119 research outputs found
Experimental Framework for Testing the Finishing of Additive Parts
Selective laser melting (SLM) is a metal additive manufacturing (AM) process involving the selective layer-wise scanning of a powder bed. It is capable of producing metal parts for applications including the aerospace and medical industries. However, components made by SLM are currently not always reaching their potential in industry, due to limitations in the process leading to inadequate part quality. One particular example is the attachment of partially melted particles to the surface which can act as crack-initiation sites reducing part fatigue life. It is therefore necessary to find finishing processes for metal AM parts that remove these particles without compromising the advantages of AM. This paper presents the challenges of finishing AM parts, outlines techniques reported in the literature, and proposes an experimental framework for analysing the effectiveness of finishing processes for AM. The outlined framework will help improve the scientific understanding of finishing processes for AM
STEP-based Conceptual Framework for Measurement Planning Integration
AbstractMeasurement aims to check the product conformance or to control the manufacturing processes’ parameters. It needs to be planned in an integrated and interoperable manner with other manufacturing activities. Integration of measurement planning is based on the information provided by the design phase. This paper aims to assist the interoperability of the measurement plans through introducing the resource-independent measurement specifications (RIMS) concept. The paper presents a conceptual framework for representing a STEP-based measurement features from the coordinate metrology perspective. The proposed framework supports the direct formulation of the measurement process specifications in an operation-based manner and the realization the process control functionality of the measurement processes
Investigation of the effects of cryogenic machining on surface integrity in CNC end milling of Ti-6Al-4V titanium alloy
This paper presents the first comprehensive investigations on the effects of cryogenic cooling using liquid nitrogen on surface integrity of Ti-6Al-4V titanium alloy workpiece in end milling operations. Titanium is classified as a notoriously difficult-to-machine material, where its machining is characterised by poor surface integrity and short tool life. Increasing productivity, whilst meeting surface integrity requirements for aerospace and medical titanium-based components has always been a challenge in machining operations. Cryogenic machining using super cold liquid nitrogen at -197°C is a method to facilitate heat dissipation from the cutting zone and reduce the chemical affinity of workpiece and cutting tool materials and therefore improving machinability. Since milling is one of the major machining operations for aerospace components, this study is concentrated on cryogenic milling. The effects of cryogenic cooling on surface integrity are compared to conventional dry and flood cooling in end milling Ti-6Al-4V titanium alloy. A series of machining experiments were conducted at various combinations of cutting parameters. Surface roughness and microscopic surface integrity were investigated and subsurface microhardness was measured for each sample. The analysis indicated that cryogenic cooling has resulted in up to 39% and 31% lower surface roughness when compared to dry and flood cooling methods respectively. Furthermore, microscopic surface defects were significantly reduced as a result of cryogenic. The investigations indicated that cryogenic cooling considerably improves surface integrity in end milling of Ti-6Al-4V.<br/
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