Parametric Cup Holder Mug/Bowl Adapter - Optional Handle Notch

Simple parametric cup holder adapter. Default .stl file is made to fit the holders in our sofa and hold all of our mugs, as well as a handful of snack bowls we have. 

The OpenSCAD file allows adjusting the radius and height of the part inserted into the mug holders - I make mine at least 1.5cm long and around 0.1cm smaller than the cupholder to make it easier to fit. You can also adjust the size of the mug holder region, as well as the size of the external rim. There is also the option to include a notch in the design for mugs with low or large handles which would otherwise hit the rim.

Printing

Material

Since this is holding hot mugs, I used PETG. If printing in PLA, I'd recommend gluing a layer of fabric onto the top surface to reduce the risk of weakening during use. ABS/ASA/Nylon should all work fine, and it should work OK in TPU too.

Walls

I've found that 3 walls is plenty with PETG since there's not much horizontal loading during use. For the top surface I used 6 layers, this was probably overkill but it's given a very sturdy surface. Bottom surface is unimportant, you could probably get away with just infill, but I used a single layer.

Infill

This is going to depend a bit on your use case - for the default size being used to hold a normal coffee mug, as long as you have plenty of top layers you can get away with as low as 5% infill just so the top surface doesn't have as far to bridge and still have a reasonably sturdy structure. If you make it bigger, more infill won't hurt.

Orientation

This is best printed with the rim facing up with supports on the lower face - you don't need a huge amount since any ugly bottom surfaces will be hidden in use anyway.