Development of CAD Software for Mechanical Chains Design

Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7): 260- 266 © Scholarlink Research Institute Journals, 2015 (ISSN: 2141-7016) Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):260- 266 (ISSN: 2141-7016) jeteas.scholarlinkresearch.com

Development of CAD Software for Mechanical Chains Design A.A. Adekunle1, S. B. Adejuyigbe2, and B. J. Olorunfemi 1

Mechanical Engineering Department, Ladoke Akintola University of Technology, Ogbomoso, P. M. B. 4000, Oyo State, Nigeria. 2 Mechatronics/Mechanical Engineering Department, Federal University, Oye Ekiti, Ekiti State, Nigeria. 3 B3/41 Ire Akari Estate 2, off Ijare road, Akure, Ondo State, Corresponding Author: A. Adekunle _________________________________________________________________________________________ Abstract The problem of designing is a major problem in the field of engineering due to the stress encountered during the manual method of operation and high risk of inaccuracy, this has brought about the need for a more reliable and accurate method, the emergence of modern technology has brought about the use of computer aided design to improve and create new atmosphere for the process of design and documentation. The use of chains have been employed over the years for various mechanical operations, for various kinds of mechanical drive such as sprocket, roller chains, in bicycles, in rotary machines, crank etc. these also includes the difficulty of designing a suitable software that will enhance the identification and application of chains. The software developed for mechanical chains is equipped with Windows XP or Windows 7 Operating System with processor speed not less than 2.3GHZ for acquiring information and logistics, Microsoft Visual Studio was used due to its worldwide acceptability, easy interface and being an open system and most importantly its ease of file format acceptability . The software can simulate mechanical chains operation and thus captures it in different phase using algorithm. The software was able to determine effectively the operations involved in design of chains such as inputting the sprocket parameters, power transmitted, the driver teeth ratio, gear ratio and the final result of the chain drive. With the help of this software there has been a rapid improvement in the design of chains automated. This research work have been able to eliminate chain design problems by generating a suitable and competent Software that can aid chains at lower cost and above all which can be operated by anybody without the requirement of programming knowledge or any special skill. _______________________________________________________________________________________ Keywords: CAD, chain, design, software, sprocket
Perform complex design analysis in short time. Implementing Finite Elements Analysis methods the user can perform Static, Dynamic and Natural Frequency analysis, Heat transfer analysis, Plastic analysis, Fluid flow analysis, Motion analysis, Tolerance analysis, Design optimization.
Record and recall information with consistency and speed. In particular the use of Product Data Management (PDM) systems can store the whole design and processing history of a certain product, for future reuse and upgrade.

INTRODUCTION Computer Aided Design (CAD) is defined as the use of Information Technology (IT) in the Design process. A CAD system consists of IT hardware (H/W), specialized software (S/W) (depending on the particular area of application) and peripherals, which in certain applications are quite specialized. The core of a CAD system is the S/W, which makes use of graphics for product representation; databases for storing the product model and drives the peripherals for product presentation. Its use does not change the nature of the design process but as the name states it aids the product designer. The designer is the main actor in the process, in all phases from problem identification to the implementation phase. The role of the CAD is in aiding him/her by providing:
Accurately generated and easily modifiable graphical representation of the product. The user can nearly view the actual product on screen, make any modifications to it, and present his/her ideas on screen without any prototype, especially during the early stages of the design process.

COMPUTER AIDED DESIGN Computer-Aided Design (CAD) involves creating computer models defined by geometrical parameters. These models typically appear on a computer monitor as a three-dimensional representation of a part or a system of parts, which can be readily altered by changing relevant parameters. CAD systems enable designers to view objects under a wide variety of representations and to test these objects by simulating real-world conditions. 260

Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):260- 266 (ISSN: 2141-7016) The increasing power of CAD has had a significant impact on the product development process, allowing improved quality, reduced cost, and aids products to get to market faster. CAD software is rapidly evolving into what might be better described as product development, or perhaps virtual prototyping software. (Adekunle and Adejuyigbe, 2012).

2. You will know that the chain is almost at the end of its life by wear, elongation or an increase in vibration caused by wear elongation. 3. It is difficult to detect toothed-belt life without stopping the machine and inspecting the belt carefully.

