Application of RFID Technology in Intelligent Management of Superhard Abrasives

The "Invisible Memory" of Grinding: The Deep Application of RFID Technology in Intelligent Management of Superhard Abrasives

In the field of precision machining, **grinding** is the "last mile" that determines the final accuracy and surface quality of a workpiece. From the **grinding wheel** for rough grinding to remove excess material, to the **oilstone** for fine polishing, and then to the **grinding head** for shaping irregular curved surfaces, the grinding Tool family undertakes the ultimate mission of "adding the finishing touch" to the workpiece. However, grinding is also the most "uncertain" link in all cutting processes.

Unlike drilling ("hole opening"), milling ("contour shaping"), and turning ("rotational cutting"), grinding presents unique challenges:

- **Invisible Abrasive Grains:** Each abrasive grain on the grinding wheel surface is a micro-cutting edge, but its wear condition cannot be directly observed;

- **Sensitive to Dynamic Balance:** Wheel imbalance is the primary cause of vibration and surface quality degradation;

- **High Dependence on Dressing:** Grinding wheels require regular dressing to reStore cutting performance, but the timing and amount of dressing often depend on experience;

- **High Safety Risk:** Grinding wheel linear speeds are extremely high (up to 80 m/s or more). Exceeding safe speeds can cause the grinding wheel to burst, resulting in major safety accidents;

- **Diverse Tool Forms:** From large grinding wheels with diameters of hundreds of millimeters to micro-grinding heads with millimeter-level precision, management is extremely complex.

The deep application of RFID technology is building an "invisible memory" system for grinding tools, making the unseen state of abrasive grains perceptible, predictable, and traceable.

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### I. The "Birth Certificate" of Grinding Wheels: RFID-Linked Basic Files and Safety Parameters

Grinding wheels are the most valuable and have the most stringent safety requirements among all grinding tools. A single ceramic-bonded grinding wheel or a superhard material grinding wheel (such as CBN or diamond wheels) can easily cost thousands of yuan, and its safe linear velocity is directly related to the personal safety of the operator.

**RFID solution: From "Visual Identification" to "Electronic Authentication"**

1. **Tag Embedding Process**: During the manufacturing process of the grinding wheel substrate, a groove is pre-reserved on the side or non-working surface of the inner hole of the substrate to embed a **high-temperature resistant and cutting fluid resistant special RFID tag**. For thin grinding wheels that cannot be embedded, the tag can be installed on the grinding wheel flange or a special adapter.

2. **Static File Writing**: The tag stores the grinding wheel's **core identity information**:

- **Basic Attributes**: Grinding wheel model, outer diameter, thickness, inner hole diameter, abrasive type (white corundum/chrome corundum/CBN/diamond), grit size, hardness grade, and bond type. - **Safety Red Lines**: **Maximum Working Linear Speed**, Manufacturing Date, Shelf Life, and Maximum Permissible Imbalance.

3. **Safety Interlock Mechanism**: When the grinding wheel is installed on the grinding machine, the RFID Reader near the spindle automatically reads its maximum linear speed. If the operator attempts to exceed the speed limit (e.g., installing a standard 35m/s grinding wheel on a grinding machine with a 60m/s allowance), the system immediately locks the spindle start and issues an audible and visual alarm, physically eliminating the risk of grinding wheel breakage.

### II. Dynamic Balancing's "Digital Memory": RFID Records Balance Status

Dynamic balancing of the grinding wheel is the most critical adjustment step in grinding. An unbalanced grinding wheel can cause vibration marks, workpiece burns, and damage to the spindle bearings. In traditional methods, dynamic balancing needs to be readjusted after each grinding wheel dressing or reinstallation, and the balance status is often "forgotten after use."

**Innovative Applications of RFID: Portable Balancing Data**

1. **Balancing Data Writing**: An RFID reader is integrated into the offline dynamic balancing machine for grinding wheels. After the operator completes the fine balancing of the grinding wheel, the system directly writes data such as **balancing date, residual unbalance, balancing block position, and balancing grade (e.g., G1.0/G2.5)** into an RFID tag on the grinding wheel substrate.

2. **Instant Recovery Upon Installation**: When the grinding wheel is reinstalled on the grinding machine, the RFID reader automatically reads the balancing data from the tag. The CNC system can quickly adjust the balancing head to the optimal position based on this historical data, significantly shortening the secondary balancing time.

3. **Trend Analysis**: Historical balancing data from multiple balancing operations is accumulated in the tag, forming a "balance state change curve." When a balancing operation requires significant adjustment of the balancing blocks, the system prompts "The grinding wheel may have internal mass offset," suggesting early replacement to prevent potential malfunctions.

### III. A "Full Lifecycle Archive" for Dressing: RFID Records Every "Shaving"

Grinding wheels gradually become dull and clogged during use, requiring dressing (such as diamond dressing or roller dressing) to restore their cutting performance. The frequency and amount of dressing directly affect grinding quality and the total lifespan of the grinding wheel.

