A silicone pencil preparation device includes: a conveying apparatus, a grabbing apparatus, a silicone injection molding machine and a control apparatus. The conveying apparatus includes an unprocessed pencil conveying apparatus and a processed pencil conveying apparatus. The silicone injection molding machine includes a main machine provided with a mold and a mold closing system, the mold includes a front mold and a rear mold, the mold is secured onto the mold closing system, and a middle portion of a front mold cavity is provided with a pencil carrying slot. The control apparatus is configured to perform the following steps: moving an unprocessed pencil to the pencil carrying slot; performing a mold closing operation; performing an injection molding operation on the front mold cavity and a rear mold cavity; performing a mold splitting operation; and moving a processed pencil in the pencil carrying slot to the processed pencil conveying apparatus.

A method for forming a preform or part including the following: dispensing an initial amount of an additive and a thermoplastic resin into an injection molding machine; forming the preform or part by operating a molding machine to inject the thermoplastic resin and the additive at the initial amount into a mold of the preform or part; measuring realized visual parameters of the preform or part; comparing the realized visual parameters to the target visual parameters and determining whether the realized visual parameters are within a predetermined acceptable range of the target visual parameters; if the realized visual parameters are outside the predetermined acceptable range of the target visual parameters, adjusting the initial amount of the additive to a modified amount estimated to achieve the target visual parameters; and forming an additional preform or part by operating the injection molding machine to inject the thermoplastic resin and the additive at the modified amount into the mold of the preform or part.