Asymmetrical pythagorean-hodograph spline-based C4 continuous local corner smoothing method with jerk continuous feedrate scheduling along linear toolpath

In computer numerical control systems, linear segments, which are generated by computer-aided manufacturing software, are the most widely used toolpath format. Since the linear toolpath is discontinuous at the junction of two adjacent segments, the fluctuations on velocity, acceleration and jerk are inevitable. Local corner smoothing is widely used to address this problem. However, most existing methods use symmetrical splines to smooth the corners. When any one of the linear segments at the corner is short, to avoid overlap, the inserted spline will be micro, thereby increasing the curvature extreme of the spline and reducing the feedrate along it. In this article, the corners are smoothed by a 𝐶4 continuous asymmetric Pythagorean-hodograph (PH) spline. The curvature extreme of the proposed spline is investigated first, and 𝐾=2.5 is determined as the threshold to constarin the asymmetry of the spline. Then a two-step strategy is used to generate a blended toolpath composed of asymmetric PH splines and linear segments. In the first step, the PH splines at the corners are generated under the premise that the transition lengths do not exceed half of the length of the linear segments. In the second step, the splines at the corners are re-planned to reduce the curvature extremes, if the transition error does not reach the given threshold and there are extra linear trajectories on both sides of the spline trajectory. Finally, the bilinear interpolation method is applied to determine the critical points of the smoothed toolpath, and a jerk-continuous feedrate scheduling scheme is presented to interpolate the smoothed toolpath. Simulations show that, under the condition of not affecting the machining quality, the proposed method can improve the machining efficiency by 7.84% to 23.98% compared to 𝐺3 and 𝐺4 methods.

I-fiber implantation robot for composite parts

I-fiber implantation is a new stitching technology that can effectively enhance the interlayer performance of laminated composites. This paper presents and evaluates the design and implementation of the I-fiber robot implantation system integrated for producing high-performance fiber preforms for advanced composites. The system was constructed and validated through I-fiber robot implantation experimentation. It was demonstrated that automated I-fiber implantation could be achieved by use of an industrial robot. The programming method and computer-aided manufacturing software of the I-fiber implantation robot were feasible and effective. The double-cantilever-beam (DCB) experiments showed that the implantation of I-fiber significantly improved the interlaminar fracture toughness of the laminated composite, where the maximum load value increased by up to 106%. The DCB load–displacement curve presented a zigzag shape, where the peaks and valleys were the location points of the I-fiber break. It was also found that for the reinforced laminated composite without an I-fiber head, the delamination failure was manifested as resin cracking and I-fiber pullout, while for the I-fiber with a certain head length, the I-fiber failure mechanism was brittle fracture. I-fiber with a certain head length could significantly improve the interlayer performance of the composite. In addition, DCB experiments also revealed that the implantation matrix had little effect on the interlayer performance of I-fiber reinforced composites, and the failure load value and the I-fiber implantation volume showed an obvious proportional relationship.

Evaluation of Adverse Events Recorded in FDA/USA and ANVISA/Brazil Databases for Medical Devices: Defibrillator, Infusion Pump, Physiological Monitor, Pulmonary Ventilator and Ultrasonic Scalpel

The use of medical technologies has grown steadily in all health fields, offering numerous benefits to patients. However, related adverse events, which may cause severe consequences for patients, also have increased. Technical factors and human aspects that cause dangers to patients may be related to the complexity of the devices, quality control in manufacturing, software used, maintenance procedures, materials, and mode of use. Thereby, our objective is to present the main alerts, dangers, and failures related to medical equipment and ways to attenuate them. For that purpose, we performed an analysis of adverse events reported for medical equipment in the Food Drugs Administration (FDA/USA) and the Brazilian Health Surveillance Agency (ANVISA) databases, since 2016. Finally, we classified the events into different categories, according to similarity. The results show a total of 3,100 cases registered in the FDA for six types of equipment at the study and 75 cases in ANVISA for two of these equipment. Based on the top ten health hazards (2016-2020) provided by the Emergency Care Research Institute (ECRI) we were able to understand which equipment most offers hazards and the main ways to mitigate them. We found that the risks are common to medical devices, therefore, it is crucial that there are preventative measures to avoid them, for example, training users to use the products, maintenance, improving quality, and reporting adverse events to manufacturers.