**RFID Dressing History Traceability**

1. **Dressing Parameter Recording**: After each dressing operation, the system writes data such as **dressing time, amount removed, dressing tool model, and post-dressing surface condition** into the RFID tag.

2. **Cumulative Amount Removed Management**: The tag has a "Cumulative Amount Removed" field. When the cumulative amount removed from a grinding wheel reaches the design threshold (e.g., diameter reduction exceeding 20% of the original size), the system automatically marks it as "end of life," prohibiting further use.

3. **Dressing Interval Optimization**: By analyzing the dressing history stored in the tag and the corresponding batch processing quality inspection data, process engineers can scientifically optimize the dressing frequency. For example, if the surface quality of the first 50 workpieces after dressing a certain type of grinding wheel is found to be optimal, the dressing cycle can be set to automatically remind the user to dress after processing 50 workpieces.

### IV. The "Miniature Identity" of Grinding Heads: Big Management of Small Tools

Grinding heads (including cylindrical grinding heads, ball grinding heads, and irregularly shaped grinding heads) have small diameters, come in many varieties, and are frequently replaced. They are commonly used for precision machining of mold cavities and polishing of complex curved surfaces. Due to their size limitations, traditional labeling or engraving methods are difficult to implement for individual piece traceability.

**RFID Miniaturization Solution**

1. **Miniature Tag Embedding**: Embedding **ultra-miniature RFID tags** in the grinding head shank (clamping section), with diameters as small as 1.25mm × 5mm, without affecting clamping rigidity and dynamic balance.

2. **Matching Relationship Recording**: The grinding head tag stores its **shape type, size specifications, abrasive grit size, and applicable material**. When an operator retrieves a grinding head from the tool cabinet, the system automatically records the person who retrieved it, the retrieval time, and the corresponding processing task.

3. **Automatic Tool Setting Compensation:** For precision grinding, the actual radius of the grinding head often varies slightly. After reading the RFID tag on the tool pre-setting device, the measured radius value is written to the tag. When the grinding head is loaded into the electric spindle, the system automatically reads this radius value and compensates for it in the CNC machining program, ensuring forming accuracy.

### V. The "Flexibility and Matching" of Oilstones: Refined Control of Deburring and Polishing

Oilstones are mainly used for manual or automated deburring, honing, and precision polishing. Unlike rigid cutting tools, oilstones are "flexible abrasives," and their effectiveness highly depends on the operator's technique and matching.

**Refined Matching Application of RFID**

1. **Digitalization of Oilstone Storage**: An oil-resistant RFID tag is embedded or affixed to the non-working end of each oilstone to record its **grain size, hardness, size, and applicable material** (e.g., fine oilstones suitable for aluminum alloys, super-hard oilstones suitable for quenched steel).

2. **Automatic Retrieval of Work Instructions:** At automated polishing stations, before the robotic arm picks up the oilstone, an RFID reader reads the oilstone's information. The system automatically determines whether the oilstone is suitable based on the workpiece material and polishing requirements. If the operator mistakenly uses a coarse-grained oilstone for fine polishing, the system automatically alarms and stops the operation.

3. **Wear Consistency Management:** For oilstones used in pairs (such as honing heads), the RFID system ensures that the grit size and hardness of oilstones installed on the same honing head are consistent, avoiding uneven wear that could lead to out-of-roundness of the machined holes.

### VI. Grinding Fluid's "Associated Memory": Invisible Process Parameters

During grinding, the supply status of the grinding fluid (flow rate, pressure, filtration accuracy) directly affects the grinding zone and workpiece quality. Cutting-edge RFID applications are beginning to link grinding tools with the grinding fluid system.

**RFID-Driven Process Integration Innovation**

When the RFID tag on a grinding wheel is read, the system automatically identifies the abrasive type and bond of the wheel:

- If it's a **resin-bonded grinding wheel**, the system automatically reduces the grinding fluid flow rate (resin is not resistant to immersion in water-based cutting fluids);

- If it's a **diamond wheel grinding carbide**, the system automatically increases the grinding fluid pressure and activates a special filtration mode (carbide grinding generates harmful dust, requiring vigorous rinsing and filtration).

This linkage of "tool identification - adaptive process parameters" brings grinding to a new level of intelligence.

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### Conclusion: A Revolution of "Transparency" in Grinding Tools

From binding the safety red line of the grinding wheel to carrying dynamic balancing data; from complete traceability of dressing history to precise matching of micro-grinding heads; from flexible control of the oilstone to process integration with grinding fluid—RFID technology is building an "invisible memory" system that spans the entire lifecycle of the grinding tool family.

- **For grinding wheels**, RFID makes every dressing process traceable and every rotation safe and controllable;

**For grinding heads**, RFID makes inventory and compensation of micro-tools precise and efficient;

**For oilstones**, RFID eliminates the reliance on experience for matching flexible grinding wheels;

**For grinding processes**, RFID enables the linkage between tools and machine tools, and between tools and cutting fluid.

When grinding tools possess "invisible memory," the once uncertain grinding process will usher in an era of true transparency and intelligence. This is not only an upgrade in tool management, but also a crucial step for grinding processes towards intelligent manufacturing.