I made a paste dispenser that uses a 1ml syringe. (The syringes used were Terumo syringes.)
*: The cylinder included in the print file is a dummy print and will not be used.

• Required parts
  • Rubber band x1
  • M2-5mm cap bolt x2
  • M2-12mm cap bolt x1
  • M2-20mm cap bolt x1
    +4 printed parts

assembly

1. Install M2-6mm bolts on latch parts. (Stop turning when the rotation becomes a little heavy, or the part will break. Smooth the hole in the yellow frame part with an M2 drill.
   
2. Attach the M2-6mm bolt to the blue frame of the handle part. Smooth the yellow frame part with an M2 drill.
3. Attach the latch to the handle parts with M2-12mm bolts.
   
4. Hang the rubber band between the M2 bolts. You may need to use several layers depending on the rubber bands you use. Please refer to the picture.
   
5. Attach the handle parts to the body using M2-20mm bolts. Make sure the handle parts move smoothly without resistance and apply grease if necessary.
   
6. Mount a syringe filled with paste or other material. The slot to be used depends on the volume of the contents in the syringe, so select the most appropriate location.
   
7. Place the gear parts over the syringe.The piston of the syringe is clamped onto the gear part.
   
8. The syringe fits into the piston part of the syringe when viewed from the rear side like this.

It works like this. If it does not work smoothly, check the hinge that is fastened with M2-20mm.