Thermoplastic Microneedle Molding via Preheating

The resin body is pre-heated to a temperature close to its softening point before the molding process begins. This preliminary heating action reduces the time required for softening during actual molding, thereby improving productivity while maintaining uniform softening quality.

The heating process is divided into periodic stages: initial pre-heating phase, followed by a rapid heating phase during molding, and then a cooling phase. This periodic action allows the resin to be uniformly softened quickly without excessive total heating time, resolving the contradiction between manufacturing precision and productivity.

Instead of using expensive pre-formed molds, the invention uses a simple flat plate as the mold that copies or imprints the microneedle pattern onto the resin body. This copying approach eliminates the need for complex, expensive molds while maintaining the ability to manufacture hollow microneedles, thereby improving ease of manufacture without sacrificing adaptability.

The invention changes the key parameter of the molding process from mechanical mold contact to thermal softening followed by pressure application. By controlling temperature and pressure parameters, the same simple mold can accommodate different shapes and materials, significantly improving versatility while keeping manufacturing simple.

The resin body undergoes preliminary heating before the actual molding operation. This pre-heating ensures the resin reaches the optimal softening temperature in advance, allowing the molding process itself to be completed quickly. As a result, high molding quality is achieved without extending the total cycle time, enabling continuous manufacturing.

The heating and molding processes are continuous and integrated. The resin body is continuously fed, heated, molded, and cooled in an uninterrupted sequence. This continuous action eliminates idle time between operations, maintaining high productivity while ensuring each resin body receives sufficient heat for quality molding.

The invention controls microneedle height and hole size by precisely adjusting temperature and pressure parameters during the molding process. By changing these parameters, the resin's viscosity and flow characteristics are controlled, allowing accurate formation of microneedles with specific heights and through-hole dimensions. This parameter control approach achieves manufacturing precision while maintaining agent delivery capability.

The molding process incorporates feedback control where the temperature and pressure applied are monitored and adjusted based on the desired microneedle specifications. This feedback mechanism ensures that each batch of microneedles achieves the target height and hole size, providing precise control while maintaining the versatility of hollow structure fabrication for agent delivery.