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Moving Mold Design From 2-D
to 3-D
Moving to 3-D mold design can provide a very effective way of improving competitiveness and helping companies win more business.

Crash Test Genius
Toolpath verification software has evolved to permit simulation of the entire machining system.

CAD/CAM Does Double Duty
CAD/CAM software makes molds faster and helps trim parts.

Putting More Engineering into Your Mold Design
How to choose the right software to assist you with engineering.

 Mold Design & Engineering Zone

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For more information visit the MMT Showroom for Delcam, Inc.

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Throughout the past 25 years the plastics industry has grown almost faster than any other. Plastic prod-ucts fill our homes, our offices, our cars, our whole world; yet, seldom do we sit back and think how these products are made, or how those manufacturing pro-cesses can be improved, unless it is our business.

A Complex Challenge
When plastics were first gaining popularity, parts were simple. Most products were designed on a drawing board, so it was natural that the tooling was designed that way as well. All that was needed was a drawing board, a box of pens, a ruler, compasses, and a razor blade for when things went wrong or the design changed. Of course, the tool designer also needed a high degree of skill, and considerable patience for doing repetitive actions, such as drawing ejector pin holes.

Sectioned view through complex screwed ejector system. Images courtesy of Delcam, Inc.

The introduction of 2-D CAD systems in the 1970s improved mold design in two key ways: (1) routine, repetitive tasks were massively simplified by the ability to copy geometry from one area of the drawing to another. This was made even easier by the introduction of symbols, allowing complicated sub-assemblies to be stored in a library and added to the drawing at the click of a mouse; and, (2) making modifications to a design also was simplified, as areas of the drawing could be deleted, moved, re-trimmed or stretched to accommodate the change. But still the biggest issue was successfully and completely defining a complex 3-D form using 2-D drawings.

As CAD has evolved into 3-D the complexity of plastic molded parts has increased. Modern plastic products seek to be increasingly creative in terms of form, while being more functional and durable. For the mold designer, these new forms have forced a requirement for CAD systems to be able to accurately reproduce complex shapes, not just for the visible parts of the product, but especially for the functional parts of the mold, such as parting surfaces.

While the modern generation of CAD systems can cope with this increased complexity, much of the mold designer’s work is still routine and mundane. Consider placing a series of ejector pins into a mold cavity block. Each pin must be placed individually, complete with its corresponding clearance hole and then trimmed to length. Even allowing for the fact that computers can do this type of operation very efficiently, the mold designer will still be spending too much time and effort on tedious tasks, and not enough on making sure the design is perfect.

Actuator-driven slide detail.

A Special Solution
In recent years a new generation of specialized mold design CAD systems has begun to appear. By automating the tedious parts of the mold design process, specialized CAD allows the mold designer to spend more time being creative with the tool design itself, helping to produce better quality molds.

Completed fixed half of games controller mold.

The upshot of this is better molds and parts, faster. Specialized mold design software allows the tool designer to quickly and accurately divide a complex component into cavity and core halves, complete with all of the necessary split and run-off surfaces. Fast and intuitive tools allow the mold designer to isolate and extract complex sliding core mechanisms directly from the initial 3-D design, and then animate them to check for fit, function and clearances.

Once the main mold parts—such as cavities, cores, slides and mold locks—have been defined, the completed mold stack is only a few clicks away. Standard and user-defined components—including complex mechanisms, such as hot runners, staged ejectors, lifters, etc.—can be added to the basic stack at any time, each with associated holes and pockets for fitting.
Powerful yet easy-to-use, process-driven Wizards guide the mold designer through the remaining operations—positioning ejectors and other components, and creating waterways. In the event of a design change, all of the Wizards—right back to the very beginning of the process—can be re-played with the new part geometry, eliminating the need for reworking.

Completed tool ready for manufacture.

For mold shops that still require paper drawings, automated drafting creates GA and a detailed sheet of any components or plates with a single click. Automated bills-of-material give instant access to online ordering systems for purchasing the standard plates and components, guaranteeing that the entire build is ready on time, every time.

Completed fixed half of mold for vacuum cleaner cover.

The end result is a complete, fully detailed and accurate 3-D model of the mold tool, and it is here that the real benefits of the process become apparent. Although the initial design can in some instances take longer than using traditional methods, manufacturing from this point forward is mostly automatic.

The 3-D model of a single plate, for example, is not simply a traditional CAD solid; it is a library of manufacturing data, allowing machining of all the holes and pockets to become a one-click operation when used in conjunction with a CAM system. Each hole or pocket is not just a geometric entity, but instead holds complete details of its function and how it is to be machined. User-defined rules are automatically applied as each plate or component is machined, creating all necessary toolpaths quickly and accurately. For complex cavities, cores and split surfaces, full 3-D CAM allows perfect reproduction in tool steel using up to five-axis simultaneous control for fine surface finish.

Productivity Gains
The productivity gains to be made using these new methods are significant, with customers typically reporting time savings of between 30 and 40 percent for complex projects. At the same time, product quality is significantly improved as a direct result of the designers spending more time in making sure that the design is the best possible.

Moldmaker Saves Weeks from Production Core block, retainer plate, ejector plate, encased by rails held on by clamp plate. Images courtesy of M2M and Delcam. Synergetic M2M Group is a Canadian moldmaking company based in Wallaceburg, Ontario. Established in 1979, it specializes in plastic injection molds, die cast dies and trim dies for automotive and consumer products. “Our objective is to continually reduce leadtime to customers in the very competitive business of moldmaking,” says Mac Mazurek, M2M CAD coordinator. “The production timetables are getting tighter and dollars are scarcer. A tool to make an air dam for a large vehicle, for example, used to be a 22-week build; we now have it down to 16 weeks and it’s shrinking as we automate the process to meet customer needs." The part in the drawings is a speed lip that fits underneath the front bumper, designed to reduce fuel consumption and improve handling. It is a thin part, but it takes a very long tool. At M2M, one of the major benefits to 3-D modeling of these complex molds is to help make its skilled workers more productive, thus turning out high-quality tools in shorter leadtimes. Automation of routine design operations means that standard calculations can be carried out more quickly and with less chance of error. The time saved can be used to focus on the design and operation of the mold. M2M now utilizes a growing library of intelligent mold bases, which is quite extensive. “Once we have designed one, we can easily alter internal details and place items where we want them. This software offers us a more integrated method of designing the large tools we use. Now, we are just about fully integrated so we have the option of taking our previously designed mold bases and inserting our new jobs into them, saving up to 40 percent of the time it took to design molds previously. “Our ability to translate data from our clients allows us to quote accurately and to quickly make changes to that data to allow a functional mold to be made. We can now respond to customer design intent and production schedules very promptly and very cost-effectively.”