Anyone ever heard of attempts to use two-part epoxies or other chemically-catalyzed resins for 3d printing? It seems like you could get the material cost pretty low if you could find a way to inkjet-print MEKP (or a suitable substitute) onto a layer of polyester resin (~$20/gallon). I wonder how the exothermic reaction would effect the layered curing process.
This is an interesting idea though from our experience, say MEKP catalysed Polyester resin would take too long to cure, making a painfully slow print process?
I think you have to mix them before printing and use a little MEKP so that it hardens but very slowly. If you would just print the MEKP on the resin it will not harden evenly.
I`ve worked a lot with resins for car-repair and if the resin is not mixed well with the MEKP it takes days or weeks to harden or it never hardens.
But i think it should be possible to print. Even polyester putty should be printable with a pastruder.
There is this arduino inkjet printer shield available:
Mounting two syringes with steppers (there are a few paste extruders on thingiverse) with a disposable mixing block would be possible.
There are epoxys (sorry, no Link) which need uv-light for harden. So maybe ad a LED near to the nozzle
UV cured epoxies would be more similiar to the DLP printers like the form1 probably. The thing about catalyzed expoxy is the cure time feels pretty hit and miss, or can it be “tuned” to be pretty precise?
I lead a research project in Spain developing a material that will be used to 3D print combustible sculptures. Our material is based on wood dust plus a monomer that hardens with UV light. Low cost is an important factor for us, using water as a solvent helps.
HI Miguel, is your material more for a DLP machine than a FDM machine? Sounds amazing that you’re working on it really!
@Funbie_Studios Our system is based on a cartersian robot but source material is a paste like clay, that is extruded and later becomes a solid due to the monomer polymerization caused by UV light. It is mostly FDM but raw material is not fused. We aim for a non-toxic combustion byproducts too.
It would have to be low viscosity enough to allow overhangs and bridges yes cure slow enough to bond with the next layer.
And you can no longer pause a print, raise the tool and continue 8h layer, when you are back from work.
@Marcus_Wolschon overhangs are not something we are considering at the moment. But actually, we can stop a print for quite a while, as UV source is what triggers curing and it can be switched off.
Does the UN uncured material slowly flow away and ruin straight vertical surfaces?
@Marcus_Wolschon Best viscosity level has yet to be determined, we are still working at it, and our curing times are not fast enough at the moment.
So cool to hear research on this is happening! Any chance there’s some information online or some website documenting this? =)
@Funbie_Studios There is not much to show yet, other than some Petri dishes with cured material at different densities. We are in the process of building our cartesian bot (quite arger than a RepRap). I will be posting an entry in 3D printing community once there is any decent progress in the project.
@Henrik_Peiss don’t use steppers with a syringe. Use air pressure.
Actually, I was thinking you would over-extrude the resin and then selectively cure it. My idea was to avoid UV-activated stuff and just inkjet print a chemical catalyst. With the right viscosity, the un-cured resin would act as a support and would just be rinsed away afterward.
@Marcus_Wolschon what is wrong with a stepper with a syringe? I work with different medical syringe pumps before, all of them are based on steppers. They can handle volumina with an accuracy of nano liters.
@Whosa_whatsis Some initiators are heat-based (instead of UV) but it is difficult to be selective with heat. On the other hand, deep UV light of certain intensity is difficult to achieve with LEDs http://www.roithner-laser.com/led_deepuv.html and you do not want to know the price.
Your idea of printing the initiator over a monomer might work, as the areas without initiator won’t cure as fast or at all. But I am not the Chemistry guy on my team.
@Henrik_Peiss the problem ist oozing when you stop the stepper since the pressure is still there. Opening an air-pressure valve however releases all pressure instantly.
Okay, how to build up the air pressure? A stepper is pressing an air filled syringe or builds a peristaltic pump?