Why does Nobody Cure their Resin 3D Prints like this? (40% more strength)

Resin 3D prints don't need to be weak! I investigated an alternative curing technique involving elevated temperatures that increased the strength of my parts by over 40%! Let's find out more.

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*Chapters*
00:00 Introduction
01:05 How 3D Printing Resin Works
01:55 Thermal Curing
02:45 Preparation
04:04 Thermal Curing Test 1
05:35 Strength Test 1
06:20 Thermal Curing Test 2
06:51 Sponsor
08:21 Strength Test 2
10:20 Impact Test
10:47 Twist!
12:11 Verdict

#3Dprinting #Resin #StrengthTest
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[CNCKitchen]

Does this open new possibilities for resin 3D printing?

[Kalvinjj]

One of the most important things for me in 3D prints for functional parts is creep. Rarely do I need higher than 60ºc temperature resistance, but often I do need parts to stay in shape while loaded for long times. This kills PLA for several of my projects, despite it's many advantages.
The same is true for the Formlabs Black resin, we also got the wash and cure station at work and we use the machine whenever we need to show pretty stuff to the costumers, but when it's time to make some functional prototypes to last field use, no no. It creeps way too much.
Creep tests is one thing I would like to see being explored more thoroughly, there's much more to part strength than short loads after all.
One thing I've often done with larger resin prints with heat is straightening warped walls. Large parts will sometimes get warped during printing or curing (specially that 60°c 1h curre that we go with the Formlabs station), a friendly Ender 3 with it's flat glass bed at 60°c for some minutes with correctly placed weights, then let it cool naturally until about room temperature, and we're good to go.
Same with PLA actually.

[C-M-E]

Evidently I need to make a resin-version youtube channel of CNC kitchen. When you devote 2 years to making graphene additives for photopolymer, the testing methods to get there paint a different story. Water-curing after an ultrasonic bath for specific formulas is also quite effective.

[Doyle]

I own a FDM printer not resin, but I use epoxy resin for projects and put them in the oven after it has had its minimum cure time.
I have always wondered why people never used heat for their resin prints and just presumed the resin used for 3D prints isn't possible, glad someone (you) have shown resin printer users this trick. Good work.

[nbeaudoin]

We post-cure our Siraya Tech and 3DMaterials resins immersed in a rotating hot water bath for at least 1 hour. The first 15 minutes are exposed to UV. The water will be heated to 60-80 Celsius depending on the resin used. Most of the time, the resin will be directly immersed in water, except those that are meant to be used at high temperatures or contain filles, such as ST Sculpt and Sculpt Ultra White. These will be put in a bag with light vacuum seal.
Most of the parts we make are meant for end-of-arm tools for industrial robots, manufacturing aid elements and injection molding tool components

[UncleJessy]

Heck yeah! I’m testing out a new resin and they sent me a toaster oven to test it out! Excited to see a detailed explanation of how this works

[nufnuf]

Hi Stefan! We print from BASF and Loctite resins at work (automotive prototyping) - and it is actually required to "bake" the finished prints for a while before UV curing. Not so high temperatures - around 40-50C for 30-60 minutes. So if manufacturers like these companies recommend it, there is actually some science behind :)
And with Siraya Blu You can even go higher - i did several tests up to 250 C - for 60 minutes. Interestingly - part remains in its original shape, but starts to crack at temperatures above 125 C. Resin prints dont melt into blobs as FDM prints - there are a lot of "undiscovered" areas of resin printing ...

[GregRosolowski]

I worked back and forth with siraya tech over a cunfusion with their blu mecha formula. One incredible technique the engineer told me to cure the resin 3D print submerged in water. I noticed a big difference in hardness and strength when doing this

[jedimario]

I print a lot of resin dental prosthetics we use temps anywhere from 20-60c for up to an hour depending on your curing unit. Some units use nitrogen filled chambers to cure while others finish cures in a 60c water bath .

[shurmurray]

Important addition: beside monomers, oligomers and photoactivator there is also up to 50% filler. Filler made of some organic molecules wich didn't parcicipate in polymerisation. They made part less brittle but also less strong. And may result in developing cracks in a part over time.
Cheaper resins usually have higher % of filler.

[sonkehaseloh]

What you mentioned about curing PLA vs resin is a usual behaviour of thermoplastics (everything on a FDM printer) vs. cross-linked materials (everything on a resin printer) and explained absolutely correctly. About your thermal curing experiment: nicely done. Many photoinitiators are also unstable towards thermal initiation, so I am not very surprised by your result without UV light, and any crosslinking reaction will be quicker due to heat (our old friend Arrhenius), but it's nice to see the data. I still admire your DIY tensile and impact testers.
edit: it might be interesting to do the same with non-transparent resin to see if the effect of thermal treatment is even higher compared to using UV light which would be expected since UV will not reach the interior of the part then or to vary the length of the curing to see if it is just an Arrhenius effect or you are actually starting new initiation reactions with the heat treatment.

[tomasdahuabe]

Not long ago I aquired a new resin printer and immediatly made a curing station with a 20 dollar used microwave that I salvaged (because I wanted something with a rotating plate and a timer) replacing the magnetron with a 405nm UV lamp like yours.
There's still two 220v terminals that were originally connected to both the normal microwave bulb and ventilation fan that I now could connect to a heater and have a fully automatic Curing and Heating station with a rotating plate and timer! I could also add a thermostat for safety

[GeorgMierau]

More SLA videos please! :) At the moment the resin printing community is sadly still at the stage "do I *really* need to buy a curing station?" as well as "do I *really* have to clean and cure my hollow prints from the inside?". But there are at least fewer people asking "but is resin *really* toxic?" and "do I *really* have to wear PPE?", which is nice.

[MoonWind]

I've been curing my abs-like resin in a very large glass container filled with water that I preheat with a old sous vide heater. Works fantastic. The water inhibits oxygen thus boosting curing rate, and it helps get far more even uv exposure!

[OddJobEntertainment]

Another banger Stefan. I always recommend your channel to newcomers to printing. Your scientific approach is such a breath of fresh air compared to so many other sources.

[cfaulkingham]

Nice work! My emake-3D resin cure station has a built in heater which I never used. I will have to give this a try.

[drewlatta]

Great stuff. Kudos to Stefan, I generally don't look for new videos in my YouTube subscriptions, but on weekends I always hope CNC Kitchen has a new video to watch while I workout.

[joshuafoster]

Last month the interlocking layers now a review of the curing its great seeing how a few ideas can really improve the usefulness of prints

[hazonku]

I actually discovered this by accident thanks to a messy house finch couple. Putting prints outside had been part of my post curing process already. I assumed it was more UV from the sun making the prints stronger but the finches knocked a part into the shade and it was still as strong as the rest. Turned out it was the heat.

[alexportiiii]

I bought a microwave convection oven with turn table and removed the magnetometer and installed a UV lamp in its place. It was a bit of work to invent a new control system, but it was worth it. I created a stand for my parts to insure even heat and UV exposure to prevent warping