## 3 Results  
### Main Design Characteristics of Cutting Part of Colloid Mill  
The machine used for the ultra-fine grinding of food materials is equipped with a rotor and a stator of different geometric configurations, which facilitate high-speed rotation. The processed material is subjected to a combination of forces, including its own weight, aerodynamic resistance, and centrifugal acceleration [13]. By adjusting the gap between the stator and the rotor, the material experiences intense shear stresses, frictional forces, impact loads, and high-frequency vibrations. The combined action of these mechanical forces results in grinding, crushing, and thorough mixing of the components, ultimately yielding a product with the desired properties [14].  
The moving grinding assembly of the colloid mill consists of a rotor composed of three truncated-cone cylinders mounted on a central shaft. Each cylinder features a central bore to facilitate installation, and the external surfaces of the cylinders are equipped with teeth inclined at 20\({}^{\circ}\). A key design feature of the rotor is the intentional variation in both diameter and tooth pitch across the three cylinders. The lowermost cylinder, positioned closest to the base, has the largest diameter and the smallest tooth pitch, providing initial coarse grinding. The middle cylinder possesses an intermediate diameter and an intermediate tooth pitch, enabling further reductions in particle size. The uppermost cylinder exhibits the smallest diameter but the largest tooth pitch, contributing to the final stage of grinding. When assembled on the shaft, the cylinders form a stepped truncated cone whose diameter progressively decreases toward the top. This gradient in tooth density along the rotor length promotes a sequential, controlled reduction in particle size as the bone material advances through the milling zone, ensuring the efficient communication and preparation of a homogeneous paste.  
Stator Design  
The stationary grinding element, or stator, complements the rotor and likewise consists of three cylinders with central bores. The internal bores are machined to a conical profile that precisely matches the outline of the truncated-cone rotor. Teeth inclined at 20\({}^{\circ}\) are cut on the inner surfaces of these stator cylinders, providing optimal meshing with the rotor teeth and thereby maximizing the shear forces applied to the material.  
Working Mechanism  
The colloid mill, incorporating the described rotor and stator components (Figure 2), operates on the principle of high-shear wet grinding. Poultry meat-and-bone raw material, preliminarily crushed to a size of approximately 3 mm, is fed into the machine through a loading hopper. From there, the material enters the working assembly containing the rotor-stator unit. The high-speed rotation of the rotor generates centrifugal acceleration, propelling the bone mass outward toward the periphery of the rotor.  
As the material passes through the narrow, adjustable gap between the rotor and the stationary stator, it is subjected to a combination of intense mechanical forces. These forces include significant shear stresses generated by the high-speed relative motion between the rotor and stator surfaces, frictional forces arising from the contact between the bone material and the teeth of both components, impact forces resulting from the collision of bone fragments with these surfaces, and high-frequency vibrations induced by rapid rotation and interaction [15].  
Larger bone fragments entering the mill initially undergo coarse grinding by the larger-diameter cylinder with a finer tooth pitch, followed by progressively finer communication as the material moves toward the smaller-diameter cylinder with a coarser tooth pitch. The adjustable gap between the stator and rotor allows precise control over the intensity of these forces, ultimately determining the fineness of the resulting bone paste.