Cad Application Computer-Aided Design is a data that can facilitate design and to assist manufacturing process. Due to the complexity of product design nowadays, there is an increasing need to integrate computer simulation and designer intelligence for maximum benefits from expediting advanced design. Computer simulation has played an important role in the design stage. It is a system, which assumes or characteristic of the object under study. (Mohd, 2008).

Some Features of Chain Drives 1. Chain can accommodate long shaft-centre distances (less than 4 m), and is more versatile. 2. It is possible to use chain with multiple shafts or drives with both sides of the chain. 3. It is easy to cut and connect chains. 4. The sprocket diameter for a chain system may be smaller than a belt pulley, while transmitting the same torque. 5. Sprockets are subject to less wear than gears because sprockets distribute the loading over their many teeth.

Software Design This is a process of problem solving and planning for a software solution. After the purpose and specifications of software are determined, software developers will design or employ designers to develop a plan for a solution. It includes low-level component and algorithm implementation issues as well as the architectural view (Wikipedia, 2006).

Sprockets The chain converts rotational power to pulling power, or pulling power to rotational power, by engaging with the sprocket (oxford English dictionary,2nd edition, oxford university press 1989). The sprocket looks like a gear but differs in three important ways: 1. Sprockets have many engaging teeth; gears usually have only one or two. 2. The teeth of a gear touch and slip against each other; there is basically no slippage in a sprocket. 3. The shapes of the teeth are different in gears and sprockets.

Chain Drive This is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles. It is also used in a wide variety of machines besides vehicles. Most often, the power is conveyed by a roller chain, known as the drive chain or transmission chain, passing over a sprocket gear, with the teeth of the gear meshing with the holes in the links of the chain. The gear is turned, and this pulls the chain putting mechanical force into the system. Another type of drive chain is the Morse chain, invented by the Morse Chain Company of Ithaca, New York, USA. This has inverted teeth. Power Transmission A power transmission machine uses chains, gears, or belts, to provide a comparison of typical applications. Usually, chain is an economical part of power transmission machines for low speeds and large loads. However, it is also possible to use chain in high speed conditions like automobile engine camshaft drives. This is accomplished by devising a method of operation and lubrication. Basically, there are lower limits of fatigue strength in the gear and the chain, but not in the belt. Furthermore, if a gear tooth breaks, the gear will stop at the next tooth. Therefore, the order is gear, chain, and belt in the aspect of reliability. In most cases: 1. An increase in gear noise indicates that the end of the service life is near.

Fig. 1: sprockets.

Source: (Ambrosio et al 2002)

Roller Chain Drive Systems The dynamics of the roller chain drives is characterized by a complex behavior with impacts between the chain links and sprockets and by discontinuities in the system components velocities giving rise to transversal and longitudinal vibrations on the spans of the chain. These events are the responsible factors for part of the noise presented by mechanical devices that use roller chains and ultimately by the wear of the roller chain drives. Though roller chains have been used for a long time as a reliable mechanical component to transmit power and to handle materials mechanically, only in the last decades their dynamical behavior is studied, (Wang and Liu, 1991 Fritz and Pfeiffer, (1995) presented a 261

Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):260- 266 (ISSN: 2141-7016) methodology where the roller-sprocket and the guide chain contacts were treated as unilateral constraints.

Wear Chain wear, or chain stretch, becomes an issue with extensive cycling. Although the overall effect is often called "stretch", chains generally wear through attrition of the bushings (or half-bushings, in the Sides design) and not by elongation of the side plates. The tension created by pedaling is insufficient to cause the latter. Because an old chain is longer than needed, its links will not precisely fit the spaces between teeth in the drive train, making gear shifts a problem and possibly resulting in a 'skipping' chain that reduces power transfer and makes pedaling very uncomfortable. Since chain wear is strongly aggravated by dirt getting into the links, the lifetime of a chain depends mostly on how well it is cleaned (and lubricated) and does not depend on the mechanical load. Therefore, well-groomed chains of heavily used racing bicycles will often last much longer than those of a lightly used, but not so well cleaned city bike. Depending on use and cleaning, a chain can last only 1,000 km (e.g. in cross-country use, or all-weather abuse), 3,000 to 5,000 km for well-maintained derailed chains, or more than 6,000 km for perfectly groomed high-quality chains, single-gear, or hub-gear chains (preferably with a full cover chain guard).

