archive_a: 2025/7

How to safely install lifting anchors in precast concrete production?

2025-07-30 - tags：Ball head lifting anchor Precast Concrete Lifting Anchors Precast concrete lifting Technical Installation Anchor Utility Anchor Lifting Anchors lifting anchors

In the world of precast concrete components, lifting anchors are the lifeline connecting the components to the lifting equipment. A single incorrect installation can cause components to slip, damage equipment, or even result in fatalities. Safely installing lifting anchors is no small matter; it's a paramount concern for both production efficiency and personal safety.

Lifting Anchors: The "Life Hook" of Precast Components

Lifting anchors are embedded in concrete components and serve as the core load-bearing point for connecting slings to facilitate lifting, tilting, and transportation. They determine the "lifeline" of the component from the production line to the installation site. Therefore, they are an essential component in precast concrete. Common types include:

Internally Threaded: Threaded holes are pre-recorded in the component surface for eyebolt installation.

Externally Threaded: An anchor with external threads is embedded in the component surface for eyenut installation.

Embedded Eyebolt: The eyebolt is embedded directly into the component.

Step-by-Step Installation Guide

Pre-Installation Checklist

Before installing lifting anchors in precast concrete, proper preparation is key to ensuring structural safety and efficient lifting. Here's your essential checklist:

Review Construction Drawings and Specifications

: Carefully review all technical drawings, lifting plans, and anchor specifications. Identify the required anchor type, location, and load rating to prevent conflicts or delays on site.

Choose the correct anchor point location and spacing: Anchor point placement must align with the panel's center of gravity and lifting direction. Incorrect spacing can cause tilting, rotation, or even panel failure during lifting.

Prepare Materials in Advance: Gather all required components: lifting anchors, groove formers, rebar templates, and sleeves. Ensure compatibility and quality compliance.

Gather Required Tools:

Use precision tools such as a laser rangefinder and level. Don't forget safety gear (helmet, gloves, vest) and installation aids such as fixing clamps or spacers.

Safety Red Lines and Key Considerations

Bearing capacity is the bottom line: Overloading is strictly prohibited! Anchors and matching rigging must be designed with the specified bearing capacity.

Thread protection is vital: The cleanliness and integrity of internal and external threads directly determine the strength of the connection. Never allow exposed threads to become damaged or clogged!

Shifting is a major risk: The anchor must be securely positioned during pouring and vibration. Any shifting can result in uneven load during lifting or even failure.

Concrete density is a guarantee: Weak concrete around the anchor can significantly weaken the anchoring force and pose a major safety hazard.

Regular inspection and maintenance: Reusable embedded sleeves, anchor plates, fixing brackets, etc. must be regularly inspected for wear and deformation and replaced promptly. Eyebolts/nuts should be regularly inspected for thread and load conditions.

Final confirmation before use: Before lifting, a dedicated person must re-check:

Anchor type and location are consistent with the drawings.

Threads are clean and intact, and the connectors (eyebolts/nuts) are correctly installed and tightened to the specified torque. The lifting rings are free of deformation and cracks.

The surrounding concrete is free of cracks, chipping, or other defects.

Carbon fiber the secret weapon that makes precast concrete as strong, light and tough as Transformers

2025-07-29 - tags：Carbon Fiber Precast Concrete Prefabricated Magnet Formwork System Prefabricated magnet templates

As the wave of prefabrication sweeps the world, the "excessive strength and insufficient toughness" of precast concrete (PC) components has always been a pain point in the industry. The emergence of carbon fiber, the "black magician", is making beams, plates and columns evolve from "fragile sharks" to "seismic iron men".

Pain point: Why can't traditional PC components "hold up"?

Brittle failure: Ordinary concrete is resistant to compression but not tension, and it is easy to break instantly when bent or impacted.

Steel bar corrosion: Chloride ion erosion in coastal areas or chemical plants has caused the "internal injuries" of traditional steel bars to increase.

Weight shackles: Increasing the cross-section to increase the bearing capacity will increase the transportation and lifting costs.

Post-earthquake repair is difficult: Once the node area is cracked, the on-site wet operation repair cycle is long, delaying the resumption of work.

Four disruptive roles of carbon fiber

Internal addition of "short fiber" - "ligament reconstruction" for concrete

• Mechanism: 0.2%-0.8% volume addition of short-cut carbon fiber forms three-dimensional random support in the matrix. When cracks appear, the fiber "bridges" to transfer stress, and the impact toughness is increased by 2-4 times.

• Scenario: Prefabricated stairs, subway pipe segments, anti-collision guardrails and other components that need to be impact-resistant.

• Data: Prefabricated beams with 0.4% carbon fiber added have a 35% reduction in mid-span deflection and a 50% reduction in crack width in the drop hammer test.

