In the field of mechanical transmission, the structural stability and safety of mixing equipment are always the core of the design. Among them, the fixed screw is used as the basic connector, and its design form and installation position directly affect the performance of the equipment. This paper will analyze whether the mixing equipment adopts internal fixed screws from a technical point of view, and discuss its engineering value.

First, the technical definition of internal fixation screws

Internal Fixation Screw refers to a fixed component hidden inside the device through a special structural design. Common forms include:

Countersunk Screw: The head is fully embedded in the mounting plane

Socket Head Cap Screw: Operated with a hex wrench

Insert nut: a metal nut embedded in the material

Its core advantages are:

Eliminate external protruding structures to avoid mechanical interference

Improve the surface flatness of the equipment for easy cleaning and maintenance

Enhance the overall structural strength and disperse stress concentration

Second, the typical fixed scene of mixing equipment

In the mixing system, screw fixation is mainly used in three key parts:

Transmission system connection

Coupling fixation of motor shaft and stirring shaft

Assembly connection between gearbox and frame

Positioning and Installation of Bearing Housing and Support Arm

Stirring assembly fixed

The blade is fixed with the keyway of the stirring shaft

Axial Positioning of Multi-layer Stirring Propeller

The connection between the auxiliary scraper and the inner wall of the container

Sealed structure strengthening

The sealing flange of the end cover and the cylinder body is fixed

Installation of observation windows and pressure sensors

Quick opening and closing design of access port

III. Engineering application advantages of internal fixing screws

mechanical properties optimization

Made of high-strength alloy steel (e.g. 35CrMoA)

Thread accuracy above ISO 6

The preload is controlled within 70% of the material's yield strength

Environmental Adaptive Design

Surface treatment: nickel plating/chrome plating/dacromet process

Anti-loose structure: spring washer/anaerobic glue/self-locking nut

Sealing design: O-ring with threaded sealant

Maintenance convenience improvement

Reserved maintenance space (≥ 2 times the operating radius of the wrench)

Adopt anti-corrosion coating (salt spray test ≥ 1000 hours)

Key screw setting torque marking (for regular inspection)

IV. Comparison of alternative fixed solutions

Fixed method, applicable scenarios, advantages and disadvantages analysis

Welded connection, permanent structure, high strength but impossible to remove

Expansion sleeve connection, high torque transmission, easy installation but high cost

Snap-on connection, quick disassembly and assembly of components, poor sealing and limited load-bearing capacity

Hydraulic nuts, large equipment installation, require special tools but are highly accurate

V. Industry standards and safety regulations

ISO 6150-1:2021: Safety requirements for mixing equipment

Specify the minimum breaking strength of the fixing screws for rotating parts

Clarify the anti-loosening torque standard of exposed screws

ASME B18.3: Hex Screw Dimensions Standard

Define the load-bearing capacity parameters of screws of different specifications

Specify the corrosion resistance grade of the surface treatment

GB 19871-2005: Safety requirements for mixers

Requires periodic non-destructive testing of key fixing screws (e.g. ultrasonic flaw detection)

VI. Future development trends

Intelligent fastening technology

Smart screws with integrated torque sensor

Wireless monitoring systems (e.g. LoRa/NB-IoT)

Application of new materials

Carbon fiber reinforced composite screws

shape memory alloy fasteners

Additive Manufacturing Innovation

Integrated embedded fixed structure

3D printed profiled thread design

In modern mixing equipment, internal fixing screws have evolved from simple connectors to systematic solutions. By optimizing material selection, structural design and installation processes, it can not only ensure the stability of equipment operation, but also meet the needs of the new era such as clean production and intelligent maintenance. In the future, with the development of intelligent manufacturing technology, the functional boundaries of fixing screws will be further expanded, becoming a key node connecting mechanical entities and digital twins.