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How conformal cooling is transforming the die and mold industry
Plastic injection molding uses a plunger to force hot, molten plastic material into a mold cavity. This solidifies over time into a shape that conforms to the contour of the mold. To use the part, the plastic material needs to solidify and cool down; this part of the manufacturing process takes time.
In a typical mold, cooling is achieved by passing a fluid through channels inside the mold so that the heat is conducted out of the plastic part, through the metal tool and into the fluid in the cooling channel. Conventional cooling channels are machined in straight lines using machining operations like drilling or milling, which severely limits the reliable cooling equally across the mold.
This is where conformal cooling comes into play. It is an innovative technology that elevates the cooling channels to a different level and is transforming the die and mold-making industry.
Here’s what I’ll cover in this article:
What is conformal cooling?
Conformal cooling makes use of additive manufacturing in a way that cooling channels can be curved and closely follow the geometry of the plastic part in the mold or core. It helps to reach hot spots and promotes temperature uniformity in the plastic materials being molded and reduces cycle times, uneven cooling, warpage and scrap.
Traditional or conventional tooling, due to its manufacturing methodology, is not able to achieve the shapes, paths and channel geometries that are made possible with conformal cooling. Looking at the images below, conventional molds have straight-line cooling channels (left), whereas conformal cooling (right) makes use of cooling lines in an injection mold that curve and closely follow the geometry of the part.
What are the benefits of conformal cooling?
An increasing number of DKSH’s customers involved in die and mold-making are discovering the advantages of using conformal cooling channels. Two of the biggest benefits of conformal cooling are the reduction of production time and the enhancement of part quality.
In terms of production time reduction, the cooling phase which accounts for nearly 70 percent of the molding process, typically determines the length of the overall cycle time. Conformal cooling can reduce the cooling time to up to 40 percent depending on the part complexity.
If thorough engineering analysis such as flow analysis, computational fluid dynamics and finite-element analysis are further applied before designing the conformal cooling channels, cycle time can be further reduced.
In addition to increased productivity, the new technology can also improve product quality by minimizing warpage and shrinkage of plastic parts. This results in decreased scrap and promotes better surface quality of plastic parts.
These benefits help to achieve cost efficiency in the long run. As the chart below shows, even though the fixed costs of conventional tooling are low compared to conformal cooling, you will be able to achieve profit earlier due to cycle time reduction.
How can you achieve conformal cooling?
Despite the notable benefits, many long-established customers in the industry still think conformal cooling is difficult and expensive. There are a variety of methods for manufacturing a conformally cooled mold including laser sintering, vacuum brazing, liquid interface diffusion. Applying the technology of additive manufacturing has made conformal cooling channels easier and more affordable to produce.
Metal additive manufacturing is a process where metal powder is melted by focused laser beams, layer upon layer. These layers which are built up and joined together as a solid block via direct metal laser melting enable designs to be complex and contour along the part surface.
Additive manufacturing can potentially build mold quicker than conventional machining, especially for multi-cavity molds utilizing additive manufacturing to build conformal cooling channels.
Conformal cooling makes use of additive manufacturing in a way that cooling channels can be curved and closely follow the geometry of the plastic part in the mold or core. It helps to reach hot spots and promotes temperature uniformity in the plastic materials being molded and reduces cycle times, uneven cooling, warpage and scrap.
Traditional or conventional tooling, due to its manufacturing methodology, is not able to achieve the shapes, paths and channel geometries that are made possible with conformal cooling. Looking at the images below, conventional molds have straight-line cooling channels (left), whereas conformal cooling (right) makes use of cooling lines in an injection mold that curve and closely follow the geometry of the part.
About the Author
Roman Ratayczak
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