Ring dies are subject to continuous abrasive wear from materials during the pelleting process, and the hole diameter gradually expands at a rate of approximately 0.01–0.02mm per 100 hours of operation. To extend the service life of the ring die and ensure the stability of pellet diameter throughout its entire lifecycle, new ring dies are factory-produced with a negative tolerance wear allowance of 0.04–0.08mm.
For a nominal 2mm hole diameter, the industry-standard factory hole diameter range is 1.92–1.98mm. The 1.94mm measurement you obtained is exactly at the optimal midpoint of this range, which is also the long-standing factory standard adhered to by Hongyang Feed Machinery Co., Ltd.
The 1.94mm hole diameter is the result of our strict compliance with internal control standards. Before each batch of ring dies leaves the factory, Hongyang Feed Machinery uses a coordinate measuring machine (CMM) to inspect 10% of the hole positions, ensuring the hole diameter is within the 1.92–1.98mm range. This design has been verified by long-term production of millions of pellet mills worldwide and is the best practice for industrial-grade ring dies.
| Design Approach | Representative Regions | Tolerance Band for 2mm Nominal Hole | Core Advantages | Main Disadvantages |
|---|---|---|---|---|
| Wear Allowance Priority | China / North America / Southeast Asia (Industrial Grade) | 1.92–1.98mm (Negative Tolerance) | 30%–50% longer service life (1200–1500 hours); Stable pellet uniformity throughout lifecycle (±0.1mm); Higher ring die strength, less prone to cracking | Slightly lower initial output for new ring dies (5%–8%) |
| Initial Performance Priority | Some European Civil / Small Machine Manufacturers | 1.98–2.04mm (Zero/Positive Tolerance) | High initial output for new ring dies; Good intuitive hole diameter matching | Short service life (approximately 800 hours); Excessively rapid hole expansion in later stages, pellet non-uniformity exceeds ±0.2mm; High comprehensive pelleting cost |
Hongyang Feed Machinery chooses the wear allowance priority design route to help customers reduce long-term production costs and achieve more stable production results.
By appropriately increasing steam temperature to 85–90°C, extending conditioning time to 30–45 seconds, and adjusting roller gap to 0.1–0.2mm, the initial output difference of new ring dies can be completely eliminated. If needed, the technical team of Hongyang Feed Machinery can provide one-on-one process guidance.
Chinese National Standard GB/T 18674-2018 “Ring Dies for Feed Pellet Mills” clearly stipulates that for hole diameters ≤3mm, the tolerance is ±0.03mm. Hongyang Feed Machinery’s internal control standard (1.92–1.98mm) is stricter than the national standard, ensuring consistency and reliability of product quality.
Use an internal micrometer with 0.001mm accuracy or a special ring die plug gauge to measure the diameter at the middle position of the ring die hole’s working land. Measure at least 5 holes in different positions on each ring die and take the average value. Hongyang Feed Machinery can arrange technical personnel to bring professional instruments to the site for accurate measurement.
Hongyang Feed Machinery can adjust the processing technology according to your usage habits and produce ring dies that meet the European positive tolerance standard (1.98–2.04mm), with a delivery cycle of 3 working days.
After adopting the positive tolerance design, the service life of the ring die will be shortened by approximately 40%, the comprehensive pelleting cost (ring die cost per ton of feed) will increase by about 25%, the pellet hardness will slightly decrease, and the transportation breakage rate will increase by approximately 2%–3%. We recommend that you make a decision after comprehensively considering the full lifecycle cost.
Taking a 2mm hole diameter ring die as an example, the full lifecycle cost comparison:
Long-term use of Hongyang Feed Machinery’s ring dies can help you reduce comprehensive pelleting costs by approximately 25% while obtaining more stable pellet quality.
If you have any questions about ring die hole diameter or usage processes, please feel free to contact our professional technical team:
Free pelleting process optimization guidance
On-site hole diameter measurement by technical personnel with professional instruments
Free ring die samples with different tolerance standards for comparative testing
Establishment of exclusive tolerance standards for long-term cooperative customers to ensure supply consistency
Post time: May-26-2026
