This is a remix which was originally made by Pomi.  Made body walls thicker, blade holding slot narrower and spring hole diameters larger.

Filament cutter for cutting 3D printer filament.  Blade is set at a 45-degree angle to filament when inserted in cutter.  Spring operated to return blade to start cutting position. 

Printer:

• Printer:  Prusa MK3s
• Filament:  Prusament PETG orange
• Slicer:  Default settings for PETG using PrusaSlicer

Parts Required:

• (1) segment from snap-off blade, 18 mm.  I used Master Mechanic #704716. 
• (2)  M3 x 24 mm or 25mm Socket Head Screws
• (2) springs 24mm long, M3 screw must fit inside spring.      I used springs from a BIC Clic Stic pen.  Springs can be shorter but must have enough expansion strength to lift cutter top. 

Assembly:

1. Print parts.
2. Take one piece of snap-off blade and put it into the upper part. Use pliers to avoid injury.  There is a small mark near one end of the blade pocket which shows you where the tip of the blade should be inserted.  Blade will fit tight. 
3. Insert both screws into the holes on the bottom of the cutter body.
4. Insert springs into holes on the top of the cutter body.
5. Place the top part on the main body and press it together.      Make sure springs insert into springs holes on top part. 
6. Tighten the screws approx. (3) turns.  Check the filament hole to see if can see the blade.      Adjust screw length until blade is just above the filament hole. Tighten screws raise the blade and loosening screws lowers the blade.