Cold Isostatic Pressing of Additive Manufactured Parts
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Solution Overview
Problem
The existing methods for increasing the green density of parts fabricated by additive manufacturing through cold isostatic pressing are time-consuming, expensive, and can damage the parts due to the bagging process, which involves placing parts in an elastomeric bag with granular media.
Innovation Solution
A method involving forming three-dimensional metal, ceramic, or cermet parts using additive manufacturing, encapsulating them in a conformable fugitive material, and then cold isostatic pressing with a pressurized incompressible fluid that contacts the fugitive material, eliminating the need for the elastomeric bag and granular media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bagging process with elastomeric bag and granular media is used for cold isostatic pressing, then the green density of the part is increased, but the process becomes time-consuming and expensive
Solution Approach 1:
The patent removes the elastomeric bag and granular media from the cold isostatic pressing process. Instead, the green part is placed directly in a rigid mold cavity where incompressible fluid applies pressure. This extraction of unnecessary components eliminates the time-consuming bagging steps while maintaining the density-increasing effect through direct fluid pressure application.
Solution Approach 2:
The patent uses incompressible fluid (hydraulic medium) to apply isostatic pressure directly to the green part within a rigid mold. This hydraulic approach replaces the mechanical granular media system, enabling faster pressure application and removal while achieving the same green density increase without the time penalty of bagging operations.
2Manufacturing precision
If the bagging process with elastomeric bag and granular media is used for cold isostatic pressing, then the green density of the part is increased, but the cost increases
Solution Approach 1:
By removing the elastomeric bag and granular media components, the patent eliminates their associated costs. The rigid mold approach uses simpler, reusable fixtures that reduce material consumption and setup costs while achieving the same green density improvement through direct fluid pressure application.
Solution Approach 2:
The patent replaces expensive, consumable granular media with a reusable rigid mold system. The incompressible fluid can be reused across multiple cycles, and the rigid mold serves as a durable fixture, eliminating the need to continuously purchase and replace granular media and elastomeric bags.
3Manufacturing precision
If the bagging process with elastomeric bag and granular media is used for cold isostatic pressing, then the green density of the part is increased, but damage can occur to the part during the bagging process
Solution Approach 1:
The patent eliminates the elastomeric bag and granular media that cause mechanical damage during bagging. By placing the green part directly in a rigid mold and applying pressure through incompressible fluid, the process removes the source of mechanical stress and damage while maintaining the green density increase through uniform fluid pressure distribution.
Solution Approach 2:
The patent replaces the mechanical granular media system with a fluid pressure system. The incompressible fluid transmits pressure uniformly without the mechanical contact and friction that cause damage in granular media systems, achieving green density increase through hydrostatic pressure rather than mechanical compaction.
4Reliability
If traditional molding processes are used for fabrication, then the structural integrity and surface finish are maintained, but the time and expense of mold and die construction and tooling increases
Solution Approach 1:
The patent performs cold isostatic pressing immediately after additive manufacturing while the part is still in its green state, before any tooling or molds would be required for traditional processes. This preliminary densification action prepares the part for subsequent finishing operations without requiring expensive mold construction, combining the flexibility of additive manufacturing with the density benefits of isostatic pressing.
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
This method effectively increases the green density of the parts from 35% to 70% without damaging them, reducing costs and processing time, while allowing for complex geometries and efficient material use.
Implementation Method 1
cold isostatic pressing the encapsulated three-dimensional metal, ceramic, and/or cermet part with pressurized incompressible fluid that contacts the conformable fugitive material
Implementation Method 2
filing the bag with an flowable granular media which transmits the externally applied isostatic pressure to the component
Data Source
AI summary
The present invention is directed towards a method for fabricating a three-dimensional metal, ceramic, and/or cermet part, the method comprising forming the three-dimensional metal, ceramic, and/or cermet part by an additive manufacturing technique; encapsulating the three-dimensional metal, ceramic, and/or cermet part in a conformable fugitive material to form an encapsulated three-dimensional metal, ceramic, and/or cermet part; and cold isostatic pressing the encapsulated three-dimensional metal, ceramic, and/or cermet part with pressurized incompressible fluid that contacts the conformable fugitive material. Also disclosed are three-dimensional metal, ceramic, and/or cermet parts fabricated according to said method.