300mm spool drying chamber for Eibos Polyphemus

Intro

This chamber is meant to stand ontop of an Eibos Polyphemus base as a temporary chamber when drying up to 300mm diameter, ~158mm width spools. This covers most 3 and 5kg spools.

Design

The chamber is designed to fit into a 256mm cubed system effortlessly and likely into an mk4(not tested). It prints in 5 main pieces (4 sides + the lid) plus some steer pins. It has a magnet interface for 8x3mm cylindrical disc type magnets to hold the upper half to the lower half.

The individual pieces of the upper and lower half are joined together by a simple dovetail interface and low viscosity CA glue. (or whatever glue method preferred)

The lid has handles integrated to not add more height to the chamber.

The main benefit is drying of large filament rolls with the polyphemus dryer. Specifically targeted towards the 300mm diameter 3kg filament rolls that Recreus filaflex 82a comes on. I prefer to center-hang the large spools and the drychamber is prepared to hold a 27mm wooden rod axle ~185mm long. The main reason for this is that center-hanging the spools assures a smoother pull force needed to unwind the filament. Sometimes larger spools are not fully round and the high mass can make for big variations in pull force if using the rollers. That said it is possible to skip the axle and place the roll on the polyphemus base if the roll is of good roundness and harder plastic.

I have used PETG to print the parts, and the lid can be printed in translucent petg with settings to make it as transparent as possible. https://wiki.bambulab.com/en/knowledge-sharing/transparent-petg

The central part of the lid is only 1,2mm thick to allow more visibility.

On the sides there are small handles to pry the magnetic force apart with one hand when the upper half is meant to be lifted off.

In the lid there are two small holes for ventilation.

Hardware

It has slots for 8pcs 8x3mm magnets. 

There are slots for 6pcs steer pins to align the upper and lower halves so the magnets aren't strictly necessary but add a nice touch.

To attach the lid to the top use up to 14pcs small wood screws 2,5x13mm approx.

Wooden rod ~27mm diameter 185mm long for center hanging the rolls. A 1" / 25mm metal tube works just as well. Additionally some spool adaptor is needed depending on what spools will be used. The provided model works well for the 3kg filaflex rolls. 

Printing

The parts are printable on a 256mm cubed bambu system and has been printed in several copies. They are designed to fit the Prusa MK4 as well, but I have not tested this myself. The lid is 248mm in the longest direction, so it is a tight fit to the available 250mm.

All parts print without support, but platform adhesion is important to get a straight seam between the lower and upper half. Some well placed brims can be useful depending on your print process. The pictured prototypes are not perfect in this regard but still work well.

Assembly

I have found it easiest to press the dovetail together rather than sliding it together.

Aligning and pushing one end of the dovetail together first and then the rest works well but requires some force.

After that a low viscosity CA will easily penetrate the joint and lock the parts together.

The printed steer pins glued into the intended slots, the remaining sockets are for the magnets. If using magnets pay extra attention to the polarity. I like to insert them all at the same time to not mix anything up. 

Tip: Slide magnets off a stack without turning them and insert them into the first half, then turn the magnet stack and do the same for the other dryer chamber half. This has eliminated installation errors for me at least. Secure with low viscosity ca glue.

Example with a 3kg filaflex roll

Will sit like this on the dryer's base.

The dry chamber is designed to use the already existing ptfe-tube outlets front and rear of the polyphemus dryer.