scholarly journals SELECTION AND CALCULATION OF STEPPER MOTORS FOR CNC

Author(s):  
M. Reytskiy ◽  
M. Kovalenko ◽  
O. Tymoshchuk

Today, modern technologies tend to develop rapidly. The application of advanced inventions, principles, systems and approaches allows to simplify the production process, reduce the cost of manufacturing finished products, replace monotonous manual work with automated systems and devices. The basis of the power drive of such systems are electric motors: with permanent magnets, direct current, stepper, etc. When developing any electromechanical system, the task of choosing the type of drive motor, its parameters and characteristics. This article is devoted to the choice of such an electric motor for an electromechanical system for three-dimensional plastic printing. As a result of comparative analysis of parameters and characteristics of different types of motors, it is established that bipolar stepper motors are optimal for use in low-power and small-sized systems for three-dimensional printing. This is due to the simplicity of their design, reliability and low requirements for nominal and maximum torque.

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 655 ◽  
Author(s):  
Seong-Woo Hong ◽  
Ji-Young Yoon ◽  
Seong-Hwan Kim ◽  
Sun-Kon Lee ◽  
Yong-Rae Kim ◽  
...  

In this study, a soft structure with its stiffness tunable by an external field is proposed. The proposed soft beam structure consists of a skin structure with channels filled with a magnetorheological fluid (MRF). Two specimens of the soft structure are fabricated by three-dimensional printing and fused deposition modeling. In the fabrication, a nozzle is used to obtain channels in the skin of the thermoplastic polyurethane, while another nozzle is used to fill MRF in the channels. The specimens are tested by using a universal tensile machine to evaluate the relationships between the load and deflection under two different conditions, without and with permanent magnets. It is empirically shown that the stiffness of the proposed soft structure can be altered by activating the magnetic field.


Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 754 ◽  
Author(s):  
Jia Ming Zhang ◽  
Qinglei Ji ◽  
Huiling Duan

Droplet microfluidics has become the most promising subcategory of microfluidics since it contributes numerous applications to diverse fields. However, fabrication of microfluidic devices for droplet formation, manipulation and applications is usually complicated and expensive. Three-dimensional printing (3DP) provides an exciting alternative to conventional techniques by simplifying the process and reducing the cost of fabrication. Complex and novel structures can be achieved via 3DP in a simple and rapid manner, enabling droplet microfluidics accessible to more extensive users. In this article, we review and discuss current development, opportunities and challenges of applications of 3DP to droplet microfluidics.


Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1313 ◽  
Author(s):  
Viacheslav Slesarenko

The design space of mechanical metamaterials can be drastically enriched by the employment of non-mechanical interactions between unit cells. Here, the mechanical behavior of planar metamaterials consisting of rotating squares is controlled through the periodic embedment of modified elementary cells with attractive and repulsive configurations of the magnets. The proposed design of mechanical metamaterials produced by three-dimensional printing enables the efficient and quick reprogramming of their mechanical properties through the insertion of the magnets into various locations within the metamaterial. Experimental and numerical studies reveal that under equibiaxial compression various mechanical characteristics, such as buckling strain and post-buckling stiffness, can be finely tuned through the rational placement of the magnets. Moreover, this strategy is shown to be efficient in introducing bistability into the metamaterial with an initially single equilibrium state.


2015 ◽  
Vol 40 (3) ◽  
pp. 400-403 ◽  
Author(s):  
Kendall F Gretsch ◽  
Henry D Lather ◽  
Kranti V Peddada ◽  
Corey R Deeken ◽  
Lindley B Wall ◽  
...  

Background and aim: Upper extremity myoelectric prostheses are expensive. The Robohand demonstrated that three-dimensional printing reduces the cost of a prosthetic extremity. The goal of this project was to develop a novel, inexpensive three-dimensional printed prosthesis to address limitations of the Robohand. Technique: The prosthesis was designed for patients with transradial limb amputation. It is shoulder-controlled and externally powered with an anthropomorphic terminal device. The user can open and close all five fingers, and move the thumb independently. The estimated cost is US$300. Discussion: After testing on a patient with a traumatic transradial amputation, several advantages were noted. The independent thumb movement facilitated object grasp, the device weighed less than most externally powered prostheses, and the size was easily scalable. Limitations of the new prosthetic include low grip strength and decreased durability compared to passive prosthetics. Clinical relevance Most children with a transradial congenital or traumatic amputation do not use a prosthetic. A three-dimensional printed shoulder-controlled robotic prosthesis provides a cost effective, easily sized and highly functional option which has been previously unavailable.


