phrozen Rock-Black Stiff 3D Printing Resin (1KG)

Used it to make prototype automotive grade pieces. prints nicely, good stuff. Not sure what is meant by "sheerness" in the evaluations rating area.

Do not follow the cure times listed in the details. Those are insanely high, most likely for colored screens. If you dig hard enough you can find so.e settings on their site. Personally I go's the best results with 1.8 seconds a layer instead of their insane 10 seconds listed on here.I could find no information on post cure or clean up though.For ruch an expensive resin, I'd expect real documentation.This does cure about 1.5 - 2x faster than Siraya blu black nylon. Both are extremely difficult to break, but this is for sure stronger. That being said, it is clear so you are going to lose details compared to an opaque. And supports are extremely difficult to remove so make sure you place them in a location accessible to some type of cutter.

Toughness is the mechanical property of resisting breakage during an impact. phrozen Nylon-Green Tough has tested to be the most impact resistant of any material I have used. It's ability to withstand breakage due to an accident is nearly as good as laser sintered Nylon-12. I test resin prints with a standard size test specimen in my Izod test stand. It's much tougher, nearly 1-1/2 times as much, at resisting impact breakage than either Tenatious or eSun Hard-Tough. Standard ABS-like resins are not even close, at around 4 times tougher. It has nearly double the toughness compared to PETG and more than double the toughness of PLA or PLA+ filament. Print detail is good, but not as good as a strong resin, like eSun Hard-Tough. I do admit that I may need to dial in settings a bit because the Nylon-Green Tough prints are not very forgiving around supports because resin gathers and makes a slight build-up. Perhaps it's lower viscosity? At any rate, toughness trumps printing problems for me.

This stuff is fantastic if you need to make functional parts with impact resistance. Good printability (better than Siraya Tech Blu in my opinion, it's not as dependent on ambient temps) and good print resolution. All-in-all I love it, but I won't be wasting it by printing miniatures with this stuff (too expensive); save it for the important prints. 10/10, would recommend. NOTE: In the pictures, I have dyed both resins black.

Although the prints were strong and acurate, a FULLY CURED test was placed in a glass of water for about an hour and significantlly degraded. Fine for dry testing before sending out to an SLS printer.

I've gone through 2L of this resin and find that it makes durable, hard parts. Most of what I have made are tools and fixtures for performing other shop tasks, and for this it is an excellent resin. My only complaint is the appearance of the cured resin. It has an almost neon navy blue appearance in sunlight, and purple/red when sun is going through it, not even close to black. Indoors in poorly lit conditions, it looks like it's black, but you can see light through anything less than maybe 2mm or 3mm thick. It's definitely not opaque.While the first photo does not show the color the way it looks in person outdoors, it is pretty accurate for how it looks indoors or in low light. The part is a MT3 fixture to hold the knob also in the photo. A .002" slip fit was designed, and the actual fit feels pretty much as expected, meaning it holds a reasonable size tolerance. After curing and installing into a metal lathe, the runout of the fixture measured at less than .001" with a digital dial indicator, which was way better than I would have ever guessed. I've had steel MT3 collet holders with more runout than that. I suspect that this resin would work great for making soft jaws for a chuck holding delicate parts, or other mechanical uses along those lines. I've made a pinion depth gauge tool, which seems to have similarly held excellent tolerance.Most of the parts I've printed are completely solid and time will tell if there is warping or distortion, but my impression is that this will probably not be a problem. The parts are very hard, and where I have tried sanding them, they sand to a fine powder very nicely. The MT3 holder pictured fell 4 feet onto a concrete floor when I tried to knock it back out of my lathe spindle and didn't have so much as a scratch. I put it back in and re-measured the runout to see if the impact changed it's dimensions, and it had the exact same runout of less than .001". It is a very durable resin, though it is a little on the brittle side and is durable simply because it is very hard and very strong, not because it has any elastic properties.Do not clean in anything waterbased (Simple Green, etc.), this seems to make the resin kind of gooey and even seems to prevent good curing. That also includes lower alcohol content IPA, stick to 90% or higher. I've had my best luck with denatured alcohol. Does not take very long to clean and it is not recommended to be in alcohol for longer than 30 seconds. I have had good luck just dunking the parts over and over for around that amount of time, then blowing the parts off with an air hose.So in summary, this is an excellent resin from a functional standpoint, but not a great resin for aesthetics. I will likely buy again for future fixture purposes as it has been very reliable (zero failed prints) and has exceptional dimensional stability critical for shop fixtures.On a Creality Halot Sky, I have found best results at 3.8 seconds with a .03 layer height or 4 seconds with a .050 layer height. First 6 layers I expose at 45-60 seconds each with good adhesion to the build plate. That said, in several cases the parts fell of the build plate during an initial dunking into the denatured alcohol, which makes me think that this is right at the lower limit of exposure time to start a print. I get the feeling I'm right at the edge of having the parts fall off the build plate during printing and would not recommend going any shorter than 45 seconds for those first layers, though my build plate seems to be a little slippery even though it is textured.Last, this is a somewhat expensive resin compared to other products, but if you are looking for a resin that is hard, durable and dimensionally stable, this is probably worth the cost. The fixture pictured probably cost around $10 but it is exceptionally accurate and very durable. If I remember, I will check back in a year after re-measuring the runout and dimensions to see how stable it is long term.

I agree with the other reviewers comments regarding lack of paperwork for exposure times, clean up/washing, and cure times. Needed to do tye cones of exposure test to get exposure times for layer height needed.