Design and Development of Valve Lapping Machine

Design and Development of Valve Lapping Machine

Pankaj Pujari1, Chetan Arote2, Tushar Kale3 ,Kiran Kawale4, Prof. D. Kotkar5

Dept. of Mechanical Engineering,

Dhole Patil College of Engineering, Pune, Maharashtra, India .

Abstract Design and development of valve lapping machine is minimize the human efforts for lapping and also reducing time consumed for valve lapping process. In the development of automobile sector advanced methodology and techniques are very important for increasing efficiency of machines. The current methods used in most automobile maintenance businesses for valve lapping process are not effective and consume a lot of working hours. 'Valve lapping Machine for Internal Combustion Engines' is a machine designed and development to overcome these problems by minimizing the human involvement in the process.

Keywords Methodology; techniques; efficiency; maintenance; involvement;

1. INTRODUCTION

   The process involved of achieving good seat, finer surfaces, closer fits, correction of minor imperfection and maintaining close tolerances between engine valves and the corresponding valve seat area in the internal combustion engine cylinder head is a task which have to be done very accurately. The importance of obtaining a good seat is that the air/fuel mixture in petrol engines or air in diesel engines is prevented from flowing in to the combustion chamber, same as the exhaust gas is prevented from flowing to the exhaust manifold from the combustion chamber until the right time. And also a good seat prevents compression leaks. The engine will lose its efficiency by huge percentages if any of the situations explained above happens. So as this is a very important task in IC engine maintenance, extra attention is given to this particular task by technicians. This process of valve lapping is typically done using a valve lapping stick or a power tool. As both of this tools are not very effective, these tools can be replaced by the ' Valve Lapping Machine for Internal Combustion Engines', specifically designed for the process of engine valve lapping. The machine employs a fully mechanical and automated system which performs two different motions in two directions previously performed by hand when using valve lapping stick and power tool. Comparatively the valve lapping machine is very effective because the human involvement is very limited in the process.

   1. PROBLEM STATEMENT

      The main purpose of the project is to minimize the human effort with excellent machines with precision although the time required for the process is the same for manual as well as the given by employee will be reduced machine but, if we use

      a machine instead of the person the person can do another job by this time. Also the efforts which are

   2. Objective

   The objective of this project is to design a machine both efficient and effective than previously used machine/methods for valve lapping and to reduce the labor cost by reducing the human involvement in the process. The objectives that had to be achieved in order to achieve the main goal were designing the basic prototype of the machine, designing the valve lapping mechanism, assembly of the whole machine by designing the parts needed, calculating and designing the cam needed, analyzing data and categorizing, analyzing data to obtain the specifications of the machine, obtaining two high torque dc motors that has specific RPM values and deciding what materials must be used in order for the design to be durable and economical.

2. LITERATURE REVIEW

Ayodhya Abeysekara [1]: Automobile maintenance is a major area in the industry of automobile and also a major income to the business. In present, Internal Combustion engine maintenance can be stated as a very important section in automobile maintenance and the valve lapping process that is subjected in this thesis is done during IC engine maintenance. The current methods used in most automobile maintenance businesses for valve lapping process are not effective and consume a lot of working hours. 'Valve lapping Machine for Internal Combustion Engines' is a machine designed to overcome these problems by minimizing the human involvement in the process. The thesis consist of the background in designing the machine, methodologies used, results obtained by data analysis in order to optimize the design and design of the valve lapping machine.

Mr. Pratheesh Kumar[2]:Lapping is a finishing process in which the material removal takes place due to relative motion between the work material, loose abrasive grains ,and the lapping plate. This process is used in achieving finer surfaces and closer fits, correction of minor imperfections, and maintaining close tolerances. Although a significant underlying science base exists with regards to physics, mechanics, and thermal effects, lapping has been considered as an art, rather than a science. Hence exploring lapping at fundamental level will help improve its application. This study discusses the effects of the various process parameters influencing the material removal rate and surface finish. This is done by conducting a series of experiments by varying the process parameters and calculating the material removal rate

and surface roughness. Then the final step is to find out the optimum combination of process parameters to determine the material removal rate and the surface finish. This is done by conducting a series of experiments by varying the process parameters and calculating the material removal rate and surface roughness. Then the final step is to find out the optimum combination of process parameters to determine the material removal rate and the surface finish. The surface finish produced on the component depends on the number of factors like abrasive concentration, time of lapping, etc. So, these factors have to be controlled efficiently for a good surface finish. Surface finish is an important factor when dealing with issues such as friction, lubrication and wear. It also has a major impact on applications involving thermal or electrical resistance, noise and vibration control, dimensional tolerance, etc. The surface finish obtained from lapping is a function of the material removal rate. Normally, the surface roughness tends to increase as the MRR increases.

