Grinding angle grinders are commonly used electric tools in our daily lives, yet we often overlook their maintenance. Therefore, this serves as a reminder that they also require care during use.
1. Regularly inspect power cable connections for tightness, ensure plug sockets are not loose, and verify that switches operate smoothly and reliably.
2. Inspect the carbon brushes for excessive wear, and replace them promptly to prevent excessive sparking or damage to the armature due to poor contact.
3. Ensure that the intake and exhaust airways of the tool are not blocked, and clean any oil stains or dust from all parts of the tool.
4. Lubricant should be added promptly.
5. The tool experienced a malfunction and has been sent to the manufacturer for repair. Generally, the manufacturer does not offer free repairs or replacements for damage caused by improper use or human error in disassembly or repair.
6. Inspect the marking on the angle grinders. Angle grinders that cannot be used include: those without markings, markings that are unreadable, unidentifiable, and those with or without defects.
7. Inspect the flaws of the angle grinder. This inspection method is2 types: Visual inspection, where you directly observe the surface of the angle grinder for cracks and other issues; Knock test, which is the main method for inspecting the interior of the angle grinder. The method is to tap the grinder with a wooden mallet. If the angle grinder is problem-free, it should produce a crisp sound; any other sound indicates a problem.
8. Test the rotational strength of angle grinders. Angle grinders of the same type and batch must undergo rotational strength inspections; those not inspected are not allowed for installation or use.
Electro-brush
Brushes can be used forDirect Current MotorOr for reversing motor exchanges, such as on general-purpose power tools, like drill presses and angle grinders, it is utilized. It is used in conjunction with the reversing switch to achieve the reversal of motor current, which is a feature of the motor (excluding squirrel-cage types).Electric MotorConduction current sliding contact body. In DC motors, it also bears the responsibility ofArmature windingThe alternating electromotive force induced in the middle coil is responsible for reversing (rectifying) the direction. Practice has proven that the reliability of the motor operation is largely determined by the performance of the brushes.
Leakage Repair
Common causes of electric leakage in angle grinders include: stator leakage, rotor leakage, brush holder leakage (for angle grinders with metal enclosures), and internal wire damage.
1. Remove the brush to determine if there is any leakage in the stator, brush holder, and internal wiring.
2. Disconnecting the wire between the stator and the brush holder allows for the detection of any leakage in the brush holder.
3. Conduct independent measurements to check for electrical leakage in the rotor.
The rotor and brush holder can only be replaced in case of leakage, while the stator can be rewound or replaced.
First, inspect the wiring insulation for any damage. A multimeter can detect this on the housing. Then, remove the rotor and measure it; this will determine if it's the rotor or stator that's leaking. A leaking rotor can only be replaced. If the stator is leaking, check if the carbon brush powder and other debris have accumulated too much, causing the leak. Clean it and measure again; if it still leaks, the stator winding insulation may be poor, possibly due to winding to the shell or moisture. If not, the winding may need to be re-wound.
Grinding Machine Faults and Solutions: The grinding machine utilizes a series motor, which is characterized by having two carbon brushes and a commutator on the rotor.
The common points of failure in this motor are the commutator and the end windings of the rotor.
If the commutator burns out, it's usually due to insufficient brush pressure. When the motor is in operation, if the current remains very high, the brush wears down quickly. Over time, the brush becomes shorter, the pressure decreases, and the contact resistance becomes significant. At this point, the commutator surface heats up severely.
If the winding part has burned, it indicates that the angle grinder exerted a significant pressure on the workpiece while in operation, resulting in high friction and the motor being in an overloaded state for too long. It's also due to the excessive current.
Exclusion Method
l Upon power connection, the motor fails to operate.
1. Power outage— Power source repair
2. Connection loose—— Inspect all connections
3. Poor switch contact or failure to operate— Repair or replace switches
4. Brush and commutator surfaces do not touch—— Brush Replacement
l Upon plugging in, there is an unusual sound and it does not rotate or rotates very slowly.
