Alloy blades for high-speed slitting

In slitting production, alloy blades often need regrinding due to chipping. Many users ask: after chipping, how many times can an alloy blade be reground? Will too many regrinds ruin it? Mingbai Mechanical Tool Technology Co., Ltd., based on materials science and resharpening experience, provides clear answers and judgment standards.   1. The Nature of Chipping   Chipping refers to small pieces of material breaking off from the cutting edge due to impact or fatigue, with depths ranging from 0.05mm to several millimeters. The purpose of regrinding is to remove the chipped layer and re-form a complete edge geometry. However, each regrinding consumes blade thickness. When the remaining thickness is insufficient to support normal cutting, the blade reaches the end of its life.     2. Four Factors Affecting the Number of Regrinds   1. Original blade thickness   Thicker blades can withstand more regrinds. For example, a carbide blade with 5mm thickness has several times more regrinding potential than a 2mm blade.   2. Chipping depth   Deeper chips require more material removal per regrind, resulting in fewer total regrinds. A 0.1mm chip can be removed with minimal grinding; a 1mm chip may require a significant amount of material removal in a single pass.   3. Grinding method   CNC grinding machines can precisely control each regrind removal amount (0.05-0.1mm), maximizing blade life. Manual grinding with a hand grinder is difficult to control and often results in excessive material removal.   4. Blade material   Different alloy blade materials have varying tolerance to grinding. Carbide blades for stainless steel strip slitting require more careful grinding due to their high hardness to avoid thermal cracks.   3. Reference Regrinding Counts for Different Blade Thicknesses     Thick alloy blades (thickness ≥ 8mm):   · Light chipping (<0.2mm): 8-12 regrinds · Moderate chipping (0.2-0.5mm): 5-8 regrinds · Severe chipping (>0.5mm): 3-5 regrinds   Medium alloy blades (thickness 4-8mm):   · Light chipping: 5-8 regrinds · Moderate chipping: 3-5 regrinds · Severe chipping: 2-3 regrinds   Thin alloy blades (thickness < 4mm):   · Light chipping: 3-5 regrinds · Moderate chipping: 2-3 regrinds · Severe chipping: recommended to scrap directly   4. When Should Regrinding Be Stopped?   1. Insufficient remaining thickness   When the remaining blade thickness is less than 60%-70% of the original thickness, the edge support strength decreases, making it prone to further chipping. Alloy blades for precision slitting are particularly sensitive to thickness changes.   2. Hardness drop after multiple regrinds   Each regrind generates heat. If cooling is insufficient, micro-cracks or hardness reduction may occur on the edge surface. Alloy blades for high-speed slitting should undergo hardness spot checks after multiple regrinds.   3. Blade deformation   After multiple regrinds, the blade may develop cumulative deformation (end face warping, flatness out of tolerance). If deformation exceeds 0.02mm, regrinding should be stopped.   4. Abnormal chip location   If chipping repeatedly occurs at the same location, it may indicate an internal defect in the blade. Continued regrinding will not solve the fundamental problem.   5. How to Maximize the Number of Regrinds?   1. Remove only the minimum necessary each time: Remove just enough to eliminate the chip; do not grind "just because." 2. Use a CNC grinder: Precisely control the removal amount and angle. 3. Ensure adequate cooling: Avoid grinding burns. 4. Record each regrind removal amount: When cumulative removal exceeds 15%-20% of the original thickness, consider replacement.   6. Mingbai Technology's Regrinding Services   Mingbai Mechanical Tool Technology Co., Ltd. offers professional alloy blade regrinding services:     · CNC grinding machines with angle control of ±0.3°. · Precise control of single regrind removal (0.03-0.10mm). · Hardness testing before and after regrinding to ensure no annealing. · Microscope inspection of the edge after regrinding to ensure no micro-cracks. · Provision of regrinding records to track each regrind removal amount and remaining thickness.     7. Case Study   A precision strip slitting plant used alloy blades for precision strip slitting with an initial thickness of 6mm. The first chip depth was 0.15mm. Mingbai Technology used a CNC grinder with 0.06mm removal per regrind. After a cumulative 9 regrinds, the remaining thickness was 4.8mm, still meeting cutting quality requirements, achieving a total life 2.5 times that of a new blade.     Conclusion   There is no fixed answer to how many times an alloy blade can be reground after chipping. It depends on the original thickness, chipping depth, grinding method, and blade material. However, by adopting a strategy of "remove only the minimum necessary + CNC precision control + adequate cooling," most alloy blades can be reground 5-10 times. Mingbai Technology is ready to help you maximize blade life with professional regrinding services. Website: www.mingbaiblade.com

