Italian Poultry Feed Mill Achieves 96.5% PDI and 18% Energy Reduction with Hongyang SZLH Ring Die Pellet Mill

Executive Summary

Background

Italy is the fourth-largest compound feed producer in the European Union, with total production reaching 15.6 million tonnes in 2025 according to Assalzoo, the national association of livestock feed manufacturers. The poultry sector alone accounted for 39.1% of national output exceeding 6 million tonnes annually and remains the dominant driver of Italian feed manufacturing. Revenue across the sector surpassed EUR 10.1 billion (+3% year-on-year), supported by a 5.3% increase in gross fixed investments directed toward production efficiency and innovation.

The Po Valley in northern Italy hosts the country’s highest concentration of feed mills, with the top five integrated producers Gruppo Veronesi, Amadori, Cargill Italia, Cereal Docks, and Martini Alimentare controlling an estimated 45 55% of national output from large-scale facilities with capacities of 200,000 to 600,000 tonnes per year. Alongside these industry giants, a network of mid-sized independent mills serves regional poultry farmers, often competing on formulation flexibility, delivery reliability, and feed quality consistency.

AgriFeed Lombardia S.r.l., located in the province of Cremona approximately 80 km southeast of Milan, is one such mid-sized independent feed manufacturer. Founded in 2003, the company operates a single-line pelleting facility with a nameplate capacity of 80,000 tonnes per year, producing complete broiler feeds across starter, grower, and finisher phases. Its customer base comprises 28 broiler farms across Lombardy and Emilia-Romagna, collectively raising approximately 1.2 million birds per cycle under contract growing arrangements with a regional poultry processor.

The Challenge

By early 2025, AgriFeed Lombardia’s production team began observing a gradual but persistent decline in pelleting line performance. Daily throughput had dropped from a historical average of approximately 8.0 t/h to 7.1 t/h, while specific energy consumption had crept upward to 14.8 kWh/t. More concerning to the quality assurance department, the pellet durability index (PDI) measured using the Holmen NHP100 pneumatic tester, the standard method widely adopted by European feed manufacturers had fallen from a consistent 95% range to an average of 91.2%.

The consequences cascaded through the supply chain. Higher fines content in delivered feed triggered complaints from three major broiler farms reporting increased feed wastage in pan feeders and reduced feed conversion ratios. Fines returned from automatic filling systems at the mill itself climbed to 8.5% of total output, requiring rework that further consumed energy and capacity. Ring die service life had shortened to approximately 1,800 effective pelleting hours before hole wear, surface scoring, and relief taper degradation compromised pellet formation.

The mill’s existing ring die supplier a European OEM proposed standard replacement dies at premium pricing with an eight-week lead time. AgriFeed Lombardia’s operations manager, Marco Bellini, sought alternatives that could deliver measurable improvements in both die longevity and pellet quality, while maintaining compatibility with the existing pellet press and steam conditioning system.

Key technical requirements identified by the production team included:

- Die specifications matched to the mill’s 4.0 mm pellet diameter and corn-wheat-soybean meal formulation typical of northern Italian broiler diets

- Effective compression ratio optimized for medium-fine grind (geometric mean diameter 600 650 µm) after hammer milling

- Consistent hole quality to ensure uniform pellet density and minimal particle size segregation during pneumatic conveying and outloading

- Competitive pricing and delivery lead time shorter than the incumbent supplier’s eight-week standard

Hongyang’s Solution

After evaluating several international ring die manufacturers, AgriFeed Lombardia selected Liyang Hongyang Feed Machinery Co., Ltd. based on technical proposal quality, documented performance data from European reference installations, and the company’s specialized expertise in ring die metallurgy and hole drilling technology.

Established in 2006, Hongyang manufactures ring dies, roller shells, hammer mills, mixers, and coolers for compound feed, aquafeed, and pet food applications. The company has supplied replacement ring dies compatible with major pellet press brands including CPM, Bühler, Van Aarsen, Andritz, and Zhengchang, with export coverage across Southeast Asia, the Middle East, Africa, Europe, and South America. All ring dies are processed on full-automatic CNC gun drilling machines using drill bits imported from Germany, ensuring consistent hole diameter, surface finish, and effective compression ratio across every die produced.

Equipment Configuration

Technical Assessment

Metallurgy and Wear Resistance. The SZLH ring die is forged from high-chromium alloy steel with chromium content in the 20 22% range, vacuum hardened to achieve a surface hardness of 60 62 HRC with a hardened case depth exceeding 3.5 mm. This metallurgical profile provides superior resistance to the abrasive wear mechanisms predominant in corn-based broiler formulations, particularly the scouring action of finely ground corn particles (600 650 µm GMD) passing through die holes at pressures exceeding 1,200 kg/cm². Hongyang’s raw material analysis protocol—conducted on every steel batch prior to machining ensures consistent alloy composition and eliminates the risk of hardness variation between production lot.

