WDM or Wax Deposition Modeling is a unique and relatively unknown 3D printing technology. It is one of the most expensive and time consuming processes.
This technique uses melted wax to build up the prints and another type of wax with lower melting point as support material.
Advantages of the WDM process:
Support material can be removed without leaving any trace on the surface.
Support material completely covers the supported surface providing 100% sustainment, therefore, there is no difference in surface quality between the supported parts and the unsupported parts of the print.
Layer thickness can be as small as 0.012 millimeters.
Even the most intricate details are accurate and visible.
The prints are suitable to be used in lost-wax casting and can be combined with regular modeling wax.
Disadvantages of the WDM process:
Slow – WDM is one of the most time consuming 3D printing processes.
No materials to choose from, the object is always printed in wax.
The 3D model is first sliced into layers by the Slicer software. Layer thickness can be specified between 0.075 and 0.012 millimeters. Among the commercially available 3D printers, this technology allows the smallest layer thickness to be specified and is the most precise in printing intricate detailwork.
Based on these slices, the software creates a file that the 3D printer can use to print the desired object.
Before the printing process starts, the printer heats up the wax to 120 degrees Celsius. Even when not printing, the printer maintains a steady 80 degrees Celsius for storing the wax.
When the printhead, the wax pipes and the containers reach ideal temperature, the printer prepares the printing tray. A 15 cm long mill head machines the surface to make it completely even.
When the tray is ready, the printer calibrates the printing heads by printing on a strip of paper, using a laser to verify the result and making adjustments if necessary.
If everything is in order, the printing process begins. After each layer, the printer monitors the printer heads, waits for the wax to cool down and solidify, then machines the top of the print with the mill head in order to guarantee, that the following layer is printed on a completeley solid and even surface.
The print is surrounded with support material, the purpose of which is not only to support the structure, but to ensure that all the fine edges are preserved.
When all the layers are complete, the printing tray can be removed from the printer. Since the first few layers of the print are made from support material, the print can be safely heated to 70 degrees Celsius and removed from the tray without causing any damage.
The rest of the support material is then completely removed in a heated bath at 55 degrees Celsius.
The WDM 3D printing technology is popular among jewlers, dentists and scale-modellers for whom accurate detailwork is of importance. The prints are themselves never the end product, but are used in creating silicon moulds or in lost-wax casting processes.