problem that NetFabb made Blobs at every? layer at the same position. He told me the solution for MY problem!

First, I have Marlin from github g9f57cdd from the october 16th.

In the firmware the default-Acceleration for z-Axis is set to 150 (DEFAULT_MAX_ACCELERATION).

We raised this value to 300!

You should set the new value with the M203 and store them into EEPROM.

The above mentioned github version has a Bug however -> it doesn't report back the EEPROM-Values, so you should use a later version that is known to work;-))

Then in NetFabb under Ulitmaker/machine settings/General settings you can enter the max z-acceleration of netfab: we changed it from 0.?? to 10m/2^2!!

This solved MY problem of z-Axis-Blobbing.....

Hope this helps a little bit ;-)

Best regards,

Toni

Thanks Tony

My Netfabb setting was right and I changed and saved your suggested settings in the EEPROM. Though M203 was 10 and changing to 300 was too much, so I changed it to 60. If you meant M201 it was 150 but it doesn't report back that it's changed when I send M201 Z300. I also tied changing M205 from Z10 to Z300 but that was too much and I ended changing it to 20. None of this worked. I Uninstalled and cleared Netfabb as per the instructions and replaced all Stepper Drivers to no avail. When I scaled the Cylinder in the X axis only by 1.5 it doesn't start the rough extrusion to a while after the Z move and then settles down again before it gets back around to the next z move (Picture included).

Ultimaker Original+ Press Kit.zip

The X, Y and E Motors are all new and bigger and replaced since I first noticed this. I think it may be in the electronics but I'm still open to ideas if anyone has any thoughts.

Thanks Owen

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Hi Owen!

Damn, I remembered wrong!!

It was not the MAX_ACCELERATION (this is OK in the firmware -> M201) but it was

DEFAULT_MAX_FEEDRATE! This is set by default to 10 for the z-axis!!!!! This value you should increase to 150 or something above that!

You use for this the M203-Command for Max-Feedrates: for example M203 X200 Y200 Z300 E10000 (from Marlin-Wiki-entry)!

Maybe you print out the values before the change to check them.......

Please excuse my fault..... but I think this is the solution to your problem -> your picture shows exactly what I had!

Hope this solves it!

Best regards,

Toni

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Thanks Toni

I did attempt changing the M203 Z setting to 300 but the Z motor made a high pitched noise and stalled.

I tried 200 and I think 100 but was also getting the high pitched noise and stalling.

I have currently it set to 60 but it doesn't fix the problem.

I'll see if I can adjust the stepper driver pot tomorrow to increase that number and see if it helps.

Otherwise I have another big stepper motor that I could replace the Z-motor with, then I'll be able to turn it up for sure.

I'll keep you informed.

Owen

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Hello Owen!

I am sorry to hear that you had still no luck solving this problem......

For your reference I put down my marlin-Values so maybe you see some difference to yours:

 

[17] echo: stored settings retreived:[17] echo: steps per unit:[17] echo:    m92 x79.872 y79.872 z533.000 e14.000[17] echo: maximum feedrates (mm/s):[17] echo:    m203 x160.00 y160.00 z150.00 e500000.00[17] echo: maximum acceleration (mm/s2):[17] echo:    m201 x9000 y9000 z150 e10000[17] echo: acceleration: s=acceleration, t=retract acceleration[17] echo:    m204 s4600.00 t7000.00[17] echo: advanced variables: s=min feedrate (mm/s), t=min travel feedrate (mm/s), b=minimum segment time (ms), x=maximum xy jerk (mm/s),  z=maximum z jerk (mm/s)[17] echo:    m205 s0.00 t100.00 b20000.00 x30.00 z10.00

 

I dialed down minimum travel because I was seeking another error ;-)

Maybe it helps in some way......

Best regards,

Toni

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Thanks again Toni

I put in your settings exactly but still no change.

It also stalled when returning Z to Home so I've gone back to Z80 on the M203

I'll probably try a bigger Motor for the Z Drive next. I'll have to print some of those feet to Raise my UM first though.

I'll keep posting my progress to here.

It's not that critical really.

It will only effect me on the calibration cylinder unless I scale it up in the X and Y or else if I print a vase or similar that is less than 25mm Diameter.

But I guess I have to fix it now at least just to find out what it was.

Owen.

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Well I put in a bigger motor and changed EEPROM settings today, shortened and re-routed wiring. Still no change.

I have noticed today that if I let the cylinder print go to the end that at top the blobbing actually occurs before the Z-movement.

So it may be related to X or Y movement.

I will check the couplings on the shafts tomorrow.

Owen

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Hi Owen!

Your Problem reminds me at a problem that I had. I visited Florian (floush) and we came across a problem that NetFabb made Blobs at every? layer at the same position. He told me the solution for MY problem!

First, I have Marlin from github g9f57cdd from the october 16th.

In the firmware the default-Acceleration for z-Axis is set to 150 (DEFAULT_MAX_ACCELERATION).

We raised this value to 300!

You should set the new value with the M203 and store them into EEPROM.

The above mentioned github version has a Bug however -> it doesn't report back the EEPROM-Values, so you should use a later version that is known to work;-))

Then in NetFabb under Ulitmaker/machine settings/General settings you can enter the max z-acceleration of netfab: we changed it from 0.?? to 10m/2^2!!

This solved MY problem of z-Axis-Blobbing.....

Hope this helps a little bit ;-)

Best regards,

Toni

Is Florian on this forum yet ?

Ian

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keep us updated on what happens owen.

I am very interested to hear what happens.

can you still produce other models using the ultimaker or is this blobbing accuring for every project ?

Ian

It only happens printing the number 7 calibration ring. Which is a small layer, thick and medium speed. If I print the same thing faster it's wore. Pretty sure it's worse if I do it at a higher temp as well. Slower or thinner ring is OK. In order to print that ring I scale it up by 1.5X in the X and the Y and then no problems.

I have tried many different firmwares and checked mechanics and most electronic bits. It doesn't effect about all of my printing so I'm not going to worry about it anymore, though I'll try other things as I think of them.

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Today this problem diminished when I printed the same Calibration cylinder at 10 Degrees less (183 Degrees) and nearly vanished at 20 Degrees less (173 Degrees).

When it nearly vanished it didn't occur till the top of the cylinder.

It was only for about 20 Degrees around and a much smaller amount.

The plastic was quite dull but was sticking together OK.

It was about 0.6mm thick instead of the 0.8mm average at the higher temp (193 Degrees) which could be expected.

Maybe if I stepped up the extrusion to make a 0.8mm line at this temp it may be just as bad.

These are the things that change it.

 

  • It's worse at higher speeds.
    Worse if pushing out more plastic.
    Worse at higher temp.
    Less for a bigger circle.

 

It almost seems centrifugal force related with the above symptoms.

What I don't get is why it doesn't start till part way up the tube. Unless it is somehow Buffer related.

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