Hybrid Fixture Assembly With 3D-Printed Shell and Machined Frame

Solution Overview

Problem

Traditional manufacturing fixtures for sheet metal stamping are costly, time-consuming to produce, and often require precision machining, resulting in single-use tools that are cumbersome and difficult to transport.

Innovation Solution

Hybrid fixture assemblies are developed, combining additive manufactured (AM) features with subtractive manufactured (SM) components, specifically integrating a 3D-printed polymeric shell with a CNC-cut sheet metal support frame, utilizing elastic averaging principles for improved dimensional accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional precision machining from metal billets is used, then manufacturing precision is improved, but production time and cost increase significantly

Engineering Contradiction:

Improvefixture dimensional accuracyVSAvoidfixture production lead time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The fixture is divided into two distinct segments: a support frame fabricated via subtractive manufacturing (CNC machining) and a shell fabricated via additive manufacturing (3D printing). Each segment is produced using the manufacturing process best suited for its specific requirements, allowing parallel production and reducing overall lead time while maintaining precision where needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different manufacturing processes are applied to different parts of the fixture based on local requirements: the support frame requires high dimensional accuracy and is made via CNC machining, while the shell requires complex geometry and is made via additive manufacturing. This localized application of manufacturing methods optimizes both precision and production efficiency.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If traditional precision machining from metal billets is used, then manufacturing precision is improved, but production cost increases significantly

Engineering Contradiction:

Improvefixture dimensional accuracyVSAvoidfixture production cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The fixture is divided into two distinct segments: a support frame fabricated via subtractive manufacturing (CNC machining) and a shell fabricated via additive manufacturing (3D printing). Each segment is produced using the manufacturing process best suited for its specific requirements, allowing parallel production and reducing overall lead time while maintaining precision where needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different manufacturing processes are applied to different parts of the fixture based on local requirements: the support frame requires high dimensional accuracy and is made via CNC machining, while the shell requires complex geometry and is made via additive manufacturing. This localized application of manufacturing methods optimizes both precision and production efficiency.

Inventive Principle:

Principle #3Local quality

3Reliability

If fixtures are designed as single-use tools, then reliability is improved, but ease of operation deteriorates due to cumbersome transport

Engineering Contradiction:

Improvefixture performance consistencyVSAvoidfixture transportability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The fixture is divided into two separable components: a durable support frame and a shell. This segmentation allows the heavy support frame to remain stationary while only the lighter shell needs to be transported or replaced, significantly improving ease of operation without compromising the reliability of the overall fixture system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fixture transitions from a static, monolithic design to a dynamic, modular system where the shell can be removed and replaced on the support frame. This dynamic configuration allows the fixture to be adapted for different applications and makes transport significantly easier while maintaining reliability through the robust support frame.

Inventive Principle:

Principle #15Dynamics

4Ease of manufacture

If additive manufacturing is used for the entire fixture, then ease of manufacture is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improvefixture production speedVSAvoidfixture dimensional accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The fixture is divided into two distinct segments: a support frame fabricated via subtractive manufacturing (CNC machining) and a shell fabricated via additive manufacturing (3D printing). Each segment is produced using the manufacturing process best suited for its specific requirements, allowing parallel production and reducing overall lead time while maintaining precision where needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different manufacturing processes are applied to different parts of the fixture based on local requirements: the support frame requires high dimensional accuracy and is made via CNC machining, while the shell requires complex geometry and is made via additive manufacturing. This localized application of manufacturing methods optimizes both precision and production efficiency.

Inventive Principle:

Principle #3Local quality

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 approach significantly reduces fixture production lead times by up to 95% and decreases production costs by up to 65%, while enabling rapid assembly/disassembly and simplified storage/shipment, with improved dimensional accuracy and adaptability for different applications.

Implementation Method 1

The AM connector junctions exploit elastic averaging principles for improved dimensional accuracy by averaging individual alignment errors over a large number of relatively compliant connector members.

Methodology Applied

Scientific EffectElastic averaging: Elasticity

Data Source

PatentUS12233447B2Hybrid fixture assemblies with additive manufactured features integrated with machined metal features

Publication Date: 2025.02.25 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

Presented are hybrid fixture assemblies with integrated additive manufactured features, methods for making/using such fixtures, and manufacturing systems equipped with such fixtures. A manufacturing fixture assembly includes a fixture support frame formed, at least in part, from a first material, and a fixture support shell formed, at least in part, from a second material distinct from the first material. The support frame, which seats on/mounts to a work surface, includes a skeletal substructure with multiple male connectors projecting therefrom. The skeletal substructure contains multiple first frame walls that are removably intermeshed with multiple second frame walls in a collapsible format. The support shell includes a support surface that holds a workpiece, an interface surface that abuts the skeletal substructure, and multiple female connectors that project from the interface surface. Each female connector removably receives therein a respective male connector to thereby detachably mount the support shell to the support frame.