Bastech, an Ohio-based one-source solution provider for shop floor, additive manufacturing services and equipment sales, has wrestled with temperature issues but believes it has found a way to introduce a new level of simplicity, efficiency and economy to conformal cooling.
Bastech’s breakthrough, documented in the benchmark tests, is based on 3D Systems’ Cimatron™ mold-making software and its ProX® 200 direct metal printing (DMP) system. Simulations for the conformal cooling mold designs are performed using Moldex3D software, a partner with 3D Systems, and the completed DMP molds are inspected using 3D Systems Geomagic® Control software.
Challenges:
Since the inception of industrial injection molding, keeping an even temperature on the surface of the mold has been a constant challenge.
In their quest to maintain even temperatures, manufacturers have used baffles, bubblers and heat pipes; they’ve laminated blocks together and added complex drilling setups to their molds.
Over the last decade or so, conformal cooling — designing cooling channels that naturally follow the contours of the part to be produced — has been positioned as a solution for controlling injection-molding temperatures. But conformal cooling adds new layers of design and production complexity to the mold-making process, placing it beyond the means of most shops.
Solutions:
Bastech’s design for the first benchmark was a tapered helix that is positioned on the inside of a spacing cone used for industrial assemblies. Conformal cooling channels were created by rotating a teardrop configuration so that one side was parallel to the outer surface of the core while maintaining a constant distance from it. By running the cross-section along a tapered helix, Bastech was able to design geometry that the ProX 200 could build in a single run.
Bastech compared two very similar parts in terms of volume, size and design configuration. One was designed with a conformal core and then 3D printed; the other was designed with a standard spiral baffle configuration and manufactured by conventional means.
The conformal cooling design was created with Cimatron, expert CAD/CAM software that covers the entire mold-making cycle — from quoting to design, applying engineering changes, NC and EDM programming. The latest version of Cimatron includes cooling design and analysis capabilities that support both traditionally drilled cooling channels and conformal cooling channels for manufacturing using 3D printing technologies.
Through close integration with Moldex3D, injection mold designers working in Cimatron have the ability to perform automated mold-filling analysis to optimize cooling channel layout.
“The combination of Cimatron and Moldex delivers expert software to help less-experienced engineers create better-quality designs,” says Staub. “This is a major consideration as the demand for experienced tool-makers is much larger than the dwindling supply.”
“Designing for 3D printing requires an understanding of structural support design to accomplish true requirement-based design as well as reducing material cost and build time,” adds Scott Young, Bastech’s Engineering Manager. “This type of expertise is built within the Cimatron software to allow our designers to think about design without having to worry about navigating through the CAD package to define complex internal channels.”
Benefits:
The design for the 3D printed mold took two days and was built on the ProX 200 in three days. To maximize its productivity, Bastech combined the 3D print run for the mold with parts required for other Bastech projects.
The ProX 200 is a cost-effective alternative to traditional manufacturing processes, offering reduced waste, greater speeds for production, short setup times, very dense metal parts, and the ability to produce complex assemblies as a single part.
“It’s a tool that enhances our capabilities on the molding side,” says Staub. “It gives us higher turnaround tooling and solves bottleneck problems in the shop. We can save 30-40 hours per mold by eliminating EDM and drilling, and drastically reducing CNC and polishing work.”
For the reverse-flow helix core, the design and analysis in Cimatron software, combined with 3D printing on the ProX 200, saved more than 40 hours of programming and shop time. When all costs were taken into consideration, the 3D printed core yielded a net savings of $1,765 (18%) over conventional methods, according to Young.
More importantly, the conformal cooling mold maintained a lower temperature throughout the run and reduced cycle time by 22%.
“Cycle time is nearly everything in injection molding, with the ability to consistently control temperature a close second,” says Staub.
“The more consistently we can hold temperature, the more consistently we can mold quality parts,” says Young. “Eliminating warping due to temperature variation and lowering cycle time represent huge performance gains.”