FACULTY OF MANUFACTURING ENGINEERING(BMFP)

ACADEMIC YEAR 2014/2015 SEMESTER 2

BMFA 3443 INDUSTRIAL AUTOMATIONASSIGNMENT 3:INDUSTRIAL AUTOMATION

NONAMEMATRIC NUMBERCOURSE

1MUHAMAD SHARUL NIZAM BIN ZIN

B0512102123BMFP

2NIK M. FARHAN SYAHMI B NIK JAAFFAR

B0512102223BMFP

3SITI NUR RAHEENA BINTI HAMDANB051210115

3BMFP

4NADIA ADRIENA BINTI ABD RAHMAN

B0512100883BMFP

5UMIRA SYAFIKA BINTI HASHIM

B0512100323BMFP

Submit to: PROF. DR. BASHIR MOHAMAD BIN BALI MOHAMAD

Submit on: 22TH MAY 2015Question 1

What type of industrial robot is more suitable for application of loading and unloading of machine tools? . After type of robot is decided, explain about it application for loading and unloading of machine tool such as CNC milling machine in about one page. Your explanation must be supported by at least one figure showing the robot performing the loading and unloading tasks.Answers:The most suitable industrial robot for loading and unloading of machine tools is jointed arm or articulated. The main reason why jointed arm is choose because all axes of robot can move in angular direction. Besides, the robot usually driven by electrical motors and very good for loading and unloading, pick and place , and assembly operation.The jointed arm robot very suitable for loading and unloading of machine tools in CNC milling application.Primary aim of this robot is is to transfer parts into or out of a production machine such as CNC milling machine. There are three classes to consider when choosing the suitable robot for load and unloading process. Firstly, machine loading which is where the actual location for robot to loads the machine. Second, machine unloading, where the actual location for robot to unloads the machine and lastly, machine loading and unloading, where the robot performs both actions. The jointed arm robot can be programming by using teach pendant programming, teach pendant is an online programming and it is carried out by using teach pendant designed for robot. The robot is taught to perform loading and loading task by using the pendant. Every position or point of the robot movement is recorded and the position will be use for writing computer program for robot to perform the loading and unloading task. The robot also can be program using keyboard programming also known as offline programming, where all the loading and unloading task is carried out and tested first by using computer software to determine the position or poin where the robot need to be move to perform the required task.For loading and unloading task, the jointed robot need to equip special gripper or holder to hold and secure raw work part tightly. The jointed arm robot have two gripper must be programmed to take one work piece from the storage and bring it into the CNC milling machine. At the CNC milling machine, second gripper will hold the finish work part and unload it from the CNC milling machine . The first gripper that hold the raw work part will load it into the CNC milling machine holder. Then, the jointed robot arm will bring back the finish work part and unload it into the finish part storage area. The robot will repeat the operation until certain amount of operation cycle is achieved by the CNC milling machine. The jointed robot must be perfectly alignment before the loading and unloading operation to maintain the accuracy and excellent repeatability of work part. It also important to know the maximum payload that the robot can handle and speed of the robot to perform loading and unloading task.The usage of jointed arm very efficient and effective for loading and unloading in industry because the robot can perform their work cycle consistently and repeatability that cannot be attained by humans. Moreover, the robot can easily be reprogrammed back if the operation layout or work part are change. The robot also can substituted human in hazardous working environment.

Figure 1.1: Jointed arm robot performing loading and unloading task.

Figure 1.2 : Example of Gripper for holding work part.

Question 2

Arc welding process is to be used to fabricate bridge trusses from standard structural steel components. For this study, compare an average arc-on time for manual welding of 40 percent with an assumed arc-on time for a robot welder of 80 percent. Also assume that the robot welder is 60 percent faster while performing the welding and that one (1) welding operator can tend simultaneously five (5) robot welders.How many manual welders would be required to achieve a productivity level the same as one (1) welder supervising this welding process of five (5) arc-welding robots?

