Dishwasher safe ceramic ware is generally ware that is not overly absorbent and therefore will not water log in use over time (and therefore weaken and become a microwave oven hazard). Dishwasher safety also refers to the ability of ware to handle the changes in temperature it will be subjected to without cracking of the ware or the glaze. To produce ware that can withstand these temperature changes glazes must be thermal expansion compatible with the body (there are many articles and videos on this site about how to achieve that). The indicators of lack of expansion compatibility are crazing and shivering.
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