This is a simple tool to more easily and securely close ziploc bags.

That sounds ridiculous, but hear me out. Consider complicating factors:

• A bag with double zippers
• A particularly heavy-wall bag, perhaps a foil-lined bag
• A bag that's stiff from being in cold storage
• A bag that has been folded, leaving creases that make zipper alignment difficult
• Nitrile gloves or moisture makes it more difficult to slide fingers across the bag

This tool solves all that. It works on heavy bags that came out of the freezer. It works on tiny little bags too. The PLA slides smoothly on PE. It's ambidextrous. It's simple. It's parametric.

Compared to other clip-style bag zippers, this actually provides mechanical advantage.

At first it seems a bit fiddly, but after a couple uses, you realize how little finesse it actually requires. You can be remarkably careless and drunk and close routinely frustrating bags almost accidentally on the first try every time. It's almost funny how well it works.

The reason is that we're trained to be cautious and attentive by the nature of the process. We must balance the applied pressure to avoid stiction while ensuring that the pressure is adequate to close the zipper while preventing the zipper from getting derailed. Without thought, we expect the process to be tediously closed-loop. This tool makes the process so immune to pressure that we can safely operate in open loop. We literally don't need feedback anymore. A blind swipe closes the bag assuredly.

Included are two sets of files:

• the full design
• a simplified test part
  For each, there's an SCAD file and a collection of STL files with incremental clearances for the print-in-place hinge (0.20mm - 0.50mm in 0.05mm steps).

The spring is a common ballpoint pen spring. See other notes in the SCAD file.