Knowledge Graph Fusion with Large Language Models for Accurate, Explainable Manufacturing Process Planning

TL;DR

This paper introduces ARKNESS, a framework combining knowledge graph construction and retrieval-augmented generation with large language models to improve accuracy and explainability in CNC manufacturing process planning.

Contribution

ARKNESS automatically builds augmented knowledge graphs from diverse manufacturing documents and couples them with LLMs for verifiable, numerically precise process planning answers.

Findings

Achieves accuracy comparable to GPT-4o with a smaller Llama-3 model.

Significantly improves multiple-choice and F1 scores.

Enhances open-ended response quality by 8.1x ROUGE-L.

Abstract

Precision process planning in Computer Numerical Control (CNC) machining demands rapid, context-aware decisions on tool selection, feed-speed pairs, and multi-axis routing, placing immense cognitive and procedural burdens on engineers from design specification through final part inspection. Conventional rule-based computer-aided process planning and knowledge-engineering shells freeze domain know-how into static tables, which become limited when dealing with unseen topologies, novel material states, shifting cost-quality-sustainability weightings, or shop-floor constraints such as tool unavailability and energy caps. Large language models (LLMs) promise flexible, instruction-driven reasoning for tasks but they routinely hallucinate numeric values and provide no provenance. We present Augmented Retrieval Knowledge Network Enhanced Search & Synthesis (ARKNESS), the end-to-end framework that fuses zero-shot Knowledge Graph (KG) construction with retrieval-augmented generation to deliver verifiable, numerically exact answers for CNC process planning. ARKNESS (1) automatically distills heterogeneous machining documents, G-code annotations, and vendor datasheets into augmented triple, multi-relational graphs without manual labeling, and (2) couples any on-prem LLM with a retriever that injects the minimal, evidence-linked subgraph needed to answer a query. Benchmarked on 155 industry-curated questions spanning tool sizing and feed-speed optimization, a lightweight 3B-parameter Llama-3 augmented by ARKNESS matches GPT-4o accuracy while achieving a +25 percentage point gain in multiple-choice accuracy, +22.4 pp in F1, and 8.1x ROUGE-L on open-ended responses.