Resin 3D prints have been known to go through shrinking in some cases, so many users wonder if they have to do something to prevent shrinking or to fix it. I wrote this article to show users some potential fixes for shrinking resin prints.
Keep on reading through this article to learn more about this topic.
How to Fix Resin Prints Shrinking
To fix resin print shrinking, you want to use resins that offer low shrinkage since they are designed to reduce shrinkage in the final parts. You can also do some exposure tests to learn the optimal exposure time for your resin, and do your post-processing quickly so that it doesn’t have extra time to shrink.
Here’s how to fix resin prints shrinking:
Use Low Shrinkage Resin
Use Optimal Exposure Times
Increase Wall Thickness
Add Supports in Better Positions
Scale Up the Resin Prints
Start Post Processing Quickly
Cure on a Rotating Turntable
Cure at Low Temperatures for a Minimum Time
1. Use Low Shrinkage Resin
One method to fix your resin 3D print shrinking is to use a resin with low shrinkage, such as Siraya Tech Fast ABS-Like Resin or ELEGOO ABS-Like Resin. Cheaper resins are more prone to shrinkage because they don’t have strong atomic bonds and are of low quality.
The average linear shrinkage for most 3D printing resin is 3-5%. Many users have got good results by using low-shrinkage resins such as Elegoo ABS-like resin as it has an average linear shrinkage of 1.10-1.40%.
You can make even better and more durable resin 3D prints by combining the low-shrinkage, strong, or flexible resin with regular 3D printing resins. Doing so will fix shrinkage along with other issues like warping.
2. Use Optimal Exposure Times
Another way to fix resin print shrinking is to get the right exposure time for resin 3D printing. Setting the right exposure time will ensure that the resin cures properly during the printing process.
Don’t let the temperature in the 3D printer exceed too much and use a less powerful light source for the appropriate time to reduce the chances of shrinkage to a minimum.
Under-exposure will result in resin prints not curing properly while over-exposing can bring comparatively better results but you should always go for a perfect balance.
This video suggests simple exposure tests to get the best exposure calibrations for your resin 3D printer.
3. Increase Wall Thickness
Another method for fixing resin 3D prints shrinking is by increasing the wall thickness, the default value in most resin slicers is between 1.5-2.5mm. When resin 3D prints are being cured layer by layer, the process of shrinkage and expansion is also happening inside.
If your model’s walls are too thin, shrinkage can happen as the model doesn’t have a good foundation or strong areas to stick to and stay in shape. Users believe that making the shrinking areas a bit thicker will allow the model to remain in the shape more perfectly.
Along with the wall thickness, the overall shrinkage will depend on exposure time and techniques used for post-processing. Thicker walls can bring strength, durability, and minimum shrinkage while making post-processing a bit easy as well.
4. Add Supports in Better Positions
One of the better ways to fix resin print shrinking is to add an adequate amount of support to your 3D model. The strong supports hold the models in their original shape even during the post-curing process and prevent deformation to a good extent.
A lot of shrinkage can happen due to not having good supports for the model to build upon.
Check out the video below to see how to position and support models in ChiTuBox.
5. Scale Up the Resin Prints
One easy method to fix resin shrinking is to simply scale the resin prints a little bit up. Scaling up means printing a bit bigger 3D model than you actually want it to be in the end. One user suggested reading resin properties to see how much it shrinks.
Another user said that he prints a disk 1” in diameter (the larger, the better) and then measures it using calipers. This gives an estimation of how much the resin 3D print can shrink so you can scale accordingly.
Suppose you printed a 20mm cube to test shrinkage and measure the side length after curing and cleaning. Divide the measured value by 20 and then multiply by 100 to get shrinkage in percentage.
One user said that scaling up may not always work because sometimes it can result in negative spaces like a hole and make the 3D print even worse. So, test print to see what works for you.
You may be able to scale up an object by around 2% for a rough accounting of shrinkage, though you always want to do your own measurements to see if you are actually experiencing shrinking in your parts’ dimensions.