When customizing custom blades, circular blades, or slitter blades, many customers encounter a puzzling problem: the edge angle is clearly marked on the drawing, but the actual machined blade always deviates from the drawing when measured. Is it due to insufficient machining precision on the manufacturer's side? Or is there a problem with the drawing itself? Mingbai Mechanical Tool Technology Co., Ltd., based on years of production experience, explains six common causes of angle deviation.   1. Different Measurement References — The Angle on the Drawing and the Actual Measured Angle Are Not the Same "Angle"   The edge angle is a three-dimensional geometric concept. The angle marked on the drawing is usually a theoretical value measured on a specific cross-section, such as a plane perpendicular to the edge direction. However, during actual measurement, if the measurement direction, cross-section position, or measuring instrument differs, the obtained values will vary.   For example, for circular blades for precision slitting, the edge angle is measured on the normal cross-section at the highest point of the edge. If the measurement is offset by 0.5mm, the angle can differ by 1°to 2°.   2. The Effect of Edge Radius (Passivation Value)   The edge angle marked on the drawing usually assumes an ideal sharp edge (R=0). In reality, all blades have a certain edge radius after grinding. Alloy blades for high-speed slitting are often micro-passivated (R=0.01-0.02mm), and this passivation makes the actual measured "apparent angle" slightly larger than the theoretical angle.     3. Thermal Deformation During Grinding   Grinding generates heat, causing localized temperature rise and metal expansion. After cooling, the blade contracts, but the contraction amount varies across different areas, potentially causing minor changes in the edge angle. Ultra-thin mechanical blades are particularly sensitive to thermal deformation; even with adequate cooling during grinding, deviations of 0.5° to 1° can still occur.   4. Grinding Wheel Wear and Dressing Frequency   In batch production, the grinding wheel gradually wears. If not dressed in time, the wheel's shape changes, causing the ground edge angle to drift accordingly. Wear-resistant circular blades for stainless steel strip slitting require extremely high angle consistency, and accumulated angle deviation due to wheel wear can reach ±1.5°.     5. Measuring Instrument Precision and Calibration   Different measuring instruments have different precision and calibration status. Measuring the same blade's edge angle with a projector, tool microscope, or profilometer can yield differences of 0.5° to 1°. If instruments are not regularly calibrated, the deviation is even larger.     6. Incomplete Drawing Specifications   Many drawings only specify "edge angle 30°" without indicating whether it is the wedge angle, rake angle, or clearance angle, nor do they specify the measurement cross-section, tolerance range, or edge radius requirements. For high-hardness custom blades, if the edge angle lacks a tolerance specification, the manufacturer will follow default standards such as ±2°, which may deviate significantly from the customer's expectations.   7. How to Avoid Angle Deviation? — Five Suggestions   1. Complete drawing specifications Clearly specify the values of wedge angle, rake angle, and clearance angle; indicate the measurement cross-section position; specify the angle tolerance (recommended ±0.5°); and state the edge radius requirements.   2. Agree on measurement method Confirm with the manufacturer what instrument will be used and at what cross-section position the measurement will be taken, ensuring both parties have a consistent understanding of "angle."   3. Request first-article inspection Before mass production, ask the manufacturer to provide a first-article inspection report to confirm the angle meets requirements before proceeding with batch production.   4. Choose a manufacturer with CNC grinding capability CNC grinders can precisely control the grinding wheel path, keeping angle deviation within ±0.3°.   5. Consider grinding allowance For custom slitter blades, you may specify "grinding allowance 0.1-0.2mm" on the drawing to allow for final precision grinding and angle adjustment.   8. Mingbai Technology's Angle Control Capability   Mingbai Mechanical Tool Technology Co., Ltd. uses five-axis CNC grinders, achieving edge angle control precision of ±0.3°. Every precision mechanical blade is inspected with a profilometer before shipment, and an angle inspection report is provided. We guarantee that the deviation between the drawing-specified angle and the actual machined angle is ≤±0.5° (and can be controlled within ±0.3° for special cases).   Conclusion   The deviation between the edge angle marked on the drawing and the actual machined result can stem from multiple factors: measurement reference, edge radius, thermal deformation, wheel wear, instrument precision, or incomplete drawing specifications. As long as both parties agree on specification, measurement, and inspection, the deviation can be controlled within an acceptable range. Mingbai Technology is committed to precision manufacturing, ensuring your drawing and the actual product match "angle for angle." Website: www.mingbaiblade.com