Elisa Vazquez
Tecnológico de Monterrey, Centro de Innovación en Diseño y Tecnología, Department Member
Recently, ultrasonic molding (USM) has emerged as a promising replication technique for low and medium volume production of miniature and micro-scale parts. In a relatively short time cycle, ultrasonic molding can process a wide variety... more
Recently, ultrasonic molding (USM) has emerged as a promising replication technique for low and medium volume production of miniature and micro-scale parts. In a relatively short time cycle, ultrasonic molding can process a wide variety of polymeric materials without any noticeable thermal degradation into cost-effective molded parts. This research work reviews recent breakthroughs of the ultrasonic injection molding and ultrasonic compression molding process regarding the equipment and tooling development, materials processing and potential applications in the medical industry. The discussion is centered on the challenges of industrializing this technology, pointing out the need for improvement of the current process’s robustness and repeatability. Among the most important research areas that were identified are the processing of novel engineered and nanomaterials, the understanding and control of the ultrasonic plasticization process and the tooling and equipment development.
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Laser Micro-Spot Welding (LMSW) of metal sheets is a process widely used in medical, automotive and aerospace industries. This paper shows a process parameter selection for LMSW with AISI 302 stainless sheets, 254 μm in thickness.... more
Laser Micro-Spot Welding (LMSW) of metal sheets is a process widely used in medical, automotive and aerospace industries. This paper shows a process parameter selection for LMSW with AISI 302 stainless sheets, 254 μm in thickness. Experimental tests considered laser power, exposure time and focal distance parameters. The experimental setup produces the laser focal point over the part surface with a focal distance of 13.00 mm. The best results were obtained with an unfocused beam at a focal distance of 16.00 mm. Under the experimental conditions of this research, successful joining of AISI 302 thin sheets through LMSW is achieved with a combination of 175 W of average laser power and 0.25 s of exposure time (or a combination of 125 W and 1.00 s.). The width of the heat-affected zone (HAZ) was found to be 8% larger than the spot weld width, in average.
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This paper explores current advances towards Smart Injection Molding, and introduces the concept of Smart Molds or Molds 4.0. It presents a case study of the manufacture of a medical device, including the experimental set-up of an... more
This paper explores current advances towards Smart Injection Molding, and introduces the concept of Smart Molds or Molds 4.0. It presents a case study of the manufacture of a medical device, including the experimental set-up of an instrumented mold, as well as general recommendations on how to implement a Smart Manufacturing vision in the plastic Industry 4.0. Furthermore, it includes a proposal of an Advanced Cyber-Physical System (CPS) Service Oriented Architecture (SOA) for real-time monitoring and data analytics of a smart microinjection molding process and for smart molds instrumentation as a way to realize such smart vision.
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The use of nanoadditives in lubricants has gained much attention to the research community due to the enhancement of tribological properties and cooling capabilities. This paper studies the advantages of using a MQL (Minimum Quantity of... more
The use of nanoadditives in lubricants has gained much attention to the research community due to the enhancement of tribological properties and cooling capabilities. This paper studies the advantages of using a MQL (Minimum Quantity of Lubrication) system and nanoadditive in the manufacture of microneedle arrays in Ti6Al4V ELI alloy. Tungsten carbide ball nose tools with a cutting diameter of 200 µm were used in experimental tests. Surface and dimensional characterization was performed to evaluate the impact of a nanoadditive to a vegetable-based oil. Additionally, cutting forces and cutting edge radius (CER) were measured while needles were machined. Experimental tests confirmed that micro end milling with nanoadditives provide slightly better dimensional features and low cutting forces compared to oil. The performance of nanoadditives resulted in a reduction of surface roughness (~ 0.3 μm). Qualitative study of microneedles illustrated burr formation on needle surface manufacture...
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AZ31 magnesium coronary stents were studied through a manufacturing process chain involving laser cutting, acid pickling, and dip coating. The purpose of this study was to evaluate surface thickness and geometrical dimensions of stents... more
AZ31 magnesium coronary stents were studied through a manufacturing process chain involving laser cutting, acid pickling, and dip coating. The purpose of this study was to evaluate surface thickness and geometrical dimensions of stents after processing. Stents were dip coated in a solution using PCL with 1% of TiO2. Additionally, AZ31 coronary stents were dynamically tested using a degradation system based on peristaltic pumps. Our results indicate that coated stents degraded slower than AZ31 uncoated control stents. After 4 weeks of dynamic degradation under flowing Hank’s solution, coated stents lost only ∼9% in weight while uncoated stents lost ∼27% in weight. Stents were qualitatively evaluated after four weeks of degradation. Our results demonstrate the formation of micro-pores after one and two weeks of degradation for coated stents. Lamination was observed after three weeks of degradation, meanwhile, uncoated stents resulted with notches and an irregular surface caused by deg...