S. M. Fulmaliet all[3]:Lapping is a micro finishing operation which is required to require getting a mirror like surface finish on the meting component. It provides a good strength to joint formed. Lapping has been used extensively in the manufacture of optical mirrors and lenses, ceramics, hard disk drive, semi-conductor wafers, valve seats, ball bearings, and, and many more parts. Several factors need to be considered during the process of lapping. This includes factors such as type of machine, condition of the lap plate surface, speed of the lap plate, type of abrasive, type of carrier fluid, slurry concentration, slurry flow rate, size and shape of abrasive, material of the lap plate, rigidity of the lap plate, applied force on the work piece, time of operation and duration between the two consecutive instances of application of fresh abrasive slurry .This paper will explore the current working condition of lapping machine in valve industry. It will elaborate the effect of abrasive particles, working speed, surface roughness and other related parameters. What are the difficulties they are facing during the valve reconditioning related to lapping, will be discussed. Current set up and the changes required in this model are suggested with the proposed model. The above research workand the proposed model can provide benefit in the lapping of valve component. Model will provide portability and reduce the set up time for lapping to some extent. The paper shows the importance of lapping operation in a valve industry. It show the size and type of abrasive used for valve lapping. As compared to the available machine for lapping, this proposed model will be the cheaper model. It will prove to be an economical model. The number of labors require to operate this machine is only one and less skilled labor can operate this model.

III PROJECT OVERVIEW

1. WHAT IS VALVE LAPPING

   Valve Lapping is basically sanding down the surface of the Valves (which allow fuel and air to flow in, and exhaust to flow out) and the Head (Holds the Camshafts and valves) where they make contact with each other. This is done by applying a Compound Paste (pretty much just oil and a fine grade of sand) to the edges of the valves and spinning them in their seats on the head. Creates a better seal between the

   valve and the head, which will prevents gases from escaping during the compression stroke of your engine and the greater contact area allows for more heat dissipation from the valves to the head which will prevent burnt valves.

   The internal combustion engine operates by achieving a certain compression ratio which is differing from engine to engine and combusting a air-fuel mixture which is compressed to a certain volume decided by the compression ratio. And if the air-fuel mixture leaks through the seating, the volume of the air- fuel mixture will change and combustion process will not be accurate resulting a reduction in productivity of the engine. Therefore it is vital to have a fully sealed combustion chamber and the valve seating is very important in acquiring a fully sealed combustion chamber.

   Fig-1: IC Engine Head

2. LAPPING PROESS

   While the valve lapping process, we have to observe the valve seat area time to time by the naked eye. It's the normal way to conclude whether the valve seat is good or further valve lapping is needed. Figure 02 shows a lapped valve and a non- lapped valve. After the valve lapping process, the most common way to observe the seating of valves is a technique using petrol. After the valve job is done, the mechanic or technician place the precise valve in the precise spot in the cylinder head and pour petrol to the stem of the valve which he have to observe. This poured petrol then reaches the seating area of the valve. Then it is observed if petrol leaks through the seat. If petrol leaks through the valve seat it concludes that the valve job is not successful and if petrol does not leaks through the valve seat it concludes that the valve has acquired a good seat, so recommending to assemble the engine using the valve.

   Fig-2: lapped and non-lapped valve

3. ENGINE VALVE

There are two kinds of engine valves, intake/inlet valves and exhaust/outlet valves. These valves could be identified easily in a cylinder head. Inlet valves are usually bigger than exhaust valves. Although more than one inlet valve and exhaust valve can be present for a single cylinder. There are different designs for inlet valves and exhaust valves. The most commonly used valve design is poppet valve design. Then there are sodium valves used in some turbo-charges engines. And mask valves, mushroom valves, tulip valves could be observed in different situations. The following figure shows a detailed diagram of a valve. Seat angle is the most important thing in the valve lapping process. Seat angle is normally 45° and 30° in most of valves. The other important factor of designing the valve lapping machine is the stem diameter of the valve. The valve is to be fixed to the valve lapping machine in order to start the lapping process by the stem of the valve. The dimensions from the collected data of valves are analyzed in order to acquire three categories of stem diameters. These analyzed data is used for the specifications of valve holding pieces of the machine to be built. Overall length of the valve is also a important factor to consider when adjusting the machines before starting the valve lapping process.

Fig-3:Detail diagram of an engine valve

IV. DESIGN

Fig-4: Trimetric view of the 3D model of valve lapping machine for internal combustion engines

1. MACHINE BED

   Machine bed is the base of the valve lapping machine. The cylinder head can be initially kept on the machine bed for measuring or observing purposes and the bed is designed to accommodate a cylinder head without any problem.

2. CYLENDER HEAD SUPPORTS

   The cylinder head supports are designed to accommodate the cylinder head while the valve lapping process. This extra feature is added to the design because it is hard to move a cylinder head when the cylinder head needed to be adjusted to a different position. Since this cylinder head supports are movable along the machine bed, it is very easy to adjust the cylinder head position.

