<![CDATA[The limited availability of actual CNC machines and high safety risks pose major obstacles to CNC programming education in vocational high schools. This study was conducted with the aim of developing a valid, practical, and effective Swansoft-based CNC Milling Simulation Learning Module to enhance the understanding of vocational high school students, particularly at SMK Negeri 1 Tuban. The study employed a Research and Development (R&D) model using the Define, Design, Develop, Disseminate (4D) framework. The test subjects were 33 students from class XI TP-3 at SMK Negeri 1 Tuban. Research instruments included validation sheets for media, language, and content experts; a comprehension test questionnaire; an implementation observation sheet; as well as pre-test and post-test questions. Validation results showed a percentage of 89.71% from media experts, 87.50% from language experts, and 86.46% from content experts, all categorized as "Very Good." The student comprehension test achieved a percentage of 87.47% in the "Very Good" category, and the implementation observation indicated that 94% of students were able to follow all practical steps well. The effectiveness test results showed a significant increase in the average score from 68.2 to 90.8, with an average N-Gain of 0.71 in the "High" category. The Swansoft-Based CNC Milling Simulation Learning Module was declared valid, practical, and effective for use as a self-directed learning medium for vocational high school students.]]>
