Ring casted in silver

This is my first ring printed last week end ! :slight_smile:

Parts are really really thin …
I was affraid of casted it, but it worked fine with silver alloy. Had a try with Co-Cr but big fail

Here is the result in grey resin before casting, and then in silver




you used a grey resin? instead of castable resin?

Yes ! I work in dental, and for casting, grey is better than castable, less flexible.

I’ve tried white and clear too, it works too, but grey is more “readable”

nice. did it not left any residue? and did you still follow the burning schedule?

Im getting problem with castable resin, im getting porous output after casting. Do you think this will resolve my problem? Using my clear resin

I tested a lot of investments …before finding NV Z4 !

Never had any problem with this one, directly in the oven at 880°C (after 30min of setting), even with big parts

It left no residue with grey/white/castable (tested with pressec ceramic) :slight_smile:

So the issue is the investment not the grey/castable resin? Next thing i will do is to just print grey resin then create rubber mold. But i will try first to cast using grey. Hope my issue with porous metal will be resolved. Thank you grog6 :slight_smile:

last question, are you following a burnout cycle?

I think you’ll get the same problem with grey or castable !

Try the N&V Z4 :wink:

What do you mean with burnout cycle ?
Nothing special, put in the oven directly at 880°C, then, let it burn during at least 45min before injecting the alloy

Ahh so you are not following the recommended burnout schedule of formlabs. Ok i will check for N&V Z4. thanks! :slight_smile:

I just found that N&V Z4 is a dental investment. Anyways, I will try it.

I’ve tried their schedule, i’ve tried without, i’ve tested with cylinder ring around my investment, without …

Believe me, N&V Z4, without metallic ring, at 880°C is the best thing !

Here some pics of the process

nice. you even not removed the supports. :), thanks

I’ve tried to remove them in resin, but parts are so thin that it breaks the ring :wink:

Beautiful ring! Thank you for sharing!
I just received my casting equipment and I am about to try my first castings this coming week.
When you say 880C do you mean you place your flask in the kiln and program it to heat to 880 C gradually within 45 minutes and then pour metal with mold at that temperature ? Or do you lower temperature to something like 550 C or 600 C for the pour? ( I am asking because I read in a few places that the metal melting temperature for casting would be around 950 C (silver) and the mold should be around 550 C - maybe your investment requires different temperatures? ).
Any advice would be greatly appreciated!! :slight_smile:

The N&V Z4 powder is a phosphate bonded type. This type is used in jewelry casting for platinum and the like ( we use this type for steel and superalloys) because it is much more resistant to the required higher metal casting temperatures. We use R&R Astro-Vest. These investment powders are “stronger”, but brittle - just ask anyone who has de-vested it. These burn out at about 870 degrees C. I suspect that Astro-Vest is a good deal cheaper than any dental powder, too, but I do not know this for sure.

The other main type is gypsum bonded type. These are good for gold, silver, brass etc. I see that Formlabs seems to be recommending Plasticast. This type burns out at about 730 degrees C. Take them any higher and you will have a yellow, sulfur stinking mess and porous metal. Ask me how I know. We have not used this type much (for SLA patterns) because most of our business requires higher melting temperatures.

If you do use any powder of either type, it is vital that you use the low temperature dwell early in the burn-out as recommended by Formlabs. Normal wax justs melts and runs out. This is NOT what is happening here with Formlabs resins. They do not melt, but decompose during the cycle. This dwell allows the investment to cure completely and -in my opinion- allows the pattern to soften a bit. Differential thermal expansion is the killer here.

Regarding porosity: yes overheating the metal and other stuff can cause it. But in my experience, it is almost always caused by incomplete burn-out. Try your own experiment and double the time you spend at the highest temperature and see if that helps. Remember, this is not wax. Also, flask size have a big influence on burn-out dwell at high temperatures.

We developed this dwell technique 15 years ago for professional, expensive SLA patterns from machines from 3D Systems. etc. We had them all. It works. One last piece of advice: follow the investment manufacturer’s directions exactly. No kidding!

Bill Box

PS Someone should try Platinite high temperature investment. It worked great, but takes longer to process and makes a mess. Sure worked well though. BB

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Very, very cool ring!

I’m not used to pour silver. Usually I pour Co-Cr.

The mold was burnt at 880°C, but I pulled it out some time before to decrease the temperature before pouring !

hi grog6,

Just to confirm, N&V Z4 resolved your problem with porosity?, I found that my casting house is using gypsum bonded investment and never tried dental investment, N&V Z4 is phosphate bonded for dental. Since I can’t just ask them to change the investment that they use I’m planning to supply them with phosphate bonded investment since N&V Z4 is not available in the Philippines. What do you think?