Modified Screw Design for Direct Injection Molding of Animal Chews
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for molding animal chews often degrade the composition during shear and melt mixing, leading to a loss in nutritional value.
Innovation Solution
A modified screw design for direct injection molding of resins, incorporating raw starch with controlled particle size and moisture, along with additives like cellulose, emulsifiers, and fermented soy, which are processed without prior thermal molding, to enhance shear and melt mixing while maintaining nutritional value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If shear and melt mixing are increased during injection molding, then mixing efficiency is improved, but the composition is degraded and nutritional value is lost
Solution Approach 1:
The patent modifies the screw design by changing geometric parameters including flight depth, flight angle, and compression ratio to optimize mixing efficiency while controlling shear stress. The screw features a gradual compression zone that increases pressure without excessive shear, and a metering zone with reduced shear to protect the composition from degradation.
Solution Approach 2:
The screw design implements different mixing intensities in different zones: a high-mixing zone with deeper flights and higher compression ratio for initial blending, followed by a low-shear zone with shallower flights for gentle mixing that protects nutritional components. This localized variation in mixing intensity resolves the contradiction between mixing efficiency and composition preservation.
2Productivity
If conventional screw design is used, then manufacturing simplicity is maintained, but mixing efficiency is insufficient
Solution Approach 1:
The screw is divided into distinct functional zones: a feed zone for material intake, a compression zone for melting and initial mixing, a metering zone for controlled shear mixing, and a nozzle for injection. Each zone has optimized geometric parameters that can be independently adjusted, allowing high mixing efficiency without requiring complete redesign of the entire screw.
Solution Approach 2:
The screw design incorporates variable pitch and variable flight depth along its length, creating dynamic mixing conditions that adapt to the material's melting and mixing requirements at different positions. This dynamic design achieves superior mixing efficiency compared to uniform screw designs while maintaining a relatively simple overall structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively increases shear and melt mixing of the composition without degrading the product, ensuring the nutritional value of the animal chew remains substantially unchanged.
Implementation Method 1
The modified screw design is provided to increase shear and melt mixing of the composition
Data Source
AI summary
Using direct injection molding, including a modified screw, a resin is formed into an animal chew. The screw may incorporate, for example, additional flights or a larger transition zone. Additionally, the particle size of the resin may be less than 2000 microns. The resins may comprise starch, wheat gluten, rubber, or other materials.