Abstract: A machining condition search device according to the disclosure includes a machining condition generation unit, a practical machining command unit, a machining evaluation unit, a prediction unit, an optimum machining condition calculation unit. The machining condition generation unit generates a machining condition defined by one or more control parameters settable on a machining apparatus. The practical machining command unit causes the machining apparatus to perform machining based on a generated machining condition. The machining evaluation unit generates an evaluation value of performed machining, on the basis of information indicating a machining result of the performed machining. The prediction unit predicts an evaluation value corresponding to a machining condition under which machining is not performed, on the basis of the evaluation value and the machining condition corresponding to the evaluation value.

Abstract: A polyimide varnish which is a solution having a polyimide and/or a polyimide precursor dissolved in an organic solvent and which is useful for forming a polyimide coating film on a substrate by coating the solution on the substrate followed by heat treatment, wherein from 5 wt % to 60 wt % of the organic solvent is a lactic acid derivative of the formula (I): ##STR1## wherein each of R.sup.1 and R.sup.2 which are independent of each other, is hydrogen, a C.sub.1-5 alkyl group or a C.sub.1-5 alkenyl group.