Chain Strength The most common measure of roller chain's strength is tensile strength. Tensile strength represents how much load a chain can withstand under a one-time load before breaking. Just as important as tensile strength is a chain's fatigue strength. The critical factors in a chain's fatigue strength is the quality of steel used to manufacture the chain, the heat treatment of the chain components, the quality of the pitch hole fabrication of the link plates, and the type of shot plus the intensity of shot peen coverage on the link plates. Other factors can include the thickness of the link plates and the design (contour) of the link plates. The rule of thumb for roller chain operating on a continuous drive is for the chain load to not exceed a mere 1/6 or 1/9 of the chain's tensile strength, depending on the type of master links used (press-fit vs. slip-fit). Roller chains operating on a continuous drive beyond these thresholds can and typically do fail prematurely via link plate fatigue failure (Fritz and Pfeiffer, 1995). Bicycle Chain A bicycle chain is a roller chain that transfers power from the pedals to the drive-wheel of a bicycle, thus propelling it. Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simply for aesthetics. Nickel also confers a measure of self-lubrication to a chain's moving parts. Nickel is a relatively non-galling metal.

The chain in use on modern bicycles has a 1/2" pitch, which is ANSI standard #40, where the 4 in "#40" indicates the pitch of the chain in eighths of an inch, and metric #8, where the 8 indicates the pitch in sixteenths of an inch,(Matt d et al, 1998). Length New chains usually come in a stock length, long enough for most upright bike applications. The appropriate number of links must be removed before installation in order for the drive train to function properly. The pin connecting links can be pushed out with a chain tool to shorten, and additional links may be added to lengthen. In the case of derailleur gears the chain is usually long enough so that it can be shifted onto the largest front chain ring and the largest rear sprocket without jamming, and not so long that, when shifted onto the smallest front chain ring and the smallest rear sprocket, the rear derailleur cannot take up all the slack. (Green et al., 1996).

Obsolete chain designs previously used on bicycles included the block chain, the skip-link chain, and the Simpson lever chain. Most modern bicycle chains used with a single chaining and single rear sprocket are conventional industrial bushing chain. However, it also wears much faster and has slightly worse mechanical efficiency than a bushing chain (wiki books, bicycle maintenance and repair, 2008). Before the safety bicycle, bicycles did not have chains and the pedals were typically attached directly to the drive-wheel, thus limiting top speed by the diameter of the wheel and resulting in designs with front wheels as large as possible. Various linkage mechanisms were invented to raise the effective gear ratio, but with limited success. Using chain drive allowed the mechanical advantage between the drive and driven sprockets to determine the maximum speed, thereby enabling manufacturers to reduce the size of the driving wheel for safety. It also allowed for the development of variable gearing, allowing cyclists to adjust their gearing to the difficulty of the terrain, on the fly (Spicer and James, 1999).

Software Design Software is a set of machine-readable instruction that directs a computer’s processor to perform specific operations. The term is used to constant with computer hardware, the physical objects which are the processor and related devices that carry out the instructions. Hardware and software require each other; neither has any value without the other. (Adekunle et al, 2014). Software is a general term. It can refer to all computer instructions in general or to any specific set of computer instructions. It is a 262

Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):260- 266 (ISSN: 2141-7016) process of problem solving and planning for a software solution. After the purpose and specifications of software are determined, software developers will design or employ designers to develop a plan for a solution. It includes low-level component and algorithm implementation issues as well as the architectural view. The need for better quality control of the software development process has given rise to the discipline of software engineering, which aims to apply the systematic approach exemplified in the engineering paradigm to the process of software development (dictionary, 2007). A software design may be platformindependent or platform-specific, depending on the availability of the technology called for by the design, (Janadekar, 2004).

language and using a compiler, which serves as an interface between the computer and user, to enable user supply various inputs or parameters of the design. The compiler translates the written program (high – level language) to a machine – readable program (low – level language) (Adekunle et al 2012). Microsoft Visual Studio This is an Integrated Development Environment (IDE) from Microsoft. It will be used to develop console and graphical user interface application along with window forms application, website, web applications and web services in both native code together with managed code for all platforms supported by Microsoft windows, windows mobile, windows CE, NET compact framework and Microsoft silver light. Visual studio comprises of a code editor supporting intelligence as well as code refractory. The integrated debugger works both as a source lead debugger and a machine level debugger. Other built in tools include a forms of designer for building GUI applications, web designer, class designer and data base schemer designer. It accepts plug in that enhance the functionality at almost every level including adding support for source control systems(like sub version and visual source safe)and adding new tool sets like editors and visuals designers for domain. Specific languages or tool sets for other aspect of the development life cycle (like the foundation server client: team explorer)

