New version 6 page

K-Cups are notoriously difficult to cut. Knives and scissors are difficult and messy. Even my first gen Recycler with no moving parts, just a slot and a blade, was hard because you have to turn with the flimsy cup, which becomes more flimsy the further you cut, until the last 10mm won't turn to complete the cut.

I decided you'd have to grip the lid of the K-Cup where it's most rigid to turn during cutting. So, I made this (possibly over engineered) K-Cup Recycler, with a gripping turning ring, a retractable razor blade, and a lid ejector.

The only two parts that are not printed are the standard household razor blade and a ball-point pen spring (5mm x 30mm).

You must glue the retainer (orange) to the gripper ring (dark purple). This is the only part that needs to be glued. If you don't, it will fly apart when you try to eject your cut lid.

Latest model video

(Update): We changed brands of K-Cups and the Amazon brand was just a tiny fraction of a millimeter smaller, which caused it to slip and not cut. So I edited the gripper ring a 3rd time. Now it has deeper teeth to cut into the edge of the K-cup, and I reduced the count of teeth to 4, so it's not so difficult to press the cup down. Now it grabs both brands' cups equally well. Amazon glues their paper filter a little deeper into the cup also, which makes it difficult to remove. So, my next edit will be a razor position that reaches deeper into the cup to catch those deeper filters.
*The base edit is complete. It now cuts a bit further down the cup to release the glued filter inside better.

(Update2): superseded by update 4

(Update3 10/17/20): DGGrant had a good suggestion to make it less slippery. I've added gripping texture on the top left corner to help keep wet fingers from slipping. The print-all file and the individual base & top files have all be replaced with v4.

(Update4 12/2/20): It has been mentioned a couple times that the "Ejector" falls out too easy. I don't know why I didn't think of it sooner... but the Ejector now has a threaded retainer nut. Much more simple than heating the split ball and spreading it. The nut will make it simple, secure and removable. The "Print All" file has been updated to v5. A new "V5 Ejector+Nut" have been uploaded separately. If you've already printed the whole thing, you can just print the "V5 Ejector+Nut" to replace your current split ball ejector. Thanks cplhicks.

(Update5 12/12/20): Version 6 has been created with elongated finger grips and a blade guard. It's different enough that I wanted to post it separately. V6 is good for weak fingers or arthritis. You'll find it here : New v6 K-Cup Recycler

Update6 12/31/20: I was having some razor blade slippage with my original tray. I've upgraded the tray with a deeper razor cut-out and and a tapered edge to hold the blade down at the outside edge. This changes how you insert the razor blade. It should be inserted at the outside edge first, then snapped down into place. See picture. This holds the blade far better. I just hope all brands of razor blades have the same dimensions. I haven't tried any others yet.

Ultimaker

Ultimaker 2

No

No

0.4 noz 0.2 layer

25

Intended for PLA.

No supports or rafts needed. To print the entire thing, just print "K-Cup Recycler pint all". All of the individual pieces are loaded in case you need to reprint one piece.

The nuts can be a little difficult to thread onto the studs. If you clean them up a little, they go on well. It really depends on your printer quality/tolerances. If you think I should post some smaller or larger nut sizes, I'd be happy to.

You must glue the retainer (orange) to the gripper ring (dark purple). This is the only part that needs to be glued. If you don't, it will fly apart when you try to eject your cut lid.

Everything was created with sufficient tolerances to make all parts move smoothly without lubrication.