The laser micro-spot welding process was studied to implement a sheet lamination process-based methodology for the fabrication of austenitic stainless steel scaffolds. AISI 302 sheets with a thickness of 254 μm were laser cut and laser... more
The laser micro-spot welding process was studied to implement a sheet lamination process-based methodology for the fabrication of austenitic stainless steel scaffolds. AISI 302 sheets with a thickness of 254 μm were laser cut and laser welded. Experimental tests were carried out with different values of average laser power (i.e., 180, 200, and 220 W) and different exposure times (25, 50, 75, 100, 125 ms). The micro-spot welds were visually inspected according to the ISO 13919-1 Class B requirements. Spot welds were qualitatively characterized, and weld dimensions were measured (i.e., penetration depth, top, middle, and bottom width and the heat-affected zone (HAZ)) to identify the cross-sectional shape. Furthermore, process efficiencies (i.e., coupling, melting, and process) were studied. A seam welding model was adapted to calculate the required exposure time and was used to obtain a micro-spot weld to accomplish the quality requirements of the scaffold. A scaffold prototype was de...
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ABSTRACT Titanium alloy Ti6Al4V is a material that has been used extensively in industries, such as the medical field for prostheses and surgical instruments, because of its biocompatibility. However, it is considered a... more
ABSTRACT Titanium alloy Ti6Al4V is a material that has been used extensively in industries, such as the medical field for prostheses and surgical instruments, because of its biocompatibility. However, it is considered a difficult-to-machine material owing to its inherent mechanical and thermal properties (which cause severe tool wear and shorten tool life), diminished surface quality, and it conducts low productivity. The aim of this work is to evaluate the efficiency of minimum quantity lubrication (MQL) in micromilling in terms of dry machining and jet application. The effect of cutting fluid flow was analyzed through Computational Fluid Dynamics (CFD) analysis and jet application, in the context of the microscale, was found to cause a disordered flow that did not reach the desired target, in this case the two flutes of the tool. These results were accordant with those obtained in the micromilling experiments. In addition, recent machining concerns are related to sustainability and aim to reduce or even eliminate the use of cutting fluids altogether; in this sense, applying MQL in micromilling would represent a substantial reduction in cutting fluid consumption.
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Applications of polymeric materials in medical field are becoming a huge opportunity to innovate in new manufacturing technologies. This work provides a preliminary study of the processability of polyamide components using ultrasonic... more
Applications of polymeric materials in medical field are becoming a huge opportunity to innovate in new manufacturing technologies. This work provides a preliminary study of the processability of polyamide components using ultrasonic molding for medical applications. With this technology, parts can be transformed form raw material to final product in a few seconds. As it is a novel technique, is it necessary know how the processing parameters affect final products properties. For this reason, in this study, tensile bars of polyamide were manufactured and tested in a universal tension machine. For this mold geometry, material, and machine configuration, it was found that 4 seconds of ultrasounds and values of 35 microns of amplitude resulted in successful molded components. The results with tensile tests provided values of mechanical properties of parts produced via Ultrasonic molding that have similar properties than the ones estimated by the raw material.
ABSTRACT The current trend in miniaturization of products and components requires appropriate technologies for the manufacture of miniature dies and moulds. The work presented here deals with the process planning of micromilling for the... more
ABSTRACT The current trend in miniaturization of products and components requires appropriate technologies for the manufacture of miniature dies and moulds. The work presented here deals with the process planning of micromilling for the production of miniature mould cavities, required in ultrasonic moulding in order to reach high precision. Several aspects of process planning are addressed, including cutting tool geometry selection, segmentation of cavity geometry, minimum chip thickness, chordal tolerance, and type of interpolation. The case study involves the successful micromilling of a complex aluminium mould cavity for ultrasonic moulding. The proposed process plan is demonstrated through the micromilling of the mould cavity and silicone replicas of the miniature geometrical model. In general terms, good precision is obtained following the proposed methodology. In a randomly located set of geometric features, the dimensional error was below 5% for most features (32 out of a total of 40).
