Impact resistance, flexibility, heat resistance of cured parts?

I actually like to wash my parts in hot running tap water right after the alcohol soak. While it does cloud the plastic a little it removes the tackiness almost immediately.  Another thing I like to do is agitate the parts in the alcohol bath, I simply pull the basket in and out.   I imagine the current of the moving alcohol helps remove unwanted uncured resin.  Maybe someone could design a bath with a fountain or fish pump to keep the alcohol moving without  the need agitate manually.  There’s a kickstarter of a washer/finisher.

Kinda like this? :smiley:

Back to the original topic (material properties i think :wink: if someone has access to an instron or an Izod impact tester I would love to see what engineering properties the clear resin has. If someone would send me a couple support bases, I could make a measurement of the stiffness (bending modulus) and strength (yield strength and tensile strength in bending), that would tell us  a  bit more about the material we’re all dying to work with.

Ultrasonic cleaner?

I received my printer Tuesday, and the resin arrived the following day. Wednesday night I printed a part for a friends medical device company. I let it sit about 5 hours (had to sleep). About 4 hours after the print had been raised out of the resin tank, I removed it and gave it a nice IPA bath (91%) for a bout 10 minutes, then dunked it in the basket for about a minute or so. The part was tacky, I was wearing yellow dishwashing gloves and they were a bit sticky after handling the part. I removed the part from its bath, and placed it under a roof window for about 3 hours. The tackiness was gone, so I removed the supports and handed it off to my buddy for testing with his team. He and I am very happy with the results. I’m thinking that a UV cure box would be a good idea to speed up the de-tack-ifying process.

If 99% is that much better, I may try ordering some, but switch to a 2-bath process.  Bath 1, agitate in 91% (like $3/quart at CVS,) bath 2 soak in 99%.

I wouldn’t think a quick wash in 91% would allow much water to get into the plastic.

Hey all, been doing a lot of experimenting with my prints, a lot of it related to testing the limits of the mechanical properties.

The first tests were very exciting, especially as compared to FDM printing.  My (audio-sync challenged) youtube video below displays some impressive qualities:

Now that my parts have had several more weeks to cure, I’m finding that the prints are a little more brittle and break prone, but still very strong.  I’m wondering if coating them with a UV protectant while they’re in their “optimum state” would keep the properties from shifting to a later degree of cure.

Now, I’ve also been playing with heat-set enamel finishes, and as a result have been cooking the hell out of the parts.  I’ve done 300, 400, and 500 F bake sessions for anything from 20 minuites to a few hours, and the parts have held up without any deformation.  At the extreme temps, there was some “softening” of the parts, but not enough to permenantly deform them with normal handling.

The Form1 is simply an amazing machine, and the resin is an equally amazing material.  I was planning on molding and casting from my prints, but the results I’ve seen so far are impressive enough that I think I can skip the “prototype” stage and just print production parts, provided a little dillegence in design and finishing to account for the material limits.

I know the Resin engineers are working on some very cool new materials, and I can’t wait to see them get released!

Back from another night of trying to enamel formed parts.  Discovered that the parts which have been exposed to extreme heat for even moderate durations, become much more brittle than normal.  I’ve had breaks at structually weak-spots, as well as fractures along print-layer-lines.

So while they won’t melt, and eventally will “burn like wood” as described in the lost-casting thread, there’s also some property shifting between initial heating and eventual combustion.

I discovered that heat or not heat, the part get very brittle after a while.

VERY helpful to know.  Loving this community.

Will definitely start testing out UV-Protecting the parts when they’re at their best and see if it’s possible to arrest the degredation.

You should be able to uv protect it with a uv blocking polyurathane. I know many outputs done on polyjet systems that use a similar material are finished off with a varnish that smooths the surface and protects it.

As far as post curing, would uv lamps or a fluorescent grow light work better?

Anyone here do any service bureau work? I do metal castings and used to use a couple of large output companies but they are sloppy and unreliable. I generally make my molds from printed parts. Any idea on cost per cm³?

I have not read through all of the comments above so this may already be covered.  Is FormLabs considering a resin that would be a type of flexible rubber with which you could create the actual mold rather than making a mold from the part that is printed? I am still waiting for my machine.

Since the materials are uv curable I would think that it might be possible to make a semi flexible mold but the mold would lack elasticity that you would expect from silicone or natural rubber.

My guess is at best the materials would be very similar to ones used on Objet printers.

I’m cuious if the parts could hold up under heat and pressure, at least enough to vulcanize a natural rubber mold.

I believe the Form Team has mentioned that they’re working on a flexible rubber-like material, not sure how far out it is, and no clue if it would perform as a traditional flexible molding material.

I’ve been having a LOT of success though using the Form1 to print rigid molds.  Mold design needs to be more like steel-injection-molding to allow for part-demold (I’ve been using semi-rigid materials, so I can get away with some slight undercuts), but the material has held up to dozens of casts so far without any sign of degredation.

The other nice thing is the resin molds are machinable enough to be able to easily adjust the mold by expanding or adding new channels/vents etc.  100% the best use I’ve devised for the machine yet!

Also, per one of my earlier comments, I’ve had MODERATE results UV-blocking the parts while green.  Required a pretty aggressive expoxy top coat to see any results, and there’s still significant en-brittleing but it seems to be less dramatic vs. untreated parts.

Now whether this is a matter of arresting property shift or just slowing it, I don’t know yet.  I’m assuming the worst and that even UV coated parts will eventually become fragile.

Do the uv blocking polyurethane such as MinWax’s  Helmsman Spar Urathane offer enough UV protection?  It can be purcahsed in standard cans or aerosol cans. I have used it for bamboo flyrods and they go back nearly 25 years with no degegration. Epoxy typically breaks down under UV light discoloring and becoming brittle.

I tried a bunch of normal off-the shelf products without much improvement.  The product I’ve had the most (apparent) success with is called ResinX.  Not really intended for this kind of application, but it’s impressive stuff.

But, as I said, not exactly great results even there.

Untreated Parts: Precariously brittle after approximately 2 weeks of normal sunlight exposure (following an initial direct-UV exposure cure post alc bath)

Off the shelf UV coats: Same result.

ResinX: Still *slightly* flexible (but nowhere near the “green state”) at 1 week, I’m now approaching the 2 week mark with my test part.  I anticipate some improvement vs. untreated, but my expetations are very moderate.

25-year stable parts are, I’m afraid not possible with current materials :confused:

Hey guys,

Im conducting a little bit of a survey. After going trough plenty of posts im noticing a pattern here… it seems like the form1 is simply unable to print large models with any amount of consistency…

If you have been able to print large models consistently, say more than 5 without a fail, please let me know here:

For the purposes of this discussion, lets define large as a larger than 10cm sans supports on the longest axis… c’mon large, you know what I mean…