The evolution of seal strength with seal process conditions was investigated in order to achieve high quality seals and high packaging production rates. This optimization of heat sealing process parameters (Time, Temperature and dwell time) in terms of seal strength was performed on a monolayer linear low-density polyethylene (LLDPE) film. Heat sealing and T-peel tests were performed with a hot-tack machine in a temperature range of 100-140˚C, dwell time of 0.1-3s and pressure of 0.1-3.6 (N/mm2). In order to analyze the seal performance, the properties examined at each process condition were: Seal initiation temperature (Tsi), plateau initiation temperature (Tpi), final plateau temperature (Tpf), plateau seal strength (SSp) and failure mode. The effect of dwell time on seal strength is enhance of seal strength by increasing dwell time until a certain amount, and after that it remains constant for a period of time. In term of temperature window broadness at each specific dwell time, narrow temperature window was observed for dwell times lower than 0.4s and higher than 2s while in between a broad temperature window was observed. By increasing pressure, Tpi shifts to lower temperatures, however, the effect of pressure was not as significant as the effect of dwell time. At very high pressure, seal curves showed narrower temperature window. Comparing dwell time and pressure effects, variation in dwell time has a larger effect than pressure on seal initiation temperature and plateau temperature window. The level of plateau seal strength changes slightly with process conditions. We introduced a 3D graph of process safety zones for seal strength in ranges of heat seal process variables for the very first time. Heat sealing is joining two polymer surfaces while they are at least partially molten by applying heat and pressure. So, as the final result, time and temperature dependence of seal strength is a consequence of the amount of heat available in the interface of films.