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September 27, 2002

5 Min Read
Shifting to 3-D mold design

Still designing tools the old-fashioned way—with a two-dimensional software package? Mold designers share their experiences leaving this method behind and embracing 3-D models. The payoff: faster results, smoother interoperability, and boosted productivity.

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For a single-cavity mold design, Kreutzberger used several components created previously and stored in the MoldWorks library, speeding design time.

Computer-aided mold design (CAMD) is a field that is finally coming into its own, as software providers begin to differentiate products specifically for the tool designer. One example in this category of products, MoldWorks by R&B Mold & Die Design Solutions (Yokneam, Israel), is a 3-D solids application that offers features specific to the injection molding industry and works with SolidWorks, a popular CAD package.

IMM asked three mold designers using the SolidWorks/MoldWorks combination to detail their experiences in changing to a 3-D design environment: John Kreutzberger, owner of JK Mold Design (Sacramento, CA); Gregory Brown, designer with Burco Precision Products Inc. (Denton, TX), a moldmaker; and mold designer Curt Westgate of Cool Polymers Inc. (Warwick, RI).

Customer-focused Contract Design
John Kreutzberger became a contract injection mold designer in 1984. At that time, he used a drafting table to create mold designs and eventually migrated to computer-aided 2-D (CADkey), and then to a CADkey add-on product that brought him into the 3-D world.

He shifted to a full-blown 3-D environment four years ago in an attempt to keep up with time pressures. “My customers are mainly small, California-based mold shops, and my biggest challenges are meeting ever-decreasing lead time requirements and maintaining quality with projects that vary greatly. I can’t limit myself to the size or scope of a mold design, so I create small molds such as unit inserts, mold bases that are typically found in standard catalogs, and large custom mold bases.

“Using this software combination [SolidWorks/MoldWorks] allows me to provide customers with usable 3-D models for CNC production capabilities. I have to be able to generate accurate drawings that my clients can show their customers as well as 3-D data for use on the shop floor. Also, 3-D software allows me to quickly incorporate components from a great number of different suppliers. To date, every CNC platform that my different customers use has been able to import my data.”

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MoldWorks allows users to select the size and manufacturer for ejector pins and specify the bearing length of the pin. Total pin length can be extracted from models. The oversize tab is used to specify clearances.

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This is the dialogue box used for changing the size of a mold base.

Faster Models
Burco Precision Products, a division of Triple S Technologies LP, designs and manufactures injection molds for consumer products, defense, telecommunications, electronics, and the automotive industry.

Burco went from 2-D AutoCAD to solids-based design more than three years ago. Brown says, “We identified several areas that would help improve our upfront modeling time—designing complex cavity core splits and creating mold bases using standard mold components.”

Designers at Burco start with the part, add shrink, and then build up the cavity, core, and any side action that may be required. They create a cavity and core assembly using the CAD software, and then devise a parting line intuitively or using an automated module called SplitWorks (a companion product to MoldWorks). To select an initial mold base and modify any dimensions as needed, Brown uses MoldWorks, which also takes care of mates, ensures that all plate sizes are correct, and verifies that all assembly screws are in the correct location.

The software allows Brown to add standard ejector pins from PCS, National, or Hasco. MoldWorks then automatically puts the ejector pinholes in the core insert, B plate, and support plate. It also counter-bores the ejector retainer plate. Brown adds, “I prefer to use one sketch for each unique pin diameter.”

From Resin to Mold
Cool Polymers manufactures thermally conductive plastics and heat transfer solutions, supplying both pellets and injection molded parts produced from these resins. It assists in the design, modeling, testing, prototyping, and tooling of customer applications, which include electronics, automotive, appliance, heating/cooling/refrigeration, lighting, medical, food, and sporting goods.

Prior to implementing 3-D CAMD, Cool Polymers was using a 2-D mold base software package as well as design tables to create mold base components. “It took a long time to design a mold because for each new mold design, components such as waterlines, knockout pins, and inserts had to be individually added,” says Westgate. “And if there was a change, each component had to be individually moved.”

With the move to 3-D, all knockout pins, inserts, and waterlines are easily added and parametrically tied to the assembly. They can be moved or adjusted with a few menu selections. Design time has improved, tooling delivery time has improved, and in turn, projects are completed sooner.

“The switch has increased our productivity by enabling us to create a mold base assembly in one week or less,” Westgate adds. Formerly, a typical mold base assembly would take from 21¼2 to 31¼2 weeks to complete. “This also includes all necessary drawings required for vendors and/or toolrooms as well as the exploded assembly drawing with part tabulation,” he says.

Contact information
Neuvotec Inc.,
  distributor of MoldWorks
Cave Creek, AZ
(480) 473-0840; www.neuvotec.com

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