So what is the verdict guys ? Can we get an opinion of the differences between the Tough and Durable with some comparisons ? I am also considering getting the Durable. One thing I found with the Tough (And here I must state I am using Tough v2 which was the latest version available here in South Africa when I bought) is that the spring memory is really weak. I printed this buckle clip https://www.thingiverse.com/thing:1074129 to test the tough resin for the clip function but the side clips when pushed in to release the clip did not really return to their original position.
I did cure the prints in the sun so for the sake of this conversation lets say curing was done correctly. What do you guys think could be the issue and do you think the Durable resin has some spring memory ?
Durable has even less spring memory. That said, There is enough memory in the material for most parts.
If you have problems with the Durable not holding shape itâs likely due to IPA left in the part. IPA makes the parts swell slightly and become soft. Parts should be allowed to completely dry before post cure. Not just dry to the touch but dry including internally. Then post cure.
You have to really cure the durable to get it to be reasonably hard. If itâs too soft itâs probably not cured enough. Tough is similar and needs a bunch of cure to get hard enough for springy applications.
My favorite comparison for the different engineering resins is at the bottom of this page. Tough Resin V4 is going to be well suited for buckles. The Youngâs Modulus (correlates with stiffness) is much higher in Tough Resin V3 and V4 than earlier versions and works especially well with snap fit mechanisms. Durable is going to be less ideal for snap-fit mechanisms and is more optimized for high wear resistance and impact resistance.
I canât offer up a true comparison as I have only now tried ToughâŠmy comments will be anecdotal at best. I have printed a few parts with Tough now. After curing for many hours the pieces withstood dropping on concrete and light hits with a hammer.
The parts I created were for a client who is a pool maintenance man. He designed a handle that goes around his skimmer pole to easily allow him to extend and grip the skimmer with one hand. He has been using it in real life conditions and loves it. (our original print in standard white resin broke on first use).
So I am a few prints into tough and I am hearing from my client he is not so satisfied with the (in his words) ânot so tough, tough material.â
I believe he is second OPing it either with a lathe or a drill press. He isnât being completely truthful with me. The item is some sort of a handle for a pool skimmer for a pool maintenance man.
The first one he gave straight to the guy and I guess in real world conditions is working fairly well. The next 3 he tried some sort of second op and each time has broken.
I am now printing the 5th iteration of the same item. Each he has made slight changes to the STL.
I guess my questions are thus.
This item in toughâŠhow long should I be curing it? I figured about 3-4 hrs was enough. need more?
Is second OPing a durable printed object asking too much?
SLA and FDM 3D printers are not a replacement for injection molding. The parts they make are âfunctionalâ but will not be as strong as something youâd get from, for example, an ABS injection molding process.
The workflow for a heavy duty part would be prototyping for form/fit with the Form2 before committing to a hard tool for volume production. If you want a 3D printed plastic part thatâs close to the same mechanical properties as a molded plastic part, you need to go with an SLS machine.
Prototype your parts with your Form2 and then have Shapeways print final parts with SLS and they will be fully functional (albeit more expensive).
While I would agree that an SLA part is never going to fully replace an injection-molded part, you can probably get away with what you have with a few modifications.
Seems like you are probably over-curing it. It is supposed to be a 120-minute cure at 60*C. That might be your issue.
You can also try and have your client run the second op while the part is still green (before you post-cure) and that might help.
Depending on what the second op is, I have found you canât take too much material off with your cut or you will fracture the part. So if he is drilling a hole, you might want to model it larger and make sure he is only taking off about 0.005" with his drill. Whatever his second op is, you can probably accommodate it better with your model so that material removal is minimized.
You can also find out what kind of cutter he is using. You can get low-helix cutters that will do less grabbing and pulling on the part - that will help prevent fracture as well.
I find that anything under about 3mm is not so durable with any material.
If the guy is trying to machine the part as a second op heâs toast unless he has experience with acrylics. The stuff doesnât cut well and can cause a ton of cracks at the machine surface. Parts should be sealed with CA after being machined. If itâs just a hand op try heating up the part and it will be easier to move around without shattering.
