Rapid Prototyping of Moulds for PDMS-based Microfluidic Chips

Abstract To shorten the production time for PDMS-moulds by additive manufacturing (AM) several 3D printers have been investigated in comparison to standard micro-milling by producing benchmark structures. These are evaluated regarding their shape accuracy, the transparency of the casted PDMS which is linked to the surface quality of the mould, and the production time until the moulds are ready to use. Even though the additively manufactured moulds showed significantly better surface quality and shorter production time, the necessary shape accuracy for non-square-structures or structures with < 250 μm edge length could not be achieved due to limiting factors like nozzle diameter, size of the digital micromirror device or spot size of the LCD-panel.

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Experimental investigation of the influence of cutting parameters on surface quality and on the special characteristics of micro-milled surfaces of hardened steels

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211013064 ◽

2021 ◽

pp. 095440622110130

Author(s):

Barnabás Zoltán Balázs ◽

Márton Takács

Keyword(s):

Surface Quality ◽

Surface Profile ◽

Cutting Parameters ◽

Relevant Information ◽

Milling Process ◽

Micro Milling ◽

Machined Surface ◽

Analysis Of Dynamics ◽

Five Axis ◽

Coated Carbide

Micro-milling is one of the most essential technologies to produce micro components, but due to the size effect, it has many special characteristics and challenges. The process can be characterised by strong vibrations, relatively large run-out and tool deformation, which directly affects the quality of the machined surface. This paper deals with a detailed investigation of the influence of cutting parameters on surface roughness and on the special characteristics of micro-milled surfaces. Several systematic series of experiments were carried out and analysed in detail. A five-axis micromachining centre and a two fluted, coated carbide micro-milling tool with a diameter of 500 µm were used for the tests. The experiments were conducted on AISI H13 hot-work tool steel and Böhler M303 martensitic corrosion resistance steel with a hardness of 50 HRC in order to gain relevant information of machining characteristics of potential materials of micro-injection moulding tools. The effect of the cutting parameters on the surface quality and on the ratio of Rz/ Ra was investigated in a comprehensive cutting parameter range. ANOVA was used for the statistical evaluation. A novel method is presented, which allows a detailed analysis of the surface profile and repetitions, and identify the frequencies that create the characteristic profile of the surface. The procedure establishes a connection between the frequencies obtained during the analysis of dynamics (forces, vibrations) of the micro-milling process and the characterising repetitions and frequencies of the surface.

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Experimental research of milling force and surface quality for TC4 titanium alloy of micro-milling

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-015-6844-5 ◽

2015 ◽

Vol 79 (1-4) ◽

pp. 705-716 ◽

Cited By ~ 22

Author(s):

Haitao Liu ◽

Yazhou Sun ◽

Yanquan Geng ◽

Debin Shan

Keyword(s):

Titanium Alloy ◽

Surface Quality ◽

Experimental Research ◽

Micro Milling ◽

Milling Force ◽

Tc4 Titanium Alloy

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Experimental and Theoretical Investigations on Tool Wear and Surface Quality in Micro Milling of SiCp/Al Composites Under Dry and MQL Conditions

Volume 2: Advanced Manufacturing ◽

10.1115/imece2018-86071 ◽

2018 ◽

Cited By ~ 1

Author(s):

Ben Deng ◽

Haowei Wang ◽

Fangyu Peng ◽

Rong Yan ◽

Lin Zhou

Keyword(s):

