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New visual inspection techniques overcome the Nyquist limit to provide high precision measurement of component positions.

Obtaining the required part top surface roughness and side roughness is critical in some applications. Each of these part properties can often be improved to the detriment of the other during selective laser melting (SLM). The purpose of this paper is to investigate the selective laser melting of Inconel 625 using an Nd:YAG pulsed laser to produce thin wall parts with an emphasis on attaining parts with minimum top surface and side surface roughness.

A full factorial approach was used to vary process parameters and identify a usable Inconel 625 processing region. The effects laser process parameters had on the formation of part surface roughness for multi‐layer parts were examined. Processing parameters that specifically affected top surface and side roughness were identified.

Higher peak powers tended to reduce top surface roughness and reduce side roughness as recoil pressures flatten out the melt pool and reduce balling formation by increasing wettability of the melt. Increased repetition rate and reduced scan speed reduced top surface roughness but increased side roughness. A compromise between attaining a relatively low surface roughness and side roughness can be attained by comparing part surface roughness values and understanding the factors that affect them. A sample with 9 μm top surface roughness and 10 μm side roughness was produced.

The research is the first of its kind directly processing Inconel 625 using SLM and investigating processing parameters that affect top surface and side roughness simultaneously. It is a useful aid in unveiling a relationship between process parameters and top/side roughness of thin walled parts.

The purpose of the work is to provide a comprehensive review of the digital image correlation (DIC) technique for those who are interested in performing the DIC technique in the area of manufacturing.

No methodology was used because the paper is a review article.

no fundings.

Herein, the historical development, main strengths and measurement setup of DIC are introduced. Subsequently, the basic principles of the DIC technique are outlined in detail. The analysis of measurement accuracy associated with experimental factors and correlation algorithms is discussed and some useful recommendations for reducing measurement errors are also offered. Then, the utilization of DIC in different manufacturing fields (e.g. cutting, welding, forming and additive manufacturing) is summarized. Finally, the current challenges and prospects of DIC in intelligent manufacturing are discussed.

The purpose of this paper is to examine the efficiency and objectivity of current Six Sigma practices when at the measure/analyse phase of the DMAIC quality improvement cycle.

A new method, named process variation diagnostic tool (PROVADT), demonstrates how tools from other quality disciplines can be used within the Six Sigma framework to strengthen the overall approach by means of improved objectivity and efficient selection of samples.

From a structured sample of 20 products, PROVADT was able to apply a Gage R&R and provisional process capability study fulfilling the pre-requisites of the measure and early analyse phases of the DMAIC quality improvement cycle. From the same sample, Shainin multi-vari and isoplot studies were conducted in order to further the analysis without the need of additional samples.

The method was tested in three different industrial situations. In all cases PROVADT's effectiveness was shown at driving forward a quality initiative with a relatively small number of samples. Particularly in the third case, it lead to the resolution of a long standing complex quality problem without the need for active experimentation on the process.

This work demonstrates the need to provide industry with new statistical tools which are practical and give users efficient insight into potential causes of a process problem. PROVADT makes use of data needed by quality standards and Six Sigma initiatives to fulfil their requirements but structures data collection in a novel way to gain more information.

Owing to the technology growth, especially in Microsystems technology and Nanotechnology, new products will provide new ways to sense variables that are crucial for product improvement and system reliability. A big concern of the scientific community is the measurement of low level flow measurements, especially for the biomedical and/or systems on a chip approaches.Design/methodology/approach – A new flow meter concept design consists of a surface micromachined sensor having an optical high reflective mirror made of gold, which is attached to unique cantilever designs that bend due to the drag force of mass flow. The bending of the cantilevers produces the mirror to approach/depart from an optical fiber end‐tip. The reflective light to fiber is modulated using a Fabry‐Perot interferometry technique to determine the mirror separation to the fiber, which corresponds to the mass flow.Findings – The new concept design shows a big potential approach to measure low flow measurements for air, gas and liquids of low viscosity. The results of this concept, through finite element analysis, show that the material used to build the sensor, makes them excellent candidates for fabrication. The stresses of the materials and allowable (readable) bending are among the tolerances of such materials/construction‐design. The sensor is not affected by electromagnetic interference and does not require electrical currents to sense, i.e. it is perfectly suited for biomedical and low mass‐flow sensing such as lab‐on‐chip applications.Originality/value – Among all approaches to sense low flow measurements, most of them need either “big” turbine approaches (dimensions over 1 cm diameter), or the need of an electrical approach needed in the end measurement sensor. This work proposes a non‐electrical approach.

The purpose of this study is to evaluate the geometric quality of small diameter holes in parts printed by direct metal laser sintering (DMLS) technology. An in-process optical inspection method is proposed and assessed during a pilot study. The influence of the theoretical hole diameter assumed in a computer-aided design (CAD) system and the sample thickness (hole length) on the hole clearance was analyzed.

The samples are made of two different materials: EOS MaragingSteel MS1 and aluminium alloy EOS Aluminium consisted of straight through holes of different diameters and lengths. Dimensional and shape accuracy of the holes were determined with the use of the image processing software and the computer analysis of two-dimensional (2-D) images. The definition of the equivalent hole diameter was proposed to calculate the hole clearance. Feret’s diameters were determined for the evaluation of the shape accuracy.

The dependency between the equivalent hole diameter and the theoretical diameter was approximated by the linear function for a specific sample thickness. Additionally, a general empirical model for determining the hole clearance was developed, allowing for calculating the equivalent hole diameter as a function of a sample thickness and a theoretical hole diameter.

Developed functions can be used by designers for a proper assignment of a hole diameter to achieve the required patency. The relevant procedures and macros based on proposed empirical models can be embedded in CAD systems to support the designing process.

The analysis of the geometric quality of the holes in parts printed by DMLS was based on the computer analysis of 2-D images. The proposed method of assessing the shape accuracy of straight through holes is relatively cheap, is widely available and can be applied to the features of other shapes produced by three-dimensional printing.

The nose radii of cutting inserts are normally measured using a profile projector or toolmaker's microscope. Since only a sector of a circle is available for the measurement using such instruments, the radii determined from these methods are inaccurate. The purpose of this paper is to present an alternative method of determining the nose radii more accurately using machine vision.

The 2D images of the cutting inserts were captured using a CCD camera with the aid of back lighting. The tool nose center in each digitized image was located based on the tool geometry. The curved nose profile was transformed into a linear profile using polar‐radius transformation. The nose radius was then varied within ten pixels of the nominal radius and the average deviation from a straight line profile in the nose region in the polar‐radius plot was evaluated. The radius corresponding to the minimum average deviation is identified as the most accurate radius value.

For the 15 simulated images of cutting inserts tested, the error in radii determine by the proposed method varied from −4.9 to 3.7 percent. But, the radii were about 9 to 22 percent higher than those measured using the profile projector on commercially available inserts. The radii measured using the profile projector was closer to the nominal radii with an average deviation of −3.2 percent compared to those measured using the proposed method.

The cutting inserts must be clean and free from dust particles when capturing the images; and the insert must be aligned accurately so that the plane of the nose profile is perpendicular to the optical axis of the CCD camera.

The proposed method can be used to determine the nose radii accurately. If the exact nose radius of an insert is known, the tool path can be programmed precisely to obtain high‐dimensional accuracy in the finished product.

The paper shows how a new method of determining the tool nose radii of cutting inserts more accurately compared to the conventional methods, based on a sector of the nose profile, has been developed.