The use of additive manufacturing to produce intricate part geometries in the aerospace, medical, and tool-and-die industries is increasingly incorporated in manufacturing process chains. However, the high costs, long production times, and material integrity issues associated with additive manufacturing technologies such as selective laser melting make the process suitable only for certain applications. In order to reduce selective laser melting production costs for selected parts, a combination of selective laser melting and milling can be used. Metal parts produced with this method are referred to as hybrid parts. A challenge in producing hybrid parts is to reduce the geometrical deviation due to processinduced warping. This paper discusses the effects of various laser scan strategies on the deviation of hybrid parts. A newly developed scan strategy is experimentally compared with its commercial counterpart with regard to as-built part warping and porosity. The novel strategy resulted in a significant reduction in warping and porosity. OPSOMMINGDie benutting van toevoegingsvervaardiging vir die produksie van komplekse onderdeel geometrieë in die lugvaart, mediese, en werktuig industrieë word toenemend geïnkorporeer in vervaardigingsproseskettings. Gepaardgaande hoë kostes, lang produksietye, en materiaal integriteitstekortkominge met toevoegingsvervaardiging tegnologieë soos selektiewe laser smelting veroorsaak dat die proses slegs uitvoerbaar is vir sekere toepassings. Ten einde selektiewe laser smelting produksiekoste te verminder vir geselekteerde onderdele, kan 'n kombinasie van selektiewe laser smelting en freesmasjinering geïmplementeer word. Metaal onderdele wat met so kombinasie geproduseer word, word na verwys as hibried onderdele. 'n Uitdaging in die vervaardiging van hibried onderdele is om geometriese afwyking deur skeeftrekking wat deur die proses veroorsaak word, te verminder. Hierdie artikel bespreek die effekte van verskeie laser skandeer strategieë op die afwyking van hibried onderdele. 'n Nuut ontwikkelde skandeer strategie is eksperimenteel vergelyk met 'n kommersiële eweknie met betrekking tot skeeftrekking en porositeit. Die skeeftrekking en porositeit van die nuut uitgevonde strategie is beduidend laer.

The objective of machining performance is to reduce operational costs and to increase the production rate while maintaining or improving the required surface integrity of the machined component. Together with industrial partners, several benchmark titanium components were selected and machined to achieve this. Titanium alloys are used extensively in several industries due to its unique strength-to-weight ratio and corrosion resistance. Its properties, however, also make it susceptible to surface integrity damage during machining operations. The research objectives of this study were to understand the effect of cutting parameters on surface integrity to ensure that machined components are within the required surface quality tolerances. The effect of cutting speed and feed rate on surface roughness, micro-hardness, and the microstructure of the work piece were studied for milling Ti6Al4V. The surface roughness increased with a greater feed rate and a decrease in cutting speed. The maximum micro-hardness was 23 per cent harder than the bulk material. Plastic deformation and grain rotation below the machined surface were found with the rotation of the grain lines in the direction of feed. There was no evidence of subsurface defects for any of the cutting conditions tested. OPSOMMINGDie masjineringsvermoë doelwit bly steeds om operasionele kostes te verminder en om die produksietempo te verhoog, terwyl die vereiste oppervlakafwerking van die komponent gehandhaaf of verbeter word. Ten einde hierdie doelstelling te bereik is verskeie komponente in samewerking met industrievennote, as maatstaaf komponente gekies en gemasjineer. Titaan allooie word op groot skaal in verskeie industrieë gebruik vanweë sy unieke sterkte-totdigtheid verhouding en korrosiebestandheid. Hierdie eienskappe maak die allooi egter ook vatbaar vir oppervlakafwerking skade tydens die masjineringsproses. Die navorsingsdoelstelling van hierdie studie was om die effek van die snyparameters op die oppervlakafwerking te verstaan, om sodoende te verseker dat die komponente binne die vereiste oppervlak toleransies vervaardig word. Die effek van snyspoed en voertempo tydens freeswerk op die oppervlak grofheid, mikrohardheid en mikrostruktuur van die Ti6Al4V werkstuk is bestudeer. Die oppervlakgrofheid het verhoog met 'n toename in voertempo en vermindering in snyspoed. Die maksimum mikrohardheid was 23 persent harder as die basismateriaal. Plastiese vervorming en korrel rotasie onder die gemasjineerde werkstuk oppervlak is gevind met die korrelgrein in die rigting van die voer. Daar was geen aanduiding van suboppervlak defekte onder enige van die toets kondisies nie.