Plastic product 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 Plastic Parts with Yingstda's Liquid Nitrogen Flash Machine

In the field of plastic part processing, the precise removal of flash and burrs is crucial for enhancing product precision and surface quality. Yingstda Intelligent Technology's Liquid nitrogen flash machine provides an efficient solution for plastic part deflashing, leveraging composite technology of cryogenic embrittlement and kinetic energy spraying. Below is the standard process for removing flash from plastic parts using this equipment, combined with Sand blasting machine and small sand blasting machine for refined processing.

I. Pretreatment: Dual Preparation of Parts and Equipment

1. Initial Inspection and Fixing of Plastic Parts

Flash Positioning: Flash distribution is identified via a visual inspection system (precision ±0.02mm), commonly found on injection molding parting surfaces, gate areas, and thread hole edges. Record burr thickness (typically 0.05-0.3mm) and plastic type (e.g., ABS, PC, POM).

Flexible Fixture Design: Parts are fixed with silicone-padded aluminum alloy fixtures. For thin-walled structures (wall thickness ≤1mm), multi-point supports are designed to avoid cracking from stress concentration at low temperatures. Fixture temperature is maintained above -50℃ to prevent plastic-metal adhesion.

2. Parameter Setting for Liquid nitrogen flash machine

Cryogenic Embrittlement Threshold: Equipment temperature is adjusted based on plastic type:

ABS plastic: -80℃~-100℃, holding for 10-15 minutes (embrittlement temperature threshold -70℃);

PC plastic: -120℃~-140℃, holding for 15-20 minutes (embrittlement temperature threshold -110℃).

This ensures flash areas are below their glass transition temperature while maintaining mechanical properties of the main part.

Spray Media Preparation: 0.1-0.2mm nylon sand (Shore D 70-80 hardness) is used, pre-dried at 50℃ for 2 hours to avoid moisture affecting spraying performance.

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

1. Gradient Cryogenic Embrittlement

Staged Cooling: After starting the Liquid nitrogen flash machine, parts are pre-cooled at -40℃ for 5 minutes, then gradually cooled to the target temperature to prevent deformation from sudden temperature changes. Liquid nitrogen atomization particle diameter in the chamber is controlled at 30-80μm for uniform flash cooling.

Temperature Field Uniformity: Infrared sensors monitor to ensure surface temperature difference ≤2℃, particularly focusing on heat dissipation blind spots like grooves and bosses. Airflow deflectors are added if necessary to optimize cold air circulation.

2. Low-Pressure Sandblasting for Flash Removal

Kinetic Energy Matching: After freezing, the equipment drives nylon sand with 0.3-0.5MPa compressed air at 60-100m/s. "Parallel spraying" (15°-30° angle) is used for thin flash below 0.1mm, while cross-spraying paths are applied to thick flash (>0.2mm), with single-pass removal ≤0.05mm to avoid over-blasting that could cause dimensional tolerance issues.

Automated Trajectory Control: For complex-structured parts (e.g., automotive air vent grilles), CNC-generated contoured spraying trajectories ensure no flash residue in delicate areas like blades and clips, while protecting the precision of snap structures (control tolerance ±0.03mm).

III. Sandblasting Finishing: Surface Quality Optimization

1. Coarse Sandblasting with Sand blasting machine

Batch Processing: For small-to-medium plastic parts (e.g., electronic connectors), a turntable-type Sand blasting machine is used. Parts are loaded with 0.2-0.3mm glass beads (roundness ≥98%) and sandblasted at 30-50rpm for 5-8 minutes to remove residual micro-flash after cryogenic deflashing, reducing surface roughness from Ra 6.3μm to 1.6μm.

Process Parameters: Sandblasting pressure 0.2-0.4MPa, spraying distance 10-15cm. The turntable angle is adjusted via servo motor to ensure uniform sand exposure on all part surfaces.

2. Fine Trimming with small sand blasting machine

Local Micro-Processing: For high-precision plastic parts (e.g., medical catheter connectors), a small sand blasting machine is used for targeted finishing. 0.03-0.08mm corn starch sand (HV 200-300 hardness) is selected, and secondary sandblasting is performed on critical areas like thread holes and O-ring grooves under a microscope (10-20x) to eliminate 0.01mm-level burrs without damaging sealing surfaces.

Static Control: An ion air bar (wind speed 8-12m/s) is activated during sandblasting to prevent static electricity from adsorbing sand particles on plastic surfaces, which could affect subsequent assembly.

IV. Post-Processing and Quality Verification

1. Cleaning and Stress Relief

Ultrasonic Cleaning: Parts are placed in an ultrasonic tank with neutral detergent (frequency 40kHz) for 3-5 minutes to remove surface sand and oil, then rinsed twice with deionized water. Medical-grade parts require additional pure water spraying (conductivity ≤1μS/cm).

Stress Relief: After cleaning, parts are kept in a thermostatic chamber (60-80℃) for 1-2 hours to eliminate internal stress generated during cryogenic deflashing, preventing cracking in subsequent use.

2. Full-Dimension Inspection

Visual Inspection: Under 3000lux lighting, flash removal is checked via visual inspection equipment (resolution 0.01mm), requiring no visible burrs on sealing and mating surfaces, and non-functional surface burr height ≤0.02mm.

Precision Verification: Key dimensions are measured using an image measuring instrument, such as the addendum circle diameter of plastic gears (tolerance ±0.05mm) and the hole diameter of medical parts (tolerance ±0.02mm), ensuring no dimensional out-of-tolerance from deflashing.

V. Technical Advantages of Yingstda Equipment

Flexible Processing: One Liquid nitrogen flash machine is compatible with various plastics like ABS, PC, and POM. Corresponding parameters can be called with one click via the intelligent process library, with model change time ≤10 minutes.

Efficiency Improvement: Single equipment can process 300-800 plastic parts per hour, increasing efficiency by 15-20 times compared to traditional manual deflashing, with 99%+ consistency in burr removal.

Safety and Environmental Protection: Food-grade nylon sand and oil-free compressed air are used, combined with a sealed sandblasting chamber design, with dust emission ≤5mg/m³, complying with OSHA safety standards. Liquid nitrogen consumption is only 0.3-0.8L per part.

Conclusion

From cryogenic embrittlement to sandblasting finishing, Yingstda's Liquid nitrogen flash machine combined with Sand blasting machine and small sand blasting machine constructs a full-process solution for plastic part deflashing. This process achieves selective flash embrittlement through precise temperature control, combined with kinetic energy removal via low-pressure sandblasting and fine polishing, significantly improving surface quality while ensuring part dimensional accuracy. It provides an efficient and environmentally friendly technical path for plastic part processing in automotive, electronics, medical, and other fields.