Projet 1200 - FTX Cast Burnout Tests

[bford903]

I just received my shipment of FTX Cast for my Projet 1200. I'll be posting the results of the printing and casting tests here.

First print



The material feels much softer, more like wax, than the FTX Green. My wax pen had little to no effect on the material and injection and sprue waxes have a little trouble sticking to it.

The Auto-supports generated by the software are very thick and are difficult to remove. Recommend that you create your own supports on the model prior to printing.

First Test:
Satin-Cast Investment (gypsum)
Standard Wax Burnout - 6hr
Mix for Standard Castings


Result:
Unusable. Investment breakdown. Heavy porosity. Pitting. Bad Surface. Reminds me of earlier casting tests with the FTX Green. Complete failure.

This result was expected, but the casting looks much worse than I anticipated. I think the poor result is mainly due to a curing issue. Maybe a cleaning issue as well. I'll extend cleaning procedure and curing time for next one and repeat test with Plasticast investment. Time to step it up.

Not even my school castings were this bad.





I also put one in the oven by itself (no investment) to watch the reaction. Very similar to FTX Green. I believe they call that a "Temperature Differential".

[bford903]

Second test:
Plasticast Investment
6hr burnout
Heavy Castings Mix

Result: Unusable. Same result as before but less severity. Failure.


I still think this is a curing issue. I believe there is still uncured resin inside the model causing the temperature differential which causes the model to expand which is damaging the investment.

I have a few more models in various stages of curing and I'm starting to notice a significant color change as the model cures. The initial color is a light yellowish-green and changes to a almost white color with a tinge of purple (this is noticeable on the first prints). The color change is occurring throughout the model from the outside in. I think curing time should be measured in days not hours.

Next test will be with Plasticast and mucho extended curing time.

Anyone know if there's a patron saint of jewelry casting?

[curious aardvark]

so is your printer fff or sla or something else ?

Sounds like you might be a candidate for the new wax filament. Yep it's pricey - but if you're making jewellery then that's a factored in cost anyway.

Won't work if you're using an sla machine though.

(checks) ok sla machine. So that won't help. Shame.

Micro-SLA 3D printer

The ProJet 1200 is designed for small, precise, detail-rich parts and casting patterns. It has excellent precision and surface smoothness, printing 30 micron layers at a 585 dpi print resolution through enhanced LED DLP technology. The ProJet 1200 is ideal for jewellery, small volume dental and electronic applications.

Fast print and network ready

The ProJet 1200 is a fast desktop 3D printer, printing at 14mm/hour vertically, equivalent to 5 rings per two hours or 12 dental wax-ups in one hour. It is network ready (via Ethernet), allowing multiple users to access the printer.

VisiJet FTX Green material, ideal for detail and castings

The ProJet 1200 uses an all-in-one, easy to fit cartridge ensuring consistent high part quality. It uses VisiJet FTX Green material which is a durable and rigid material, tailored for plastic prototyping and casting patterns. VisiJet FTX Green burns out cleanly for ash-free castings.

Maybe it's your burnout temp ?

[bford903]

It might be the burnout temp but I don't think so. We're ramping to 1350 degrees F (732 C) and holding for 2hrs. Approaching 1500 degrees F (815 C), the investment will start to break down. The material turns black and starts to burn at 800 degrees (see picture above). In previous tests, extending the time at max temp didn't really improve the casting. Look at the letters in the picture; you can see the rough edges where the letters broke off on the inside of the mold as the material was expanding. The porous outside surfaces are most likely caused by residual ash residue in the mold.

I have to get this job done and out the door pronto so I'm moving to phosphate-bonded investment. I'll experiment with gypsum investments after I finish this one.

[bford903]

Fully cured piece. The green shade is completely gone.

[bford903]

The previous piece came out excellent but I didn't get a picture after it was completed. After it completely cured, used Plasticast and an 8hr burnout and it came out great.

Here's the test using phosphate-bonded investment. Came out better, but not quite there. This is definitely a curing issue. Larger pieces are concealing uncured resin, and since the new material is more opaque than FTX Green, curing time may need to be extended. Thinking about building an external curing chamber.

[locator]

Wow.. You are so great. I'm using projet 1200 with cast. I have some questions.
1. Support is too large(despite i set this small size ) and I think that software fixed to largest size. you too?
2. How many hours does it take to fully cure? (average time in bulit-in chamber)

I think that projet 1200's built-in curing chamber is crap. It works only 10min and it couldn't cure all side of printing. We need to use a more strong external chamber.

[bford903]

Wow.. You are so great. I'm using projet 1200 with cast. I have some questions.
1. Support is too large(despite i set this small size ) and I think that software fixed to largest size. you too?
2. How many hours does it take to fully cure? (average time in bulit-in chamber)

I think that projet 1200's built-in curing chamber is crap. It works only 10min and it couldn't cure all side of printing. We need to use a more strong external chamber.

Oh thank you.
1. I create my own supports in Rhino and attach manual supports to the bottom of each in Geomagic. You're absolutely right. Even the small supports in Geomagic are too big. When I tried to remove them, sometimes the piece would break. My supports range from 0.6mm to 1mm in diameter and are tapered at the tip for easier removal.

2. Smaller pieces seem to cure completely after 2-4 cycles in the curing chamber. Larger pieces take much longer (I have a ring in there right now, and at the time of writing this it's on its 6th cycle). Keep curing the piece until the green shade is completely gone and you'll minimize expansion during burnout. The color changes to white, then a light pink. I'm looking into building an external curing chamber as well. Something I can setup to cure overnight.

Good luck to you and if you ever need any help, please feel free to contact me.

[bford903]

It was indeed a curing issue. I cured these until the green shade was completely gone, and used Plasticast (heavy mix) with an 8hr burnout and they came out very well. Little to no porosity.

With the FTX Green, the cured piece was strong enough where I could file all of the grow lines off before casting. The FTX Cast is much more brittle so I'm apprehensive to start filing on it. That's why the surface is a little rough on these.

IMAG0492.jpg

IMAG0494.jpg

[bford903]

Been having issues with incomplete prints. Random areas seem to be delaminating. Seems like it's sticking to the bottom. Not sure why this is happening or how to fix it. This is occurring to more than half of my prints. Large or small supports don't seem to make any difference. There doesn't seem to be any way of changing things like print speed, layer thickness, etc. in the software. Not sure what to do.

IMAG0507.jpg


EDIT: No updates on software or firmware recently that would have caused it.