Gas pressure printing process

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The gas pressure process ( GHD for short ) is a specialized injection molding process in which the shaping of a molded part is supported by a gas cushion between the molded part and the mold wall.


The gas pressure injection process is similar to internal gas pressure injection molding with the difference that the gas is not introduced into the injection material itself, but between the mold wall and the outer skin of the molded part. The molded part is supported by the gas cushion during cooling, so that sink marks can be avoided. The process is used for heavily ribbed molded parts, molded parts with partial mass accumulations (e.g. domes) and molded parts with long flow paths.


  • excellent surface quality
  • low-stress parts
  • lower tendency to warp
  • Stiffness maximization through thicker ribs (rib savings)
  • Reduction in the formation of cavities
  • The tool can still be used conventionally.

Individual evidence

  1. Helmut Schüle: Special process in injection molding . In: Peter Eyerer, Thomas Hirth, Peter Elsner (Eds.): Polymer Engineering . Technology and practice. Springer, Berlin / Heidelberg 2008, ISBN 978-3-540-72402-5 , gas background printing process, p. 223 ( limited preview in Google Book search).