Artificial fingernails for classical guitar

UPDATE (February 2025): Now with Step and Fusion files to allow adaptation to individual finger shapes.

My fingernails break often, but I didn’t find generic artificial fingerpicks adequate.

PATH TO A SOLUTION: Create a 3D scan of the fingers, then build a 3D printed, made-to-measure design around them.

PROBLEM 1: Acoustic properties of the nail need to be addressed:

• Softness & springiness
• Friction with string
• Internal structure

SOLUTION: Separate nail from the base. Flat printing gives the best internal texture and boundary texture. Moreover, it allows for a flexible choice of materials: Recall the Shore scale of 3D printing materials:

• PLA: 80D
• PETG: 76D (Ultimaker data sheets)
• FiberFlex: 40D (Fiberlogy data sheets)
• Equine hoof (keratin): 70D (https://www.researchgate.net/publication/324722739_Nail_Properties_and_Bone_Health_ A_Review)
• Foot sole: 30D (https://doi.org/10.1016/j.foot.2012.01.003)

Friction: The flat print allows tangential boundary structure with no steps between layers.

PROBLEM 2: The finger changes shape when bending, pushing the fingertip forward.

SOLUTION: Reshape the midsection of the fingertip. The finger has a relatively fixed width at the nail and joint but is compressible in the mid-section. Build support around compressible the part.