Analysis of Corona Roll Fracture Causes and High-

1 Introduction

For enterprises equipped with high-speed BOPP and BOPET biaxial stretching production lines, sudden cracking and fracture of corona rolls will lead to unplanned production shutdowns, massive waste of plastic film raw materials and substantial economic losses. This article systematically sorts out three typical fracture positions of corona rolls and their corresponding mechanical inducements, elaborates the core performance advantages and complete technical parameters of high-performance silicone corona rolls, and presents global cooperative application cases, so as to help film manufacturers extend roll service life and realize stable continuous production.

2 Three Typical Fracture Positions and Root Mechanical Causes of Corona rolls

2.1 Central Fracture of roll Core

This type of failure mostly occurs on rolls assembled by multiple outer steel tubes connected by welding. If the thermal assembly process is blocked during production and installation, constructors will cut the outer tube and carry out thermal assembly and secondary welding from the opposite side. Multiple welding operations and forced thermal assembly will form persistent hidden structural stress inside the roll core, which will gradually expand and cause complete core fracture after long-term high-speed rotating operation.

2.2 Crack Defects at the Connection of roll Shaft and Disc

Excessive interference fit between the shaft and disc is the main inducement of this fault. The corona roll adopts double-shell water circulation cooling design; long-term circulating water will cause tiny seepage to corrode the welding seam, form invisible microcracks, and gradually expand to produce water leakage and structural fracture in the later operation stage.

2.3 Fracture at the 1/3 Axial Position of roll Core

Different from the excessive interference fit problem, this fault is triggered by insufficient matching allowance. Loose assembly clearance will make the metal core bear alternating tension during long-time high-speed rotation, resulting in continuous metal fatigue, and finally produce obvious splitting cracks at the one-third position of the roll barrel length.

3 Core Performance Advantages of High-Performance Silicone Corona roll

The corona roll is the core functional component of the film corona surface modification system, which undertakes the conveying work of BOPP and BOPET substrates and cooperates with the discharge electrode to generate plasma corona discharge under high voltage. The product is wrapped with imported special silicone rubber that passes strict 200KV high voltage withstand inspection. The high-quality silicone coating can realize uniform transfer of surface energy on the film, significantly improve the adhesion of ink, adhesive and coating on the substrate, and effectively eliminate peeling and bubbling defects of finished film products in subsequent printing, coating and composite processes.

4 Standard Complete Technical Parameters of Corona roll

1. Structural form: Double-shell integrated design, water inlet and outlet ports are arranged on the same end of the rollbody
2. Raw material matching: Inner and outer shells adopt Q345B steel; the journal and outer shell are connected by 42CrMo alloy steel interference assembly process
3. Dynamic balance standard: G2.5 grade, matching the maximum production line speed of 630 m/min
4. Silicone coating index: Coating thickness 4 mm, rubber hardness 75–80 Shore A, surface roughness Ra1.6 μm
5. Precision tolerance: Overall runout ≤0.10 mm, cylindricity ≤0.10 mm
6. Dielectric performance: Stable continuous operation under 200KV high voltage environment

5 Global Production Line Application Cases

The enterprise has supplied customized corona roll products to more than 100 BOPP and BOPET complete production lines covering over 10 countries and regions worldwide, and has established long-term cooperative relations with many well-known film manufacturing groups. After replacing the original old rolls with our optimized corona roll products, the comprehensive operating efficiency of the film stretching production line of all cooperative customers has increased by 5% to 10%, and the defective product rate and daily equipment maintenance frequency have been significantly reduced.

6 Customized Technical Service Support

The professional engineering team provides one-stop customized matching services for corona rolls, and can formulate targeted product schemes according to the actual production line speed, film processing width and process characteristics of customers. Customers can consult technical drawings, parameter comparison and detailed quotation at any time.

Contact Information

Email: sale05@huataogroup.com Mobile / WhatsApp: +86 17743789775 Official Website: www.huataorolls.com