Unified Blockchain Provenance and Bayesian Reputation for Additive Manufacturing Supply Chains

In additive manufacturing (AM) supply chains, systems that record provenance and score reputation as separate transactions let lifecycle records and assessments diverge. We present a Hyperledger Fabric chaincode that commits a provenance event, the Bayesian reputation update it implies and their link in one read–write set. An on-chain policy admits ratings only from counterparty organizations; reputation gates authorize future activities but never block recording outcomes. Under client crashes in the measured partial-write window, the unified design produced no divergence in 3900 trials (2900 with version 1.0, 1000 with version 1.1), while a client-orchestrated two-chaincode deployment diverged in all 1000 trials of two control batches. A same-channel InvokeChaincode arrangement also produced none in 1000, at 4.5 ms more endorsement and 11.7% lower throughput at 100 transactions in flight. On four desktops, open-loop load saturates near 12 tx/s, and a 12-hour soak at 6 tx/s committed 98.7% of submissions with no partial record found. Ledger experiments cover gate refusal, failed outcomes, recovery and disputes; with client retry, 540 contended ratings each committed once. A simulation quantifies gate errors and shows that evaluation-time decay reacts slowly when active actors’ performance drops. The scores record submitted outcomes; they are not validated measures of performance.