Time management is a crucial soft skill in industrial design, influencing creativity, decision-making, and design outcomes. However, the design process is full of uncertainties, making time estimation challenging. Therefore, this study explores the relationship between self-estimated time constraints and ideation outcomes among industrial design students. A preliminary survey of 18 students identified common challenges in time estimation and ideation efficiency. To further investigate this phenomenon, a rapid design experiment was conducted with six subjects, dividing them into a control group (not required to strictly follow their estimated time) and an experimental group (required to strictly adhere to their estimated time). The results indicate that while self-estimated time constraints did not significantly influence satisfaction with ideation outcomes, they influenced ideation speed, thought processes, and emotional responses. Some subjects reported improved focus and accelerated decision-making, while others experienced anxiety. Additionally, precise time estimation required considering both task complexity and personal design experience. The findings suggest that self-estimated time constraints can serve as an effective time management tool in design education while allowing flexibility for individual adaptation.