LDM extruder kit offers adaptability & versatility

With the launch of the extruder, the group aims to promote the printing of fluid-dense materials and advanced ceramics. The extruder is able to interrupt and restart the extrusion flow, and can reach a level of precision very close to that of plastic polymer extruders thanks to the combination of screw and pressure extruders. With this technology it is possible to accurately control the flow of material and to use retraction to interrupt deposition.

The set includes a 3l tank, an extrusion piston, a stand for the tank, a pressure reducer, a return preventing valve, a safety valve, 1kg of porcelain, a cochlea and interchangeable pressure chamber, a high-couple stepper engine and an SD card which contains the .stl file for the two models PowerWASP and DeltaWASP, assembling instructions and some videos for preparation of the mixtures.

The WASP system includes a 7kg tank, which can be substituted with a 15kg model on demand. The preceding needle experimental models did not allow middle size printing because of the limited amount of mixture they could contain.

The tank can be refilled or cleaned simply by opening the caps located at the extremes. Inside, there is a piston with two 4 bar gaskets which pushes the material through the teflon pipe (diameter 12mm) which supplies the extruder. The cap located on the back has a safety valve set at 8 bar. On the stand of the tank there is a pressure regulator and a return preventing valve.

Inside the chamber, the material is funneled toward a screw which pushes it out producing a pressure of 40 bar without damaging the system. It would be impossible to reach such a pressure level with a common pressure extruder. This technology allows the air to outflow upward , eliminating the probability of finding bubbles inside the mixture. Like for a common pressure extruder, if there were bubbles the flow would be interrupted and the print would be damaged.

Furthermore, thanks to the screw, the density of the printing materials is higher. This allows to reduce the time for their change of state, from liquid to solid, thus eliminating the risk of collapse of the printed object. In the case of damage to the screw or chamber, the parts can be easily substituted. 

The set was created to be installed on WASP printers, but can be adapted to most existing machines. It is very easy to install WASP LDM extruder on other machines. Firstly, it is necessary to print the supporting cover (the source files are provided by WASP). Secondly, the extruder must be linked to the wire and the “number of steps per millimeter” must be set to 400.

This configurations are provided by the most common slicing softwares, like Slic3r or Cura.