Tool Wear ◽

Metal Matrix Composites ◽

Surface Quality ◽

Wear Mechanism ◽

Metal Matrix ◽

High Stress ◽

Micro Milling ◽

Matrix Composites ◽

Fe Simulations ◽

Theoretical Investigations

During the machining processes of ceramic particle reinforced metal matrix composites, the severe tool wear constrains the quality and cost of the parts. This paper presents the experimental and theoretical investigations of the tool wear behavior and surface quality when micro milling the 45vol% SiCp/Al composites under dry and minimum quantity lubrication (MQL) conditions. The results of scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) show that the wear mechanism of diamond coated micro mills are adhesive, abrasion, oxidization, chipping and tipping, even though it has been reported that abrasion is the most important tool wear mechanism when machining particle reinforced metal matrix composites. Compared with dry lubrication condition, the environmentally friendly MQL technique can enhance the tool life and surface roughness, and reduce the cutting force significantly under given cutting parameters. Then, finite element (FE) simulations are employed to investigate chip formation process in micro orthogonal cutting to reveal the effects of reinforced particle on tool wear and surface quality. The FE simulations shows the local high stress, hard reinforced particles in metal matrix, debonded and cracked particles are the key factors leading to the severe tool wear and the unsmoothed surface morphology.

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Handheld Enzymatic Luminescent Biosensor for Rapid Detection of Heavy Metals in Water Samples

Chemosensors ◽

10.3390/chemosensors7010016 ◽

2019 ◽

Vol 7 (1) ◽

pp. 16 ◽

Cited By ~ 7

Author(s):

Kirill Lukyanenko ◽

Ivan Denisov ◽

Vladimir Sorokin ◽

Anton Yakimov ◽

Elena Esimbekova ◽

...

Keyword(s):

Heavy Metals ◽

Rapid Detection ◽

Limit Of Detection ◽

Detection System ◽

Test Procedure ◽

Enzymatic Reaction ◽

Water Quality Assessment ◽

Micro Milling ◽

Microfluidic Chips ◽

Silicon Photomultiplier

Enzymatic luminescent systems are a promising tool for rapid detection of heavy metals ions for water quality assessment. Nevertheless, their widespread use is limited by the lack of test procedure automation and available sensitive handheld luminometers. Herein we describe integration of disposable microfluidic chips for bioluminescent enzyme-inhibition based assay with a handheld luminometer, which detection system is based on a thermally stabilized silicon photomultiplier (SiPM). Microfluidic chips were made of poly(methyl methacrylate) by micro-milling method and sealed using a solvent bonding technique. The composition of the bioluminescent system in microfluidic chip was optimized to achieve higher luminescence intensity and storage time. Results indicate that developed device provided comparable sensitivity with bench-scale PMT-based commercial luminometers. Limit of detection for copper (II) sulfate reached 2.5 mg/L for developed biosensor. Hereby we proved the concept of handheld enzymatic optical biosensors with disposable chips for bioassay. The proposed biosensor can be used as an early warning field-deployable system for rapid detection of heavy metals salts and other toxic chemicals, which affect bioluminescent signal of enzymatic reaction.

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The Investigation of a Micro-Component Machined on a Custom-built Miniature Machine Tool

Jurnal Teknologi ◽

10.11113/jt.v59.2563 ◽

2012 ◽

Vol 59 (2) ◽

Author(s):

Syaimak Abdul Shukor

Keyword(s):

Surface Quality ◽

Milling Process ◽

Micro Milling ◽

Batch Size ◽

Geometrical Accuracy ◽

Custom Made ◽

Micro Parts ◽

Solid Carbide ◽

Steel Aisi

Custom-built Miniature Machine Tools (MMTs) are now becoming more popular with the demand for reduced energy consumption and workshop floor when machining small/medium batch size micro-components. This paper investigates the capability of a custom-built 4-axis MMT through machining an “adapted standard‟ of micro-testpiece. The experiments have been carried out in two different materials: Carbon Steel (AISI 1040) and Titanium Alloyed (TiAl6V4) using solid carbide flat end mill cutters with 0.6mm diameter. From here, the surface quality and geometrical accuracy of the machined testpiece are evaluated and analysed. The investigation has shown that acceptable geometrical accuracies and surface quality of the machined micro-parts can be achieved using the in-house developed MMT. These results show that the use of the custom-made MMT does not hinder the micro-milling process to produce a good and satisfactory surface quality (Ra=0.04-0.07μm) and acceptable geometrical accuracy.

