Quick but not dirty printing

So, my son scavenged two 320GB drives from two laptops that were not very functional. He had space inside his own cavernous computer for them, and even a drive cage where he could fix the 2.5″ drives side by side. He screwed the drives onto the cage and it looked solid enough, but surely it’d look even better if there was something holding the tops of the drives. It was also a question of having space for the connectors, because this is not a standard layout, but would enable him to install both at one go. Using Autodesk Inventor, he designed a flat panel with four M3 screw holes in the corners, with the dimensions 67mm x 82,6mm x 2mm. Needless to say, this is a very simple print project, but the question was, would the measurements hold properly. My son is very handy with Autodesk products, so he wanted to use Inventor. I had never seen it in use, so I tagged along to see what was happening. Apparently, when you boot it, you see a three-axis plane setup, from which you can select the one you want to work in.

Inventor main window at start
Inventor main window at start

After that he drew a plane with the given dimensions, to which he added four holes. This is markedly different from Blender, where you could either first make the plane, extrude it to a flat cube, and then use Boolean modifiers to drill the holes. This results in a very complex face arrangement. The other option is to start with a hole (a circle), duplicate and size it and form a face between them, and after a bit of juggling, you have a corner to mirror twice on the X and Y,  and then you can size it all.

Dimensions on the 2D panel
Dimensions on the 2D panel

I have to say the Inventor way was very nice to see, and easy too. So, the next step was merely to extrude to a thickness of 2mm, and use the Print command (not Export as I would have expected) to create the STL file.

Extruded panel
Extruded panel

I imported it into Blender to see the design and I must say it is very elegant.

STL file imported into Blender
STL file imported into Blender

When you look at the corner in Edit mode, you see the face structure. Note that the material thickness of the corner is only 1.5mm from the hole to the edge. I was a little sceptical at this point, but wanted to have a go at printing anyhow.

Faces in the corner
Faces in the corner

We then went to the print lab and turned on Huey, the oldest printer. It needed calibration, which we found out the hard way, after we tried to print and no extrusion happened. The extruder was too close to the glass. Fortunately Z calibration is nowadays a two-click operation, and we did it in moments. After that we sliced again just to be sure and added a 6mm brim to the print. This is such a thin object that I wanted it to adhere properly and avoid warping.

Print ready sliced object in RepetierHost
Print ready sliced object in RepetierHost

Hit Print, and the MiniFactory started working well straight off the bat. Print time was around 50 minutes, because this thing is only 2mm thick, and it has no infill – there are three solid layers on the bottom and three on the top, but in this case, only two. So it’s all solid actually. And hey presto – when the print was done, and five minutes were spent waiting for the table to cool and the piece to loosen from it, we had the print. This image shows it in its place, holding the tops of the two drives securely in place. Even the holes for the M3 screws were of the right size straight out, so all he had to do was to clean out some debris from them and fit the screws.

Quick but perfect print
Quick but perfect print

I have to say I am very happy with the dimensional stability of MiniFactory, since we got the right size piece at the first try. A nice little exercise, this one.

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