In the realm of eyewear production, achieving impeccable appearance and surface finishing is crucial for assessing product quality. Glasses frames, often considered as jewelry and among the most expensive daily accessories, differ significantly between regular and luxury models, primarily in terms of weight. Lighter glasses, preferred for their comfort, require advanced materials like titanium. Titanium is prized for its ultra-lightweight, flexibility, durability, hypoallergenic properties, biocompatibility, and resistance to corrosion. However, its hardness poses challenges in achieving a perfect surface finish.
Traditionally, achieving a flawless surface finish for metallic eyewear parts required labor-intensive, time-consuming manual processes that demanded high skill levels and extensive workspace. These manual methods also involved repetitive mechanical movements and the use of toxic polishing compounds.
This case study explores how dry electropolishing can reduce time, improve results, and cut costs in the surface finishing of glasses frames.
Project Background
The client, a European Union-based manufacturer, specialises in producing high-value eyeglasses from materials such as plastic, stainless steel, bronze, brass, titanium, gold, silver, and platinum. The company is committed to continuously seeking innovative technologies to enhance product quality and overcome challenges, ensuring the delivery of flawless eyeglasses.
Previously, the customer relied on manual polishing methods. These procedures were resource-intensive, cost-inefficient, and resulted in high defect rates and subpar final product quality. The company's goal was to enhance production productivity and the quality of metal eyeglasses. The aim was to achieve a mirror surface finish while preserving the original design, especially for laser-engraved surfaces.
Solution: Surface Finishing Glasses Frames in 34 Minutes
The customer prepared a batch of stamped eyewear frames and parts (rims, temples) made from titanium, nickel silver, bronze, brass, and stainless steel. These were sent to GPAINNOVA for trials. The appropriate electrolytic media was selected based on material type, initial and targeted surface quality, and part geometry. The Engineering Department developed fixtures to hold the pieces without causing shadows or damage, maximizing cycle capacity.
The recommended equipment was the DLyte PRO500, a compact machine designed for high-output mass production, processing up to 48 parts per cycle. The defined movement and speed ensured perfect media and electrical flow throughout each piece.
Trials were conducted with varying process times and parameters, measuring roughness in different areas using a profilometer and microscope to detect defects. The best surface finishing results were achieved with dry suspension media, containing gel particles and an electrically non-conductive liquid, which protected the eyewear surface from oxidation. This process, particularly suitable for brass and bronze alloys, took 30 minutes per batch of 48 glasses frames, with a mass removal of 0.02 grams per part.
Considering a weight removal of 0.02 grams per piece and the full media workbowl capacity of 210 liters (4.04 kg metal extraction for steel with dry suspension media), it was determined that the client could treat 200,000 parts per media charge.
Results
- Surface Finish: Achieved mirror surface finish in approximately 34 minutes.
- OPEX Cost per Part: €0.15
- CAPEX Cost per Part: €0.55, amortized over 5 years with 168,000 parts/year
- Operational Efficiency: Reduced from 10 manual buffing stations to 1 DLyte PRO500
- Output: Daily output of 672 frames, annual output of 168,000 units with one shift over 250 working days.
- Quality: Parts were finished to the client’s specifications without altering the geometry.
- Process Repeatability: The DLyte PRO500 provided a high-quality, repeatable process.
This innovative solution significantly enhanced the efficiency and quality of the client's production process, ensuring the delivery of high-value eyewear with impeccable surface finishes.
If you would like to learn more about the process steps and technology used, you can request the Eyeware Case Study. You can also email our technical team for technical support with your fashion and jewellery components.