Transparent or translucent filaments look promising on the shelf, but FDM printing often produces only milky blocks. PETG in particular often remains cloudy despite a clear mixture. Maker Tej Grewal shows how customized slicer profiles can be used to produce significantly more transparent components.
The central problem is the toolpath, i.e., the path that the print head travels inside the component. With standard profiles, the nozzle moves in a zigzag pattern or in complex patterns such as gyroid infill. This means that the individual extrusion paths lie in many different directions. Small transitions and cavities are created between these paths, where light is scattered. This makes the part appear dull and milky, even though PETG itself is transparent.
Grewal reverses the approach and treats the core of the component like a solid infill block. To do this, he sets the wall count to one, deactivates the top and bottom layers, and sets the infill to 100 percent. Another crucial factor is a fixed infill direction of 0 or 90 degrees. This allows the nozzle to lay down long, parallel paths layer by layer, through which light can travel relatively unhindered.
The material flow also plays an important role in the appearance. The print should run rather slowly, at about 20 millimeters per second. Many users run the nozzle at the upper end of the recommended temperature range and increase the flow slightly to close micro-gaps between the paths. Component fans are used sparingly so that the strands fuse well with each other.
Using these settings, Grewal produced a cover for a display, among other things. In a direct comparison, the version with directional infill appears much clearer than a version with the usual zigzag pattern. This does not replace visually perfect panes, but the results are often sufficient for light covers, simple light guides, or decorative parts.
Subscribe to our Newsletter
3DPresso is a weekly newsletter that links to the most exciting global stories from the 3D printing and additive manufacturing industry.
