Customizable nozzles for SikaFlex / industrial glue / caulk (FreeCAD)

I needed to spread an evenly thin and wide layer of SikaFlex glue in a recent project. So I made myself a modular system for a variety of parametric nozzles.

When you first open the project file in FreeCAD it looks a bit messy…

So let's hide all bodies but master_nut and flat_nozzle and bring up the dim spreadsheet.

As you see, each nozzle to be printed consists of two parts: a nut for the glue cartridge and the nozzle as such. By modelling nuts with different threads, you can simple re–use all the nozzle design with no further effort because nuts and nozzles are interchangeable.

In the upper rows of the dim spreadsheet you find the parameters for two nozzles (to be true, l_tuelle is used by almost any nozzle design) – these are values intended to be altered, so they are marked bold.

In the second section there are the parameters for the nut fitting SikaFlex cartridges. 

You can take these as templates for your own nozzles.

When exporting a nozzle for print, select both the nut and the nozzle in the project tree–view on the left, then choose “export”.

Both bodies will be saved in one single (.step) file which you can import into the slicer. There you can see the two bodies per printable object.

When designing new nozzles, start making the diameter smaller close to the nut (not the tip) – this reduces waste of glue when disposing a used nozzle.

The closed_cap model is obviously not a nozzle – it's to seal the cartridge for storing. You can store open but sealed cartridges for days, weeks or even months (depending on the glue etc. inside) in a fridge or freezer. I've had SikaFlex that survived several months (at -18 °C) so I was able to use every bit of it.

Printing

I printed the nozzles in transparent PETG with perimeters only, no support needed. PLA should also be fine. I like the transparency because it makes the flow of the material inside visible.