Case Study

Whirlpool Refrigerator Liner Thermoforming Simulation

Creating Refrigerator Liners by Simulating the Thermoforming Process — Whirlpool of India

Engineers can better predict the best refrigerator liner thickness using simulation with Ansys Polyflow. 

Introduction

Thermoforming is widely used for mass production of refrigerator liners. Liner thickness distribution variation is an important quality parameter that has been traditionally controlled by trial and error. This typically involves choosing different input sheet thicknesses and process parameters (temperature, pressure, etc.), which wastes material and manufacturing time. A thermoforming simulation could predict liner thickness and its distribution quickly and efficiently, eliminating such waste.

“Using Ansys Polyflow for thermoforming simulation helps us to solve a major challenge for the manufacturing team regarding liner thickness prediction in the thermoforming process.”

— Dr. Biswadip Shome, director, Simulation Based Design, Whirlpool of India

Business Challenges

Thermoforming simulation is a problem of estimating viscosity and strain coupled with heat transfer and contact algorithms under governing equations of conservation of mass and momentum. Preparing a robust finite element model, incorporating comprehensive material modeling and mapping actual production environment conditions to quantifiable loads and boundary conditions are major challenges. Other hurdles include incorporating fluid-to-mold contact and release algorithms, along with conjugate heat transfer across contact surfaces.

Engineering Solutions

• Ansys Polyflow offers different equations to model the strain rate and temperature dependence of viscosity.
• Ansys Polyflow offers various material models and contact algorithms to effectively replicate the thermoforming process and predict accurate outcomes.
• The adaptive mesher of Ansys Polyflow helps to refine the sheet mesh when it comes in contact with the mold to closely follow mold geometry.

Benefits of Ansys DesignSpace

• Thermoforming simulation helps to solve a major challenge of thickness prediction for the manufacturing team, replacing the traditional time-consuming trial-and-error process of tool builds and rework.
• Simulation reduces cost and time for the company by optimally selecting the sheet thickness, setting the operating parameters and testing the liner geometry before final tool builds.
• Using simulation, the liner can be rigorously designed for thermoforming (DFM).