Some of my best design ideas pop up while browsing hardware and kitchen supply stores for items to repurpose and incorporate into my 3D printing projects.
You envision some preliminary concept of a project. You have a rough idea about shape and size, perhaps even the material. But you have absolutely no clue whether to start looking in the pet supplies aisle or the household goods department.
Let’s say you were to make a (let me think…) 3d printed paraffin wax mould! It’s a device for embedding microscope specimens in paraffin before sectioning it with a microtome.
I bet you have equally weird project ideas rattling around in your head…
Looking for… “it”
Come on, it will be fun! It’s like going on a treasure hunt in a warehouse. You can’t look it up on the customer computer terminal because you haven’t the slightest idea what to search for.
As for the paraffin mould: It should probably be some kind of cylindrical, hollow item. Maybe a spice can or some kind of tube that can be embedded in some 3D printed fixture.
Eureka!
On my third lap around the store, I spotted these ice trays for making small ice cups. The reverse side turned out to be perfectly shaped for casting paraffin wax blocks!
After measuring the size of the individual cavities in the silicone mould, I went ahead and designed a plastic fixture in FreeCAD. I designed the fixture with a screw-fastened cover that clamps the silicone mould firmly in place.
I embedded four M2-sized nuts inside the base to ensure proper grip for the cover screws. The lid functions as a holder for the mounting rod that goes into the specimen holder on the microtome. Two grub screws holds the mounting rod in place during hardening.
The silicone mould fitted like a glove over the 3D-printed fixture. I also added four alignment notches near the bottom of the mould to help centre the paraffin block on the mounting rod as it sets.
Finally, I topped it off at the very bottom: Four self-adhesive rubber feet of the kind you’ll get from any large web store.
At least the first test run went well. The hardened paraffin block came out of the mould effortlessly and perfectly shaped. Loosening the grub screws on the lid made it easy to remove the block and its mounting rod.
