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Xiang Ren, Qingwei Zhang, Kewei Liu, Ho-lung Li and Jack G. Zhou
The purpose of this paper is establishing a general mathematical model and theoretical design rules for 3D printing of biomaterials. Additive manufacturing of biomaterials…
Abstract
Purpose
The purpose of this paper is establishing a general mathematical model and theoretical design rules for 3D printing of biomaterials. Additive manufacturing of biomaterials provides many opportunities for fabrication of complex tissue structures, which are difficult to fabricate by traditional manufacturing methods. Related problems and research tasks are raised by the study on biomaterials’ 3D printing. Most researchers are interested in the materials studies; however, the corresponded additive manufacturing machine is facing some technical problems in printing user-prepared biomaterials. New biomaterials have uncertainty in physical properties, such as viscosity and surface tension coefficient. Therefore, the 3D printing process requires lots of trials to achieve proper printing parameters, such as printing layer thickness, maximum printing line distance and printing nozzle’s feeding speed; otherwise, the desired computer-aided design (CAD) file will not be printed successfully in 3D printing.
Design/methodology/approach
Most additive manufacturing machine for user-prepared bio-material use pneumatic valve dispensers or extruder as printing nozzle, because the air pressure activated valve can print many different materials, which have a wide range of viscosity. We studied the structure inside the pneumatic valve dispenser in our 3D heterogeneous printing machine, and established mathematical models for 3D printing CAD structure and fluid behaviors inside the dispenser during printing process.
Findings
Based on theoretical modeling, we found that the bio-material’s viscosity, surface tension coefficient and pneumatic valve dispenser’s dispensing step time will affect the final structure directly. We verified our mathematical model by printing of two kinds of self-prepared biomaterials, and the results supported our modeling and theoretical calculation.
Research limitations/implications
For a certain kinds of biomaterials, the mathematical model and design rules will have unique solutions to the functions and equations. Therefore, each biomaterial’s physical data should be collected and input to the model for specified solutions. However, for each user-made 3D printing machine, the core programming code can be modified to adjust the parameters, which follows our mathematical model and the related CAD design rules.
Originality
This study will provide a universal mathematical method to set up design rules for new user-prepared biomaterials in 3D printing of a CAD structure.
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Calvin Ling, Muhammad Taufik Azahari, Mohamad Aizat Abas and Fei Chong Ng
This paper aims to study the relationship between the ball grid array (BGA) flip-chip underfilling process parameter and its void formation region.
Abstract
Purpose
This paper aims to study the relationship between the ball grid array (BGA) flip-chip underfilling process parameter and its void formation region.
Design/methodology/approach
A set of top-down scanning acoustic microscope images of BGA underfill is collected and void labelled. The labelled images are trained with a convolutional neural network model, and the performance is evaluated. The model is tested with new images, and the void area with its region is analysed with its dispensing parameter.
Findings
All findings were well-validated with reference to the past experimental results regarding dispensing parameters and their quantitative regional formation. As the BGA is non-uniform, 85% of the test samples have void(s) formed in the emptier region. Furthermore, the highest rating factor, valve dispensing pressure with a Gini index of 0.219 and U-type dispensing pattern set of parameters generally form a lower void percentage within the underfilling, although its consistency is difficult to maintain.
Practical implications
This study enabled manufacturers to forecast the void regional formation from its filling parameters and array pattern. The filling pressure, dispensing pattern and BGA relations could provide qualitative insights to understand the void formation region in a flip-chip, enabling the prompt to formulate countermeasures to optimise voiding in a specific area in the underfill.
Originality/value
The void regional formation in a flip-chip underfilling process can be explained quantitatively with indicative parameters such as valve pressure, dispensing pattern and BGA arrangement.
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Points out that emerging designs of modules housing electronic components, such as engine control modules, are putting greater demands on dispensing and robotics equipment. Looks…
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Points out that emerging designs of modules housing electronic components, such as engine control modules, are putting greater demands on dispensing and robotics equipment. Looks at the key issues of decreased gasket diameters, zero‐knit lines and speed of processing which are facing equipment suppliers.
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Steven C. Moore and Timothy J. Kurcz
Describes the rationale, purpose, and design of the Loctite Corporation One‐PassTM (patent pending) robotic flange cleaning system. Also details two complementary LoctiteTM…
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Describes the rationale, purpose, and design of the Loctite Corporation One‐PassTM (patent pending) robotic flange cleaning system. Also details two complementary LoctiteTM formed‐in‐place (FIP) gasket sealant dispensing systems: AccuPump 1000 (a progressive cavity positive displacement pump for silicone and anaerobic FIP technology), and PressPakTM 1000 (patent pending) (a pumpless dispensing system for silicones, anaerobics, and high viscosity abrasive‐filled adhesives or solder pastes). Integrated with a high‐performance Loctite dispensing system, the One‐PassTM creates a highly robust, robotically controlled FIP flange‐sealing assembly process. This technology combination enables worldwide producers of engines, transmissions and axles to replace expensive molded gaskets with higher‐performing FIP adhesives and sealants at a fraction of the cost.
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Claims that, although the use of adhesives in automated assembly is common, the use of structural adhesives is not so. Indeed, the use of structural adhesives can be termed a “new…
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Claims that, although the use of adhesives in automated assembly is common, the use of structural adhesives is not so. Indeed, the use of structural adhesives can be termed a “new technology”. Offers advice on their use and concludes that the benefits outweigh the threat of failure.
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SIMPLIFIED CONTROL OF THE MOTOR CAR has occupied the minds of designers ever since the earliest days of the industry. In the many attempts to make driving a car easier for the…
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SIMPLIFIED CONTROL OF THE MOTOR CAR has occupied the minds of designers ever since the earliest days of the industry. In the many attempts to make driving a car easier for the man‐in‐the‐street, steam was one of the forms of propulsion used until the early ‘thirties’ but when the internal combustion engine finally won the day, efforts were concentrated on finding something better than the friction clutch and manually operated gearbox for use in conjunction with this type of engine. Before World War II several fully automatic transmissions for passenger cars had already been developed, especially in the U.S.A., and it was during this war that these transmissions found application in fighting vehicles. With the return of peace, motor manufacturers turned to fully automatic transmissions in a big way. It is hardly surprising, considering the generally advanced state of mechanisation in that country, that in the volume production of this type of transmission the U.S. again took the lead. Also, the large output of the domestic motor industry offered the best chances for a favourable return on the considerable capital investments inherent to volume production of complex transmission designs.