Material shrinkage - automatic compensation ?

[Juzer99 0]

If this is already solved please just post the link in response. I searched but could not find the answer hence my post here

 

I am correcting my prints for material shrinkage by scaling the parts by a factor I calculated from test prints using given filament. 

I have to do that for every new spool if I want very close tolerances and good fit.

 

An obvious question occurred to me - why not tie this parameter to the material profile and have Cura automatically compensate for shrinkage?

Well, it appears this obvious question did not yet occur to the Ultimaker programmers. Why?

[Juzer99 0]

18 minutes ago, Juzer99 said:

If this is already solved please just post the link in response. I searched but could not find the answer hence my post here

 

I am correcting my prints for material shrinkage by scaling the parts by a factor I calculated from test prints using given filament. 

I have to do that for every new spool if I want very close tolerances and good fit.

 

An obvious question occurred to me - why not tie this parameter to the material profile and have Cura automatically compensate for shrinkage?

Well, it appears this obvious question did not yet occur to the Ultimaker programmers. Why?

It appears this question has already been raised by Prusa slicer users

https://github.com/prusa3d/PrusaSlicer/issues/3078

https://github.com/prusa3d/PrusaSlicer/issues/4475

Hopefully someone will get it implemented and that will be the slicer I will use.

It would be nice if Ultimaker implemented it first.

[nallath 1,124]

Cura already has this implemented, but due to some issues that we had with finding the right values for materials (in the sense that it worked for all models that we wanted to print with it), the setting is disabled in the frontend .

However, you can set it if you change the material files.
 

<cura:setting key="material_shrinkage_percentage">100</cura:setting> 

You can also set it for XY and Z separately
 

<cura:setting key="material_shrinkage_percentage_xy">100</cura:setting>
<cura:setting key="material_shrinkage_percentage_z">100</cura:setting> 

 

[Juzer99 0]

Thanks for the answer. It is great the development already started working on it. 

While you are searching for the right values you could at least stick this parameter in Experimental section and let users find the value that works for them. 

That would be much better than having to scale EVERY object EVERY time it is imported onto the plate.

A lot of filament and productivity has been wasted because of this critical manual step in the process.

 

In any case, I would gladly set this parameter as you posted, however, paraphrasing the old Microsoft and the helicopter pilot joke, your answer is technically perfectly accurate, but unfortunately useless to me.

I design parts, I am not a programmer that knows the ins- and outs- of the software you are so close to.

Where do I find the "material files"?

I checked 

C:\Users\UserName\AppData\Roaming\cura\4.13\materials - folder is empty

C:\Users\UserName\AppData\Local\cura\4.13 - not there

C:\Program Files\Ultimaker Cura 4.13.1 - not there

 

 

 

[nallath 1,124]

I'm not on windows myself, but i think it should be in the program files one under resources/materials.

 

 

[Juzer99 0]

Getting warmer, but still not there...

The material files are indeed located in  C:\Program Files\Ultimaker Cura 4.13.1\resources\materials folder

But which section should I add the "shrinkage" key in? Under <properties>, <settings> or ...?

 

<?xml version="1.0" encoding="UTF-8"?>
<!--
Generic PLA 1.75mm profile. The data in this file may not be correct for your specific machine.
-->
<fdmmaterial xmlns="http://www.ultimaker.com/material" version="1.3">
    <metadata>
        <name>
            <brand>Generic</brand>
            <material>PLA</material>
            <color>Generic</color>
        </name>
        <GUID>0ff92885-617b-4144-a03c-9989872454bc</GUID>
        <version>8</version>
        <color_code>#ffc924</color_code>
        <description>PLA is good enough for draft copy

</description>
        <adhesion_info>Print on glass coated with glue or hair spray

</adhesion_info>
    </metadata>
    <properties>
        <density>1.24</density>
        <diameter>1.75</diameter>
    </properties>
    <settings>
        <setting key="print temperature">200</setting>
        <setting key="heated bed temperature">60</setting>
        <setting key="standby temperature">175</setting>
        <setting key="adhesion tendency">0</setting>
        <setting key="surface energy">100</setting>
        <setting key="build volume temperature">28</setting>

        <machine>
            <machine_identifier manufacturer="BIQU" product="biqu_b1" />
            <machine_identifier manufacturer="BIQU" product="biqu_b1_abl" />
            <setting key="print cooling">100</setting>
            <setting key="standby temperature">180</setting>
            <setting key="print temperature">180</setting>
        </machine>
 

[nallath 1,124]

Settings

[Juzer99 0]

I modified a copy of the Generic PLA profile. After adding the "shrinkage" key Cura reported an error:

"Your configuration seems to be corrupt. Something seems to be wrong with the following profiles:

-generic_pla_176

-MyPrinter_A10 #3

would you like to reset to factory defaults? Reset will remove all your current printers and profiles."

 

Any suggestions how to overcome this error? 

[nallath 1,124]

Ah. I see the mistake. Sorry. You should change

<fdmmaterial xmlns="http://www.ultimaker.com/material" version="1.3">

to
 

<fdmmaterial xmlns="http://www.ultimaker.com/material" xmlns:cura="http://www.ultimaker.com/cura" version="1.3">

 

[Juzer99 0]

No errors  now 🙂

I printed few test cubes with different shrinkage parameters. Results are not consistent.

Is this feature supposed to work the same way as scaling? 

A 5% increase in shrinkage parameter seems to produce results similar to 1% in scaling. 

[Juzer99 0]

Still testing different ratios, but it is better than setting the scale every time on every object.

Thank you very much to revealing this secret feature 🙂