Know About How to Manufacture a Rewinder Circular Blade

Rewinder Circular Blade Function

The rewinder circular blade is the core cutting component in rewinders and slitters. Their primary function is to perform precise slitting, edge trimming, and cross cutting on continuously moving materials. Blade performance directly impacts cut quality, production efficiency, and the consistency of the final product.

The blades are widely used across various industries to process materials such as paper, film, foil, textiles, packaging, and nonwovens.

When you select the rewinder blades, simply understanding their classifications and functions may not fully address all your questions. In this article, Sun Hong explains how these rewinder cutting blades are manufactured. This information can help you choose the right rewinder slitting blade type, material, and even supplier.

Rewinder Circular Blade Production Process

Generally speaking, the manufacturing processes for straight slitting knives and circular slitting knives are not identical. However, rewinder circular slitting blades used in rewinding operations are more widely employed in practice. This article focuses on the manufacturing process of circular rewinding slitting knives.

• Material Selection

Selecting the appropriate steel or alloy for your rewinder blade is crucial. It depends on the specific application, the properties of the material being slit, and the required blade performance. Commonly used materials include 65Mn, 9CrSi, SKD11, SKH9, and tungsten alloys. These materials combine high hardness and high toughness with excellent wear and corrosion resistance. This will make the rewinder blade effectively prevent the cutting edge from rolling while ensuring long lasting sharpness and cutting stability.

• Blank Preparation

Once the material has been selected, the sheet is processed into circular blade blanks using laser or waterjet cutting. Compared with traditional mechanical cutting, these methods yield superior dimensional accuracy and smoother cut edges, thereby creating favorable conditions for subsequent heat treatment and precision machining. Furthermore, precise control over blank dimensions helps minimize processing deformation, thereby enhancing the final rewinder blade's concentricity, balance, and dimensional consistency.

• Forging & Rough Machining

Following forging, the rewinder blade blanks undergo rough machining. High precision CNC lathes and milling machines are always used to pre-process the circular blade blanks, initially shaping key dimensions such as the central mounting hole, outer diameter (OD), inner diameter (ID), and thickness. Rather than machining directly to final dimensions at this stage, appropriate machining allowances are retained to accommodate subsequent heat treatment and grinding processes.

Efficient rough machining not only removes excess material and improves the efficiency of subsequent processes but also minimizes the impact of heat treatment distortion on the final precision of rewinder blade production. This establishes a stable and reliable foundation for subsequent heat treatment, precision grinding, and edge finishing, thereby ensuring that the rewinder cutting blades possess exceptional dimensional accuracy and cutting performance.

• Heat Treatment

Heat treatment is a critical process that determines the performance and service life of slitting blades. Sun Hong employs a vacuum heat treatment process to manufacture the rewinder circular cutting blade, comprising quenching, tempering, and, where necessary, cryogenic treatment, to optimize the material's internal microstructure through precise control of heating temperatures, holding times, and cooling rates.

Compared to conventional methods, vacuum heat treatment effectively minimizes oxidation and decarburization, thereby preserving the integrity of the rewinder circular cutting blade surface and ensuring dimensional stability. This process results in a highly uniform and stable internal microstructure, endowing the slitting blades with a combination of high hardness, high toughness, and excellent wear resistance.

For common tool steels such as SKD11 and SKH9, the rewinder circular cutting blade's hardness typically reaches 58 to 65 HRC after heat treatment. Proper control of hardness not only enhances wear resistance but also mitigates the risk of edge chipping associated with excessive hardness, ensuring stable cutting performance and an extended service life under high speed, high load slitting conditions.

• Precision Machining & Grinding

Following the heat treatment, circular cutting blade production enters the final finishing stage.

As minor deformation may occur during heat treatment, high precision grinding equipment is employed to adjust dimensions and refine surface finishes.

Sun Hong utilizes high precision surface grinders, cylindrical grinders, and CNC machining centers to precisely process the slitting blade's outer diameter (OD), inner diameter (ID), thickness, flatness, parallelism, and concentricity. Dimensional tolerances and surface roughness are strictly controlled throughout the process to ensure exceptional operational precision for every circular cutting blade we manufacture.

Subsequently, the cutting edge undergoes precision sharpening and mirror finish grinding. A sharp, uniform edge effectively reduces cutting resistance, minimizes the generation of paper dust and burrs, and enhances cut quality. Furthermore, precise dynamic balancing and geometric accuracy control reduce vibration and runout at high speeds, ensuring stable, reliable slitting performance of the circular cutting blade over extended periods of operation.

• Quality Inspection

Of course, no matter what products you purchase, the quality inspection before shipment is mandatory. For circular cutting blades, this process includes checking the dimensions, hardness, edge sharpness, and surface quality of the slitting knives.

Particular attention must be paid to ensuring there are no residual micro burrs and that the edge angle is accurate.