"“Resin Stone Grinding Wheels (GC Green Silicon Carbide Resin Bowl-shaped Grinding Wheels – the product you see in the image, Konaflex) – Comprehensive Introduction  
This product uses phenolic resin binder combined with green silicon carbide for Type 27 grinding wheels. It is specifically designed for grinding granite, marble, concrete, and raw stone materials, as well as for chamfering and leveling. Its formulation is completely different from ordinary metal grinding wheels.  

1. Complete Production Process  
✅ Step 1: Preparation of Raw Materials (the formula is the core of the product)  
Grinding abrasive: Green silicon carbide GC (specialized for stones; sharp and self-sharpening. Common particle sizes are GC#80/#120/#180/#240. The particles need to be screened and graded to ensure uniform particle size.)  
Resin binder: Phenolic resin powder + phenolic resin liquid (the key bonding material; determines hardness, toughness, and heat resistance.)  
Fillers and additives: Pyrochlore, pyrite, hollow microspheres, coloring agents (green color). Their functions include lubrication, cooling, adjusting hardness, and reducing weight.)  
Metal flanges: Pre-stamped inner holes with rivet holes; used to securely connect with the grinding wheel body, preventing cracking during high-speed rotation.)  

The difference between high-end and low-end products lies in this step: high-end products use high-purity silicon carbide and high-quality modified phenolic resin; low-end products use recycled materials and inferior resins, which tend to become soft, have inconsistent particle size, and crack at high speeds.)  

✅ Step 2: Mixing of Materials  
The silicon carbide particles are first immersed in the resin liquid to fully wet them, then mixed with resin powder and various fillers. The mixture is stirred at high speed. The temperature and humidity are controlled to prevent premature curing. After mixing, the material remains in a loose, moist state with dispersed particles.)  

Uneven mixing results in uneven hardness of the grinding wheel and large pieces of sand falling off.)  

✅ Step 3: Placement of the Steel Flange in the Mold  
The steel mold is cleaned, and the mixture is evenly filled into it. The metal flange is placed in the middle, and the material is manually spread out to ensure uniform thickness.)  

✅ Step 4: Hot Press Forming (critical process)  
The mold is pressed under high temperature and pressure to form a bowl-shaped shape (depressed center):  
Pressure is about 80–120 MPa, and the mold temperature is 160–180°C. The pressure is maintained for several seconds.)  
The pressure determines the density of the product. Insufficient pressure leads to loose and non-wearable grinding wheels; excessive pressure makes them too hard, prone to slipping and causing deep scratches.)  

After removing from the mold, we get the raw grinding wheel.)  

✅ Step 5: Curing in the Curing Oven (the most common area for cutting corners)  
Curing is done in stages. The standard procedure is: slow heating → holding temperature → slow cooling. This takes about 3–5 hours, with the maximum temperature around 190–200°C, allowing the phenolic resin to cross-link properly.)  

Large factories: Have a complete temperature control program, stable hardness, good heat resistance, and the grinding wheel doesn’t become soft or sticky during grinding.)  
Small factories: Shorten the curing time and use lower temperatures → “undercured” state. The grinding wheel becomes soft and loses its effectiveness quickly, reducing its lifespan.)  

✅ Step 6: Post-processing  
Turning/grinding the outer circle and ends, adjusting thickness and diameter; removing burrs; printing labels with logos (Konaflex, specifications: 100×6×16, particle size, maximum speed, etc.).  

✅ Step 7: Safety Testing Before Shipment (required by national standards)  
Rotational impact test: Test at 1.5 times the rated speed for 30 seconds; no cracks allowed (GB/T2493).  
Visual inspection: Cracks, bubbles, delamination, and loose flanges must be identified and rejected.)  
Hardness and thickness checks; if passed, packaging and storage.)  

2. How to Determine Product Quality (Practical Methods for Purchasing and Inspection)  
🔍 1. Initial Visual Inspection  
✅ High-quality: Uniform color, even distribution of sand particles on the surface; the bottom flange and grinding wheel are tightly connected, without any looseness; ends are smooth, without holes, bulges, or hidden cracks; printed text is clear.)  
❌ Low-quality: Irregular colors, holes in some areas; the flange is loose; edges are missing or have tiny cracks (easily broken at high speed.)  

🔍 2. Sound Test (simple and quick screening method)  
Tap the grinding wheel gently: A clear, loud metallic sound indicates proper curing; a dull sound suggests poor quality.)  

🔍 3. On-site Hardness and Wear Resistance Tests  
Take samples of the same size and grind granite on-site:  
✅ Good quality: Smooth cutting, even dust, gradual wear on the working surface; no large pieces of sand falling off; after continuous grinding, the grinding wheel doesn’t become soft or deformed; surface scratches are uniform, no deep scratches.)  
❌ Poor quality: Fast initial grinding, then noticeable slipping after a few minutes; large pieces of sand fall off; the grinding wheel becomes soft and deformed after heating.)  

🔍 4. Safety Label Verification (important for export)  
Must include: maximum speed, particle size, dimensions, safety warnings, and applicable standards. No labels mean a product without specifications; this will cause problems during export and CE certification.)  

🔍 5. Laboratory Tests (deep inspection)  
Rotational strength, hardness, density, bending resistance, thermal stability. For high-end orders, request the factory to provide batch inspection reports.)  

A practical tip for export inspection: Weigh multiple units from the same batch. Smaller weight variation indicates better consistency in formula and process; inconsistent weights indicate unstable quality.)  

3. Main Applications of the Product  
This GC green silicon carbide bowl-shaped grinding wheel is commonly used in stone processing plants:  
Grinding and leveling of granite, marble, and sandstone; trimming, chamfering, and removing chips from stone surfaces; grinding and polishing concrete and cement floors; grinding glass and refractory materials.)  

Difference: Diamond grinding wheels are used for fine polishing; this resin-based GC grinding wheel is suitable for rough grinding, large amounts of material removal, and shaping of raw materials.)  

4. Usage Precautions (Safety and Longevity)  
Never exceed the recommended speed: The image shows MAX SPEED 4300 r/min. The speed of a 100 mm angle grinder at idle is usually 11000 r/min. Make sure the grinder has a speed control function; using higher speeds can cause the grinding wheel to crack, leading to serious safety issues.)  

Protective covers must be installed, along with goggles, dust masks, and gloves. Stone dust contains free silica, and long-term inhalation can lead to silicosis.)  

Check before use: Visually inspect for cracks and loose flanges before each use. New grinding wheels should run idle for 30 seconds before use to ensure stability.)  

Grinding technique: It’s recommended to move the grinding wheel horizontally or at a small angle at a constant speed. Continuous heavy pressure on one point can cause local overheating, softening the resin binder and damaging the grinding wheel, as well as scratching the stone surface.)  

Dry vs. Wet Use: Most of these products are used dry. If used wet, confirm that the product supports wet grinding. Prolonged water exposure can cause slow degradation of the resin, reducing its strength.)  

Storage: Store in a cool, dry place away from heat sources; avoid direct sunlight. Resin degrades when stored at high temperatures, and grinding wheels stored for more than 1 year need re-inspection before use.)  

Flange compatibility: Inner hole size 16 mm; the flange must be flat. Do not use deformed or rusty flanges to avoid imbalance and cracking at high speed.)  

Additional Information for Export (for your Konaflex brand)  
English name: Green Silicon Carbide Resin Grinding Cup Wheel  
Specifications: 100×6×16 mm GC180  
HS code: 68042210 (resin-bonded silicon carbide tools)"