# Multi-layer and multi-channel deposition defects and inter-layer control strategies in additive manufacturing materials

## TL;DR

This paper introduces a new fuzzy logic control strategy to improve the accuracy of additive manufacturing in complex multi-layer and multi-channel structures.

## Contribution

A novel real-time inter-layer control strategy based on fuzzy logic is proposed to reduce deposition defects in additive manufacturing.

## Key findings

- Residual stress is higher at pipe junctions than in weld zones.
- The fuzzy logic controller reduced maximum deviation to 0.13 mm in vertical structures.
- The strategy achieved a maximum error of 0.25 mm in funnel structures.

## Abstract

Additive manufacturing faces significant challenges in ensuring the quality and dimensional accuracy of components, particularly in complex multi-layer and multi-channel deposition processes. In this study, a novel real-time inter-layer control strategy based on fuzzy logic was proposed. Finite element analysis (FEA) was employed to simulate the temperature field and residual stress distribution in a representative pipeline joint. The simulation revealed that residual stress is significantly higher at the junction of the main and branch pipes compared to the weld zone, with the center of the weld zone exhibiting greater stress than its edges. Deformation analysis indicated a subsidence tendency at the intersection center point (Z-direction: −3.75 × 10 ⁻ ⁵ mm) and a slight inclination of the branch pipe. A fuzzy logic controller was designed to adaptively regulate the stacking speed of each deposition channel by utilizing the real-time height deviation and its rate of change as inputs. Experimental validation was conducted on three distinct structures: a simple vertical structure, inclined structures (60° and 70°), and a complex funnel structure with varying channel numbers. Results demonstrate that the proposed strategy effectively minimizes deviations: a maximum of 0.13 mm in vertical structures, stable layer growth in inclined structures, and a maximum error of 0.25 mm in the top layer of a funnel structure.