eSUN filament reel silica drying pod

A variation on a theme

After seeing various ideas for a filament reel desiccant holder, I decided the concept seemed like a good idea.

As mentioned in previous posts, I am now using open source filament in my Sindoh printer and my Qidi. The filament is fed from a ‘hot box’ via a 4mm OD/2mmID PTFE tube into the Sindoh or the Qidi. The ‘hot box’ is not continuously powered but is just switched on occasionally to provide background drying. By adding a desiccant holder fitted into the reel centre hole, the background moisture level can be better controlled between powered heating sessions.

I have settled on using eSUN PLA filament and I modelled my desiccant holder specifically to fit the eSUN reel size. The Fusion 360 model for the silica holder is designed using Fusion Parameters. For those familiar with this Fusion facility, you can use the FX functions to customise the size of the holder to suit other reel sizes.

This finished holder is shown below.

The holder has two parts, the cavity and the end cap. The end cap is screwed and held in place with a print modelled 11tpi BSP thread. Both parts are printed with the large gripping flange face down on the bed. Slicer generated internal support will be needed for the overhanging threaded flange at the top of the cavity. After printing, inspect the two threads and where needed clean off any flash PLA. My prints meshed without any aftercare.

Note that while I have put ventilation slots in the barrel sides, these are probably not so effective once the holder is mounted into the reel centre. This leaves the end holes as the dominant air path. To help the air circulation in the latest download I have added additional holes on the end flanges (not shown in image above).

The desiccant can either be left in its supplied pouches or can be poured directly into the core cavity. Note that if the silica crystals are tipped lose into the cavity, the model will initially act as a sieve with any broken pieces of crystal falling out of the holes. If you are using lose crystals, don’t overfill the cavity. This will allow the natural printing revolution of the reel to cause the crystals to tumble in the cavity. This provides a more even exposure to the air.

You can buy bulk quantities of silica crystals that change colour with moisture absorption content. When dry they appear to be clear or orange and change to green when moist.

UPDATE – Linked below is a ZIP file containing the Fusion 360 file for the desiccant holder and the screw on lid. James at Clough42 gave me some pointers on this. The updated file uses the Fusion parametric functions (Fx) so that the depth of the gel holder can be changed to suit the width of the filament reel. Just change the Barrel_Length value to match the width of the reel in use.

Also in the ZIP are the STL files for a 68mm width holder and associated lid This will suite the width of most 1kg filament reels.

silica-gel-holder-programmable-height-v1

Links to similar or related post are listed below : –