External "CFRP cloth" - "invisible armor" with 10 times the strength of steel bars

• Mechanism: CFRP cloth with a tensile strength of ≥3000 MPa is glued to the tensile surface of the component with epoxy glue to form a secondary force system, which can increase the bending bearing capacity by 30%-50% without increasing the cross section.

• Scenarios:

– Rapid reinforcement of old prefabricated hollow slabs;

– Seismic upgrade of prefabricated bridges (such as CFRP cloth wrapped around the plastic hinge area of piers).

• Case: After two layers of CFRP cloth were attached to the bottom of the prefabricated box girder of a certain overpass, the ultimate bearing capacity was restored to 1.45 times the original design.

Prefabricated "CFRP bars/grids" - "super steel bars" that never rust

• Mechanism: Using CFRP bars to replace traditional steel bars has a density of only 1/5 of that of steel, but a tensile strength of 10 times that of steel, and is resistant to chloride ion corrosion.

• Scenarios:

– Prefabricated exterior wall panels for coastal docks and LNG storage tanks;

– Prefabricated bridge panels that need to be protected from salt corrosion in high-altitude cold areas.

• Economical: The cost of the entire life cycle is reduced by 30%, eliminating the need for later anti-corrosion coating.

Intelligent "perception layer" - let the components have their own "health checkup"

• Mechanism: The evenly dispersed short carbon fibers make the resistivity of concrete change linearly with strain, realizing self-diagnosis of cracks.

• Scenarios:

– Prefabricated integrated pipe corridors, real-time monitoring of settlement;

– Prefabricated building exterior wall panels, rapid assessment of damage levels after an earthquake.

How much has the durability of prefabricated components improved after being "armored" with carbon fiber? We have obvious data comparisons, which are mainly reflected in two aspects;

1. Quantitative indicators of improved durability

Crack width: After CFRP cloth reinforcement, the crack expansion rate decreased by 60%-75%; after 120 dry-wet cycles, the stress intensity factor at the crack tip decreased by 50%.

Rebar corrosion: After CFRP bars/grids replaced steel bars, the chloride ion permeability coefficient decreased by one order of magnitude, and the steel bar corrosion rate was <0.01 mm/year.

Freeze-thaw cycle: After 300 rapid freeze-thaw (F-T) tests, the CFRP-concrete interface bond strength retention rate was ≥85%, while the unreinforced specimens only had 50%.

Ultraviolet aging: After continuous irradiation with UV-A 340 nm lamp for 1000 h, the tensile strength attenuation of CFRP cloth was <5%, which is much better than the 20% attenuation of epoxy-coated steel bars.

2. Environmental adaptability: Performance under extreme working conditions

High temperature and high humidity (40 ℃, RH 95%)

After 3000 h, the shear strength of the CFRP-concrete interface decreased by <8%, meeting the 30-year equivalent requirements of JTG/T J22-2011 for hot and humid environments.

Salt spray + dry-wet cycle (NaCl 5%, 120 cycles)

The bond strength of traditional reinforced concrete decayed by 50%, while the CFRP reinforced specimen only decayed by 12%.

Freeze-thaw + deicing salt (-18 ℃↗+5 ℃, 300 cycles)

The ultimate load of the CFRP cloth specimen decreased by <10%, while that of ordinary concrete decreased by 35%.

Therefore, carbon fiber is not simply "more expensive steel bars", but the key to the evolution of precast concrete from "passive load-bearing" to "active sensing". Whoever masters this key first will be able to open up a high value-added blue ocean in the red ocean of prefabricated buildings.

Magnetic Materials in Food Processing Invisible "Guardians", How to Ensure Safety and Efficiency?

2025-07-25 - tags：Drawer Magnet Hopper Magnet Magnetic Separators Rotary Iron Remover Suspended Magnets Thermal insulation Magnetic Liquid Trap

In a food processing plant that pursues deliciousness and health, you may not think of "magnets" at the first time. However, these invisible magnetic field forces are indispensable key players in ensuring the safety of our dining tables and improving production efficiency. They are unknown, but they have a great responsibility - they are specifically designed to deal with those "uninvited guests" that may be mixed into food: metal impurities.

* Wide range of sources: Metal impurities may come from raw materials (such as harvester parts fragments and ore residues in grain), production equipment (such as screen wear, loose and falling mechanical parts), employee negligence (such as screws, washers), and even packaging materials.

* Huge harm:

Physical damage: Sharp metal fragments are a major threat to consumer safety and may cause damage to the mouth, esophagus, and even internal organs.

Equipment damage: Hard metal particles can seriously wear or even jam expensive crushers, grinders, pumps and valves and other key equipment, causing unexpected downtime and high repair costs.

Reputation and legal risks: Once products containing metal foreign matter enter the market, they will inevitably lead to consumer complaints, large-scale recalls, serious damage to brand reputation, and even face severe regulatory penalties and lawsuits.

