Muscle Fascicle — Build Guide

Overview

A fascicle is the base actuator unit — a self-contained artificial muscle fiber consisting of a load-bearing core, a heating element, and protective sleeving. Multiple fascicles bundle together to form a muscle group.

Structure

Each fascicle has 4 concentric layers (outside → inside):

Layer Material Function
4. Outer termination Heat shrink Strain relief, fray prevention at sleeve ends
3. Protective sleeve PET braided sleeving (6mm) Mechanical protection, abrasion resistance
2. Heating element Nichrome wire (0.15mm) Resistive heating of nylon core
1. Load-bearing core Nylon + Kevlar (twisted) Contractile element, tensile strength

Cross-Section

     ┌─────────────────────────┐
     │     PET Braided Sleeve  │ ← Layer 3 (outer)
     │  ┌───────────────────┐ │
     │  │  Nichrome Coil     │ │ ← Layer 2
     │  │  (tightly wound)   │ │
     │  │ ┌───────────────┐ │ │
     │  │ │ Nylon+Kevlar  │ │ │ ← Layer 1 (core)
     │  │ │ (twisted)     │ │ │
     │  │ └───────────────┘ │ │
     │  └───────────────────┘ │
     └─────────────────────────┘
         HEAT SHRINK at both ends
         FERRULE at actuator connection end

Side View

[Heat Shrink]──[PET Sleeve with core + nichrome inside]──[Heat Shrink]──[FERRULE]
   end                    middle                    end         (crimp to cable)

Materials Per Fascicle