1. Switch contact burnt out— Repair or replace switches
2. Mechanical part jammed—— Inspecting Mechanical Components
l Arcs or large sparks occurring on the commutator
1. Armature Short Circuit—— Armature Repair
2. Brush and commutator poor contact—— Brush Replacement
3. The commutator surface is not smooth——Clear away debris, ensuring the commutator surface is smooth
l Work with slow rotation and abnormal sounds
1. Blade damage—— Blade Replacement
2. Blade hits rebarRe-selecting Work Sites
Operation Procedures
The angle grinder is a type of abrasive tool used for cutting and polishing. The lightweight multi-purpose angle grinder is suitable for deburring and polishing.
Operation Regulations:
1. Wear protective eye masks.
2. After turning on the switch, wait3 to 5 minutes, observe the grinding wheel's stable rotation before operation.
3. Employees with long hair must tie their hair up first.
4. Cutting directions must not be aimed at individuals.
5. After working continuously for 30 minutes, take a 15-minute break.
6. Do not process the diagonal grinder with small parts by hand.
7. Clean up the work environment after completing the task.
Ensure to check the manual before operating, as angle grinders vary by brand and model.
Preparation before Polishing
1. Before starting work, check for any damage to the grinding wheel and ensure the protective devices are intact.；Test the machine and make adjustments.，Ensure the grinding wheel does not exhibit any vibration.。
2. Wear your masks and goggles, and don your protective work attire.。
3. Before polishing, ensure the workpiece surface is free of any debris. If surface defects are found, weld them first before proceeding with the polishing.。
4. Perform the first piece polishing, inspect if it meets the polishing requirements, and upon confirmation by quality inspection or a supervisor, production can commence in bulk.。
Operation Standards:
1. When installing the grinding wheel, it is essential to verify that the wheel's maximum allowable speed is compatible with the spindle speed.
2. Products requiring polishing should be placed flat and small pieces should be secured to prevent movement during the polishing process, which may lead to machining defects.
3. Properly use grinding tools and promptly inspect and replace worn-out abrasive disc blades.
4. Hold the sanding tool firmly during sanding, and maintain the sanding disc in contact with the work surface.5-15°, proceed gradually (A→B), avoid excessive force to prevent surface indentation.
5. During the polishing process, if surface pores, slag inclusions, and cracks are discovered, it is essential to promptly notify the welder for re-welding.
6. After polishing, an internal inspection is required. The polished area should be free of noticeable scratches and dents, with no welding spatter around. It must meet the product design and process requirements. Products should be categorized and stored neatly and orderly.
Pre-weld Sanding
1. Scope of Polishing: Both Sides of All Welds20～50mm
2. Operation Method: Use a straight-hand grinder equipped with a stainless steel brush to sand the weld seam in the direction of the seam; when performing multi-layer welding, sand after each layer to remove irregular welds, spatter, and oxidation layers to ensure a smooth transition in welding.
3. Technical Requirements: Achieve a metallic luster, ensure no oxidation film on the welding area, the polishing patterns are parallel and even to the weld seam direction, and the polishing depth does not exceedBase Material Thickness5%For Standard。
Grinding of weld bead excess
1. Grind Range: Both sides of the weld20-50mm area.
2. Operation Method: The angle grinder should be parallel to the surface being ground during operation to remove excess weld bead; when there are dents in the weld, the standard is not to damage the base material. It is strictly prohibited to use the sharp end of the abrasive disc to scrape the grinding surface and to exert excessive force, which may cause surface indentation.
3. Technical Requirement: The polished surface must be smooth; it should not damage the base material, with the amount of base material removed not exceeding5%For standard; the surface patterns of the polished parts must be uniform, strictly prohibiting irregular polishing along the welding seam direction.
