Designing A Kinematic Device In Fusion For Manufacturing And Testing Essay.

Objective:

You are to design a kinematic device in Fusion that you can later manufacture and test.

• Your design must have a rotating part that causes periodic motion elsewhere in the device (ideally this motion will not be symmetric).

• Your design must allow for subsequent testing if it is manufactured – i.e. you must design it with space to place sensors in mind.

The deliverable for this assessment item will be a report which covers the design of the device.

This report should also cover all of the dynamics and demonstrate that the device meets the design criteria (manufacturable, testable, rotating part and have at least 1 component that has subsequent periodic motion). Additionally, the report will detail how the device would be manufactured, including the manufacturing costs.

What is Kinematics?

Kinematics was one of the important thing need to be considered during the design of any components that undergoes to the relative motion.  Kinematics is the study of the motion of points or objects or group of objects. It deals with any motion of an object without considering the causes of its motion (Bergonzoni et al., 2018). The study of kinematics also referred as "geometry of motion". Kinematics is used in various fields such as astrophysics; mechanical engineering etc., The Kinematic equations can be used to calculate the trajectory of particles or objects. The physical quantities relevant to the motion of a particle include mass, position, velocity, and acceleration. The problem of kinematics is to describe the geometry of the system (object) and assign the initial conditions to points of velocity, acceleration, and position within the system or object (Arakelian, Le Baron & Mkrtchyan, 2016) .

Fusion 360 software is the first 3D CAD and CAM tool of its kind. It has the clear interface between design and manufacturing. Here in this software, the product development is based on the online cloud (Lee, Kim & Lee, 2014). We can retrieve the data about the software easy through this cloud storage at anywhere. It is easy to use because everything is integrated into the same software. It is used to connect the product development process in a single cloud-based platform. This fusion 360 software is used to make the design and test in a single tool. It is the most reasonable price 3D software. It is a standard tool for all steel case. This software has the generative design technology (Racu (Cazacu), Doroftei, Plesu & Doroftei, 2016). It is used to make the CAD solution based on the manufacturing requirements. This software needs the high-level requirements. It needs DSL internet connection and 4GB RAM. In this the standard tier still keeping the product development functionality. It had many features along with the tiers. In the simulation, it had some advantages. They are shaped optimization, bolted connections, mesh control. It has flexibility with the cloud storage. Because cloud storage has the completion time as faster. And several cloud renderings can progress simultaneously (Sawyer, Diaz, Hamilton & Micklos, 2003). These renderings stored in the cloud for easy access. The simulation of fusion 360 has some benefits based on the cloud. It uses the alternative workspaces. It solves the complex problems without the concern of local resources. It can access the results of fusion through this cloud storage.

Scotch yoke mechanism is a reciprocating motion mechanism. It converts rotating motion of the slider into the linear motion.  The piston is connected with the yoke. It consists of slots to tightening the pin which helps in the rotation part of the slider. Crankshaft rotation part makes the conversion of rotating motion into the linear motion. During this process the connected rod and the piston are connected together (Pramoth Kumar, Akash & Venkatesan, 2016).

The conversion of rotary motion into the linear motion is takes place by following steps. First, the DC supply from the motor is given to the rod. Then the crank rotates the pin slider in the yoke part. It leads to move the shaft in forward direction (Wang & Zhu, 2015). The displacement of the yoke occurs when the crank is rotating in clockwise direction. Then the displacement of the yoke depends on the crank length. This movement of yoke is getting completed by moving forward completely and getting back to its starting position. It is said to be the full revolution of the crank. The displacement of the yoke is controlled by the length of the crank (Wilson, n.d.).

Fusion 360 and Generative Design Technology

The degree of Freedom of a system or the system components is defined as "the number of independent variables or coordinates required to describe the position of the system or its component", which is related to the possibilities of rigid bodies' motion. The degree of freedom of a fixed object is zero (Yu, Hu, Huo & Wang, 2009). The degrees of freedom, revolving joints and sliding joints in scotch yoke mechanism is calculated in 3D printing and given below (Waldron, Kinzel & Agrawal, n.d.).

No of rotating joints present in the system =  1

No of sliding joints present in the system =  2

No of links present in the system, L =  3

No of joints present in the system, n =  4

No of Higher pairs in the system, H = 0

Degrees of Freedom, F = 3 (n -1) – 2 (L) – H

F = 3 ( 3-1) – 2 (4) -0

F = 2

Scotch yoke mechanism was designed based on the calculation results. For the calculation part the standard books were used (Praveen Kumar, Navaneetha Krishnan, Venkadesh & Premkumar, 2015). Based on that the following design was developed. The developed design was shown in the below context with dimensions (Norton, 2013).

The developed scotch yoke mechanism has three major components, and they are Base frame, Rotating Disc and Sliding arrangement. All these parts are designed based on the standard calculations.

Base frame was the main element of the mechanism. It was the rigid part in the mechanism. This part gives space for all other functional parts and sensors in the arrangement. The frame has the length of 80 mm, width of 40 mm and the height of 70 mm. The frame for the scotch yoke mechanism was shown in the below figure. That gives the additional information about the frame.

Figure 1 Base Frame

It has one hole for pivot the disc and support for the sliding arrangement. The distance between the sliding supports was taken as 55 mm. It was made by the 3D printing technology. The ABS material was selected for this system. The detailed explanation of the manufacturing process was given in the below context.

Disc was the second important element of the system. It is a rotating part of the mechanism. It was pivoted in the frame. And also it has the contact with the sliding arrangement. It was made by the 3D printing method. ABS was selected for produce this component. The detailed discussion about the manufacturing process was given in the below content. It has the outer diameter of 50 mm and the thickness of 5mm. It has the pivoted shaft on its center. The shaft has the diameter of 5mm. The diagram of the disc was shown in the below figure.

