1038 J SCI IND RES VOL 68 DECEMBER 2009 Journal of Scientific & Industrial Research Vol. 68, December 2009, pp. 1038-1042 *Author for correspondence Tel: +381-18-500-660; Fax: +381-18-588-244 E-mail: jeki@masfak.ni.ac.rs Rapid tooling of tyre tread ring mould using direct metal laser sintering Jelena Milovanovic*, Milos Stojkovic, Miroslav Trajanovic Faculty of Mechanical Engineering Niš, A. Medvedeva 14, 18000 Niš, Serbia Received 04 May 2009; accepted 26 October 2009 Paper outlines a feasibility study of using direct metal laser sintering (DMLS) for rapid tooling (RT) of tread ring of tyre vulcanization mould. Lead time and costs for rapid tooling with DMLS is acceptable for small mould segments (1/64 of tread ring). RT strategy that utilizes DMLS appeared to have significant advantages concerning lead time and costs as compared to conven- tional tooling of tyre mould including CNC-HSM engraving. Simplicity of tread ring tooling by DMLS makes new tyre develop- ment and test easier and faster. Keywords: DMLS, Rapid prototyping, Rapid tooling, Tyre mould Introduction Direct metal laser sintering (DMLS) is an additive manufacturing process, in which high-power laser sinters fine layers (20 μ each) of metal powders layer-by-layer from bottom up until build is complete 1 . Fabricated tool inserts may be applied in die-casting, injection molding and a variety of other applications 2,3 . Geometrical and mechanical properties of parts produced by DMLS are comparable to those machined or produced by investment casting 4 . Tyre vulcanization mould is a very specific and complex type of tread ring mould, which is characterized by inverse tyre tread geometry (Fig. 1). Complexity of tread ring mould is manifested primarily by its toroidal shape containing different kind of ribs 5-10 (circumferential, lateral, spines or lamellas and esthetic). Conventional manufacturing process of tread ring mould involves complex (4- or 5-axis) machining and precise die-casting making tooling process very intricate, time consuming and expensive 11-13 . A preliminary study 14 has shown that rapid prototyping (RP) and rapid tooling (RT) seems to be promising technologies for manufacturing of complex shapes. RP and RT include applications of LOM (Laminated object manufacturing) 15 , FDM (Fused deposition modeling), SLA (Stereolithography), 3DP (3D printing), SLS (Selective laser sintering), DMLS (Direct metal laser sintering) and SLM (Selective laser melting) 16 technologies and their immanent RT procedures) 17 . In present study, most suitable RP technology (DMLS) was identified for optimal rapid tooling solution concerning main manufacturability parameters of quality, time and costs. DMLS Technology for Manufacturing of Tread Ring Segments Feasibility study of DMLS includes: i) Direct-metal sintering of tread ring segment [study was conducted with one-pitch-segment (1/128 of tread ring mould) by testing the most important utilization features of segment (geometrical and dimensional accuracy, surface roughness (SR), hardness, density and porosity, tempera- ture and pressure endurance, thermal conductivity and chemical reactivity)]; ii) Time and costs consideration; and iii) Identification of optimal rapid tooling procedure to employ DMLS in the production of tread ring mould. Tread Ring Segment Prototype DMLS one-pitch segment was manufactured by EOSINT M270 machine (with Yb fibre laser 200W). Material used for making tread ring segment was Direct Steel H20 (composition: Cr, Ni, Mo, Si, V, and C), which is a very fine grained steel-based metal powder.