A DIGITIZING CRAFTSMANSHIP: A COMPARATIVE STUDY OF TRADITIONAL VS. SDF-BASED SHOE LAST MAKING USING 3D SCANNING AND CNC (COMPUTER NUMERICAL CONTROL) TECHNOLOGIES

Surya G¹Anbarasan P^1*Suresh B²

• ¹VIT University, Vellore, India
• ²2. Department of Engineering & Maintenance, Sanghavi Shoe Accessories Pvt. Ltd., Tamil Nadu, India., vellore, India

This paper presents a comparative study of traditional versus advanced shoe last making processes, with a focus on the integration of 3D scanning technologies and the SDF (Sistema Definizione Forma) manufacturing system. In the traditional approach, physical models are sculpted manually and digitized using mechanical digitizers, after which the digital files are processed in CNC machines. However, due to limitations in clamping and access, the toe and heel areas typically require manual finishing post-machining. Final stamping or branding is done using conventional heat embossing tools. In contrast, the advanced method minimizes manual intervention by using digital modeling tools such as Rhino software to design the shoe lasts directly. These digital files are then machined using SDF-enabled CNC systems, where an innovative dovetail gripping mechanism allows full-surface precision turning, eliminating deformation and manual finishing requirements. Once machining is completed, reference markings and customer logos are added using laser printing, ensuring high consistency and presentation quality. This study evaluates both methods in terms of dimensional accuracy, production speed, surface finish quality, repeatability, and readiness for mass customization, supported by practical insights from real-world applications.This study found that the SDF-based method improves production speed by over 70%, reduces manual intervention by 80%, and achieves sub-millimetric accuracy, supporting sustainable and scalable production in the footwear industry. Introduces a comparative study between traditional and SDF-based shoe last manufacturing. Explains the SDF (Sistema Definizione Forma) system and its patented dovetail clamping mechanism. Demonstrates how SDF technology reduces manual intervention by 80% and improves production speed by over 70%. Shows sub-millimetric accuracy and deformation-free machining using 9-axis interpolated CNC systems. Presents a real-world case study from Sanghavi Shoe Accessories Pvt. Ltd. validating the efficiency and economic feasibility of SDF integration.  Highlights sustainability benefits through reduced material waste, energy consumption, and operator dependency.