According to Adekunle et al, (2014), Software can be developed for a variety of purposes, the three most common being to meet specific needs of a specific client/business (the case with custom software), to meet a perceived need of some set of potential users (the case with commercial and open source software), or for personal use (e.g. a scientist may write software to automate a mundane task). Embedded software development, that is, the development of embedded software such as used for controlling consumer products, requires the development process to be integrated with the development of the controlled physical product. Software design can be considered as putting solution to the problem(s) in hand using the available capabilities. Hence the main difference between Software analysis and design is that the output of the analysis of a software problem will be smaller problems to solve and it should not deviate so much even if it is conducted by different team members or even by entirely different groups. But since design depends on the capabilities, we can have different designs for the same problem depending on the capabilities of the environment that will host the solution (whether it is some OS, web, mobile or even the new cloud computing paradigm). The solution will depend also on the used development environment. (Janadekar, 2004).

RESULTS AND DISCUSSIONS The challenges of this century have brought about drastically changes in the techniques used in the design of any mechanical system. Due to this revolution of change it has been discovered that vast majority of companies uses computer aided design programs to design their products. The application developed here enables the user to define specifically the length of the driver and the driven teeth of the sprocket, the power transmitted, the gear ratios and so on showing this stages through different interface. When the specifications are being entered correctly, there is a design button, after clicking on this design command, this same program converts it to computer aided design (CAD) commands that can be immediately tested for detailed design

METHODOLOGY Programming the computer to handle a design work involves the development of a set of instructions (program) in line with the design procedures, coding the instruction set with a high level programming

Plate 1: Initial interface 263

Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):260- 266 (ISSN: 2141-7016) This is the users’ friendly set up interface where all the required parameters would be inputted.

Plate 2 The interface is where sprocket parameters such as drivers teeth, driven teeth, driver revolution and other parameters were been inputted

Plate 3 This is practically the first stage of operation where the dimension for the driver teeth is being supplied.

Plate 4 This is where the parameters for the driven teeth and the sprocket parameters were being inputted

Plate 5 264

Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):260- 266 (ISSN: 2141-7016) This is where the driver revolution per minute required is specified by the user.

Plate 6 At this stage other parameters needed in the chain design such as the power transmitted was supplied.

Plate 7 This is the most important stage of the design process, where simulation takes place, after clicking on the design button, the software automatically designs it to conform it to the given parameters and it shows the result of the design such as the gear ratio, driven revolution, link joint motion angle and in some exceptional cases it gives advice on a

reasonable value for optimum speed for the driver teeth where values exceeds a standard value. The diagrammatic representation of the design is shown on the right side of the interface showing the length between the driver and driven sprocket joined together with the aid of a chain

or not, after clearing the fields the interface automatically changes to a new page.

Plate 8 This is the final stage in the design. Having completed the design, the result generated shows the Gear ratio, Driven revolution and link angle were generated There is a clear button option, with a red sign, after clicking on the clear option, there is a confirmation drop down box asking whether to clear

CONCLUSION In summary, we have been able to derive a very easy means of designing chains with the aid of a CAD interface being used in the process of designs of 265

Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):260- 266 (ISSN: 2141-7016) Spicer, James, (1999) "Pedal Power Probe Shows Bicycles Waste Little Energy". The Complete Guide to Chain © 1997 by U.S. Tsubaki, Inc. ISBN 09658932-0-0 Library of Congress 97-061464.

chains. This process have been the most preferred by design engineers and craftsmen since it is very easy to access and it doesn’t need rigorous calculations in its application, mistakes can be easily corrected and it does not involve special techniques thus it can be said that it is very efficient in term of accuracy when compared with that of the manual design.

Wang, K. W. and Liu, S. P. (1991), “Noise and Vibration of Chain Drive Systems” The Shock and Vibration Digest 23(4), 8–13.

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