Author Topic: Shrinkage?  (Read 454 times)

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Showme

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Shrinkage?
« on: March 25, 2025, 07:02:47 AM »
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  I am in the process of designing a non-dynamic brake filler for Intermountain SD40-2's. I have an original to measure from for dimensions, but I am wondering if I should slightly oversize due to the part shrinking while drying. Or, is this even an issue for N scale? My printer is an Anycubic Mono 4K and I have printed hundreds of items but never really paid attention to final sizes. This piece will be meant to fit with tight tolerances in a closed space.

Bob

John

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Re: Shrinkage?
« Reply #1 on: March 25, 2025, 07:38:27 AM »
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Resins will swell as it cures, including during the printing process .. You can print a cube of known size 20x20x20 - but not directly on the print plate - use supports)  then adjust the settings on your printer after you finished curing it .. don't forget the post print cure will also swell slightly .. You would probably need to do that for each bottle of resin ..

« Last Edit: March 25, 2025, 07:43:56 AM by John »

Chris333

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Re: Shrinkage?
« Reply #2 on: March 25, 2025, 07:56:32 AM »
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Just scale it down like 1% and see if it fits.

learmoia

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Re: Shrinkage?
« Reply #3 on: March 25, 2025, 02:38:26 PM »
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basementcalling

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Re: Shrinkage?
« Reply #4 on: March 25, 2025, 11:42:09 PM »
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And the Railwire never fails to disappoint. I knew that clip would be here before I clicked to open the thread.

 :scared: :RUEffinKiddingMe: :tommann:
Peter Pfotenhauer

peteski

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Re: Shrinkage?
« Reply #5 on: March 26, 2025, 12:41:42 AM »
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And the Railwire never fails to disappoint. I knew that clip would be here before I clicked to open the thread.
So did I. I was wondering just how long it would take for it to appear.  :)
. . . 42 . . .

basementcalling

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Re: Shrinkage?
« Reply #6 on: March 26, 2025, 01:11:38 AM »
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So did I. I was wondering just how long it would take for it to appear.  :)

Didn't Peteski's law say a RW thread will have the first off topic post within the first 4 replies? Not sure if that is truly an off topic post or not though.
Peter Pfotenhauer

Showme

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Re: Shrinkage?
« Reply #7 on: March 26, 2025, 06:54:57 AM »
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  Honestly, when I named my post, that episode never crossed my mind. Thanks for the bonafide replies though. I will try both of those methods.

Bob


Lemosteam

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Re: Shrinkage?
« Reply #8 on: March 26, 2025, 07:31:07 AM »
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Snicker, he said "bona fide".... :D :trollface:

Phrasing!

peteski

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Re: Shrinkage?
« Reply #9 on: March 26, 2025, 09:45:54 AM »
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Didn't Peteski's law say a RW thread will have the first off topic post within the first 4 replies? Not sure if that is truly an off topic post or not though.

I know you're joking, but it is not that simple.   :P
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GGNInNScale

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Re: Shrinkage?
« Reply #10 on: March 27, 2025, 10:41:44 PM »
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Here is the data:
"Photosensitive resin 3D prints do shrink as you print and cure your models. Typically, a linear shrinkage of approximately 3% can be expected. Shrinkage occurs due to a chemical loss of volume due to the polymerization reaction, accompanied by thermal contraction during cure cool down."
"...Shrinkage of resin 3D prints is unavoidable due to changes in temperature and molecular structure of the resin as it solidifies. Excessive resin shrinkage causes your prints to deform, also referred to as warping."  Source:  Printing It 3D

Also, the amount of shrinkage will depend on the base chemistry of the resin, the amount of carrier fluid, and temperature (small effect as thermal expansion is about 1 part in 10^5 per degree)