Progress Report:Materials

TestingManoTech AssociatesJina KimForrest LiauDavid LinTeresa Wang

Review of Project Goals

Fulfills two criteria: Low-cost materials Anatomically user-matched

Does not include: Detailed hand aesthetics (color, texture, etc.) Articulating joints

Progress Overview

Interview with Charles Mathis

“Clay Block” Materials

Reversible Glove Possibilities

The 4-Step Process

Interview with Charles Mathis ManoTech met Charles last Thursday, 3/9 Watched and practiced making wax molds

Wax

Advantages Gives better detail and shape of hand in final mold little shrinkage Is relatively easy to use Allows for mistakes

Disadvantages Must be maintained at 120 degrees F in a larger

pot or deep-fryer

Kidz EZ Cast Mold

Advantages MoldGel sets in 4 – 5 min. Works at room

temperature

Disadvantages Lumpy mixture Water leaks from bottom Air bubbles reduce detail

5-Minute Molding Putty

Advantages Not messy Takes ~10 minutes to set at

room temperature

Disadvantages Requires significant amount of

material Difficult to mold exactly around

the hand and maintain shape

Mini Casting Kit

Advantages Comes in a kit

Disadvantages Vapor and powder is toxic Requires 4 – 8 hours for mold to set around hand

Cannot be used

Gypsum-based Plaster of Paris Advantages

Cures at room temperature in 1.5 hours

Retains detail of initial mold

Disadvantages Hardened material is brittle,

easily cracked Transfers bubbles and

cracks to solid hand

Brushable Latex

Advantages Brushes on easily Reversible Maintains shape Able to use leftover latex

Disadvantages Needs ~10 coats with a 20-minute incubation

between coats

RTV Polyurethane

Advantages Very elastic Potential to be reversed

Disadvantages 30-minute pour time Messy By dipping, creates non-uniform layer Dipping twice gave a thin coat that rips

Summary of Materials

Initial Mold

Solid Hand

Reversible Mold

Wax EZ Mold Molding

Putty Casting Kit

Plaster of

Paris

Brushable

Latex RTV

Polyurethane

Prosthetic Hand

Silicone

Rubber Polyurethane

Foam

Schedule

March April May6 13 20 27 3 10 17 24 1 8 15

Init. Mold Solid Hand Rev. Mold Fin. Und. Prod. PrototypeMaj. Test.B. PlanPoster/present.

Materials Selection Process Optimization

TODAY

Future Plans Procedures

Improve reversible mold-making method

Materials Optimization Solid hand mold Prosthetic

Hardness & Elasticity Testing Underlayer: silicone rubber Reversible material: latex, RTV polyurethane