The above factors are the stage where magnetic separators come into play. They use the magnetic field generated by powerful permanent magnets (such as neodymium iron boron) or electromagnets to accurately "capture" ferromagnetic metals (iron, steel) and some weakly magnetic metals (such as some stainless steel) at key points in the food processing process. The working principle is that when food materials flow through or approach a strong magnetic field area, the ferromagnetic metal impurities in them will be firmly adsorbed on the surface of the magnet by the magnetic force, while the pure food passes smoothly, achieving precise separation.

What types of magnetic separation equipment are used in the food industry?

There are several types of magnetic separation equipment commonly used in the food processing industry, including:

 Plate magnets: These flat magnetic plates are most commonly found in conveyors or chutes. They are often used to remove metal contaminants from dry goods such as grains, seeds or pet food.

 Grid magnets: Similar to plate magnets, grid magnets are also suitable for dry material applications. These magnetic separators are composed of multiple magnetic bars through which the material passes. The magnetic bars collect and remove iron impurities from the material. Grid magnets are available in a variety of designs to suit a variety of material types, such as flour, grain, sugar, and more.

 Rotary magnets: These magnets are most effective for dry, sticky, difficult-to-flow products that have bridging issues, such as milk powder or sugar.

 In-line magnets: These types of magnetic separators include designs suitable for both dry and wet applications, as well as high-speed product lines, pump lines, and pneumatic conveying.

Magnetic Materials in Food Processing

Magnetic separation technology ensures safety: not only equipment, but also a system

* Comply with regulations and standards: HACCP (Hazard Analysis and Critical Control Points) system, ISO 22000, FSSC 22000 and other global food safety standards all list metal foreign matter control as a critical control point (CCP) or prerequisite program (PRP). High-performance magnetic separators are the basic hardware to meet these requirements.

* Equipment selection and verification: The magnetic strength, form and installation location must be scientifically selected based on material characteristics (dry/wet, particle size, flow rate), expected metal size and type. Equipment performance needs to be verified regularly (such as using standard test pieces).

* Strict maintenance procedures: This is the lifeline to ensure the continued effectiveness of magnetic separation equipment! Must establish and implement:

* Regular cleaning: Clean the metal impurities adsorbed on the surface of the magnet according to the plan (such as every shift, every day) to prevent accumulation from causing magnetic field shielding or re-mixing of impurities.

* Regular inspection: Check whether the magnet is damaged, whether the coating is intact (to prevent food contamination), and whether the magnetic force is attenuated (regularly use a gauss meter to test).

* Records and traceability: Detailed records of cleaning, inspection, and metal impurities found to ensure the process is traceable.

In the field of food processing, magnetic materials and their separation technology are by no means dispensable supporting roles. They are the cornerstone of building a food safety defense line and the guardian of efficient operation of the production line. Intercepting every potentially harmful metal impurity from the source is a manifestation of the modern food industry's responsibility for consumer health and a wise investment for companies to achieve sustainable development and win market trust.

Therefore, please pay attention to these "invisible guardians":

* Scientifically select applicable magnetic separation equipment.

* Strictly implement maintenance and cleaning procedures.

* Deeply integrate it into your food safety management system.

Why is rare earth magnet indispensable for new energy vehicles?

2025-07-18 - tags：NdFeB Neodymium Iron Boron New Energy Vehicles Rare earth magnets

In new energy vehicles, NdFeB permanent magnets are usually installed on the rotor of a permanent magnet synchronous motor (PMSM). When current passes through the stator winding to generate a rotating magnetic field, the permanent magnet's inherent magnetic field interacts with it, generating torque to drive the rotor to rotate - this is the precise physical process that occurs when you step on the "gate". Therefore, rare earth permanent magnets are called the "invisible heart" of new energy vehicles.

Rare earth permanent magnets: the "magnet king" of modern motors

The history of the development of rare earth permanent magnet materials can be described as an evolution of materials science. From the earliest natural magnets, to AlNiCo magnets in the early 20th century, to ferrite permanent magnet materials in 1947, humans have been constantly pursuing stronger magnetic properties. The real revolution occurred in 1983 when the third-generation rare earth permanent magnet material neodymium iron boron (NdFeB) came into being.

Why is neodymium iron boron called the "king of permanent magnets"? Its magnetic energy product is 10 to 15 times higher than that of ferrite, 5 to 8 times higher than that of traditional electric excitation materials, and second only to superconducting excitation. This material has extremely high remanence and coercivity, strong anti-demagnetization ability, and can allow the motor to generate a strong magnetic field in a smaller volume.

Why is it necessary for new energy vehicles?