2021 ◽  
pp. 1-5
Author(s):  
Michael D. Seckeler ◽  
Brian A. Boe ◽  
Brent J. Barber ◽  
Darren P. Berman ◽  
Aimee K. Armstrong

Abstract Background: Three-dimensional printing is increasingly utilised for congenital heart defect procedural planning. CT or MR datasets are typically used for printing, but similar datasets can be obtained from three-dimensional rotational angiography. We sought to assess the feasibility and accuracy of printing three-dimensional models of CHD from rotational angiography datasets. Methods: Retrospective review of CHD catheterisations using rotational angiography was performed, and patient and procedural details were collected. Imaging data from rotational angiography were segmented, cleaned, and printed with polylactic acid on a Dremel® 3D Idea Builder (Dremel, Mount Prospect, IL, USA). Printing time and materials’ costs were captured. CT scans of printed models were compared objectively to the original virtual models. Two independent, non-interventional paediatric cardiologists provided subjective ratings of the quality and accuracy of the printed models. Results: Rotational angiography data from 15 catheterisations on vascular structures were printed. Median print time was 3.83 hours, and material costs were $2.84. The CT scans of the printed models highly matched with the original digital models (root mean square for Hausdorff distance 0.013 ± 0.003 mesh units). Independent reviewers correctly described 80 and 87% of the models (p = 0.334) and reported high quality and accuracy (5 versus 5, p = NS; κ = 0.615). Conclusion: Imaging data from rotational angiography can be converted into accurate three-dimensional-printed models of CHD. The cost of printing the models was negligible, but the print time was prohibitive for real-time use. As the speed of three-dimensional printing technology increases, novel future applications may allow for printing patient-specific devices based on rotational angiography datasets.


Author(s):  
T. Tatarchuk ◽  
Yu. Kravchuk ◽  
V. Pelykh

Purpose. Analysis of methods of manufacturing centrifugal blades by 3D printing methods on the example of a modernized cooling system of the AI-450M engine of the Mi-2MSB helicopter. Research methods: calculation method of finite elements, analytical. Results. Studies have shown that the use of layer-by-layer printing technology of the centrifugal wheel of the cooling system provides the following opportunities and improvements: - reduce the percentage of rejection of finished products by 8–9 times; - reduce material consumption by 300–400 %; - increase the speed of production, experiments and testing the manufacture of working elements through the development of new technologies for rapid production (rapid fabrication); - easy printing of previously “impossible” geometry. The analysis of possible types of manufacturing of  working centrifugal wheel and the calculated estimation of thermodynamic parameters in the course of step-by-step drawing of layers of metal is carried out. The problem of a large percentage of defects in the process of classical-mechanical milling of blades was solved by changing the type of production to additive one. Scientific novelty. In today's world, the spread of CAD / CAM / CAE / PLM technologies and the accumulation of a wide library of materials open up a large number of new and more efficient, in terms of economy and quality, methods of manufacturing components and units. Following the example of such giants in the production of aircraft engines as Rolls-Royce Motor, General Electric and Pratt & Whitney, it is clear that the use and development of the latest methods of three-dimensional printing is appropriate. Practical value. The obtained results are important in the further process of production and modernization ofMi-2 helicopter of all modifications with the latest engines, as well as for projects for the development of helicopter construction in Ukraine - МСБ-2 “Hope”, МСБ -6 “Otaman”, МСБ-8 and others. The ability to increase the efficiency of manufacturing the main working elements - blades allows you to reduce the cost of components, their further repair, operation. The most important factor is to increase reliability, as in the manufacture reduces the likelihood of defects, which will not be detected at the stages of intermediate and final control.


2009 ◽  
Vol 00 (00) ◽  
pp. 090730035508060-7
Author(s):  
Deng-Guang Yu ◽  
Chris Branford-White ◽  
Yi-Cheng Yang ◽  
Li-Min Zhu ◽  
Edward William Welbeck ◽  
...  

2020 ◽  
Vol 13 (12) ◽  
pp. e239286
Author(s):  
Kumar Nilesh ◽  
Prashant Punde ◽  
Nitin Shivajirao Patil ◽  
Amol Gautam

Ossifying fibroma (OF) is a rare, benign, fibro-osseous lesion of the jawbone characterised by replacement of the normal bone with fibrous tissue. The fibrous tissue shows varying amount of calcified structures resembling bone and/or cementum. The central variant of OF is rare, and shows predilection for mandible among the jawbone. Although it is classified as fibro-osseous lesion, it clinically behaves as a benign tumour and can grow to large size, causing bony swelling and facial asymmetry. This paper reports a case of large central OF of mandible in a 40-year-old male patient. The lesion was treated by segmental resection of mandible. Reconstruction of the surgical defect was done using avascular fibula bone graft. Role of three-dimensional printing of jaw and its benefits in surgical planning and reconstruction are also highlighted.


Author(s):  
Leandro Ejnisman ◽  
Bruno Gobbato ◽  
Andre Ferrari de França Camargo ◽  
Eduardo Zancul

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