3. CAM AND FOLLOWER

   Cam is the main part responsible for the vertical movement of the valve lapping mechanism. Actually a cam works as a system that consist with a follower, a cam drive and a follower system. The vertical motion is gained by the valve lapping mechanism when the cam is rotated by the rotary motion, high torque and heavy duty DC motor which is the cam drive and the rotary motion is then converted in to linear motion using shape of cam nose and it is transmitted to the valve mechanism through the cam follower. The vertical motion of the valve lapping mechanism helps to break the contact between valve seat and the corresponding surface of a cylinder head. The importance of this action the rotary motion is converted into linear motion. Cam follower is tensioned using a spring in the valve lapping mechanism and as the cam rotates, follower gain space to move upwards and when the cam nose area returns follower move downwards creating a linear motion.

4. RPM, HIGH TORQUE AND HEAVY DUTY DC MOTOR FIXING BRACKET

   This bracket holds the motor which transmit motion to the cam and as the cam subjects to some amount of torque, the same torque is transmitted though the motor to the bracket and therefore bracket is also subjected to the same torque.

5. MACHINE STAND

   Machine stand is assembled to the machine bed in one end. Other end of the machine stand is the mounting for the valve lapping mechanism and also the holding bracket for High torque, heavy duty 12V DC gear motor, mounted near the same end. Therefore allowing the access to any valve position of a cylinder head placed on cylinder head supports. The load generated while the valve lapping process is transmitted to machine bed through the machine stand and the integrity of the structure is a very important factor to consider when designing. Lower end of machine stand which is assembled to machine bed is one of the areas of the machine with highest stress concentration. The assembly area of the machine stand to machine bed is subjected to loads from machine bed surface and valve lapping process.

6. TENSION SPRING

   Tension spring is the link between upper mounting bracket and lower mounting bracket. They are connected by welding both ends of the spring to the two brackets.

7. VALVE HOLDING PIECE

   This is one of the most important parts in this machine. Most of the valve lapping power tools and valve lapping sticks doesn't have an effective valve holding unit. Due to that reason, sometimes while the valve lapping process is going on, the engine valve disconnects from the valve holding unit. This is a real inconvenience. To prevent that from happening, valve lapping machine for IC engines has a special valve holding piece. valve holding piece that can be either assembled to the valve holding piece mounting screw or the extension piece. The head of this part is made from steel and body is made from natural rubber since natural rubber has the best elasticity of all rubber types. The head and the body is merged together using an industrial grade adhesive.

8. VALVE HOLDING PIECE MOUNTING SCREW

Fixing of engine valves to the machine in order to lap them is another important task that has to be completed before the valve lapping process begin. This small screw is the first part of the unit designed to hold any king of valve.

V CONCLUSION

l. To observe the functionality and the efficiency of the valve lapping machine, it is needed to be developed. This has The problem of holding engine valves was solved by designing valve holding pieces. Valve lapping mechanism was implemented replacing manual labor. Cylinder head supports have eased the moving of cylinder heads horizontally. Vertical height adjustment problem was solved by extension piece. 20 RPM DC motor is able to handle the torque necessary to valve lapping process. Valve lapping mechanism was designed as a assembly of several parts easing any

maintenance to the machine. Structural integrity of machine bed, machine stand, cylinder head supports, tension spring and cam against loads and torques were fine and the designs are successful To observe the functionality and the efficiency of the valve lapping machine, it is needed to be developed.

VI ACKNOWLEDGMENT

Ths a great pleasure and immense satisfaction to express our deepest sense of gratitude and thanks to everyone who has directly or indirectly helped us in completing our project work successfullly. We express our gratitude towards project guide Prof. Dattatray Kotkar and project co-ordinator Prof. Vikram Avhad and Prof. Y. G. Ingulkar, Head of department of mechanical engineering, Dhole Patil College of Engineering, Pune who guided us in time being. We would like to thak our Principal Dr. Nihar Walimbe for providing us congenial environment to work in.

VII REFERENCES

1. Ayodhya Abeysekara[1]: Valve Lapping Machine for Internal Combustion Engines,October 2015 DOI: 10.13140/RG.2.1.1277.0000, Pitigala A. G. Abeysekara School of Technology, University of Wolverhampton.

2. M. R. Pratheesh Kumaret all[2]: Optimization of Process Parameters In Lapping of Stainless Steel, International Journal of Engineering Research & Technology (IJERT),2013.

3. S. M. Fulmali all[3]: Need of Lapping Machine for Valve Component: A Case Study, International Journal of Modern Engineering Research (IJMER),2012.

4. Owat Sunanta[4]: flat surface lapping: process modeling in an intelligent, Environment, University of Pittsburgh, 2002.

5. Arpreet Singhet.all[5]: A comparative study of precision finishing of rebuild engine valve faces using microgrinding and ECH, Singh and Jain Journal of Remanufacturing,2015.