Conformal Cooling Automation

This project was completed while employed with Instaversal. All proprietary photos are used with explicit permission.

Background

Traditional injection molding techniques for manufacturing molding blocks utilize subtractive manufacturing to remove material to form cooling systems composed of linear circular cross-sectional paths that self-intersect to create each cooling line. Conformal cooling seeks to conform the cooling system around the part to decrease cooling time for each IM cycle.


Additive manufacturing using Direct Metal Laser Sintering (DMLS) can create metal blocks and provides the manufacturing ability to create complex shapes. However, due to limitations in the maximum overhang angle, may not be able to produce perfectly circular channels every time. To do so would require the removal of support material from regions that may not be accessible after the part has been created.

Example of a traditional cooling system created by Upmold

Problem Statement:

Eliminate the need for support structures in complex conformal cooling injection molding cavity blocks manufactured using DMLS. Create a process other engineers can use without significant additional training or complex mathematical computations.

Process:

Implement concepts and techniques found by former co-workers in published AM research to automatically create print-valid cooling channels

Concept

Using the concepts outlined in Automated design of additive manufactured flow components with consideration of overhang constraint by Biedermann et al., channel profiles are calculated. The study outlines a series of geometric characteristics that can be used to create support-free channels. A new profile is calculated at equal increments along a path. This path can be specified by the user or automatically generated around a solid body.

Challenges:

Path Generation:

Body Generation:

Figure from Biedermann et al. showing general profile generation process 

Results

Channel Generation on Path

Profile channels can be generated along a user-defined path. The non-circular profiles can be selected based on a number of different geometries, each optimizing to hold channel properties constant (area, surface area, etc.)

Channel Generation around Body

Path for profile generation can be automatically built around simple solids or can produce simple guide paths for the user to manually select for more complex solids. This generated profile can support inflection points.

Outcome:

I wrote two scripts written in onShape FeatureScript for use by other design engineers internally and provided documentation for both scripts including documentation for use and process flow for each script. 

Both scripts were employed to several client projects, resulting in an 11% reduction in cooling time. 

The program written to utilize this production technique was included in patent application for Instaversal's CoolTool.