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INFORMATION USEFUL/REQUIRED FOR SIMULATING EXISTING INJECTION MOLD TOOLING/PROCESS

A key aspect of an effective flow analysis project is accurately simulating processes that have already be run. When troubleshooting problems, this is obviously crucial. When the analysis aim is optimizing an existing process, it is very useful to establish a baseline by using processes with know results. These replications of known phenomena are useful in extrapolating results from analysis data to their likely physical outcomes and serve to develop a basis for confidence in the predictions of the analytical models.

Certain information is mandatory, and can be determined in several different manners, while other information is useful, but not essential.

In general, the accuracy of the results, predictions and interpretations is directly proportional to the amount and quality of this foundation data. The following outlines the required and useful parameters and how to determine and represent them. The mandatory information will be note as such. While, in many cases, several options are presented and one may be sufficient, it can be assumed that all options would preferred.

  1. PHYSICAL TOOL DIMENSIONS
    1. CAVITY DIMENSIONS( at least one required)

The cavity dimensions can be represented in several ways. Ideally, this would include any scaling of the final product that would be added to compensate for shrinkage. In most cases nominal product dimensions are adequate and using them should impact the results noticeably. It is important to be consistent in how the cavity is represented when design changes are evaluated. Any one of the following can be used to describe the cavity physically.

When considering how best to describe the cavity, keep in mid that the FEM model used for flow analysis is a mesh of triangles representing the mid-plane surface of the cavity. Each triangle is assigned a thickness attribute that tells the analysis routines the local wall section in that area. One half of that thickness is added to each side of the triangles, resulting in wedges that approximated the cavity extents. For parts with thin wall sections (relative to overall dimensions) it is usually acceptable to use either inside or outside surfaces for most of the FEM model

  1. PART OR CAVITY DETAIL PRINT(S)

        Hard copy detail drawings should always be provided it available.

    1. CAD MODEL

        CAD models can be extremely useful. the following are listed in order of preference

    1. Solid models using ACIS format

Provide model in .SAT file if possible

  1. ACAD R13, Designer, or Mech Desktop
  2. ARIES
  3. .SAT file from others including current versions of HP, Graftek.
  1. Surface or Wireframe 3D Models

Should provide wireframe edges as well as surfaces, for IGES files it is helpful to separate the features by layers.

  1. Moldflow surface model (.MFL)
  2. IGES (w/ trimmed surfaces)
  3. ACAD R13 AutoSurf
  4. AutoSurf .MOD file
  5. Aries
  6. Patran
  7. SDRC
  8. PRO-E
  1. Other Solid models
    1. SDRC
    2. PRO-Engineer
    3. AutoCAD AME
  2. 2D or Wireframe (section cuts are very useful)
    1. ACAD R10 or later
    2. ARIES
    3. DXF
    4. IGES
  3. FEM MODEL

        Shell Model representing mid-plane model can be very useful or totally useless depending on how it is made.

    1. Moldflow .MFL file
    2. Patran File
    3. MSC Nastran Mesh
    4. Ansys Mesh
    5. SDRC Mesh
    1. PRODUCT SAMPLE

        strongly desired EVEN IF OTHER REPRESENTATIONS ARE PROVIDED

    1. Production piece

A sample of a production component made using the processing and tooling to be evaluated

  1. Production part from different tool or process

A part from another tool, process or material

  1. Prototype

        if production sample is not available...

    1. Injection molded
    2. Machined
    3. StereLithography or other Rapid prototype technology
    4. other such as hand sculpted or cast
    5. Similar product of same general configuration
    1. FEED SYSTEM DIMENSIONS

        Required for proper process simulation

    1. TOOL PRINT(S)

        Hard copy detail drawings should always be provided if available.

Should include runner centerlines, shapes, and dimensions.

  1. SPRUE details

A detail drawing or, If a standard bushing is used, copy of a catalog page will suffice. If not available, a supplier and product number is OK.

  1. Gate Details

Detail drawing with centerlines, shapes and dimensions.

  1. Other Hardware Details such as Hot Manifolds, Heated drops or Valve Gates
  2. RUNNER/SPRUE SAMPLE

        DESIRED whether OR NOT drawings are provided

    1. MOLD BASE DESCRIPTION
      1. TOOL DRAWING
      2. CATALOG NUMBER
      3. CORE and CAVITY PLATE Extents
      4. PLATE MATERIAL
        1. Thermal Conductivity
        2. Density
        3. Heat Capacity
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Copyright 2005 -  S. B. EglI