SINTERING question.

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digimiller

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Hello Friends,

I am trying to maintain a "GOOD" milling centre, i have a problem in terms of colour from sintered crowns. I am using AG and it is coming out: Dark, Shiny, Not enough translucency and Dead looking". I have increased the overall temp 100 degress more than suggested 1450.

On the other hand I do Argen STML and the colours come out very good. Please advise what I could improve? Is is the furnace or my temperature or hold time (130 mins). I do use beads and beadless with same results.
 
JMN

JMN

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Hello Friends,

I am trying to maintain a "GOOD" milling centre, i have a problem in terms of colour from sintered crowns. I am using AG and it is coming out: Dark, Shiny, Not enough translucency and Dead looking". I have increased the overall temp 100 degress more than suggested 1450.

On the other hand I do Argen STML and the colours come out very good. Please advise what I could improve? Is is the furnace or my temperature or hold time (130 mins). I do use beads and beadless with same results.
Last Calibration?
Have you had it come out reliably pretty on a regular basis before?
bad puck?
Bad element?
What furnace?


Lots of places to start.
 
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digimiller

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Sintra pro... Argen I used recommended temp and it's good colour. It's a brand new furnace. I'm getting a Dakema this week as well. I can't remember last time it was good... I sinter about 20 units minimum in a tray
 
JMN

JMN

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Sintra pro... Argen I used recommended temp and it's good colour. It's a brand new furnace. I'm getting a Dakema this week as well. I can't remember last time it was good... I sinter about 20 units minimum in a tray
Brand new firnace itself mqy he the issue. Takes a couple to 'hurn in'
 
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A. M.

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If the Argen zirconia comes out good, it's not the furnace.
 
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ztech

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What material of AG are you using?
 
RDA

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In the Sintra Pro, if you are not stacking the trays, the muffle platform sucks about 30 degrees of temp out of the lower tray. We stack the trays, using an empty lower one directly on the muffle platform first. If we have more units to fit in, we will put lower sintering zirconia in the lower tray.
 
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digimiller

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AG: Zolid Preshaded... Muffle Information... WOw
 
Sda36

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AG: Zolid Preshaded... Muffle Information... WOw
Like RDA said above, use both dishes but only utilize the uppermost restorations for sintering with the Sintra Plus. Seems to under fire from my past experience, a while back now. Definitely get your units up from the base and in fact, closer to the thermo-coupler at the same time, Hope this helps!
 
The Veneer Guy

The Veneer Guy

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I had major issues with my Sintra plus ovens and I spent enough time to get a phd in sintering, struggling to figure this problem out myself. This is what worked for me:
I would do a few calibration cycles with the Orton ceramics temp tabs. In the Sintra plus you can go to options and increase or decrease the calibration (base) temp from there. Follow the instructions. I increase or decrease the temp by 1/2 of the discrepancy until I get it just right. Make sure you use a good micrometer preferably from the same temp tab manufacturer. Doing this type of change will increase/decrease the temp universally for all types of restorations you use so keep that in mind. You can pm me for the calibration chart and calibration program specs or contact Orton directly. I used to get greening, and milky look to the crowns as well as the dreaded milky “margins” but now I calibrate and purge regularly (at least every month depending on how often you sinter) and no more issues. Also remember that preshaded pucks and acid based stains will contaminate quicker so either you have to degass ( with white pieces of old zirconia pucks as it sucks up the contaminants) more often and/or use a degass (air compressor connection) period of time in the beginning of you sintering program as this will eliminate more of the contamination from each cycle. Remember to degass until your pieces of old Ziconia come out pure white. Any shade in them indicates contaminates are still present. Remember to change out your elements as directed by manufacturer. And don’t go cheap on them. Third party places aren’t reliable IMO. You know, the ones that ask you for the dimensions of you old elements so they can “custom” make them? In the Sintra plus, there are three elements. I got them for $200 a piece from some place that makes them (usa) and they didn’t work. I had to buy them from Zahn at $533 a piece and even though it was more expensive, it fixed the issues. I have two Sintra plus furnaces and haven’t had any more issues since I changed the elements out. Cost of doing business I guess. I change them out now every three yrs as recommended. Remember, you get what you pay for with tech stuff, Especially with elements. And remember your ROI. With high tech stuff like this it’s best to stick to manufacturers’ instructions and recommendations. They got it down to a very accurate science.
Sorry for the rant but I struggled for yrs trying to figure out the problem only to lose a ton in revenue and gain more gray hairs than I care to admit in the process. Not worth it IMO. Hope this helps! Pm me with any other questions I may help with. I know this is a very frustrating thing!
 
tehnik

tehnik

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I only got milky margins and opaque crowns, when the elements were bad. Change them and all ok.
 
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