Resin cracks while heat curing

A lost wax capable resin tuned for 30 - 50 micron slice thickness
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TAJS
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Resin cracks while heat curing

Post#1 » Tue Oct 07, 2014 11:05 am

Never had this happen before. I printed these last night with pure cherry, 30xy,25z, defaults. I cleaned them off in the ultrasonic and heat cured them for 1.5 hrs at 350 degrees F. When I pulled them from the oven, the large signet had cracked/split.....in several places. The other models are fine......................any ideas?
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TAJS
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Resin cracks while heat curing

Post#2 » Tue Oct 07, 2014 11:06 am

...continued.
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akgold
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Resin cracks while heat curing

Post#3 » Tue Oct 07, 2014 12:19 pm

The only thing I have to say is WOW
Those are some fantastic results from the B9
as for the break that is strange. what did you clean it with in the ultra sonic?
how long did you clean it?
I'm so far behind I think I'm First !!

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Robert Howle
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Resin cracks while heat curing

Post#4 » Tue Oct 07, 2014 12:30 pm

In the paper that Gary wrote about oven curing he suggested ramping to the 345 F. I usually do 150 for 1/2 hr. (I start with cold oven) before going to the 345 f temp. I have left prints in the ultrasonic for up to an hr or two with no problems.

Robert
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TAJS
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Resin cracks while heat curing

Post#5 » Tue Oct 07, 2014 1:02 pm

I use ammonia and dawn...a fairly strong mix. My ultrasonic has a heater on it as well...I usually clean the models for an hour or so.
I guess it is the thickness of the heavier models...maybe have to UV cure these......

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joyas3d
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Resin cracks while heat curing

Post#6 » Tue Oct 07, 2014 1:12 pm

Hello TAJS
I see you are using textures Artcam, please tell me how you repair your 3D models or create your textured solids to send B9. Thank you
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Robert Howle
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Resin cracks while heat curing

Post#7 » Tue Oct 07, 2014 1:14 pm

You do know that u have to save the files as .stl if they need repair u can try Netfab its free and can fix your stl files. pretty sure.

Maybe better answer from TAJS.
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TAJS
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Resin cracks while heat curing

Post#8 » Tue Oct 07, 2014 1:28 pm

Quote from joyas3d on October 7, 2014, 19:12
Hello TAJS
I see you are using textures Artcam, please tell me how you repair your 3D models or create your textured solids to send B9. Thank you


I do not do anything.....I just save the model to my desktop...... import into the layout, save and slice.

What do you mean "repair the 3d model"?

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behold3d
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Resin cracks while heat curing

Post#9 » Tue Oct 07, 2014 2:47 pm

i believe lamp hrs are saved in your log automatically. No organization needed

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panastation
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Resin cracks while heat curing

Post#10 » Tue Oct 07, 2014 3:18 pm

hes prob asking about trying to fix 3d models he finds on web.. wich are triangulated, have more than 5 faces, nonplanar, or have holes..
like bad poser models or sketchup wich does horrible things. joyas 3d if u wana repair stuff and have a mid level in 3d id suggest u do retopology in zbrush or in 3dcoat wich is even better..but sometimes models are so bad u cant fix em... thats why having nice clean geometry and doing the models yourseld saves you time and money.

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PandaP
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Resin cracks while heat curing

Post#11 » Tue Oct 07, 2014 5:31 pm

Beautiful models! Thanks for the tip Robert about ramping up oven curing, I will try that.

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Robert Howle
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Resin cracks while heat curing

Post#12 » Tue Oct 07, 2014 7:03 pm

U can check lamp hrs here. Top left "print anaysis" just scroll down.


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fcort
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Resin cracks while heat curing

Post#13 » Wed Oct 08, 2014 7:39 am

TAJS - Great prints you got there
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bvwjewelers
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Resin cracks while heat curing

Post#14 » Tue Oct 21, 2014 12:15 pm

FYI, I have had a couple prints crack after leaving the lid on in my UV box and letting them sit for about 6 hours.....I never knew you could over "cook" the prints.
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panastation
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Resin cracks while heat curing

Post#15 » Sun Nov 23, 2014 5:56 pm

its happened to me also... i put about 10 earings and 5 rings into my kiln. i decided 270 was fair enough as i had alredy cured resin for about 2 hours in a double box uv light setup. so i gave it 2 hours at 270.
i had some flowers and ---some of the top flower layers cracked and flaked . The thicker rings one of them had a fine crack going through the top. i super glued it and then melted some wax on top.
i have noticed the best way is to leave in uv box for about 6 hours or so...o direct sunlight i have a mirror box i put that under the sun for a whole day. I dont use the kiln to fast cure stuff anymore until i understand why u have a 50% of cracking prone to happen,,, i just casted some earings . Tjas ive seen ure other post on casting.
i also use satin cast but my flask are about 4inch in daimeter and 2.4 inch in height.
i have tried to raise temps slowly i start at 250 one hour 300 2 hours.* to get rid of water in investment*********- 700 2 hours 1350 2 hours
1000 2 hours ---then cast/// results sometimes vbery good this time around i had a few imperfections. il post some pick later on ..
Theres no doubt in my mind u need to get rid of that water in investment slowly... but after that do u raise temps like to 1350 for more than 2 hours...I know u use smaller flask than i do but i would like 2 know ure burnout cycle. I have also done test using rio grandes vacu film prior to investing, krylons plastic finish, even brushing rcherry red to get smoother finish then light curing... but its that dam burnout i cant just get right.
any info would be greatly time saving fo me --Tajs throw me some info. thanks,

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Robert Howle
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Resin cracks while heat curing

Post#16 » Mon Nov 24, 2014 10:36 am

One thing to remeber is how long it takes the center of the flask to reach the temp of the oven. With small 2 inch flask it takes approx. 30 min. for the temp to reach the center. With the 4" it may take a full hr. So the first hr at 1350 some areas of your flask are just not hot enough.

Based on Gary's info on heat curing the ramp rate should be about 4 degrees per minute (240 F / hr) to get to 345 F and hold for 1 hr. Just thinking outloud.

Robert Howle
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TAJS
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Resin cracks while heat curing

Post#17 » Mon Nov 24, 2014 10:59 am

Hi panastation, the key for me has been to invest the day before and let the flasks cure over night. Then the next morning, proceed with an 8 hour burn out. I use a kilnminder and am not sure of the times and temps as the kiln heats up.....although I know it does hold at 1350 for 2 hours and i cast at 900....all Fahrenheit. HTH...keep us posted. Good luck!

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Robert Howle
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Resin cracks while heat curing

Post#18 » Mon Nov 24, 2014 11:14 am

Tajs, he is talking about his models cracking when being post print cured in the oven (heat curing vs UV curing) , not his castings.

Pretty sure.

Robert
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TAJS
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Resin cracks while heat curing

Post#19 » Mon Nov 24, 2014 11:33 am

Hi Robert, slow down and re-read his post :)

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Robert Howle
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Resin cracks while heat curing

Post#20 » Mon Nov 24, 2014 1:06 pm

I know his post had two parts, The cracking was about heat curing models, and I know u had dealt with that issue in the past. I wasn't saying anything about your casting post, just though u might could also help him with his model cracking problem. Prob should have worded differently.

Robert
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