Modern CNC systems use precise automation and integrated control to efficiently machine complex, high-precision parts.
Blockchain enables transparent, verifiable CNC data sharing without a central authority, ensuring authenticity and consistency.
Blockchain has significant advantages in data collection, information transfer, quality tracing and compliance guarantee.
Smart contracts automate quality control and adjustments, reducing human intervention and boosting flexibility.
Overview of blockchain technology
Blockchain technology, as a decentralized distributed ledger technology, is widely used in various industries.
The technology ensures secure, transparent, and trusted data via a tamper-proof, consensus-verified ledger shared across nodes.
Application of blockchain technology in CNC machining quality control
Real-time collection and recording of CNC machining data
Traditional CNC machining uses PLCs and sensors for local data storage, with low transmission efficiency and high risk of data loss or distortion.
A CNC milling machine monitors 10+ real-time cutting parameters like spindle speed, feed rate, force, tool wear, and temperature.
If these parameters are recorded in real time in the zone, they will be recorded and stored in the data storage system.
Recording these parameters on blockchain in real time ensures data accuracy, transparency, and traceability.
Blockchain-based systems use smart sensors and embedded units to collect key machining data in real time from each machine tool.
Sensor data is sent via IoT to edge nodes, then securely uploaded to the blockchain.
Data blocks on the blockchain are secured and verified by cryptographic hash algorithms.
Tool wear on a CNC lathe can be monitored in real time using micro vibration sensors or laser instruments.
Blockchain enables timely upload and analysis of tool wear data for quick adjustments to prevent issues.
Blockchain’s decentralized storage enables instant data synchronization across production nodes.
Due to the decentralized nature of the blockchain, each participating node is able to access the data and confirm its validity and consistency.
Improvement of data credibility and transparency
Traditional CNC data collection faces delays, tampering risks, and equipment compatibility issues.
These issues can, in some cases, lead to data distortion and decreased productivity.
Blockchain’s decentralized, secure, and tamper-proof features enhance data credibility and transparency.
Blockchain’s decentralized structure stores data across multiple nodes, ensuring high redundancy and security.
The data is processed through a cryptographic hash algorithm that generates a unique hash value.
Machining data (spindle speed, force, temperature, etc.) is collected in real time and hashed via an algorithm.
The hash value is packaged with related data into a block, joining the blockchain to ensure data integrity and tamper resistance.
Given cutting force 2500 N, spindle speed 8000 r⁃min-1, and temperature 70°C, the hash value is calculated as follows.
𝐻=Hash(𝑋1,𝑋2,𝑋3)
Where: H is the generated hash value; X1 is the spindle speed; X2 is the cutting force; X3 is the temperature.
When these data changes, the corresponding hash value will also be updated, and generate a new block.
Each block contains the previous block’s hash, ensuring data consistency and security throughout machining.
The transparency of the blockchain is reflected in the fact that each participant is able to query the data in real time with authorization.
When a parameter changes (e.g., cutting force exceeds limits), data is auto-recorded and synced to blockchain in real time.
This transparency boosts collaboration and supervision efficiency, avoiding information lag and human manipulation.
The use of smart contracts further enhances the transparency and credibility of data.
Smart contracts enforce quality rules, triggering warnings and recording events when parameters deviate during processing.
Blockchain enhances CNC data credibility and transparency for real-time, accurate traceability and efficient management.
Quality Inspection and Traceability
In the blockchain-driven quality system, key processing data and inspection results are collected and uploaded in real time.
In an enterprise machining task, the quality system automatically collects size, surface roughness, hardness, and other part data.
After processing, inspectors use CMM to measure dimensions, roughness, and hardness, comparing results to blockchain data.
If tests meet design, data is marked qualified; otherwise, unqualified with reasons like size or roughness.
The quality traceability function is based on the non-tamperability of the blockchain.
Blockchain permanently records processing data and test results with timestamps and hash links.
When a part’s size is out of tolerance, blockchain records the value with a timestamped hash, ensuring traceability to the original data.
This traceability prevents tampering and errors, ensuring authentic, reliable inspection results.
Blockchain smart contracts can also automatically enforce quality control rules.
When a part exceeds tolerance, the system logs it, triggers a smart contract warning, and starts corrective actions.
The flow of quality inspection and traceability is shown in Figure 1.
Quality Certification and Compliance Assurance
All key CNC and inspection data are digitally uploaded to blockchain, time-stamped, and tamper-proof.
Through the decentralized nature of the blockchain, all data are stored in multiple nodes, ensuring the transparency and security of the information.
The smart contract mechanism of blockchain enables the automatic and efficient quality certification process.
If test results exceed size tolerance, the smart contract triggers a warning and records the data for timely quality control.
Smart contracts embed quality standards and customer requirements into production for automated quality certification.
In terms of compliance assurance, the blockchain’s immutability provides a solid foundation for compliance audits.
Every time data is processed, it is permanently recorded on the blockchain, ensuring that the process can be traced back at any time.
Traceability covers raw materials, process settings, and equipment status, ensuring compliance with standards and requirements.
In the quality certification process, the use of formulaic data verification standards is an effective means to improve the accuracy of certification.
With a ±0.02 mm tolerance, the product’s dimensional error ∆𝐷 is calculated by:
∆𝐷 = 𝐷measured-𝐷target
where :𝐷measured is the actual measured size; 𝐷target is the target design size.
If |∆𝐷| > 0.02, the product is unqualified; blockchain records this and triggers correction.
Standardized calculation models can also perform the quality assessment in compliance assurance.
For example, the quality pass rate 𝐷rate is calculated as
𝑄rate = (𝑁pass/𝑄 𝑁total) × 100%
Where :𝑁pass is the number of qualified products ;𝑁total is the total number of tested products.
Through the automatic execution of the smart contract, the pass rate will be recorded in real time and used to generate the quality certification report.
Effectiveness assessment
To test blockchain’s impact on CNC quality control, an enterprise compared production data before and after its implementation.
Data collection targets key indicators—annual output, pass rate, and traceability time—with output growth reflecting blockchain’s impact.
Output growth shows blockchain’s optimization, pass rate its quality control, and traceability time its issue resolution speed.
The data of the enterprise before and after the implementation of blockchain technology are shown in Table 1.
Before blockchain: 50,000 output, 96% pass rate, 48h traceability; after, faster quality traceability and issue resolution.
After blockchain, output rose to 55,000, pass rate to 98%, and traceability time dropped to 12 hours.
Table 1 shows blockchain implementation significantly boosted the enterprise’s annual output and quality conformity rate.
Blockchain enables real-time, transparent, and accurate quality traceability and compliance via smart contracts and distributed ledgers.
Conclusion
Blockchain has revolutionized traditional manufacturing by enhancing efficiency, improving quality control, ensuring data credibility, facilitating traceability, and ensuring compliance.
Blockchain’s decentralized ledger solves data silos and asymmetry, enhancing transparency and credibility.
Smart contracts’ automatic, tamper-proof execution improves quality control accuracy and reduces manual intervention.
