So I just received my new Sunlu S2 Filament Dryer and it had the chance to be better than my current favourite, the Eibos Easydry. It gets hotter internally and heats evenly from all sides. There are however two major design flaws that keep it from the number one spot.

1. The filament output path is perpendicular to the spool center, going out diagonally upwards, so awful for direct drive from the top and also pretty bad for bowden setups from the side.

2. It does not have a fan installed or ventholes, so any moisture thats taken out of the filament just fills the chamber and stays inside. Opening the chamber slightly remedies this effect to a point

To make up for this I designed this simple wedge you can put in the front of the dryer, which keeps the lid ever so slightly open for the damp air to escape the machine. From testing I can say that this mod increases the machines performance by up to 40%! and helps cut down drying time and effectively energy consumption.

Additionally, the wedge includes a 4.4mm hole which should snuggly hold a bowden tube for 1.75mm filament with an outer diameter of 4.1mm so you can actually get a better filament path inside the dryer and less strain on the path. You can route the filament directly downwards for direct drive style systems or directly upwards for bowden style systems that are angled either horizontally or vertically upwards.

VERY IMPORTANT:
Make sure to print this wedge out of the most heat-resistant material you want to dry inside the machine. If you print it out of for example PLA and dry Nylon or PC at 70°C your PLA part will melt and deform. So if you want to dry Nylon, print it out of Nylon, for PETG out of PETG etc.

Prints oriented as it is without supports needed.