Mold Design—A Critical And Rapidly Changing Technology

In mold shops, design is a major and critical function that is currently undergoing significant transformation. Although its importance has long been known to moldmakers, CIMdata believes that many CAD/CAM and CAM-centric vendors have not fully recognized the required level of effort and the value of this function.

Columns From: 10/1/2000 Modern Machine Shop,

In mold shops, design is a major and critical function that is currently undergoing significant transformation. Although its importance has long been known to moldmakers, CIMdata believes that many CAD/CAM and CAM-centric vendors have not fully recognized the required level of effort and the value of this function. As such, viable software products to enhance mold design productivity have been slow in coming. However, help is on the way—those vendors focused on moldmakers are now introducing a new generation of software products to aid in the design of core and cavity inserts and full mold bases. In addition, use of product design software is also evolving. Much of this new technology was on display at the recent IMTS show in Chicago.

In a recent study of the moldmaking industry, moldmakers told CIMdata that design elements account for about 20 percent of the total work effort expended in mold shops. Approximately half of that 20 percent is associated with core and cavity design, and the remaining 10 percent of the total work effort is evenly divided between mold base design and preparation of a design model for manufacturing. In comparison, this same group of moldmakers stated that approximately 8 percent of their total work effort is associated with CAM programming. Thus, the level of effort associated with all aspects of design is more than twice the amount of effort related to CAM programming.

As a further comparison, these users said that the work effort associated with design is approximately equal to the amount of machinist labor expended in three-axis machining, which is also approximately 20 percent of the total work effort in mold shops. The remaining 60 percent of moldmaking effort is associated with other planning, machining, hand work and support functions. Given this data, it is clear that design is a large and important function in worldwide mold shops.

The evolution in utilization of product design software continues to occur. CIMdata research reveals that mold shops now receive approximately 80 percent of their product designs in an electronic format, and that electronic transfer of design data is expected to increase to 90 percent in two years. Currently, 53 percent of transfers are made by electronic transfer of surfaces, 23 percent by electronic transfer of solids and 4 percent by direct access to a database. As a side note, there is a significant difference in the mode of transfer among the three geographies surveyed. For example, hard copy is currently used to transfer product design information 35 percent of the time by Japanese moldmakers and 13 percent of the time by North Americans. As such, most moldmakers now utilize design software to receive a product model, edit designs and make appropriate changes to prepare a design model for manufacturing.

Moreover, use of software for mold design is now undergoing a dramatic transition. In the past, most mold design was done manually without the use of software or basic 2D drafting products, and many mold shops still operate in this manner. To meet this requirement, vendors focused on the tool design market now are introducing a new generation of software products for both the design of cores and cavities and mold bases.

The new generation software products for design of cores and cavities are often solid-based, associative, parametric and knowledge-based. They contain automation features to assist in establishing parting lines, parting surfaces, bi-directional shrinkage and electrode extraction. They also permit the parting line and surfaces to be easily modified, which can result in significant productivity enhancement.

Advanced software products for design of mold bases also tend to be solid-based, associative, parametric and knowledge-based. They typically utilize mold base libraries, include highly interactive or automatic placement of mold base components, provide intelligent interference checking when creating a mold assembly, and offer CAE analysis codes to compute factors such as mold flow and mold cooling. In addition, one vendor recently introduced digital mockup software to permit users to conduct collaborative design reviews among appropriate people across an enterprise prior to expending the effort to physically build a tool.

Respondents to the previously mentioned CIMdata survey rated the most important functions in mold design software to be ease in changing parting lines and surfaces, automatic determination of parting lines and surfaces, automatic extraction of an electrode model, and highly interactive assembly of mold base components. Readers can obtain further information on availability of the moldmaking research report by contacting CIMdata.

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