Hi!
We're getting a slightly darker reddish-brown shade with our pre-shaded Cercon HT zirconia BLANKS, as well as less translucency. Cubic zirconia come out fine. The problem seems to be more intense when we fire a lot of pieces in the same cycle.
We're sintering in a sirona furnace. We regularly regenerate and calibrate it.
What could lead to this kind of problem?
Since you say it's worse when there are multiple pieces it's highly possible that you need to bump your temps for that material's cycle.
The increased mass of multiple units should not make any notable difference in outcome unless you are really overloading it.
Try 5-10 deg rise in temp and see what happens. then another 5-10 degrees.
the reported temperature is from a different location in each specific furnace, having to tweak a few degrees is not abnormal since the thermocouple will be in a differnet place in every device's design.
taht may not be the only issue or the only solution, but it should be considered.
and Take Notes!
You won't remember what and why and how in 9 months. Keep the data, not the headaches.