# GE Plastics Engineering Design Calculator

## Introduction

Welcome to the GE Plastics Engineering Design Calculator!

An introduction to the calculator is available. Help is also available at any time by choosing "Help" from the main menu.

## List of Selected Calculations

- Properties of Selected Material
- Spur Gear Calculations
- Related Information
All use of this system is subject to certain terms and conditions.

## Properties of Selected Material: (Contents...)

The following sheet gives material properties used in a number of calculations. For demonstration purposes, you can get the values for a representative general-purpose ABS material.

    E        Tensile modulus (psi)
    G        Shear modulus (psi)                     112319.0
    nu       Poisson ratio
    alpha_K  Coefficient of thermal expansion (/°K)
    alpha    Coefficient of thermal expansion (/°F)  5.22222e-05
    rho      Specific gravity
    rho_lb   Density (lb/in3)                        0.0379337
    sp_ht    Specific heat                           0.57336
    C_p      Heat capacity (J/kg °K)
    k        Thermal conductivity (W/m °K)

## Available calculations:

Help:
    Introduction to the calculator
Mechanical:
    Beams (including snap fits)
    Plates
    Tubing
    Rotating discs
    Gears
    Press fits
Thermal:
    Cooling time

## Spur Gear Calculations: (Contents...)

Tooth shape:
Number of teeth:

Lewis form factor Y = `0.358`

    D_p      Pitch diameter (in)                     2.0
    F        Face width (in)                         0.209497
    P_d      Diametral pitch (/in)
    P_c      Circular pitch (in)                     0.20944

- For safe torque limit for the life of the gear, enter one of the measures of service life, obtain the material's fatigue limit for the computed number of cycles, apply an appropriate safety factor, and enter the factored fatigue limit as bending stress.
- For maximum stall torque, enter the material's flexural yield strength as the bending stress.
- For stress analysis, enter applied force or torque and read the resulting stress.

NOTE:All calculations assume that a full width radius is extended to the tooth root. Plastic materials are notch sensitive, and shock loading may be a concern.

    speed    Rotational speed (rpm)
    PLV      Pitch line velocity (ft / min)          188.496
    life     Service lifetime (hr)
    cycles   Number of cycles in service life        2.16e+08

    T        Torque (in lbf)
    W_b      Tangential load (lbf)                   12.0
    sigma_b  Bending stress at root (psi)

## Related Information: (Contents...)

- CAMNET Plastics Welcome Page
- Plastics Application Design Guide
- Design-Based Material Selection
- Material Properties Data Base
All use of this system is subject to certain terms and conditions.