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ABSTRACT Increasing demand on micro-product has driven the development of innovative manufacturing process to this new requirements as well as the adaptation of conventional metal cutting process to these micro-scale applications. In the... more
ABSTRACT Increasing demand on micro-product has driven the development of innovative manufacturing process to this new requirements as well as the adaptation of conventional metal cutting process to these micro-scale applications. In the medical field a huge variety of products can be found in prosthesis, surgery devices or tissue engineering. This paper researches the application of the conventional EDM process to manufacture micro cavities with the objective to obtain how the process parameters could effects on the result. As a result the dimensions and shape of the micro-cavities are analyzed. (C) 2013 The Authors. Published by Elsevier Ltd.
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... In order to avoid severe burr formation, they suggested keeping both the axial engagement and the feed at a minimum. Aramcharoen and Mativenga [17] investigated the influence of the size effect on product quality in micromilling of... more
... In order to avoid severe burr formation, they suggested keeping both the axial engagement and the feed at a minimum. Aramcharoen and Mativenga [17] investigated the influence of the size effect on product quality in micromilling of H13 hardened tool steel. ...
Research Interests: Materials Engineering, Decision Making, Process Optimization, Swarm Intelligence, Response Surface Methodology, and 16 moreTitanium, Genetic Algorithm, Surface Roughness, Cell Culture, Human Body, Manufacturing Engineering, Multicriteria decision making, Medical Device, DNA Array, Evolutionary Computing, Regression Model, Very high throughput, End milling, Process Parameters, Response surface, and Particle Swarm Optimizer
ABSTRACT The increase in the demand for micro-parts, in combination with an ample range of shapes and materials, has created strong interest in micro-mechanical machining. The field of medicine provides an opportunity to use... more
ABSTRACT The increase in the demand for micro-parts, in combination with an ample range of shapes and materials, has created strong interest in micro-mechanical machining. The field of medicine provides an opportunity to use micro-production to manufacture micro-devices for tissue engineering surgery, surgical instruments and minimally invasive devices (catheters, stents, aneurysm clips, etc.). In an effort to understand the relationship between process parameters and the quality of the geometrical features of the final micro-part an experimental analysis was carried out using stainless steel (316L) and titanium (Ti6Al4V) with hardnesses of 88 HRB and 107 HRB respectively. The experiments were performed with varying parameters such as spindle speed (N), depth of cut per pass (a<sub align="right"> p ), channel depth (d), feed per tooth (f<sub align="right"> z ) and coolant application. This study finds better results when micro-channels were made in wet conditions. When coolant was used, the shape profiles of micro-channels created in titanium were of better quality than those made in stainless steel.
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ABSTRACT The demand for micro holes, micro-molds, and micro forms continues to grow as high-tech industries demand miniaturized products. Sectors such as aerospace, microelectronics, medicine, and even the automotive sector, are just some... more
ABSTRACT The demand for micro holes, micro-molds, and micro forms continues to grow as high-tech industries demand miniaturized products. Sectors such as aerospace, microelectronics, medicine, and even the automotive sector, are just some examples of enterprises that are taking advantage of micro-manufacturing technologies. Within this framework, the need to adapt the knowledge of macro-scale manufacturing processes to micro-scale is evident. This paper provides the insight needed to improve milling as a micro-manufacturing process. The goal is to characterize motion system to reduce error and improve accuracy with different process parameters on final shape for micro-parts while standard milling machine with linear motor and servomotor is used. Geometrical error and accuracy caused by motion control and control software error sources is evaluated and analyzed. Results will help decision on process parameters and it verifies that standard milling machine is useful to produce micro-parts. The work is carried out by theoretical principles and experimental work, the machine-tool motion accuracy of a medium machining center specializing in the micro-milling of elliptical cavities on aluminum workpieces. Measurements were taken to evaluate deviations and/or errors in geometric accuracy and the geometric quality errors caused by motion control and control software. The results show that due to the structure and inertia of the machine tool, acceleration and deceleration do indeed affect the accuracy and quality of the micro-part. Furthermore, errors from motion control and/or control software are present because differences in the moving carriages create instabilities.