Platypus skull 3d print9/25/2023 ![]() The cap of a Platypus pen has an outer layer made with shiny, colourful filament and has an interesting surface pattern and the plastic. The strength of the sandwich is much, much higher than the strength of the two printed layers. Furthermore any weakness is especially problematical when the object is printed with a single wall, as are most parts of a Platypus pen! What to do? Well, the solution to this problem is conceptually easy: make an epoxy-bonded sandwich of nested components. That inter-layer weakness is not much of a problem for thick-walled objects and for solid objects, but for a long thin-walled thing like a fountain pen it can be critical. The plastic is strong in the direction of its layer plane because it consists of a continuous strand of extruded plastic, but the object can be weak at the layer junctions because the plastic of adjacent layers is incompletely welded together. The layer by layer nature of 3D printing usually leads to uneven strength. You may need a magnifying glass to see it because the part was printed with a high quality printer fitted with a direct drive extruder and the printing settings are optimised to minimise the seam. It does have a seam at the thread that connects to the pen body. There is one component in the Platypus pens that is printed in the conventional layer after layer mode: the section inner. Single wall helical printing is often called ‘vase mode’ printing, and it eliminates seams and pimples by removing the need for filament retractions and un-retractions. Well, not exactly one layer, but the extrusion path is a single helix. Most of the components are printed in a single layer and so there is no seam or pimples. Platypus pens are designed to almost entirely eliminate this problem. The retractions and un-retractions almost always leave visible defects on the surface of the object, defects that are called seams where they are vertically aligned and pimples where they are randomly scattered over the surface. That problem is typically combatted by having the filament retract suddenly just before the layer change and then un-retract when the nozzle reaches the start of the next layer. Each will be dealt with in turn below.Ĭloseup of an FDM 3D-printed object showing clear layer lines and defects that arise during the transition between layers. The layer by layer process of FDM 3D printing brings some important limitations to the objects that can be printed, and those limitations are relevant to fountain pen production. Limitations of FDM printing for pen production It may not need to be said, but Platypus pens are the product of rapid prototyping and iterative design. My second 3D printer-the one on which I print the Platypus pens-is constructed with parts printed by my first, and the first was repaired and improved with new parts printed by the second: a nice RepRap circle. The first RepRap machine was able to print many of the components of itself, which were then used to make a second RepRap machine which printed the parts for a third, and so on. The “Rep” part of RepRap is short for self-replicating. The 3D printers that sparked the development of consumer-level 3D printers were called RepRap in recognition of that role: the “Rap” part is short for rapid prototyping. It’s the total turnaround time from design to inspection and testing that is rapid with a 3D printer, and that short turnaround facilitates design iteration and optimisation prior to the product being manufactured by more conventional methods. A 3D print might takes hours to complete which stands in contrast to a few seconds to injection mould an object from plastic, but the 3D printer is ‘rapid’ because the tooling for the injection moulding process might take weeks or months to make or procure. (And then more time is taken to assemble and finish the pen, but that is not the topic of this blog post.) Rapid prototyping and developmentĭespite their slowness 3D printers are widely used in the process called ‘rapid prototyping and design’. The components for one Patypus fountain pen take about four hours to print altogether. The layer by layer process intrinsic to 3D printers allows for a remarkable range of object shapes and designs to be formed, but that flexibility comes with a downside: 3D printers are quite slow. If you are interested in learning more about 3D printing then you can read some of my other blog posts, and I recommend the video series about the basics of 3D printing created by YouTuber Tom Sanladerer.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |