Wondering if someone with experience casting Solidscape materials can help with an issue that I am having. I have been 3D-printing and CAD designing for 15 years however, I just started casting in-house. I’m having some trouble with surface craters on my castings. It seems possible that I am boiling the Solidscape material in my first ramp. Here is my burnout schedule:
RA1 - 300F/per hour
Target Temp - 300F
Hold - 1 hour
RA1 - 700F/hour
Target Temp - 700F
Hold - 2 hours
RA3 - 675F/hour
Target Temp - 1350F
Hold - 2 hours
RA4 - 600F/hour
Target Temp - 1000
The material sheet for Solidscape says it melts at 200F - 225F so if I am running at 300F, it would seem possible to boil the material. The above is for casting 14k white gold. Please note, I am using a closed unit vacuum system by Indutherm. The investment is mixed to the letter of the law lol, everything is weighed and prepared as specified by R&R, ratio 40/100. I’ve spoken independently with Romanoff Supply and United Precious Metals, and they both agree that I have a burnout issue. However, before I go on a wild chase to change my process…I wanted to check with someone that has good results with Solidscape materials. I would greatly appreciate your help!
Thanks in advance,
If it is the Solidscape wax material, it melts just like wax and I rarely had a problem with it.
In your Indutherm machine, where is the melted wax going? Is the flask button side up? That means it stays in the flask and perhaps it doesn’t vaporize long enough? Maybe you need to increase your first hold for another hour to see if you can reduce the amount of wax before you push to the next level?
In a standard kiln, I either put a drip tray under the flask button-down and melt it out, or I steam dewax. Since your machine is closed, steam dewaxing might be a better option.
Thanks for the response! I have a drip tray and put the flask button side down in the kiln. What temp do you use for the first ramp? I was thinking about lowering the temp to 225 and adding an hour. The material sheet for Solidscape said it melts at 205 degrees.
If that is how you do it, then you should be fine unless there is trapped wax inside the flask that your sprues aren’t able to remove. Do you see any issues with clearing the wax from your models?
The only time I had trouble is when I put my flask in button up and it sprayed wax all over the interior of my kiln during the first ramp. Let’s say it made for some fireworks when the kiln moved up to 700°F and I opened the door.
Do you have any photos of the surface defects you can share? They might be other problems like broken out investment causing cavities, etc.
Can you notice the cratering and pockmarks? Solidscape suggests soaking the models in mineral oil to help the material release from the flask. Do you do this?
So depending on the flaw, positive defects are erosion of the investment and negative defects are broken pieces of investment or ash getting trapped. Based on what I am seeing, it might be a combination of both.
How much air gets inside your kiln when you do your burnout? The more oxygen that enters the chamber, the better the resin is able to burn out of the flask. I have two holes drilled into the bottom of my Paragon SC3 kiln to let air flow from bottom to the top exhaust hole and into my ducted fan exhaust system. I think I need to add another two holes to make sure I get enough outside air in there to do a better job.
However, since your print is more wax like than most resins, I am surprised you are seeing this type of defect.
I’ve heard of using barrier sprays to keep the resin in 3d prints from causing damage to the investment, but not mineral oil. I am not sure how the investment would cure next to that, but it is certainly worth a try if Solidscape recommends it.
I have a 1/2 hole on the door, and a 1 inch hold on top. I’m really at a loss because I’m doing everything text book and Solidscape material casts so well.
Try the mineral oil and see what happens. If Solidscape suggested it, I’m guessing it worked for some other customers.
So two thoughts -
One, slow down your first stage ramp from 300/hr to 150/hr and take an extra hour to soften and drain the wax from the flask.
Two, you could also try to blow the ash out of the flask at the end of your burnout before you put it in the casting machine using some air from a compressor. Tilt the (hot) flask upside down and give it a quick light blast of air into the tree sprue to see if any ash comes out. If you cool down the flask too much, you will need to put it back into the kiln to get back to temperature.
A variation on this uses a blowhole-style sprue that comes off the end of the print and heads back to the button, allowing them to push air through the blowhole and drag ash out the main tree sprue using the venturi effect. Requires more metal though so not as economical with gold, etc.
I hope that helps! Let us know how it works for you.
This is great advice, I appreciate your attention and generous responses!! I’ll keep you updated.
Update! Took the advice to slow down the burnout to 150/hour for water removal. Held at 300 for 2 hours instead of 1 and OMG what gorgeous castings!! Thanks so much everyone!! Pics don’t even do it justice.