During the use of resin cutting discs, improper operations by workers directly cause issues like abrasive shedding, edge chipping, and cracking, even posing safety hazards. Below is a concise breakdown of specific improper operations and their corresponding disc malfunctions, combined with principles and practical scenarios.
I. Improper Cutting Parameter Operations
Cutting parameters (speed, feed rate) are core design indicators for discs. Deviating from these parameters disrupts the disc's force balance and thermal stability.
1. Cutting Speed Exceeding Rated Value
Improper Operation: To boost efficiency, workers illegally increase the cutting machine's spindle speed, making the disc's actual linear speed exceed the rated value (typically 40–80 m/s for resin discs). Alternatively, they install large-diameter discs on equipment designed for smaller ones (e.g., using a 150mm disc on a machine for 100mm discs, doubling linear speed at the same rotation).
Disc Malfunctions:
Overload centrifugal force tears abrasives from the resin bond, causing large-area, frequent abrasive shedding (often with partial abrasive layer peeling).
Severe over-speed leads to base (fiberglass/metal) fracture, resulting in complete disc cracking (high risk of splashing fragments).
2. Excessive Feed Rate (Over-Force)
Improper Operation: Manual cutters (e.g., angle grinders) apply excessive pressure for speed; mechanical cutters have illegally accelerated feed motors, exceeding the disc's pressure tolerance.
Disc Malfunctions:
Excessive axial pressure crushes the abrasive-base interface, causing local large-chunk shedding (with dents/chipping at the shed area).
Uneven pressure leads to one-sided over-wear (abrasives shed fast on one side, thick on the other) and skewed cuts.
Instant overheating (over 800℃) carbonizes the resin, triggering cracked shedding or circular surface cracks (risk of further breakage).
3. Insufficient Cutting Speed (Low Rotation)
Improper Operation: Equipment rotation fails to meet disc requirements (e.g., 1500r/min instead of the rated 2800r/min) or drops under load without adjustment.
Disc Malfunctions:
Low speed causes abrasives to rub repeatedly at the same point, leading to continuous fine abrasive shedding (excessive dust and fast abrasive wear).
Debris clogs abrasive gaps; forced cutting then breaks the bond, creating a "clogging-shedding" cycle (pitted abrasive layers).
II. Mismatched Disc and Workpiece
Discs are designed for specific workpieces. Misuse accelerates wear.
1. Low-Hardness Discs Cutting High-Hardness Workpieces
Improper Operation: Using corundum discs (HRA 91–92, for low-carbon steel) on stainless steel/quenched alloys, or silicon carbide discs (for stone) on metals.
Disc Malfunctions:
Abrasives are crushed by hard workpieces, causing massive fine abrasive shedding (high abrasive fragments in dust) and rapid thinning of the abrasive layer.
Broken abrasives scrape the bond, leading to uneven pitting (base exposure in local areas).
2. Thin Discs Cutting Thick/Hard Workpieces
Improper Operation: Using thin discs (<3mm, for thin pipes/sheets) on thick steel bars (>50mm) or hard granite.
Disc Malfunctions:
Thin bases lack support; lateral pressure fractures the abrasive layer, causing whole-piece abrasive shedding (only the base remains).
Edge chipping occurs from collisions with workpiece edges, worsening into progressive shedding (more chipping as cutting proceeds).
III. Improper Cooling and Protection
Heat damages the resin bond. Neglecting cooling accelerates disc failure.
Dry Cutting Without Time Control
Improper Operation: Dry-cutting discs (for stone/ thick metal) used continuously (e.g., cutting 10 steel bars nonstop) without intermittent cooling.
Disc Malfunctions:
High temperatures carbonize the resin, causing blackened abrasive shedding (abrasives fall off when touched).
Base deformation cracks the abrasive-base interface, leading to flaky shedding (bent bases in shed areas).
IV. Improper Installation and Pre-Inspection
Poor installation will effect safety risks.
1. No Pre-Installation Inspection
Improper Operation: Using cracked, shed, deformed, expired, or damp discs without checks.
Disc Malfunctions:
Existing cracks expand into complete breakage (splashing fragments).
Damp resin hydrolyzes, causing uniform shedding (declining cutting efficiency).
2. Loose/ Skewed Installation
Improper Operation: Unfastened flanges, mismatched flanges (small flanges for large discs), or skewed alignment with the spindle.
Disc Malfunctions:
Loose discs slip, turning cutting friction into sliding friction, leading to overall uniform wear and shedding (wear marks around the center hole).
Skewed discs cause one-sided shedding and over-wear; eccentric force fatigues the base, resulting in cracking.
Summary
Improper operations force discs to endure excessive force, heat, wear, or misalignment, leading to shedding, chipping, or cracking. Standard practice-matching parameters, controlling force, cooling properly, and inspecting before use-reduces waste and safety risks.