Unlike traditional fuel vehicles, new energy vehicles have almost stringent requirements for drive motors: high power, small size, light weight, and high efficiency. Rare earth permanent magnet synchronous motors just meet these requirements perfectly:

Efficiency king: The efficiency can reach up to 97%, which is 6% higher than the efficiency of the induction motor used by Tesla in the early days, which directly translates into a longer driving range.

Power density king: Small size, light weight, and power density far exceeds other motor types, making vehicle layout more flexible.

Precise control: High speed regulation accuracy, fast response speed, and smooth and immediate power response.

In contrast, although AC induction motors are low in price and high temperature resistance, they have low power density; switched reluctance motors are low in price but have high noise and vibration. In terms of comprehensive performance, rare earth permanent magnet synchronous motors are undoubtedly the optimal solution for current new energy vehicle drive motors.

According to research, each new energy vehicle consumes an average of 2.5 kg of NdFeB permanent magnet materials. With the explosive growth of new energy vehicles:

In 2025, the global demand for rare earth magnets for new energy vehicles is expected to reach 30,000 tons.

The compound growth rate of rare earth magnet demand from 2021 to 2025 is 35%+, and new energy vehicles contribute about 60% of the growth.

Although rare earth permanent magnets are small, they have become an indispensable "industrial vitamin" for new energy vehicles. In the field of new energy vehicles, the essence of competition has shifted from the application level to the basic science level. With its advantages in rare earth resources and processing technology, China is transforming this strategic resource into a fulcrum for defining the future automotive technology paradigm.

What is a magnetic lifter? Why is it called the "invisible giant arm" in heavy industry?

2025-07-18 - tags：Electro Lifting Magnet Electro Permanent Lifting Magnet High-Intensity Permanent Magnet Lifts Magnetic Steel Lifting Equipment Steel Permanent Magnetic Lifts magnetic lifter

At the heavy steel plate lifting site, the crane moves slowly, but there are no steel cables or hooks below - only an inconspicuous metal plate adsorbing several tons of steel, hanging steadily in the air. Behind this is the power of the magnetic lifter, which uses the "invisible hand" of the magnetic field to completely revolutionize the way heavy materials are transported.

Core principle: precise control of magnetic field

Magnetic lifters are mainly divided into two types: permanent magnet and electromagnetic. The core of both types is to achieve adsorption and release through the control of magnetic field.

- Permanent magnet lifter: It uses high-performance permanent magnet materials such as neodymium iron boron (NdFeB) inside, and changes the distribution of magnetic lines of force by rotating the mechanical handle. When turned on, the bottom forms a longitudinal magnetic pole to adsorb the load; when closed, the magnetic lines of force are closed inside to achieve "zero magnetic leakage" release. The feature of not requiring power makes it extremely safe in power-off scenarios.

- Electromagnetic lifter: It relies on current to pass through the coil to generate a magnetic field, and the size of the magnetic force can be flexibly controlled by adjusting the voltage. The advantage is that it can be remotely controlled and is suitable for accurately separating single pieces of material from stacked plates. However, it requires continuous power supply and a backup battery to deal with the risk of power outages.

- Innovative combination: Electro-permanent magnet technology (such as Magswitch) combines the advantages of both. It only needs to be powered on for a moment to switch the magnetic state, and no power is required to maintain the magnetic force thereafter, with an energy saving rate of 95%, and supports remote control operation.

Why is it the darling of the industry?

1. Safe and reliable:

The maximum pull-off force of the permanent magnet type is 3.5 times the rated load, eliminating accidental falling off; the electromagnetic type avoids the arcing failure of the traditional contactor through contactless control technology (such as thyristor module) and improves stability.

2. High efficiency and energy saving:

Permanent magnets do not require electricity, and electromagnetics only consume electricity when working. Compared with hydraulic or mechanical clamps, energy consumption is reduced by more than 90%, and the cost of the cooling system is eliminated.

3. Lightweight design:

The high magnetic energy product of neodymium magnets reduces the size of the equipment by 50%, and it can be carried by manpower, greatly reducing the load of the crane.

Key usage tips: Avoid "magnetic traps"

The performance of magnetic lifters is affected by multiple factors, and ignoring these details may lead to accidents:

Influencing factors	Performance changes	Solution
Insufficient material thickness	Lifting capacity decreased by 30%-50%	Select equipment with higher rating
Surface roughness＞50μm	Magnetic force attenuated by 40%	Clean the surface or increase the number of magnets
High carbon steel load	Magnetic force weakened by 5%-10%	Calculate at 95% of the rating
High temperature environment (＞80℃)	Neodymium magnets are irreversibly demagnetized	Use samarium cobalt magnets (resistant to 350℃)

Good maintenance and monitoring can extend the life:

- Avoid impacting neodymium magnets (brittle materials are prone to breakage);

- Check magnetic force attenuation every two years and replace aged magnet modules;

- Electromagnetically check the battery capacity regularly to ensure that the power-off magnetic retention function is effective.