Curing Question

Based on the results that was given from Formlabs at https://formlabs.com/support/finishing/post-curing-prints/ I was wondering if the temperature suggested impacts the materials performance or just the time it takes to completely cure the part?

To clarify, if I use just a UV light source such as https://www.amazon.com/Salon-Edge-Acrylic-Shellac-Curing/dp/B006QO4BRM/ref=sr_1_2?ie=UTF8&qid=1411571438&sr=8-2&keywords=uv%20nail%20dryer will the part if cured for long enough time have the same final properties as if it were cured by a heated chamber such as http://www.b9c.com/shop/b9-model-cure-post-curing-3dprinting for example.

Thanks to all those who respond, just looking for clarification since Formlabs states a temperature for optimized curing but they also suggested the Salon cure option above which obviously has no way to adjust temperatures.

It is my understanding that the nail salon device you have linked will cure just as well, it will just take longer. (I was told this by a FL support tech). I was also told by this support tech that they use the same salon item in the FL offices, so we also bought one. I was surprised to take out one of the bulbs to see it is only 9w, 365nm…well below the 405nm they recommend.

  • Kevin

Good to know, so a 405 nm source would only cure it faster and if it were heated it would do just the same but more quickly.

I just wanted to clarify, it doesn’t seem that clear in the Formlabs literature.

You are correct it isn’t 100% clear. Not to mention all I read about is 405nm. so when i learned FL uses those salon kits in their offices and they are 365nm I was a bit shocked.

Please don’t take my words as truth however…I am still trying to work this all out as well.

  • Kevin

The curing process is a chemical reaction. It’s governed by the Arrhenius Equation, which dictates how temperature accelerates the rate of chemical reactions. Basically, heat makes things go faster. But it’s an exponential equation. So twice the heat produces more than twice the acceleration. What the actual equation parameters are depends on details I don’t have about the resin. But it’s possible that UV light at ambient temperatures might never (in any practical sense) fully cure where a short time at elevated temperature would.

The 405nm is probably more important than temperature. I cure my parts in cold water with a 405nm laser pointer and they cure very quickly. Typically I go over the surface and it only takes a min or so depending on the part size.

I never tried curing under hot water so I don’t have a comparison.

Temperature does make a difference on the viscosity of the resin where warmer thinner resin gives a cleaner support side print and less chance of blobs or waves.

We’re not talking about the just the surface. The print needs a lot more than a few passes with a laser pointer to fully cure throughout. Each layer is not printed fully cured. It’d never come off the PDMS if it was. If you’re making display pieces it may not matter that the interior of the print isn’t fully cured. But if you’re making functional parts that need to take some mechanical load or shock, you have to get the entire print fully cured and that takes heat as well as light.

There’s a white paper someplace on the FL support site that explains why heat is so important to cure time and completeness.

Perfect! That is kind of what I was thinking in terms of functional parts but wanted something else to gauge it off of. So I am most certainly looking for a heating chamber as well as appropriate temperature adjustment.

Any suggestions based on that need? Considering FL only recommends the salon one shown above or other DIY solutions I am looking for some possible feedback to ensure appropriate function of a part.

http://www.santafesymposium.org/2016-santa-fe-symposium-papers/2016-a-new-method-for-preparing-3d-printed-acrylic-photopolymers-for-investment-casting provides an alternative solution courtesy of Jim Binnion.

I see what you mean. I noticed that with the way the laser draws the perimeter of the layers and does a sort of infill. I wondered if the interior was really fully cured and it makes sense how pliable a part is when first printed.
Once I cure the tackiness off the surface I usually just leave it on my desk. For functional parts though, the wall thicknesses are usually less than 1/8" if they are to be injection molded down the road so maybe just sitting a desk is sufficient.

With the castable resin I definitely see the need to fully cure the part prior to burnout. Solarez has what looks like a nice 405nm high powered lightbulb that should do the trick quickly but it can’t be run for long periods of time without burning out. Wonder if there are better products out there?
I have a 150 watt hotlight for lizards that is supposed to have uva and uvb but it really doesn’t do much but it does run warm.

There are plenty of examples of “home brew” curing boxes on this forum, including one from me that I highly recommend. Search for “budget curing jar” for mine, or similar themes for others.

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Based on the test results from FormLabs and just being a light source I think I am on the hunt for a heated solution. This could be a great lesson to learn for my students in the curing results if we vary heat and time.

Why doesn’t FormLabs JUST MAKE ONE!!!?

They would most certainly sell them.

Maybe they’ll do just that! You never know…

Well I am hopeful since they seem to be releasing new engineering materials!!:slight_smile:

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