After multiple iterations from my first design (Low profile Iqos Heets/Terea ashtray by Joesn | Download free STL model | Printables.com) I eventually came up with a design that's robust and works smoothly.
Independent of the material, only use mechanically strong filament. Avoid “silk” filaments as well as most matte filaments as they are either too weak or have bad layer adhesion.
PLA generally works well, but I'd probably recommend PLA+ for improved toughness, especially for the slider. With standard PLA, the slider will also become quite loose rather quickly so it might slide open on it's own in your pocket
PETG is likely a better choice, but is harder to get working properly, especially during the break-in period (instructions below). Also stringing can cause issues with the sticks getting stuck.
I had some quite good results when mixing PLA+ and PETG with the container, slider and end-stop (optional) being printed in PETG and the lid & locking bar printed in PLA+
I personally use Cura, so the names and availability of these settings may vary…
Layer Height: 0.2
Walls: 2
Top/Bottom Layers: 3
Infill: Doesn't really matter… 10+% but I use 30% Gyroid
Support: Standard with XY Distance of 1mm (otherwise removing the support is a real pain)
I also added support blockers on the slider as there no supports are needed (see print orientation screenshot)
Ironing: All layers (This is recommended for smooth operation)
The model has very tight tolerances to ensure a perfect fit. Therefore a dedicated break-in routine is needed.
There is no difference in the break-in between PLA and PETG, but the tougher and “stickier” nature of PETG make it a bit harder.
Pre-Check: Make sure there are no blobs or malformed edges. Cut them off before starting to break things in.
The author marked this model as their own original creation.