O-ring deburring machine

4 month ago

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Dongguan YingSiDa Intelligent Technology Co., Ltd.

4 month

Product details

Comprehensive Process of Removing Flash and Burrs from Rubber O-Rings with Liquid Nitrogen Flash Machine

In the rubber products processing industry, the treatment of flash and burrs on O-rings directly affects sealing performance and service life. Liquid nitrogen cryogenic deflashing technology has become the mainstream industry solution due to its high efficiency and precision. This article details the full process of removing flash from rubber O-rings using a Liquid nitrogen flash machine, and introduces the application of Sand blasting machine and small sand blasting machine in fine processing.

I. Pretreatment: Dual Preparation of O-Rings and Equipment

1. Initial Inspection and Fixing of O-Rings

Visual Inspection: Manually inspect O-rings for severe defects like missing rubber or bubbles, and record flash distribution positions (commonly found on parting surfaces and injection ports).

Fixturing: Place O-rings into special fixtures, selecting suitable positioning grooves based on size (φ5-φ200mm) to ensure flash is exposed without obstruction. Fixture materials must resist -196℃ (e.g., 304 stainless steel).

2. Parameter Calibration of Liquid nitrogen flash machine

Temperature Setting: Precool the equipment to -150℃~-196℃, adjusting freezing time according to rubber type (nitrile rubber/silicone rubber): nitrile rubber requires -180℃ for 8-12 minutes, while silicone rubber needs -190℃ for 15-20 minutes, making flash brittle at a temperature lower than the main material.

Spray Media Preparation: Use nylon sand with 0.1-0.3mm particle size (Shore D 80-90 hardness), which must be dried at 120℃ for 4 hours before loading into the equipment hopper to prevent moisture affecting spraying effect.

II. Liquid Nitrogen Cryogenic Deflashing: Flash Embrittlement and Initial Removal

1. Cryogenic Freezing Stage

Equipment Operation: Start the Liquid nitrogen flash machine, send the fixture with O-rings into the freezing chamber, and spray liquid nitrogen uniformly through atomizing nozzles to form an ultra-low temperature environment of -196℃. Flash parts become embrittled due to molecular chain contraction (hardness increases to Shore D 95+), expanding the toughness difference with the main rubber.

Temperature Monitoring: Real-time monitoring via built-in PT100 sensors ensures the temperature difference between O-ring surface and flash ≤5℃, avoiding incomplete embrittlement caused by local overheating.

2. High-Speed Spray Deburring

Kinetic Energy Adjustment: After freezing, the equipment automatically switches to spray mode. Compressed air (pressure 0.5-0.8MPa) carries nylon sand to spray onto flash at 80-120m/s, leveraging the friability of embrittled flash to make it break off.

Omnidirectional Spraying: The fixture is driven by a servo motor to rotate (5-10rpm), ensuring flash on O-ring inner holes, outer diameters, and cross-sections are all impacted. For small O-rings below φ10mm, reduce spray pressure to 0.3MPa to prevent nylon sand from embedding into the rubber surface.

III. Sandblasting Finishing: Surface Quality Enhancement

1. Coarse Sandblasting with Sand blasting machine

Equipment Selection: For mass-produced O-rings (e.g., automotive seals), use a roller-type Sand blasting machine, load O-rings and 0.3-0.5mm glass beads (hardness HV 500-600), and perform rolling sandblasting at 30-50rpm for 5-8 minutes to remove residual micro-flash after cryogenic deflashing.

Process Parameters: Sandblasting angle 45°-60°, distance from workpiece 10-15cm, ensuring surface roughness Ra≤1.6μm on O-ring sealing surfaces (especially at cross-section R corners).

2. Fine Trimming with small sand blasting machine

Local Fine Processing: For precision O-rings used in aerospace (sealing accuracy requirement ≤0.05mm), use a small sand blasting machine for targeted sandblasting. Select 0.05-0.1mm alumina sand and perform secondary processing on parting surfaces and chamfers under a microscope (10-20x) to eliminate fine burrs difficult to reach by cryogenic deflashing.

Antistatic Treatment: Immediately remove surface static electricity with an ion air gun (wind speed 10-15m/s) after sandblasting to prevent residual sand particle adsorption.

IV. Post-Processing and Quality Control

1. Cleaning and Drying

Ultrasonic Cleaning: Place O-rings in an ultrasonic tank with neutral detergent (frequency 40kHz) for 3-5 minutes to remove residual sand and oil, then rinse 2-3 times with deionized water.

Hot Air Drying: Dry in a constant temperature drying oven (60-80℃) for 15-20 minutes to ensure no moisture remains on O-ring surfaces, avoiding misjudgments in subsequent inspections.

2. Full-Dimension Inspection

Visual Inspection: Under 3000lux lighting, use visual inspection equipment (precision ±0.01mm) to check flash removal. Sealing surfaces should have no visible burrs, and non-sealing surface flash height ≤0.03mm.

Performance Testing: Sample for pressure resistance testing (water pressure 20-50MPa) and airtightness testing (air pressure 0.5MPa, pressure holding 30s) to verify O-ring sealing performance, with leakage rate ≤0.1%.

V. Equipment Advantages and Process Key Points

Efficiency Comparison: A single Liquid nitrogen flash machine can process 500-1000 O-rings per hour, increasing efficiency by 10-15 times compared to traditional manual deflashing, with consistency exceeding 98%.

Cost Control: Liquid nitrogen consumption is about 0.5-1L/piece, nylon sand can be reused 50-80 times. Combined with local fine trimming by small sand blasting machine, comprehensive costs are 30% lower than dry ice cryogenic deflashing.

Safety Specifications: Wear special liquid nitrogen protective gloves (resistant to -200℃) and goggles during operation. Equipment must be equipped with an oxygen concentration alarm (threshold 19.5%) to prevent oxygen deficiency risks from liquid nitrogen leakage.

Conclusion

From liquid nitrogen cryogenic embrittlement to sandblasting finishing, this deflashing system composed of Liquid nitrogen flash machine, Sand blasting machine, and small sand blasting machine achieves fully automated and precise flash treatment for rubber O-rings. This process not only solves the efficiency bottleneck of manual deflashing but also ensures comprehensive improvement in O-ring sealing performance, surface quality, and service life through the scientific combination of cryogenic embrittlement and kinetic energy spraying, providing a reliable technical solution for rubber products processing in high-end fields such as automotive, aerospace, and medical.