The following chart should be used in determining the first digit for all *injection molded* parts:

Figure 11.1 Classification System for Basic Tool Complexity | ||||
---|---|---|---|---|

Basic Complexity | First Digit | |||

Parts without internal undercuts(1) | Parts whose peripheral height(2) from a planar dividing surface(3) is constant | Part in one half(4) | 0 | |

Part not in one half(4) | 1 | |||

Parts whose peripheral height(2) from a planar dividing surface(3) is not constant - or - parts with a non-planar dividing surface | 2 | |||

Parts with internal undercuts(1) | On only one face of the part | Parts whose ONLY dividing surface is planar, or parts whose peripheral height(2) from a planar dividing surface(3) is constant | 3 | |

Parts whose peripheral height(2) from a planar dividing surface(3) is not constant - or - parts with a non-planar dividing surface | 4 | |||

On more than one face of the part | Parts whose ONLY dividing surface is planar, or parts whose peripheral height(2) from a planar dividing surface(3) is constant | 5 | ||

Parts whose peripheral height(2) from a planar dividing surface(3) is not constant - or - parts with a non-planar dividing surface | 6 |

The following chart should be used in determining the first digit for all *die cast* parts:

Figure 11.1 Classification System for Basic Tool Complexity | |||
---|---|---|---|

Basic Complexity | First Digit | ||

Parts without internal undercuts(1) | Parts whose peripheral height(2) from a planar dividing surface(3) is constant | Part in one half(4) | 0 |

Part not in one half(4) | 1 | ||

2 | |||

Parts with internal undercuts(1) | Internal undercuts cannot be generally die cast |

**Internal undercuts**are recesses or projections on the inner surface of a part which would prevent the mold cores from being withdrawn in the line of closure. The following figure shows an example of an internal undercut:- The
**peripheral height**from a planar dividing surface is considered constant if the height does not vary by more than 3 times the wall thickness. - A part is said to be molded in
**one half the mold**when the entire part is on one side of a planar dividing surface: - If the dividing surface of the mold is in one plane then it is termed to have a
**planar dividing surface**. The following figure shows examples of planar and non-planar dividing surfaces: