Seven good reasons why you should consider 3-D CAD.

Ask molders why 3-D CAD is a good investment, and they'll tell you it helps build tools faster, it's essential to getting some customers' business, and it may cost less than you think.

Custom molders don't have many reasons to shy away from 3-D CAD/CAM software. There's really just one big one - the price tag. With software prices alone exceeding $20,000, many molders think 3-D costs too much to buy and is too much trouble to learn, especially if their cur rent 2-D package does the job. "A molder with a high-end CAD seat is an anomaly," says Drew Santin, president of Santin Engineering, an injection molder in West Peabody, Mass. "3-D CAD is a very big step for a small molder."

Yet many world-class custom molders and their counterparts in captive and proprietary molding do count 3-D CAD among their competitive advantages. Santin Engineering, for example, first adopted 3-D CAD because of its prototype-development business, but the company has watched 3-D aid its production injection molding operations too. "In hindsight, 3-D CAD looks like a good idea for a molder," says Santin, though he adds that he might not have seen things that way had it not been for the push of prototyping.

Innovative blow molders can also reap some benefits from 3-D CAD. Premier Plastics, a Pittsburgh producer of HDPE containers, embraced 3-D CAD when it started making its own tools. "The benefits of 3-D CAD/CAM are very real. We can go from a 3-D model of a container to a prototype bottle in six hours and then to a prototype mold in 24 hours," says company president Mark Lasser. "The cost reduction has been incredible. We're paying 70% less for our tools since we started making them ourselves."

Why else should what was once considered a fancy designer's tool catch on in a molding shop? The reasons are the never-ending scramble for productivity gains, customer satisfaction, and better part quality. 3-D CAD supports these goals by providing better information for pre-production tasks such as filling analysis and toolmaking. Even if these tasks are performed by outside contractors, 3-D CAD will ensure better results.

Ask molders why 3-D CAD has been a good investment, and you'll likely hear these seven key reasons:

1 Satisfied Customers

Perhaps the most compelling incentive for going 3-D is that your customers may demand it. OEM end-users increasingly want you to have 3-D CAD, so they can satisfy their own ever-shortening product-development cycles. In fact, molders have heard OEM customers say, "Get 3-D CAD or you won't be a vendor."

Consider Tredegar Molded Products, a large custom molder competing in the packaging, electronic, medical, and optical markets. This Richmond, Va., company runs not just one CAD package, but three. "Our customers demanded it," says Carl Medlin, a plant manager who has overseen both tooling and molding operations. Because different customers wanted Tredegar to use different CAD packages, Tredegar now uses 3-D software from both Intergraph and Parametric Technology for part design. The company also uses a 2-D package from Computervision for the bulk of its tool-design work.

2 Sharing Data

Working alongside your customers in a 3-D CAD environment makes it easier to manage design data. "Our big customers design all their products in 3-D CAD," explains Medlin. "So it makes our life simple to communicate with them that way. And it's a whole lot easier than redrawing designs every time we get a new job." Santin says Parametric's Pro/Engineer is the 3-D package most commonly used by his customers.

Sharing design data in electronic form can make a difference in-house too. Arrow International, which molds proprietary medical parts in Reading, Pa., went with the 3-D EMS package from Intergraph because it forms the backbone of an extensive product-data-management (PDM) system. "To keep up with FDA regulations, we used to have a small army of documentation clerks," says Benton Levengood, administrator of the company's graphics and CAE applications. "Ultimately, we realized we couldn't grow as a company without integrating design with a large relational database."

Arrow has significantly cut product-development cycles now that product designers, draftsmen, and NC machining specialists all work from the same 3-D model. "We reuse data over and over again, but we enter it only once," says Levengood. Lead time for mold-design creation alone has dropped from over 12 weeks to just one week since Arrow installed 3-D CAD three years ago.

3 Gateway to Mold Analysis

3-D CAD facilitates injection mold-filling analysis, a task that increasingly falls to the molder - or the molder's subcontractor. "It's hard to do analysis effectively without a [3-D] surface or solids model," Santin says. He can run through a litany of "molder's headaches" that a filling analysis will flag: knit lines, short shots, warpage, gas marks, and other cosmetic problems. Analysis won't solve all your problems, he says, "but it confirms your worries about a mold design."

And with 3-D CAD, mold analysis can confirm those worries when it counts - early in the part-design process. Peter Medina, president of AC Technology North America, explains that 3-D models can even allow product design and process analysis to take place simultaneously (see story on p. 31). "With 2-D, you can't really do anything interesting with the geometry other than generate mold drawings," he says.

4 Early Involvement

As a tool that fosters communication with customers, 3-D CAD helps molders get involved in a project earlier. And the earlier the involvement, the smaller the chances of becoming a victim of designs that aren't molder-friendly. "Molders are usually at the end of the food chain. Someone throws a finished design at the molder and says, 'Go make this,'" says Medina of AC Technology.

The alternative scenario, for those with the 3-D CAD resources to pursue it, is early involvement to improve the processability of part designs and cut costs (see graph, p. 62). Allen-Bradley Co.'s plastics technology/production operation in Milwaukee uses SDRC's IDEAS Master Series to achieve both goals - easier processing and lower costs. A-B process engineering analyst Rick Terasek estimates that use of flow and cooling analysis saved the company $170,000 the first year alone. He attributes the savings to reduced tool rework, material savings through more efficient part design, and better processing.

