Joseph Paris
gantry construction (1)

Original page created on 25/01/2020.

First realization in 3D printing

I won’t go into much detail on this realization, because using 3D printing did not entirely satisfy me on several points:

• Long parts are too flexible and deform quite easily, albeit moderately;
• All the parts require, because of the layer-by-layer printing process, significant sanding, easy on large surfaces, much more delicate or even impossible on small ones, all the more so since small relief details have been provided which may disappear during the operation. See photo below.
• Parts which, in reality, are made of sheet metal, are poorly rendered in 3D because of the minimum thickness required, around 0.5 mm.
• Associating 3D parts, of a quite approximate dimensional precision, with much more precise photo-etched metal parts is not so easy, and requires for example fixing holes larger than initially planned.
• Finally, 3D printing is globally more expensive than photo-etching, the downside being that the latter requires more time and skills.

Curiously, the surface roughness has no obvious relation with their obliquity.

Each realization, this one as the other described further, requires a combination of both techniques, 3D printing and sheet metal soldering, but in different proportions.

Seen from afar, 3D realization seems pretty good. Its assembly is still faster and requires less technicality than that of soldered metal which will also use 3D parts, but in small number, and will be globally cheaper.

Here are some pictures of this first realization, presented on a small diorama built for the occasion. The only parts that are not in 3D printing are the footwalks, the ladders and the entire spreader. This spreader, more detailed, will be described in the second construction.

It will be noted that the driving cab is absent. Indeed, this part posed the most difficulties for me, and the first ended up exploded into pieces! As of this writing, I’m not finished with these issues yet.

You can move the mouse over the images to see more details.

Testing the spreader horizontality with an LS Models swap body. Note that the gripping is carried out without problem, as long as the container meets the NEM standard. The rope length adjustment is very simple.

Marking

The markings were made on special decal paper, with my inkjet printer. It’s fairly simple and inexpensive, but there are a few drawbacks:

• It’s impossible to print in white with the local means. So if you need white characters on the underlying background, you can’t use a transparent sheet; the background must be printed with the colour of the support on a white background sheet. However, this colour is not easy to reproduce exactly.