Figure 2 Disc

Sliding arrangement was the next important element of the mechnism. It has the sliding contact with the disc and frame. Its center part has the slot of 5 mm. The eccentric shaft in the disc was connected with this slot in this sliding arrangement. There are two cylidrical rods are present in the sliding part it makes sliding contact with the base frame. The below diagram gives the dimensional details as well as the orientation of the sliding element.

Scotch Yoke Mechanism

Figure 3 Sliding Bar

Assembly diagrams represents the full finished model. It consists all the parts of the system. It gives the details about the position and orientation of the each and every element of the system. The assembly diagrams for the scotch yoke mechanism was shown in the below figures. It gives the better visualization of the final component to be produced.

Figure 5 Assembly diagram

The important use of the fusion 360 software was its capability to simulate the motions of the component. In dynamical modeling it is the important process. The developed model has two sliding pairs as well as one rotating pair. Consider that the rotating pair undergoes to the angular twist. During that motion the eccentric rod connected with the shaft starts to move. It has the sliding contact with the sliding bar. Then the sliding bar starts to slide. It was shown in the below images.

Bill of materials and its approximate cost was shown in the below table.

The three dimensional solid objects are created from the digital file is called 3D Printing.  It helps to produce the difficult shapes of the machines (Lee si chang & Park,Kwang-Cheol, 2017). Then it will take less amount of material to make a large machine when compared to the normal manufacturing process.  It is created by using 3D modeling software. 3D scanner used to take a copy of an image of the machine. FFF and FDM printers are used for 3D printing. This printing is widely used in many applications such as in education, construction, manufacturing, architecture, product design, medical fields. The technologies in 3D printing differ by using the layers in the creation of the object.  Here, Acrylonitrile Butadiene Styrene (ABS) material is used for printing the machine.  This is commonly used for household or personal 3D printing (P?curar, P?curar, Popi?ter & Popi?ter, 2015). The melting degree of this material is 200 degree Celsius. So it is used in safe machines and it is easy to operate.  

Conclusion

Thus the Kinematic model of the scotch yoke mechanism was developed successfully. Then the analysis on the developed model was carried out. Also the manufacturing process for the developed model was discussed, and the bill of materials for the scotch yoke mechanism was created.

References

Arakelian, V., Le Baron, J., & Mkrtchyan, M. (2016). Design of Scotch yoke mechanisms with improved driving dynamics. Proceedings Of The Institution Of Mechanical Engineers, Part K: Journal Of Multi-Body Dynamics, 230(4), 379-386. doi: 10.1177/1464419315614431

Bergonzoni, M., Campagnolo, A., Pellinghelli, D., Riboli, M., Spagnoli, A., & Meneghetti, G. (2018). Experimental tests and fatigue strength assessment of a scotch yoke valve actuator. Procedia Engineering, 213, 58-68. doi: 10.1016/j.proeng.2018.02.007

Lee si chang, & Park,Kwang-Cheol. (2017). The ABS Material Characteristic Compensation Method for Reflection 3D Printing Modeling Compensation Method for the Design Prototype Production. Journal Of Integrated Design Research, 16(2), 9-20. doi: 10.21195/jidr.2017.16.2.001

Lee, G., Kim, J., & Lee, T. (2014). The rolling scotch yoke mechanism applied to a small air compressor for oil-free operations. International Journal Of Precision Engineering And Manufacturing, 15(1), 97-103. doi: 10.1007/s12541-013-0310-9

Norton, R. (2013). Kinematics and dynamics of machinery. Singapore: McGraw-Hill.

P?curar, R., P?curar, A., Popi?ter, F., & Popi?ter, A. (2015). Finite Element Analysis to Improve the Accuracy of ABS Plastic Parts Made by Desktop 3D Printing Method. Applied Mechanics And Materials, 760, 509-514. doi: 10.4028/www.scientific.net/amm.760.509

Pramoth Kumar, M., Akash, K., & Venkatesan, M. (2016). Scotch-Yoke mechanism for a syringe pump - A case study. IOP Conference Series: Materials Science And Engineering, 149, 012221. doi: 10.1088/1757-899x/149/1/012221

Praveen Kumar, R., Navaneetha Krishnan, G., Venkadesh, V., & Premkumar, N. (2015). Dual Side Water Pumping System using Scotch Yoke Mechanism. Indian Journal Of Science And Technology, 8(36). doi: 10.17485/ijst/2015/v8i36/87556

Racu (Cazacu), C., Doroftei, I., Plesu, G., & Doroftei, I. (2016). Simulation of an ankle rehabilitation system based on scotch- yoke mechanism. IOP Conference Series: Materials Science And Engineering, 147, 012084. doi: 10.1088/1757-899x/147/1/012084

Sawyer, W., Diaz, K., Hamilton, M., & Micklos, B. (2003). Evaluation of a Model for the Evolution of Wear in a Scotch-Yoke Mechanism. Journal Of Tribology, 125(3), 678. doi: 10.1115/1.1537271

Waldron, K., Kinzel, G., & Agrawal, S. Kinematics, dynamics, and design of machinery.

Wang, X., & Zhu, W. (2015). Design, Modeling, and Experimental Validation of a Novel Infinitely Variable Transmission Based on Scotch Yoke Systems. Journal Of Mechanical Design, 138(1), 015001. doi: 10.1115/1.4031499

Wilson, C. Kinematics and dynamics of machinery.

Yu, J., Hu, Y., Huo, J., & Wang, L. (2009). Dolphin-like propulsive mechanism based on an adjustable Scotch yoke. Mechanism And Machine Theory, 44(3), 603-614. doi: 10.1016/j.mechmachtheory.2008.08.011