5 Seeing Is Believing 

3-D CAD, particularly solid modeling, can let you see what a part truly looks like before committing designs to steel - and that visualization can have processing implications. "The process of solid modeling opens up the visual understanding not just for the designer and mold maker but also for the molder," says Santin. "Having CAD enables the molder to get a better look at problems that have to be addressed, like the effects of changing a gate location."

"You can only conceptualize so much on a drawing board," agrees Levengood. For example, Arrow makes a Y-shaped multi-lumen junction hub that joins three tubes to a single multi-lumen tube. "It was easy to lay lines on the board. It was easy to burn the design into a cavity. But it did not mold well," Levengood says. Sink marks were a particular problem. When subsequent hub designs were produced in 3-D CAD, Arrow specified the crucial inside diameter dimensions but let the computer generate the outside surfaces. "No way a designer could have come up with some of these shapes," says Levengood. NC toolpaths produced molds for the new hubs, which run without any sink marks to this day.

As a related benefit, 3-D computer models facilitate integration rapid-prototyping systems. At Santin Engineering, 20% of the jobs go into stereolithography, sometimes for no other reason than letting the toolmakers see the geometry before making a mold. "A part in hand or on the CAD screen takes away a lot of the dartboard effect," says Santin.

6 Faster Toolmaking

Another benefit of using 3-D CAD in mold design is quick generation of NC toolpaths for mold components. Most CAD/CAM vendors offer specialized mold-making tools for creating cores and cavities around a 3-D part model. Vendors also offer electronic "libraries" of mold-base components whose geometry can be dropped into a mold model. Most recently, for example, Matra Datavision came out with Mold Maker, $25,000 stand-alone CAD/CAM software for mold design and machining. It integrates Matra's "Euclid" solids and surface modeling, two- to five-axis machining, and a parametric library of mold components.

Though primarily for injection tools, Mold Maker is what Premier Plastics uses for designing blow molds. The other major component of Premier's tool-making operation is a Sharnoa five-axis CNC machining center with integrated laser digitizing. "We liked this system so well, we decided to bundle it with the software and offer it to other plastics processors," says Premier's Lasser. For about $250,000, Premier will deliver a turnkey tool-making operation consisting of Mold Maker software, a Silicon Graphics workstation, and the CNC machine. Besides the hardware and the CAD package, Premier also offers application engineering services to teach molders how to use the toolmaking system. So far, Lasser says, two systems have been ordered, one by an injection molder with toolmaking experience and another by a blow molder starting from scratch. "We feel that any processor can get a fast return on their investment, just as we did," says Lasser, who notes that Premier's 18-month-old toolmaking operation has already paid for itself.

7 It's Cheaper

Getting started in 3-D CAD may not cost as much as you think. Over the past year, several suppliers have introduced new entry-level PC or workstation versions of their 3-D packages. "Feature-based solid modeling is now available at an affordable price, providing a foundation for integrated flow analysis," explains Gil White, an Intergraph application specialist. Several other vendors, including Parametric, have come out with feature-based solid-modeling packages priced around $8000.

What's more, all these new low-cost 3-D packages will let a user work with models created by outside designers or OEM customers using a high-end CAD system. For example, a molder using EMS Lite from Intergraph or Pro/Jr. from Parametric could work easily with CAD models created by a part designer on full-fledged software from either company. The molder might want to change a model's sharp corners into radii or make other modifications to prevent molding problems.

On the downside, these packages do not offer all the capabilities of the high-end versions. Neither Pro/Engineer Jr. nor EMS Lite have all the surfacing or draft-angle capabilities of Parametric's or Intergraph's high-end packages. Also, some questions remain about just how much plastics design and analysis can be accomplished on an entry-level package. Several CAD-savvy molders privately express reservations about the capabilities of the low-cost solid-modeling packages.

At least one supplier agrees. "For injection molding, 'entry level' is a fully integrated solids, surfacing, and analysis package with three-axis machining," says Roger Stafford, v.p. of product development at SDRC. This vendor will soon introduce a fully functioning version of I-DEAS Master Series, including plastics flow analysis, for personal computers running Microsoft Windows NT. While high-end PCs don't necessarily cost much less than entry-level workstations, the Windows NT version of SDRC's software will make it easier for some companies to make use of their current PC hardware. "I-DEAS for PC addresses users who already have a base of PCs and want to move up from 2-D CAD," says Stafford.

NOT FOR EVERYBODY

While 3-D CAD is clearly worthwhile for some injection molders, some others do not see an adequate payback because of the nature of their particular parts. Consider NuTone Inc., a Cincinnati company that molds mostly flat parts for a proprietary line of ventilation products. "I've used Pro/Engineer and think ifs an excellent product if you're designing very complex parts or have to deal with large families of parts," says product development engineer Tony Schrank. "But that's not what we do, so its perceived value for us just doesn't match the price tag." Although NuTone owns a 3-D version of AutoCAD (supplied by AutoDesk, Inc.), the company mainly sticks with its familiar 2-D AutoCAD package, Schrank says.

FOR MORE INFORMATION ON ITEMS IN THIS ARTICLE, USE READER'S SERVICE CARD

AC Technology, Louisville, Ky.

AutoDesk, Inc., Sausalito, Calif.

Computervision, Bedford, Mass.

Intergraph Corp., Huntsville, Ala.

Matra Datavision, Windsor, Conn.

Parametric Technology Corp., Waltham, Mass.

SDRC, Milford, Ohio