Semi-circular cup lid

Semi-circular or dome lids are widely used for beverages like bubble tea, milkshakes, smoothies, and specialty coffee drinks. These lids provide extra headspace for toppings such as boba pearls, whipped cream, or chocolate syrup, accommodating the tall drink profiles common in modern beverage service.

Dome lids have a higher draw ratio than flat lids due to their three-dimensional shape. The draw ratio calculation must account for the full surface area, including the raised dome portion. Higher draw ratios require careful temperature control and plug-assist design to ensure material stretches without thinning excessively at the dome apex.

PET is the preferred material for transparent dome lids due to its exceptional clarity and good formability. PP offers good transparency with better heat resistance, making it suitable for hot beverages. PLA is also available as a biodegradable alternative, though it may require specialized processing conditions.

Yes, thin-gauge roll-fed thermoforming machines can produce dome lids. However, the mold design must accommodate the deeper draw and complex curvature, and the machine must provide sufficient heating capacity and forming pressure to achieve proper material distribution across the dome shape.

Common issues include thinning at the dome apex, uneven wall distribution causing weak spots, and warping or distortion after cooling. Proper plug-assist design is critical to ensure even material thickness across the entire lid surface. Temperature control during heating and cooling also plays a key role in preventing defects.