《塑料技術手冊 熱成型（1 影印版）》：

　　Product geometries are limited to forms attainable by deformed sheets and consist mainlyof recesses and projections orthogonal to and arranged on either side of the plane of the sheetpreforms.This makes it convenient and reasonably accurate to classify thermoforming molds ashaving female or male cavities.The female mold consists of a recessed cavity or cavities formed ina mold block.This is the most common mold form， because it is easy to clamp the heated sheetacross the unobstructed mold face.The resulting product has a clearly defined male form and nota precise female form.

　　Often the simplicity of the female mold outweighs the cosmetic requirements of the product；thus， it is common to see a packaging product， such as a nest—type box liner， in which the recessedpresentation face is the imprecise second surface.

　　The male mold consists of a form or punch projecting from a mold block.The punch interfereswith the plane of the sheet preform so that sheet clamping takes place outside the mold.Subse—quently， the sheet is moved into contact with the mold.This action of a male mold requires using anincrease in the mechanical action of the process.The resulting product has a clearly defined femaleform and a not too precise male form.

　　The third mold type used in thermoforming is the matched mold （chapter 17）.This is a closedmold consisting of two halves， each defining one surface of the finished article.The matched moldis similar in concept to a compression mold （chapter 14）， but the cavity geometries remain limitedto shapes attainable by sheet preforms.

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