-Deviations in the energy effect on the zirconium oxide
· Final temperature too high or too low
o A deviation of the final temperature may lead to differences in the material structure. This has negative impacts on the translucency and the color indication.
· Extreme fluctuation of current
o The change in the energy effect may have the same impacts as described above.
· Wear of the heating elements
Pollution
· Pollution of the heating chamber
o If coloring liquids are used in combination with low sintering temperatures the result may be a saturation within the insulation after several sintering cycles. This saturation may have influenced the workpieces during the sintering process in return.
Regular execution of the purging/regeneration program is strongly recommended <<
· Damaged heating elements
o If the oxide layer of the heating elements is damaged, this may result in pollution of the heating chamber leading to greenish discoloration.
Regular execution of the purging/regeneration program is strongly recommended <<
· Pollution of the sintering tools (bowls, beads)
o Please refer to the heating chamber
· Pollution of the workpiece
o If the workpiece is not cleaned carefully, this may lead to the inclusion of particles of dirt during the sintering process. This has a negative impact on translucency.
o Exhausted or polluted cooling liquid of the milling machines
Coloring liquid
· Age of the coloring liquid
o During the lifetime of the coloring liquids the proportion of the color particles within the coloring liquid changes.
· Degree of dilution of the coloring liquid
o If the coloring liquid is diluted too often, the proportion of the color particles decreases. The result is a deviation although the working process may be the same.
· Usage of unsuitable diluting agent
o Unsuitable diluting agents may damage the color particles within the liquid and lead to different results.
· Wrong storage of the coloring liquid
o Manufacturers’ storage instructions have absolutely to be observed.
Problems caused by the drying process
· Drying temperature is too high
o If the temperature is too high or the heating is too fast, this may lead to an increased vapor pressure within the workpiece and thus to a negative impact on the structure or/and the translucency/coloration.
· Drying time is too short
o If the drying time is too short, this may have the same consequences as a drying temperature that is too high.
