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@@ -46,6 +46,13 @@ The BOM for the air purifier is:
   - Heatshrink tubing 8mm (30mm long).
   - 4x rubber fan screws: https://www.pccasegear.com/products/34741/noctua-black-chromax-anti-vibration-mounting-bolts-20-pack. These unfortunately only come in a pack of 20, so you may find them in smaller amounts at other outlets. Alternatively you can use 4mm screw heat bolts and nuts, you will need to check the length you need depending on the thickness of your fan. For the fans I linked above you would need 30mm bolts.
 
+### 3D printing notes
+Just a couple of notes about the 3D print files.
+  - I designed the fan housing using Fusion 360 and exported STLs from there.
+  - I tweaked the design a number of times to get it to print easily on my Ultimaker 2+. You'll see in the images here (the magenta housing) an early version where the edges curled up badly. I recommend you print with a brim and a heated buildplate as that's what I have used.
+  - If you have a printer with a smaller buildplate I have included a folder in [3D_print_files](DIY-Air-Purifier/3D_print_files/small_printer_files/) with a version of the housing I split into 4 so it can be printed in parts then glued together. I have not tested this print at all so if you do print it please let me know how it goes. If there are changes required that's easily done.
+  - I've been printing in PLA with no requirement for supports on the default Cura settings for Ultimaker PLA, except I turn down the buildplate temp to 50ºc after the first layer, which helps prevent the edges curling. If you print in other materials then let me know how it goes.
+
 ## Tools
 You will need the following tools to assemble the device:
   - Soldering iron and solder