Tehnologije dodavanja materijala u metalurgiji – Studija slučaja produkcije ventila iz sivog lijeva

Additive Fabrication technologies are well known from the last two decades. In that time Additive Fabrication technologies have evolved from strictly prototype part production into an option that can also be used to produce end-user parts. With development of Additive Fabrication machines capable of producing metal parts, a complete substitution of conventional metal casting technologies is possible. However, direct Additive Fabrication of metal parts is still not time/cost effective when producing large volume parts, and nowadays there is still lack of materials that can be used on those machines. This paper presents a method how a conventional sand casting process can be assisted by Additive Fabrication technologies. A sand mould pattern is produced by Selective Laser Sintering. Additive Fabrication is also used in direct manufacturing of cores.Tehnologije sa dodavanjem materijala dobro su poznate od posljednja dva desetljeća. U to vrijeme tehnologije dodavanja su se razvije od tehnologija koje se upotrebljavaju strogo za brzo proizvodnju prototipnih dijelova, do tehnologija, sa kojima se može direktnu proizvodnju konačne produkte. Sa razvojem tehnologija za direktnu izradu metalnih dijelove, moguća je potpuna zamjena konvencionalnih tehnologija lijevanja metala. Međutim, direktna izrada dijelova još uvijek nije dovoljno ‘’cost efficient’’ kada su u pitanju komadi velikog volumna i danas još uvijek je samo nekoliko materijala , koji su testirani na strojevima za direktnu proizvodnju metalnih komada. Ovaj rad predstavlja metodu kako se mogu tehnologije dodavanja koristiti kao pomoć kod konvencionalnih lijevarskih procesa. Pješčani kalup izrađen je po postupku selektivnog laserskog sinteriranja pijeska, a postupci direktne proizvodnje su korišteni kod proizvodnje jezgra ventila

Reverse Engineering of Parts with Optical Scanning and Additive Manufacturing

AbstractThis paper presents reverse engineering of car volume button. The purpose of article is to introduce reverse engineering procedure, what we need to do this kind of procedure and how we can remanufacture car's volume button. The purpose of reverse engineering is to manufacture another object based on a physic and existing object for which 3D CAD is not available. The first we need digital version of object. Because our car's volume button has free formed surfaces we decided to use 3D scanning technology to obtain the point cloud of existing object. With the help of point cloud we can developed 3D CAD model which will be used for manufacturing of button pair. We used for manufacturing of pair of buttons machine for selective laser sintering Formiga P 100. In the paper are also described costs of making of one pair of buttons and whole workspace

A Holistic Approach to Cooling System Selection and Injection Molding Process Optimization Based on Non-Dominated Sorting

This study applied a holistic approach to the problem of controlling the temperature of critical areas of tools using conformal cooling. The entire injection molding process is evaluated at the tool design stage using four criteria, one from each stage of the process cycle, to produce a tool with effective cooling that enables short cycle times and ensures good product quality. Tool manufacturing time and cost, as well as tool life, are considered in the optimization by introducing a novel tool-efficiency index. The multi-objective optimization is based on numerical simulations. The simulation results show that conformal cooling effectively cools the critical area of the tool and provides the shortest cycle times and the lowest warpage, but this comes with a trade-off in the tool-efficiency index. By using the tool-efficiency index with non-dominated sorting, the number of relevant simulation cases could be reduced to six, which greatly simplifies the decision regarding the choice of cooling system and process parameters. Based on the study, a tool with conformal cooling channels was made, and a coolant inlet temperature of 20 °C and a flow rate of 5 L/min for conformal and 7.5–9.5 L/min for conventional cooling channels were selected for production. The simulation results were validated by experimental measurements