Hole Drilling Precision. Unlike conventional drilling methods that can produce variable hole diameter (±0.10 mm or more) and inconsistent counterbore geometry, Hongyang deploys full-automatic CNC gun drilling machines equipped with German-imported drill bits. This process achieves a hole diameter tolerance of ±0.03 mm across all 7,932 holes on a single die, ensuring uniform pellet density and minimizing the standard deviation of individual pellet weight within a production sample. The three-stage tapered counterbore relief design reduces frictional back-pressure during pellet extrusion, contributing to lower specific energy consumption without compromising pellet compression intensity.

Compression Ratio Optimization. The effective compression ratio (L/d) of 10.5:1 was jointly determined by Hongyang’s application engineering team and AgriFeed Lombardia’s production staff, based on the mill’s specific formulation characteristics. Northern Italian broiler diets typically contain 55 60% corn, 20 25% soybean meal, 5 8% wheat bran, and supplementary fats, minerals, and amino acids. This formulation, with a moderate fat content of 3.5 4.5% at the mixer, requires a compression profile that achieves adequate starch gelatinization (target 35 40% as measured by the amyloglucosidase method) without excessive frictional heating that could denature heat-sensitive amino acids particularly lysine and methionine, heavily supplemented in modern broiler diets.

Results

Twelve months of continuous operation with the Hongyang SZLH ring die and matched roller shells have yielded consistent, measurable improvements across all key performance indicators.

Performance Comparison

Operational Impact

The PDI improvement from 91.2% to 96.5% directly addresses the fines-related complaints that had been the primary operational pain point. At 96.5% PDI, pellet integrity during pneumatic conveying, bulk storage, and auger distribution to pan feeders remains high, with field reports from broiler farms confirming visibly reduced dust accumulation in feeding systems and improved feed intake uniformity across flocks. One contract grower documented a 2.8-point improvement in feed conversion ratio (from 1.68 to 1.65) over a complete grow-out cycle, attributing the gain primarily to reduced feed wastage from fines.

Energy savings of 18.2% per tonne represent an annual reduction of approximately 216,000 kWh based on the mill’s 80,000-tonne annual output equivalent to roughly EUR 32,400 in direct electricity cost savings at Italy’s average industrial electricity rate of approximately EUR 0.15/kWh (Eurostat, 2025). The 47.2% extension in ring die service life translates to fewer die changeovers per year, reducing annual die procurement costs by approximately 32% and associated production downtime by over 75%.

Customer Feedback

“When we first considered sourcing ring dies from a Chinese manufacturer, there was understandable skepticism within the team. The European OEMs have long dominated this market segment, and feed mill operators tend to be conservative about process-critical components. But the data after twelve months speaks for itself. The Hongyang ring die has outperformed our previous supplier’s product on every metric we track durability, energy consumption, and most importantly, pellet quality. Our broiler customers have noticed the difference on their farms, and that’s the ultimate validation.”

Marco Bellini, Operations Manager, AgriFeed Lombardia S.r.l.

Conclusion

The AgriFeed Lombardia case demonstrates that ring die quality is not determined by geographic origin or brand legacy, but by metallurgical precision, drilling accuracy, and application-specific optimization. Hongyang’s investment in German-imported CNC gun drilling equipment, rigorous raw material analysis, and vacuum hardening processes produces ring dies that meet the demanding performance standards of European poultry feed manufacturers operating in one of the world’s most mature and quality-sensitive compound feed markets.

For Italian and European feed mill operators evaluating ring die procurement options, this case provides a documented reference point: a mid-sized mill running corn-wheat-soy broiler formulations on a 250 kW pellet press achieved 96.5% PDI, 18.2% energy reduction, and 47.2% die life extension over 12 months of continuous operation all at a procurement cost materially below European OEM pricing with a standard delivery lead time of under four weeks.

Data Sources

1. Assalzoo Annual Meeting 2025. Italian feed industry production statistics: 15.6 million tonnes total, poultry sector 39.1% share, EUR 10.1 billion turnover. Reported by Il Sole 24 Ore, June 2025.

2. IndexBox. “Bird Food Market in Italy: Analysis, Forecast, Size, Trends and Insights.” 2026. Compound feed production estimate: 8.5 9.5 million tonnes for all avian species in Italy.

3. FEFAC. “EU Compound Feed Production Market Forecast 2025.” Brussels, December 2025. EU27 poultry feed production forecast: 50.653 million tonnes (+1.5%).

4. Eurostat. Electricity price statistics for industrial consumers in the EU, 2025. Italy average: approximately EUR 0.15/kWh for consumption band ID (500 2,000 MWh).

5. Liyang Hongyang Feed Machinery Co., Ltd. Company profile and ring die manufacturing specifications. en.ringdies.com.

6. Kansas State University. “Pellet Durability Index (PDI) Testing Methodology.” Standard tumbling can method and Holmen pneumatic method comparison.

7. KSU. “Starch Gelatinization Measurement in Feed Pellets.” Amyloglucosidase method for feed applications.

This case study is based on operational data documented over a 12-month period (March 2025  March 2026) at AgriFeed Lombardia S.r.l., Cremona, Italy. Customer name used with permission. PDI measurements conducted using the Holmen NHP100 pneumatic pellet tester. Starch gelatinization determined by the amyloglucosidase enzymatic method at an independent feed analysis laboratory in Piacenza, Italy.