Patent ID: 7790070

Claim:
A setup method of a mold assembly for optical parts, in which a fixed mold and a movable mold are clamped while adjusting a temperature so as to inject a molding material into a molding cavity provided between the fixed mold and the movable mold to produce an optical part, the setup method using: the fixed mold and the movable mold, at least one of which includes a locating projection protruding toward a side opposite to a mold matching surface; a holding member for holding at least one of the fixed mold and the movable mold, the holding member having a locating hole formed on a part of a surface of the holding member on a mold side; and a locating member which is formed of a material having a smaller linear expansion coefficient than linear expansion coefficients of materials of the holding member and the locating projection and which has external and internal surfaces, the external surface being adapted to be fitted into the locating hole and the internal surface being adapted to be fitted by the locating projection; the setup method comprising: a first step for making adjustment to obtain a first temperature of the holding member meeting a following relationship: t 1+40≦first temperature≦ t 1+60° C. wherein “t1” indicates a temperature of the holding member at a time of molding an optical part in the mold assembly; a second step for installing the locating member in the holding member under a temperature condition obtained in the first step; a third step of adjusting a temperature of the holding member within a range of t1±5° C. and adjusting a temperature of at least one of the fixed mold and the movable mold to a second temperature meeting a following relationship: Second temperature≦ t 1−10° C.; a fourth step for mounting the locating member with the locating projection of at least one of the fixed mold and movable mold under a temperature condition obtained in the third step; and a fifth step for adjusting a temperature of at least one of the fixed mold and the movable mold within a range of t2±5° C. wherein “t2” denotes a temperature of at least one of the fixed mold and the movable mold at a time of molding an optical part in the mold assembly.