Sovol/Comgrow SH02 Filament Dryer Enhancement Suite

The Sovol / Comgrow SH02 filament dryer has been deservedly criticised for inadequate venting and noise. I have attempted to improve both. The design shown should be self explanatory but don't attempt it unless you are prepared to drill holes in your dryer - It's very easily done and I guess can be as easily undone by printing blank plates and covering holes should you wish to (unlikely) Part 1 - Noise Abatement Boy, was this a screamer !! Intolerable high pitched whine. Some have changed fans and there are various ways to attempt to improve this aspect. I am only part way there but I have managed to drastically reduce the noise level. Several mods on Printables show axial fans being used. This fan type is not well suited for this purpose as axial fans are not pressure fans and drying times using one of these will be greatly extended. The centrifugal fan used in the SH02 is the correct type - There may be quieter ones out there but improvements can be made to the stock fan. Step 1 - the fan is held in with 2 screws - fully tightened against the plastic base - I noticed that there is clearance between the screw diameter and the fan mounting holes - so I carefully applied RTV silicone to the screw threads leaving only the bottom of the screw clear - messy operation - just do your best - the finished cured articles have to fit in the fan holes of course - and if you do it properly, each screw will be isolated from the fan casing - Next you will need 2 tiny O-rings - feed the screws through the fan case and fit each with an O-ring - This will further isolate the fan from the dryer case. This approach could be further improved by using slightly longer screws which would allow O-rings under the screw heads as well as at the bottom. Refix the fan and tighten only enough to keep it secured - Extra tightness = extra noise Step 2 - I removed the white silicone seal from the base and used soft casting silicone to fill in the 'egg-crate' stiffeners in the base. This material handles the heat, increases the density of the base and provides sound insulation. I have also run RTV silicone around the borders of the side panels to create closed wells and next time I open the case I'll pout more silicone into the sides as well. Part 2- Fan Directors - Not photographed - The stock SH02 is very badly engineered in this area - Basically, the fan output is generally aimed at the heater inlet but is open all around so the fan just blows hopefully. - I inserted silicone isolated aluminium baffles between the fan and the heater (like an open V) - the baffles seal against the silicone pad in the base - a small gap has been left between the V and the heater inlet. This measure will largely prevent fan losses to each side. Part 3 - Vent Improvements The SH02 recirculates internal air - sucks (sort of) from the front base, passes humid air across everything in the base section (!) - enters the fan - out of the fan into the heater - into the top chamber and around again - with only the tiny stock vent hole at the top to supposedly release humidity - as Teaching Tech reported - it does not do a good job . https://youtu.be/ZHFjeUGFvrk Lifting the lid repeatedly will let out steam and drop the humidity quickly - but is a poor solution imo. I decided to increase the top vent hole so I tried that first - no real improvement - then 3 holes - one over each reel position and the central one - enlarged to approx 10mm and a single vent control panel siliconed into position. By itself - this was not enough so I drilled 5 more holed along the front panel - added the baffle at the rear and the triple vent panel. The baffle is intended to assist in directing returning air to the font vents. I used vehicle push pins to secure the vent controls to the panels, but you could print snap pins if you like - just don't use metal pins/screws unless they're stainless. The combination shown sems to work quite well - I run it with all vents open and it still reaches 70c without getting moisture build up. Part 4 - Desiccant Boxes The stock desiccant recesses needs sealed bags - I decided to print oversized boxes which can be filled with re-usable beads. The box lids clear a full filament reel nicely - can be lifted out for separate drying, or I guess can be dried (slowly) in the dryer if not being used for filament drying - Probably the best method is to dry them out in a microwave if you've used PC or other heat resistant filament to print them. Since printing these I have found several alternative desiccant boxes designed for the SH02 which fit the ridged compartment - mine is simpler - it is reduced in plan size to fit withing the recess ridges, but lifted in height to increase internal volume - the lid clips just rely on layer lines and tightness to keep them in place - You may want to pursue other designs. Future Improvements - I need to address the filament feed - I would prefer to pass the filament from the rear to suit my printer arrangement - Will update this once I sort it out I printed all items in CC3D PC+PETG filament blend - Plain PETG or other temperature resistant filament would be OK - Just don't use PLA or similar