A Novel Bespoke Hypertrophic Scar Treatment: Actualizing Hybrid Pressure and Silicone Therapies with 3D Printing and Scanning

The treatment of hypertrophic scars (HSs) is considered to be the most challenging task in wound rehabilitation. Conventional silicone sheet therapy has a positive effect on the healing process of HSs. However, the dimensions of the silicone sheet are typically larger than those of the HS itself which may negatively impact the healthy skin that surrounds the HS. Furthermore, the debonding and displacement of the silicone sheet from the skin are critical problems that affect treatment compliance. Herein, we propose a bespoke HS treatment design that integrates pressure sleeve with a silicone sheet and use of silicone gel using a workflow of three-dimensional (3D) printing, 3D scanning and computer-aided design, and manufacturing software. A finite element analysis (FEA) is used to optimize the control of the pressure distribution and investigate the effects of the silicone elastomer. The result shows that the silicone elastomer increases the amount of exerted pressure on the HS and minimizes unnecessary pressure to other parts of the wrist. Based on this treatment design, a silicone elastomer that perfectly conforms to an HS is printed and attached onto a customized pressure sleeve. Most importantly, unlimited scar treating gel can be applied as the means to optimize treatment of HSs while the silicone sheet is firmly affixed and secured by the pressure sleeve.

The Essence of Cloud Manufacturing

Cloud manufacturing is a service-oriented, knowledge-based smart manufacturing system. It is integrated with cloud computing technology, Internet of Things, and high-performance computing. Through cloud manufacturing, manufacturing resources (such as manufacturing software tools, manufacturing equipment, and manufacturing capabilities) are “virtualized” and offered as consumable in the same way as electricity, gas, and water. The manufacturing resources are provided to users as services over the Internet (cloud) in a pay-as-you-go manner. This paper presents a brief introduction to cloud manufacturing.

Machine tool movement control method combining the benefit of software and real-time interpolator for sculpture surface machining

In the traditional sculpture surface machining process, the G01 code is still the mainstream trajectory. Furthermore, real-time feedrate scheduling and corner smooth algorithm in controller constitute the mainstream method to improve the machining process of short line G01 code in sculpture surface machining. However, the G01 code’s discontinuity and the limits of real-time calculation capacity hinder the use of high-speed machine tools and the accuracy of the machined part. In this article, a new method for sculpture surface machining that considers the advantages and disadvantages of both the computer-aided manufacturing software and the real-time controller is presented to promote the use of a continuous curve tool path. The method mainly transfers the computing-intensive feedrate scheduling and trajectory optimization algorithm in the real-time controller to the computer-aided manufacturing software. Furthermore, the computer-aided manufacturing software generates the machining data, which contain the geometry and feedrate information of the machining process. Finally, the real-time interpolator and the mathematical form of computer-aided manufacturing–generated data are designed simultaneously. In the method, the real-time controller can be designed as simple as possible to release more computing resources to the other real-time intelligent modules. The powerful computational capacity of the software guarantees the optimality of the machining process.

Performance Assessment of Stress Concentration Reduction Methods in Mild Steel Transmission Shaft

A shaft is subjected to tensile stress, compressive stress, torsional force and bending moment due to reaction on the components. The stress distribution in a shaft can be is similar to the flow of fluid in a channel. So, it is perfectly logical to use the fluid analogy to understand the phenomenon of stress concentration. When the cross section is uniform the flow is uniform whereas if there is a sudden change in the cross section then the velocity increases to keep the flow rate constant .The same phenomenon is observed in the shaft i.e. when the cross section of the shaft is uniform throughout , the stresses are uniform where as if the cross section changes abruptly then the stress lines come closer to each other in order to keep the force same . When there are sharp changes then it results in stress concentration.The effect of stress concentration can be reduced effectively as there are numerous discontinuities which makes it impossible to eradicate it fully .This could be done by numerous some of which are removal of material , providing fillet radius and also by choosing appropriate material for manufacturing . Software like Solid works can be used for the design and analysis of the component. An object drawn with Solid works can be analysed interactively and physical information can be extracted from it

Fiber, Fingers, and Code: Manufacturing Software and Seamlessness in the Garment Industry

This article describes how software is imagined and used to disrupt garment industry practices. Drawing from interviews, fieldwork, and discourse analysis of marketing from two companies, Stoll and Resonance, we argue that software is integral to the creation of a new kind of designer, a “digital craftsman,” that directly interfaces with a new kind of supply chain. This interaction is defined by its “seamlessness”—what we describe as both an emergent technical design element and an imaginary of software-enabled manufacturing free from friction between sites of concept development and its material execution. Counter to this imaginary, we mobilize the “tactile grammar” of seams to foreground the role of embodied communication and labor practices in shaping software-defined industrial futures. Studying the connections between fiber, fingers, and code, this article opens up new lines of inquiry into industrial software and into the links between media production and larger spheres of commodity production.