Electrochemical Smoothing of Lattice Workpieces Without Stress

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Solution Overview

Problem

Additive manufacturing of workpieces results in rough surfaces and bulk structures that require post-process smoothing, which introduces thermal and mechanical stresses, and conventional methods are inadequate for finishing lattice structures.

Innovation Solution

Utilizing electrochemical machining (ECM) with a bipolar pulsed voltage to smooth the surfaces of lattice structured workpieces, ensuring electrical isolation between the workpiece and electrode, and optionally reversing polarity to dissolve or retain electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional post-build processes (grit blasting, grinding, sanding, or polishing) are used to improve surface finish, then surface quality is improved, but thermal or mechanical stresses are transferred to the workpiece causing potential failures

Engineering Contradiction:
Improvesurface finishVSAvoidthermal or mechanical stresses
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces conventional mechanical post-build processes (grit blasting, grinding, sanding, polishing) with an electrochemical machining process. This substitution eliminates mechanical contact and associated thermal/mechanical stresses while achieving superior surface finish quality through controlled electrochemical material removal.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental parameter of the machining process from mechanical force-based to electrochemical reaction-based. By controlling electrical parameters (current, voltage, electrolyte composition, pulse duration) instead of mechanical parameters (pressure, speed, abrasiveness), the process achieves surface finishing without inducing thermal or mechanical stresses in the workpiece.

Inventive Principle:
Principle #35Parameter changes

2Strength

If a bulk structure is used for the workpiece, then structural strength is maintained, but the workpiece becomes too heavy to meet industry requirements

Engineering Contradiction:
Improvestructural strengthVSAvoidworkpiece weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies segmentation by dividing the bulk workpiece structure into a lattice structure composed of interconnected struts or beams. This segmentation reduces material volume and weight while maintaining structural integrity through the distributed load-bearing network of the lattice geometry.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention utilizes porous lattice structures as an alternative to solid bulk materials. The controlled porosity of the lattice architecture reduces density and weight while the geometric configuration of the lattice elements maintains necessary mechanical strength and stiffness for the application.

Inventive Principle:
Principle #31Porous materials

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

Achieves high-quality surface finish without thermal or mechanical stress, enabling weight reduction by converting bulk structures to lattice structures, and effectively smoothing smaller lattice structures that conventional methods cannot handle.

Implementation Method 1

Utilizing electrochemical machining (ECM) with a bipolar pulsed voltage to smooth the surfaces of lattice structured workpieces

Methodology Applied
Scientific EffectElectrochemical machining: Electrolysis

Data Source

PatentEP3478438B1System and method for machining workpiece of lattice structure
Publication Date: 2025.11.12 GENERAL ELECTRIC CO
  • EP3478438B1 patent drawingFigure 1
  • EP3478438B1 patent drawingFigure 2
  • EP3478438B1 patent drawingFigure 3

AI summary

A system is configured for machining a workpiece (102, 104, 110) of a lattice structure, the system includes an electrode (902, 904, 905) of a lattice structure, an electrolyte supply, and a power supply. The workpiece and the electrode are intertwined with each other and electrically isolated from each other. The electrolyte supply is configured for circulating an electrolyte around and between the workpiece and the electrode. The power supply is configured for applying a voltage between the workpiece and the electrode to facilitate smoothing surfaces of the workpiece.