Eliminate Surface Scratches
1. Polish Scope: Scratch Areas
2. Operation Method: Sand along a specific direction using sanding tools.
3. Technical Requirement: The polished surface must be smooth; it should not damage the base material, with the amount of base material removed not exceeding5%The polished surface must have consistent patterns; irregular polishing is strictly prohibited.
Remove Weld Spatter
1. Polishing Range: Both Sides of Weld Seam40-50mm; any splashes outside this range should be sanded using the polishing method for surface scratches.
2. Operation Method: Use a grinding tool to grind along the weld seam direction
3. Technical Requirements: Achieve a metallic luster; ensure no spatter on the welding area; the sanding pattern is parallel to the weld seam; the sanding depth does not exceedRaw material thickness5%For standard。
Grinding Weld Joints
1. Grinding Scope: Use a straight grinder for sanding weld joints and starting/ending points of sectioned welds.
2. Operation Method: Use a straight grinder equipped with an alloy rotating file to grind the weld joint and the starting and ending points of the segmental welds.
3. Technical Requirement: The grinding of weld joint surfaces must match the appearance of the weld bead; the grinding at the start and end points of the segment must remove welding defects without leaving sharp edges on the surface; and must not damage the base material, ensuring the amount removed from the base material does not exceedRaw material thickness5%For standard。The finished product should be free of burrs, dents, and poor welds.。
Weld Seam Smoothing
1. Grinding Scope: Weld Seam and Both Sides of the Weld Seam15～25mm。
2. Operation Instructions: First, use an angle grinder and a disk blade to grind along the weld seam, ensuring the disk blade is in contact with the working surface.5～15°The angle, progressive smoothing, ensures that the weld seam is flattened with the standard being the removal of the base material not exceeding 0.2mm; in case of dents in the weld seam, it should be re-welded before sanding, and excessive force should be avoided to prevent surface indentation.。
3. Technical Requirements: Weld bead height should be at the same level as the base material. The machined surface must be smooth (or smoothly transitioned) without damaging the base material, and the amount of base material removed should not exceedBase Material Thickness5%For standards。The finished product should be free of burrs, dents, and poor welds.。
Stainless Steel Surface Brushing Treatment
1. ProcessScope: All Product Surfaces
2. Operation Method: The weld joints are sequentially ground using a straight grinding machine.The 120#, 240#, and 320# centrifugal wheels are being ground, with the straight sanding machine parallel to the workpiece surface and the centrifugal wheel perpendicular to the workpiece surface performing reciprocating movements. The wire drawing machine is used for surface and weld seam wire drawing effects.
3. Technical Requirements:The machined parts exhibit a smooth surface with no irregularities or burrs, voids, or sand holes; the overall surface must be glossy, with stainless steel products and焊接部位（welding joints）also meeting these standards.The XX process features a consistent direction of the wire surface after drawing, with uniform thickness. There should be no obvious stratification, discoloration, or yellowing.LathingThe product should be free of burrs, dents, and poor welds.
Stainless Steel Surface Polishing
1. Scope of ProcessingWeld splices and surface finishes of products
2. Operation Method: Weld bead and weld seam positions are sequentially treated.120# to 240# to 320# to 450# abrasive grinding, the subsequent grinding must cover the marks and scratches from the previous step. After achieving the 450# abrasive, use a wool wheel and polishing wax for the final polishing.
3. Technical Requirements: Ensure that the overall dimensions of the product meet the specifications after polishing and finishing based on the product's characteristics and process requirements; the surface of the polished part must be smooth without any unevenness, pockmarks, or poor welding; there should be no visible inconsistency in the polishing and finishing of the part surface, and the overall surface should be uniform.
Polish Quality
1. During the polishing process, if quality defects (such as pores, inclusions, cracks, etc.) are found, the operation should be halted and relevant personnel should be notified to address the issue.
Prohibit handling私自处理 based on personal experience.
2. The finished product should be free of burrs, dents, and poor welds.
3. The overall dimensions after polishing should meet the product's size specifications, with no obvious uneven polishing on the surface.
