Nozzle tolerance

[aabfm 0]

Hi,

I've recently changed both the x and y axis motors and the nozzle (0.4mm).

Whereas before I always took in consideration 0.2mm of tolerance 'around' my prints (for instance a 10x10x10mm cube would 'grow' 0.2mm on all 4 sizes becoming a 10.4x10.4x10mm cube, or designing it as a 9.6x9.6x10mm and then the result would be 10x10x10mm), now it doesn't! I've tried to calibrate the number of steps but it's becoming annoying to say the least... If I set it to 100steps per 10mm it returns exactly a 10x10x10mm cube. And, if I compensate for the tolerance, bigger parts grow accordingly... (for instance a 60x10x10mm brick grows approximately 1mm to 61x10x10mm).

My problem is that all my previous designs have always been designed taking into consideration this tolerance issue, and therefore, if I print them now they'll come out with the wrong size.

Bottom line: is there a way to set Cura to have the printing head following the exact size of the part in the STL file so that it will grow 50% of the nozzle diameter in every direction? For instance a "Ignore nozzle size" kind of setting...

Thanks in advance.

AM

[GregValiant 1,248]

Given a line width of 0.40 and a 10mm cube - Cura's Outer Wall toolpath will be 9.6 by 9.6.  Adding 1/2 line width to each side of the cube that comes out to your model dimensions of 10 by 10.

There are a couple of different settings to adjust that.

• Use the "Scale" tool and scale the model by a dimension rather than as a percentage.
• You could use Horizontal Expansion set it to 0.20.
• In the Material section as some scaling settings for shrinkage.  Rather than a hard number they scale as a percent so the larger the part the more "offage" you get.  Scaling a 10 x 10 cube to 96% would make a smaller toolpath and the 10mm cube should be correct, but a 100mm cube would print at 96mm.
• I don't know if you are on windows, but MS 3D Builder has some decent tools for altering model files.  You can scale them in Builder and then bring them into Cura.

The problem I see here is that you had a workaround because your printer wasn't accurate.  Now that it is accurate, you want Cura to make adjustments.  That's fine, but it's always better to give Cura (any slicer really) the model you want rather than one that is "close except for...".

  

 

 

[aabfm 0]

Thanks for the reply.

 

BTW, I might have found the solution...

In this link, using "Slicing tolerance" parameter and set it to "Inclusive" may do the trick. I'm going to give it a go and I'll come back with the results shortly.

[aabfm 0]

BTW, it's kind of a strange "accuracy" issue after all the printer was printing find apart from that offset, i.e. look at the following examples of what use to happen:

- Ex 1: Cube 10x10x10mm would print 10.4x10.4x10mm;

- Ex 2: Box 60x60x10mm would print 60.4x60.4x10mm;

and now it prints:

- Ex 1: Cube 10x10x10mm would print 10x10x10mm;

- Ex 2: Box 60x60x10mm would print 60x60x10mm.

Thus, the scale factor can't really be applied...

 

Horizontal expansion may be a workaround - another test for me.

 

[GregValiant 1,248]

If the models are consistently printing 0.4mm too big regardless of the size of the model then yes, the shrinkage settings won't help.  Actually scaling the model in Cura is still an option as you can set the actual dimensions (rather than setting a percentage).

 

If there was a problem with the steps/mm of your steppers then that would show up as a "scale" issue as the error would be cumulative over any distance.

 

The more I think about this the odder it seems.  Load a calibration cube and use the "File | Save Project" command and post the 3mf file here.  It could well be a setting issue.

 

[Phil0110 0]

Check your printer's firmware settings: Make sure that the steps/mm values for each axis are correct. These values determine how many steps the motors need to take to move the axis a certain distance, so it's important that they are set accurately. You may need to adjust these values after making changes to the printer's hardware. Calibrate your extruder: The extruder is responsible for pushing filament through the nozzle. If it is not calibrated correctly, it can lead to under or over-extrusion, which can affect the dimensional accuracy of your prints. Adjust your print settings: In Cura, you can adjust various print settings that can affect the dimensional accuracy of your prints, such as the extrusion width and flow rate. Experimenting with these settings can help you achieve better accuracy in your prints. Consider designing your parts with a smaller tolerance: If you are having trouble with parts coming out too large, you can try designing your parts with a smaller tolerance to compensate for the changes in your printer's hardware.