Most advanced technologies developed nowadays focus on issues such as minimizing manufacturing cost and improving product quality. Cooling system design is one of the most critical factors to reduce cycle time. Conformal cooling is the concept which can reduce cooling time and improve product quality as well. However, cooling system layout is restricted by traditional molding method. For cavities with irregular geometry, the distance between cooling channels and cavity may vary throughout the part. This causes local heat accumulation and some product defects such as sink mark and warpage. By using some non-conventional methods such as laser sintering, cooling channels can get closer to the cavity surface than using traditional method. This leads to a shorter cooling time. The current study uses a true three dimensional simulator to predict cooling time and compare the results from a conventional and a conformal cooling design. The results also show flow behavior inside cooling channels which provide important indices for cooling system design revision. With a shorter cycle time and an improved product quality, conformal cooling has a great potential in injection molding industry.

Power dissipation of chip-scale atomic clocks is one of the major design considerations. The largest power dissipation is for temperature control of the vertical-cavity surface-emitting laser (VCSEL) and cesium vapor cell. For example, the temperature of the VCSEL and Cs cell have to both be at 70±0.1°C or there will be frequency shift which will ruin the lock of the clock. These temperatures have to be maintained even under a large temperature variation such as −40°C to 50°C. There are three major thermal designs to consider: a) micro-heaters to fine-tune the temperatures of VCSEL and Cs cell, b) use of waste heat from other units to heat the system when outside temperature is low, and c) use of a thermal switch to release any extra waste heat when ambient temperatures are high. These three thermal designs have been incorporated in to a thermal test vehicle, which will be used to develop a thermal management design for the clock. This paper describes the proposed clock design, creation of the thermal test vehicle and development of a bimetallic snap based thermal conduction switch. The switch has been demonstrated to change thermal resistance from 52.9±2.8 K/W when the switch is open to 19.5±1.1 K/W with the switch closed.