3D PRINTING (PART 16)

Part 123456789101112, 13, 14, 15, 16

This is a short review on printing all sorts of things in 3D. So far, I use my printer at least twice a week; one printing session may consist in one or multiple iterations.

Since the beginning (check this post), many rolls of ABS and PLA have been melt and turned to technical or decorative parts. As explained below, I brought multiple refinements and fixes to the original printer.

Heating bed: mandatory for printing ABS; helpful for printing PLA too. This is a rather simple upgrade, a very good investment. It proved to be very reliable (check this post)

Printing surface: I originally used Buildtak adhesive mats. I use the plural as these surface may degrade along the time, partly due to “normal” wear” and also due to mistakes like: scratching the surface with a hot nozzle, damaging the surface while removing a sticky part. Many alternative are available now at moderate prices. I even tried the magnetic printing surfaces, but they are less convenient for printing ABS

Glass printing plates: I had a bunch of plates cut for me at the local glazier shop. Although thick glass plates seem to be very rigid, they are still flexible. I advise you to use retaining clips at the median points of each side and not at the corners in order to prevent “bending” the printing plate and thus generating adhesion problems while printing large parts.

Filament pusher: The Vertex K8400 printer features a Bowden type filament pusher. Which means that the pushing mechanism is note part of the printing head. As a consequence, the head is smaller and lighter. However the mechanism must be able to push at least 30/40 cm of filament through a nylon guiding tube down the the heated nozzle. So that the driving mechanism (a hobbed gear attached to a stepper motor) is busy pushing and pulling (during retraction cycles) during the whole printing process, leading to progressive heat up of the motor, the gear and ultimately the filament which start softening and loosing the grip. To prevent this I added a flat dissipator (same as for CPUS) to the stepper motor in order to prevent printing failures on large parts.

Belts: I once experienced a printing problem which resulted in a large mess of thin extruded filament. This filament hank travelled back and forth during this “mock” printing sequence so that some of the filament managed to escape and to stick in between a pulley and a conveying belt. This event resulted in a slight elongation of the belt and consequently to some play which was pretty visible while printing cylindrical parts. Replacing a belt is not so difficult. All you have to do is to free the pulleys (use proper Allen keys for the fragile set screws), remove the end ball bearing retaining covers, pull the rods and you’re almost done.

Grease: Think about the cumulated travel distance of the print head! The XY mechanism of the Vertex 3D printer features guiding brass rings sliding on steel rods. As the rods came greasy from factory, I assume that the rings are not self lubricated so that I do apply some grease periodically in order to prevent excessive wear. I am using MAGNALUBE PTFE grease because it sticks very well to the mechanical parts and proved to keep its lubricating properties for extended periods of time. As usual, clean the rods prior to applying a thin film of fresh grease.

Power switch: Well, as I was fed up plugging and unplugging the power cord before and after printing, because you do need and emergency switch on such equipment, I added a power switch at the bottom of the left side of the printer were a nice hole is ready to make this upgrade easy.

Spot light: Instead of using a light torch, I managed to build a simple spot light with a white LED sleeved in heat-shrinkable tube which illuminates the printing area. This is very useful while surveying the early stages of a print.

Software: I am a big fan of FreeCad (actually rev. 0.18) and I recently switched to Cura (actually rev.4.8.0) as a slicer.

So far so good, my 3D printing experience is (very) positive and I cannot imagine living without it !

HTH

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