Batch Compounding, Homogenisation, Filtration and Filling of Photoresins: Which Process Variables Must Be Declared and Controlled, and the Evidence That Does Not Yet Exist

This Engineering Review examines routine compounding, homogenisation, deaeration, filtration, transfer and filling of unfilled photoresins as controlled material-state transitions. It distinguishes recorded operations from measured associations and transferable causal claims. The directly read evidence shows that order of addition can be deliberately varied and measured in a ceramic-filled vat-photopolymerisation feedstock, but it does not establish the direction, magnitude or practical consequence of that variable in an unfilled photoresin. The review therefore defines the evidence gap, the batch information that must be declared and a minimum coupled experimental design linking composition or chemical proxy, rheology, cure and printing or part response. It supplies no manufacturing recipe, mixer setting, vacuum condition, filtration grade, acceptance limit or scale-up rule.