pitting in emax press

[user name]

Dont use any cleaner, surfactant, smoother, and DONT use too much vibration! Use a brush to get the investment in the details. When you vibrate the ring, the pattern is 'buzzing' and creating a more liquid mix right at the pattern/investment interface. Consiquently, the mold youve created once the wax is gone, is soft and chalky.

 

[actittle]

Ok, so first thought is typical: calibration on track? Surface looks hot. High burnout temp 850?

Second: Vacuum issue. Run a vacuum test. Mine just took 1:02 min to clear 80mbar.

I just calibrated both ovens. I guess it's time to get some stuff invested!

 

[paulg100]

so how much out were the ovens?

 

[actittle]

The burnout oven was 50+ degrees too hot and the pressing furnace was only 0.5 degrees too cool.

 

[sidesh0wb0b]

im seeing the same result at the lab im running now. (ive never had to deal with such an aggressive reaction layer)
they are using an EP600 ..... lets start by throwing out the caveat that they NEVER did anything to the press. zero calibrations, and had vac errors for 9+ months. never fixed it SIGH!

anyway, ive replaced the head seals, run calibrations, and replaced the vac pump. all errors are gone. also had the techs stop using debubblizer.....and while some of the issue has disappeared, its still there. and basically as bad as ppl here have shown/noted. my next step is burnout......but they are using ancient burnouts and i can tell just by opening the oven its running 100-200 degrees hot. of course im having a brain fart and cannot remember the model....but most techs would recognize it

anyway, please keep us posted if any of you guys get a solution. Ivoclar (at least the rep here) hasnt done much for me. again ive never seen such horrible pressing results. its 15-25 mins of rubber wheeling EVERY dang crown.....such a waste of labor hours!!!

 

[Zubler USA]

Time & temperature. I would check both the pressing oven and burnout ovens. ovens are notoriousely innacurate because of the type of thermocouple they use, and the contamination they are exposed to. However, you might want to ask how long your pressing time is. How fast you cool down. Are you using disposable plungers or alox. alox plungers can add reaction layer because they are much more dense than disposable. They keep the ring in the oven longer, because they take longer to heat up, then they continue to heat the ring when it is removed from the oven. Just a thought.

 

[Gru]

The burnout oven was 50+ degrees too hot and the pressing furnace was only 0.5 degrees too cool.

Oh, one thing I forgot: All investments start to break down after too much time in the burnout. This happens at an accelerated rate when the high temp is off (high) because of calibration issues or set too high. Make sure they aren't leaving the rings in the burnout excessively long, as there is a max time on the directions too.

sidesh0wb0b, tell them to get a new burnout or at least buy new parts for you! Easily worth the money from what you say about labor.

 

[user name]

Calibration of a burnout...Ney Vulcan D-130. I dont have papers for this one; can you tell me how to calibrate please.

 

[charles007]

The pitting is most likely caused by temp....
Check exact of sprue,,, 200g ring may help
Calibrate both pressing and burnout ovens..

 

[Gru]

Calibration of a burnout...Ney Vulcan D-130. I dont have papers for this one; can you tell me how to calibrate please.

Not so easy. See this:

http://www.dentsply.cl/productos/laboratorio/Ceramco/Vulcan D Multi-language.pdf

Good luck. Maybe an old Dentsply tech can walk you through it if needed?

 

[JohnWilson]

Are you using the INVEX acid? even the worst reaction layer using this material and light blasting eliminates it.

The entire point of this all is that once you have everything dialed in the product is bullet proof. We started using the EP500 back in the empress 2 days and made 1000's of pressing with that oven for more than 10 years. Started to have a few issues with the new versions of EMAX and decided to drop the bucks on the new oven. Of course the price tag is just ridiculous but the damn thing works perfectly. I would buy it again, but I say that about most of Ivoclars stuff over the years.

The best things we did for consistency prior to getting the new oven was to go back to Ivoclars speed investment. We follow the instructions to the letter and the stuff works, once we purchased the new oven the #1 thing that changed for us was amount of reaction layer. We still use both ovens today with similar results EXCEPT we press bridges only in the new oven.

 

[desertfox384]

I did not see anyone mention blasting pressure.. I wont divest emax with much more than 2.5-3 bars pressure. Cant too high a pressure cause the same issue?

 

[Gru]

desertfox384, good point about pressure, although I believe it only causes chipping, not surface damage like the photo. According to e.max press manual: Rough divesting 4 bar with glass beads, Fine divesting 2 bar w/ glass beads, after Invex 1-2 bars w/ Aluminum oxide.

 

[sidesh0wb0b]

sidesh0wb0b, tell them to get a new burnout or at least buy new parts for you! Easily worth the money from what you say about labor.

man you have no idea how i wish it was that easy......i could tell you stories....sigh
short story......they wont. wont even consider.

 

[sidesh0wb0b]

Are you using the INVEX acid? even the worst reaction layer using this material and light blasting eliminates it.

The entire point of this all is that once you have everything dialed in the product is bullet proof. We started using the EP500 back in the empress 2 days and made 1000's of pressing with that oven for more than 10 years. Started to have a few issues with the new versions of EMAX and decided to drop the bucks on the new oven. Of course the price tag is just ridiculous but the damn thing works perfectly. I would buy it again, but I say that about most of Ivoclars stuff over the years.

The best things we did for consistency prior to getting the new oven was to go back to Ivoclars speed investment. We follow the instructions to the letter and the stuff works, once we purchased the new oven the #1 thing that changed for us was amount of reaction layer. We still use both ovens today with similar results EXCEPT we press bridges only in the new oven.

that was my thought too, but no dice. even after the invez its still horrid. ive never seen it so bad. turned down the burnouts this afternoon. lets see what tomorrow brings.

 

[Garrett]

I see this crop up from time to time. I get this liquid from Vlad at Shofu. We put something like six drops in the investment liquid and it all goes away. It even cut the Invex treatment down to one 15 minute stage. Give Vlad @ Shofu a call 1-706-473-7400

 

[actittle]

These are photos of what I pressed yesterday.

I'm using an Ivoclar EP5000, PressVest investment, HT e.max ingot, Jelrus Temp-Master M Two Stage furnace, both furnaces have been calibrated and I followed all of Ivoclar's instructions word for word.

Is this the way it is supposed to look? I'm new to pressing, we just bought the EP5000 a few months ago.


Before Invex




After Invex and blasting

 

[paulg100]

no thats not right, still to much heat.

i fixed my issues by adjusting the press temp.

 

[Gru]

ac, No, it shouldn't be that pitted. Still looks like the burnout is a little too hot unless the ring was burned out too long and the investment started to break down. I know you said everything is calibrated, but don't be afraid to lower your burnout a few degrees (like 3degrees c) on the next run. Oh, do a vac test on the ep5000 to make sure that's good.

 

[Toast]

Actittle, someone posted an emax update a while back that had a different spruing method than the ifu from ivoclar. Here's the link http://www.ivoclarvivadent.com/zoolu-website/media/document/14733/Guidelines+to+Optimized+Pressing

Also what gauge sprues are you using? The manual says sprue diameter should be between 2.5 and 3 mm which would be 10 gauge wax wire. Your sprue looks a little larger than 10 gauge. When I first starterd with emax I was using a larger gauge sprue and was having issues with the surface texture. After calibrating ovens and checking everything else I noticed I was using a larger diameter sprue than ivoclar recommended. I reduced sprue size and I'm getting very clean presses ever since. If you checked everything else try this and see if it helps.