如何去除加工毛刺

In metal processing, machining burrs are inevitable. In general, deburring methods can be divided into four categories:

1. Coarse level (hard contact): This category includes machining, grinding, filing and scraping.

2. Medium level (soft contact): This category includes belt sanding, polishing, elastic grinding wheel and buffing.

3. Precision level (flexible contact): This category includes jet machining, electrochemical machining, electrolytic grinding and rolling.

4. Ultra-precision level (precision contact): This category includes abrasive flow deburring, magnetic abrasive finishing, electrolytic deburring, thermal energy deburring, and high-power ultrasonic deburring. These deburring methods can achieve adequate part machining precision.

Manual deburring

Manual deburring is the earliest deburring method, using mechanical tools to grind down burrs where they occur. It involves high labor intensity, is time-consuming, and deburring quality is hard to guarantee. For complex shaped parts, meeting requirements with manual deburring is very difficult.

Brush deburring

When a deburring brush moves over the part surface, the multitude of bristles can flex to naturally conform to the workpiece contour, reaching into grooves, holes and other areas hard for general tools to access, removing the burrs. The brush action on the machined surface does not have enough force to cut material, only buffing the surface, so part dimensions are unaffected.

High-pressure water deburring

High-pressure water deburring is one of the most widely used deburring methods today. The principle is very simple high-pressure water jets are sprayed onto locations on the workpiece prone to burr formation. The water, through high-pressure impact, delivers sufficient impulsive force to knock off burrs, while also cleaning the part during jetting, killing two birds with one stone. Moreover, high-pressure water deburring uses regular tap water and a small amount of detergent, avoiding environmental pollution.

Thermal energy deburring

The principle of thermal energy deburring is to seal the workpiece inside a combustion chamber, fill the chamber with pressurized combustible gas and oxygen, and ignite it with a 20,000V spark plug, generating an instantaneous thermal shockwave that rapidly increases the temperature to around 3315°C. The speed of the combustion shockwave can reach 8 times the speed of sound, raising the temperature of burrs needing removal above the self-ignition point so that they combust in oxygen. When the combustion reaches the main body of the workpiece, the larger heat capacity of the part quickly absorbs the heat and causes the temperature to sharply drop, extinguishing the flame. Thermal energy deburring is widely used for aluminum alloy materials.

Electrochemical deburring

The principle of electrochemical deburring is to fix the workpiece in a container filled with electrolyte, insert electrodes at locations with burrs, use the workpiece as the anode and the electrodes as cathodes, then pass current so that the burrs are removed by the electrolytic effect. However, electrolytes are usually acidic while workpieces are aluminum alloys, so chemical reactions occur when placed in the electrolyte, damaging the part.

Abrasive flow deburring

Abrasive flow deburring uses an abrasive medium that is a semi-solid viscoelastic carrier loaded with abrasive grains. Different viscosities of the carrier, abrasive types, and grit sizes can produce varied effects. The abrasive specification depends on the workpiece shape, material, and desired finishing. The specification is formulated by combining carrier viscosity, abrasive material and grit size.

Common abrasives used are silicon carbide grains for standard deburring of cast iron, aluminum and steel parts. Diamond abrasives are used for super hard or ceramic materials.

Ultrasonic deburring

Ultrasonic deburring is a deburring technique that utilizes ultrasonic energy. The equipment consists of an ultrasonic generator, transducer, amplitude transformer and superhard abrasive tool. The ultrasonic generator converts 50Hz AC into ultrasonic frequency electrical oscillations. The transducer converts these into mechanical vibrations at ultrasonic frequencies. Since the vibration amplitude is very small at around 4μm, it cannot be used directly for machining. Instead, the amplitude transformer enlarges the amplitude and transmits the vibrations to the tool holder, driving the superhard abrasive grains into longitudinal vibrations, and superimposing ultrasonic vibration on the abrasive tool.

At the vibration node (theoretically a circumferential line), the amplitude is zero, allowing the whole vibrating system to be fixed to the housing there.

This method is mainly used for complex mold cavities, deep holes and other areas where other deburring methods are difficult to implement. By applying 20kHz mechanical vibration (15μm amplitude) to a superhard abrasive tool system (diamond or CBN), the ultrasonic energy can efficiently remove burrs. For high-strength, complex-shaped parts, using superabrasive media for deburring can achieve up to 100% efficiency.