Extrusion chamber general

Extrusion-based 3D printers are generally efficient with feed roller mechanisms that push the feedstock wire downwards in to the heating chamber. Although smaller in number, pelleted-base printers use a screw-type mechanism to delivery molten material to the nozzle. The most recent example is the David 3D Printing by Sculptify (from Kickstarter ). 

The high pressures used in mercury porosimetry gives erroneous results with deformable material such as fabric. A more general version of liquid porosimetry, based on the same principles, uses a variety of liquids and can be carried out in the extrusion mode [79,80]. In this technique, a pre-saturated specimen is placed on a microporous membrane supported on a rigid porous plate in an enclosed chamber. The gas pressure within the chamber is increased in steps causing the liquid to flow out of the pores. The amount of liquid removed is monitored by a top-loading recording balance. One also has the... 

---