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Shape Accuracy and Surface Quality of Additively Manufactured, Optimized, Patient-Specific Bone Plates

Journal of Medical Devices ◽

10.1115/1.4049193 ◽

2020 ◽

Vol 15 (2) ◽

Author(s):

Michael Seebach ◽

Christian Fritz ◽

Johanna Kerschreiter ◽

Michael Friedrich Zaeh

Keyword(s):

Additive Manufacturing ◽

Surface Quality ◽

Bone Ingrowth ◽

Medical Application ◽

Bone Plates ◽

Patient Specific ◽

Shape Accuracy ◽

Quality Requirements ◽

Medical Quality ◽

Manufacturing Technologies

Abstract Powder-based additive manufacturing technologies such as powder bed fusion (PBF) using a laser beam (PBF-LB) and PBF using an electron beam (PBF-EB) allow the manufacturing of complex, patient-specific implants from titanium alloys at appropriate manufacturing expenses and thus production cost. To meet medical quality requirements, mechanical post-treatment (e.g., grinding and polishing) is often required. However, different medical applications require specific quality characteristics. It is therefore necessary to assess the fulfillment of the requirements for each case individually with regard to the manufacturing technologies. This study investigated the potential of the two mentioned additive manufacturing technologies for manufacturing patient-specific, topology-optimized bone plates that are used for osteosynthesis (the joining of bone segments) in the reconstruction of the mandible (lower jaw). Identical individualized implants were manufactured and subsequently treated with established industrial processes and examined according to medical quality requirements. Crucial quality requirements for this medical application are the shape accuracy (for exact bone positioning and even load transmission) as well as the surface quality (to enhance fatigue strength and prevent bone ingrowth in view of the subsequent easy removal of the plates). The machining of the implants is shown in comparison to distinguish the two manufacturing processes from established procedures.

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Surface quality and shape accuracy of multi-point warm press forming Corian sheets

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-019-04339-0 ◽

2019 ◽

Vol 104 (9-12) ◽

pp. 4727-4733

Author(s):

Heli Peng ◽

Mingzhe Li ◽

Zhongquan Li ◽

Xifeng Li

Keyword(s):

Surface Quality ◽

Shape Accuracy ◽

Press Forming

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Investigation on micro-milling of micro-grooves with high aspect ratio and laser deburring

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405419893491 ◽

2019 ◽

Vol 234 (5) ◽

pp. 871-880 ◽

Cited By ~ 2

Author(s):

Yinfei Yang ◽

Jinjin Han ◽

Xiuqing Hao ◽

Liang Li ◽

Ning He

Keyword(s):

Aspect Ratio ◽

Tool Wear ◽

Surface Quality ◽

High Aspect Ratio ◽

High Conductivity ◽

Cutting Fluid ◽

Micro Milling ◽

Free Alcohol ◽

Processing Efficiency ◽

Machined Surface

High aspect ratio micro-grooves are critical structures in the micro-electromechanical system. However, problems like rapid tool wear, low processing efficiency, and inferior machined quality in micro-milling of high aspect ratio micro-grooves by length–diameter ratio tools are particularly significant. In this work, a combined micro-milling method based on water-free alcohol as the cutting fluid and laser deburring is proposed to investigate the high aspect ratio micro-groove generation of oxygen-free high-conductivity copper TU1. Parametric experiments and high aspect ratio micro-groove experiments were conducted to investigate the surface quality, cutting forces, and tool wear. The water-free alcohol was employed to improve the tool life and machined surface quality. In the case of the oxygen-free high-conductivity copper TU1 material, a satisfactory high aspect ratio micro-groove (groove-width = 0.2 μm and aspect ratio = 2.5) with a nanoscale surface roughness ( Ra = 68 nm) was obtained under the preferred machining conditions. Furthermore, the deburring process of the high aspect ratio micro-groove by the laser technology was conducted to achieve ideal machined quality of the top surfaces.

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