Comprehensive Process and Technical Advantages of Removing Flash and Burrs from Silicone Watch Straps with Dongguan Yingstda Intelligent Technology's Cryogenic Deflashing Machine
In the field of silicone product processing, the treatment of flash on watch straps directly affects product appearance and wearing experience. The cryogenic deflashing equipment developed by Dongguan Yingstda Intelligent Technology Co., Ltd. provides an efficient solution for the refined processing of silicone watch straps, leveraging innovative low-temperature embrittlement and precise spraying technology. This article details the full process of removing flash from silicone watch straps using its Liquid nitrogen flash machine and analyzes the key roles and technical advantages of Sand blasting machine and small sand blasting machine.
I. Pretreatment: Dual Preparation of Straps and Equipment
1. Initial Inspection and Fixing of Silicone Watch Straps
Flash Positioning: Flash distribution is identified via a visual inspection system (precision ±0.01mm), commonly found at strap buckle joints, parting surfaces, and strap edges. Record burr thickness (typically 0.05–0.3mm) and silicone hardness (Shore A 30–60).
Custom Fixture Design: Medical-grade silicone fixtures are used to fix straps, with special slots designed for different widths (8–24mm) and shapes (straight/wavy) to avoid deformation from stress concentration at low temperatures. Fixture surfaces undergo hydrophobic treatment to prevent silicone adhesion.
2. Parameter Setting for Liquid nitrogen flash machine
Cryogenic Embrittlement Threshold: Equipment temperature is adjusted to −160℃–−196℃ based on silicone type, with a holding time of 10–15 minutes. This embrittles flash areas due to molecular chain contraction (hardness increases to Shore A 90+), while maintaining the soft elasticity of main straps (elongation ≥350%).
Spray Media Preparation: 0.1–0.2mm nylon sand (Shore D 70–80 hardness) is used, pre-dried at 120℃ for 4 hours to ensure no moisture residue, avoiding impact on silicone surface properties.
II. Liquid Nitrogen Cryogenic Deflashing: Flash Embrittlement and Batch Removal
1. Gradient Cryogenic Embrittlement
Staged Cooling: After starting the Liquid nitrogen flash machine, straps are pre-cooled at −80℃ for 5 minutes, then gradually cooled to the target temperature to prevent internal stress from sudden temperature changes. Liquid nitrogen atomization particle diameter in the chamber is controlled at 40–80μm, with a circulating fan (wind speed 10m/s) ensuring uniform flash cooling and surface temperature difference ≤2℃.
Temperature Field Monitoring: Real-time monitoring via infrared thermography focuses on heat dissipation blind spots like buckle grooves and holes. Auxiliary nozzles are added if necessary to ensure consistent flash embrittlement.
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 60–90m/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 surface damage.
Automated Trajectory: CNC-generated contoured spraying trajectories ensure no flash residue in delicate areas like strap edges, holes, and buckle joints, protecting strap flexibility and color coatings.
III. Sandblasting Finishing: Surface Quality Optimization
1. Coarse Sandblasting with Sand blasting machine
Batch Processing: For conventional silicone watch straps, a turntable-type Sand blasting machine is used. Straps are loaded with 0.2–0.3mm glass beads (roundness ≥98%) and sandblasted at 40rpm for 6 minutes to reduce surface roughness from Ra 6.3μm to 1.6μm.
Process Parameters: Sandblasting pressure 0.2–0.4MPa, spraying distance 12cm. The turntable angle is adjusted via servo motor for uniform sand exposure, avoiding local over-blasting.
2. Fine Trimming with small sand blasting machine
Local Micro-Processing: For high-end silicone watch straps (e.g., sports watches, smart bracelet straps), a small sand blasting machine is used with 0.05mm corn starch sand. Under a 20x microscope, secondary sandblasting eliminates 0.01mm-level burrs on critical areas like buckle holes and LOGO engravings, avoiding damage to decorative textures.
Static Control: An ion air bar (wind speed 10m/s) is activated during sandblasting to prevent static adsorption of sand particles, ensuring surface cleanliness meets consumer product standards.
IV. Post-Processing and Quality Verification
1. Cleaning and Performance Recovery
Ultrasonic Cleaning: Straps are placed in an ultrasonic tank with neutral detergent (40kHz) for 4 minutes, then rinsed three times with deionized water to ensure no chemical residue.
Disinfection Treatment: For children's or medical-use straps, ultraviolet disinfection (wavelength 254nm, 15 minutes) is performed to ensure hygiene safety.
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 strap surfaces and key areas (e.g., buckle hole edges) with burr height ≤0.02mm.
Physical Performance Testing: Samples undergo tensile testing (breaking strength ≥8MPa) and abrasion testing (500 friction cycles without fuzzing) to ensure deflashing does not affect mechanical properties.
V. Analysis of Yingstda Equipment Technical Advantages
1. High Precision and Customized Adaptation
The Liquid nitrogen flash machine achieves ±0.01mm-level deflashing precision through precise temperature control and CNC sandblasting, supporting one-click parameter switching for different hardness and shape silicone straps to adapt to diverse production needs.
2. Efficiency and Cost Advantages
Single equipment processes 500–800 straps per hour, 15 times more efficient than manual deflashing. Nylon sand can be reused 50–80 times, with liquid nitrogen consumption only 0.3–0.8L/part, reducing costs by 40%+.
3. Environmental Protection and High-Cleanliness Production
A sealed sandblasting chamber design ensures dust emission ≤5mg/m³, complying with ISO 14001 standards. The deflashing process is chemical-free, meeting hygiene requirements for food-grade and medical-grade silicone straps.
4. Intelligence and Flexible Production
The equipment integrates IoT modules for real-time monitoring of temperature, pressure, etc. Combined with local finishing by the small sand blasting machine, it realizes fully automated processes from roughing to finishing, reducing manual intervention errors.
Conclusion
From liquid nitrogen cryogenic embrittlement to sandblasting finishing, Dongguan Yingstda Intelligent Technology Co., Ltd.'s Liquid nitrogen flash machine combined with Sand blasting machine and small sand blasting machine constructs a complete technical system for silicone watch strap deflashing. With advantages of high precision, efficiency, and flexibility, this solution not only enhances strap appearance and wearing experience but also provides standardized and intelligent solutions for silicone product processing in smart wearables, medical protection, and other fields, promoting industry upgrading to high-end manufacturing.