6. Start Post Processing Quickly
A good trick to fix resin print shrinking is to start post-processing as soon as the printing process is completed. Many chemical reactions are going on inside the 3D model printed with liquid resin and letting it sit can affect its shape.
Once the printing process is completed, your first step should be to clean the 3D model to remove resin from its surface and cure it. Removing supports and smoothing the surface should be done afterward.
7. Cure on a Rotating Turntable
Another good way to prevent resin print shrinking is to have a UV light Curing Station with a rotating turntable. This will keep on turning the model during the whole curing process ensuring an evenly cured model from all angles.
The Anycubic Wash and Cure is a good choice and you can buy it from Amazon. The 360° rotating curling tables combined with the bottom reflector with no dead ends ensure balanced curing of the whole model. The light source intensity distribution is uniform which ensures a smooth surface.
8. Cure at Low Temperatures for a Minimum Time
A method suggested by many users to prevent resin shrinkage is to cure the 3D prints quickly at a reduced temperature.
UV lights emit heat when curing a 3D model, so make sure you don’t have your resin print too close to the UV light. You want to have it at a decent distance, and make sure you aren’t curing it for too long.
Curing for a longer time can cause the delicate or thin areas of the resin 3D prints to shrink because of too much exposure to UV lights. Over-curing can also lead to other resin 3D print issues such as warping.
The Siraya tech fast ABS-like resin is a good option when it comes to low shrinkage. The resin helps in printing 3D models with high precision, wear resistance, rigidity, strength, and ease to post-process.
Its properties make it suitable for a wide range of applications and 3D printing projects that require higher dimensional accuracy such as industrial parts, tools, covers, cases, etc. Compatible with MSLA, LCD, DLP, and 3D printers of many other brands and types.
ELEGOO ABS-like resin is another good option if you want your resin 3D prints to have minimal shrinkage. It is specifically developed to reduce volume shrinkage in 3D models during the curing process.
This helps in getting 3D models with high precision, dimensional accuracy, and a smooth finish. The resin is compatible with almost all kinds of resin 3D printers such as DLP or LCD. However, it works better with LCD resin 3D printers.
One user said that it is nothing but great all around because he mostly prints functional parts with little shrinkage. The accuracy is so spot on that he doesn’t have to scale the parts. Though he uses one, you can print resin 3D models using ELEGOO ABS-like resin, even without a heater.
One resin suggested by many users and experts for low shrinkage is Phrozen Onyx Rigid Pro 410. It is best suitable for miniatures because of the high detail, precision, and accuracy it offers.
It is an industrial-grade resin that is specifically developed to be used in a wide range of applications.
One user said that the resin has a good balance between rigidity and flexibility. There was surprisingly zero shrinkage when he measured the printed model using digital clippers.
The resin is a bit more viscous and takes longer layer exposure time but as far as shrinkage is concerned, it is worth the trade-off.
With an exposure time of 42 seconds for bottom layers and 6 seconds for normal parts, he is getting good results on the Photon Mono resin 3D printer. Do keep in mind that curing times will vary widely depending on what 3D printer you are using, so do some of your own exposure tests.
This Sunlu 3D printer resin is another great choice for a resin that has a low shrinkage and high precision. It cures fast when hit with the standard 405nm UV light from a resin 3D printer or the curing machine.
There is a wide compatibility with various 3D printers and it’s easy to use. A benefit of this resin is how it’s easy to clean and has a light odor which doesn’t linger like other resins.
The bottle design was made to be leak-proof and has a strict packaging process to reduce damage to the bottle during transportation.
Michael Dwamena is the founder of 3D Printerly, a platform dedicated to simplifying 3D printing for hobbyists and professionals alike. Owns over 20 3D printers (filament and resin) and has plenty experience 3D printing. Michael has authored over 900 articles, helping millions navigate the exciting world of 3D printing.
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