Patent ID: 6547995
Filing Date: 2003-04-15
Classification: B29C

Abstract:
In an extrusion apparatus having a liquifier which receives a solid element of a material that exhibits thermal expansion, heats the material, and deposits a flow of the material through a dispensing tip thereof along a predetermined tool path at an output rate, said apparatus using a material advance mechanism to supply the solid element of material to the liquifier at an input rate which controls the output rate, a method for matching the output rate to a predetermined target output rate which is selected to achieve a desired extrusion profile of the material deposited along the tool path, comprising the steps of:predicting a melt flow component (QMF) of the output rate for a time step corresponding to a segment of the tool path, the melt flow being a rate of flow attributed to thermal expansion of the material heated in the liquifier; and commanding the input rate (QiS) for that time step so as to compensate for the predicted melt flow.