Fastener Support Structure for Stable AM Joint Voids
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Solution Overview
Problem
Additive manufacturing of joints with voids for fasteners faces challenges due to thermal stresses causing deformation and geometry variations, leading to fitment issues between fasteners and voids.
Innovation Solution
An additively manufactured structural assembly comprising a base with voids and supports across these voids, where the fasteners are secured within the voids and the supports are captured within the fastener's distal end, maintaining dimensional stability through the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If additive manufacturing processes use thermal sintering or heating, then material bonding and part formation are achieved, but thermal stresses deform material around voids causing geometry variations beyond acceptable tolerances
Solution Approach 1:
The support structure is additively manufactured in advance within the void before the thermal sintering process. This preliminary placement of the support prevents material deformation around the void during heating, maintaining void geometry within acceptable tolerances while still allowing thermal bonding to occur.
Solution Approach 2:
The support structure acts as an intermediary element between the void space and the surrounding material. During thermal sintering, the support restrains the material around the void, preventing thermal stress-induced deformation while allowing the thermal bonding process to complete successfully.
2Ease of manufacture
If voids are created in additively manufactured joints for fastener insertion, then fastener assembly is enabled, but thermal stresses cause void shape deformation leading to fitment issues
Solution Approach 1:
The support structure is manufactured and positioned within the void before the thermal processing step. This preliminary action ensures the void maintains its nominal geometry throughout the heating process, guaranteeing proper fitment for subsequent fastener assembly while preserving the ease of manufacturing benefits.
Solution Approach 2:
The support structure modifies the thermal and mechanical parameters within the void region during sintering. By providing thermal mass and mechanical restraint, the support changes the local conditions to prevent deformation while allowing the overall part to be formed through thermal processing.
3Strength
If material is heated during additive manufacturing, then sintering and bonding occur, but thermal expansion and contraction cause dimensional variations in voids
Solution Approach 1:
The support structure serves as a thermal and mechanical intermediary during the heating process. It absorbs and distributes thermal stresses, preventing localized expansion and contraction around the void that would otherwise cause dimensional variations beyond tolerance limits.
Solution Approach 2:
The final structure becomes a composite of the base material and the support structure. This composite configuration provides dimensional stability to the void region while maintaining the bonding strength achieved through thermal sintering of the surrounding material.
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 solution ensures precise fitment and improved joint strength by maintaining the dimensional stability of voids during additive manufacturing, allowing for reliable staking of fasteners and assembly of vehicle components.
Implementation Method 1
In certain additive manufacturing processes, thermal stresses from sintering or other heating may deform material around the voids
Implementation Method 2
applying metal powder and a liquid adhesive into a plurality of layers and heating the plurality of layers to remove the adhesive
Data Source
AI summary
A structural assembly includes a fastener and an additively manufactured component. The additively manufactured component includes a base, a void defined in the base, and a support disposed across the void. The fastener is secured to the base within the void, and the support is captured within a distal end portion of the fastener.