AnswerManual welders = number of robot x percentage of robot welding time / percentage of manual welding time x faster percentage (efficiency) of robot compare to welder. = 5 x x 1.6 = 16

b) Differentiate between Token Ring Network and Token Buses of Local Area Networks. Support your differentiation with at least one figure.AnswerToken Ring is a strategy for constructing a LAN to avoid the problem of message collisions is by providing a message carrier that travels around to all devices connected to the network. This message carrier is called a token as shown in Figure 1.The token is merely a bit pattern that is packaged with the data to permit the package to be recognized by each device on the network. The token travels around to every device in the loop during every cycle, regardless of which or how many devices are intended to receive a given message.

Figure 2.1 Token Ring NetworkToken buses are a combination of the concepts of token rings and the Ethernet bus as shown in Figure 2. There are two routing modes for the token, depending upon whether the token is carrying a message or is simply empty and looking for a device that wants to send a message. If the token is carrying a message, that message has an address; hence, the message is received directly by the device on the bus without waiting for it to be relayed through the system by the successive operations of the repeaters of each of the devices, as is done in the token ring arrangement.

Figure 2.2 Token Buses NetworkQuestion 3a) A flexible manufacturing system (FMS) is used to do machining on pistons for vehicles. The FMS consists of four (4) cells (or workstations). Each cells consists of one (1) CNC machine and one(1) robot to load and unload the machine. All the four(4) cells are served by a single(1) continuous line conveyor that runs alongside the robots and machines in the cells.

i) Draw a layout diagram to show the proper arrangement of the robots, machines, conveyors, and work pieces (pistons) in the FMS (The drawing can be simplified by using block diagram). Label all the elements in the FMS.

Figure 3.1 Layout diagram

Table 1 Description of the symbolSymbol

Description

CNC machine

Robot (load & unload)

Work piece

ii) If the operation of all the cells in the FMS is sequential production line, each of the CNC machine cycle time is 12 minutes including machine loading and unloading by the robot, what is the daily ideal production capacity/rate of the FMS per hours.

Time = 8hours x 60mins = 480 mins

For one CNC machine, Cycle time = 12minsFor four CNC machines,Cycle time = 12mins x 4 = 48mins

Therefore, the daily ideal production capacity/rate of FMS per 8 hours is : Time / Total cycle time =480mins/48mins = 10mins

Question 4a) Discuss the function of machine vision system. Support discussion with atleast one figure.

Figure 4.1 Typical Vision System Components

Machine vision system is the technology and methods used to provide imaging-based automatic inspection and analysis for such application as automatic inspection, process control and robot guidance in industry. It is often thought of as the capability to sense, store and reconstruct a graphic image that matches the original as closely as possible. This system usually have a specific assignments such as checking for the proper orientation , identifying parts, searching for specific defects, or checking alignment for assembly. A procedure can be devised to efficiently and effectively accomplish the specific goals of the machine vision requirements, usually without requiring a full implementation of the graphics-reproduction capability of the system. Vision systems are classified as being either 2D or 3D. Two dimensional systems view the scene as a 2D image. This is quite adequate for most industrial applications, since many situations involve a 2-D scene. Machine vision uses sensors (cameras), processing hardware and software algorithms to automate complex visual inspection tasks and precisely guide handling equipment during product assembly. The application includes positioning, identification, verifications, measurement and flaw detection. Machine vision eliminates the need for many machine operators by performing many of the complex tasks once done only by humans. Systems used for assembly and inspection have had a major impact in the automotive and electronics industries. For example, todays printed circuit boards often contain thousands of individual parts. If even a tiny fraction of these parts is incorrectly placed on the board, the cost of finding and repairing the problem is enormous. When human workers perform circuit board assembly, fatigue can cause as much as a 20 percent error rate. Using robots with machine vision for circuit board assembly significantly reduces the error rate.

b) Discuss the function of sensors and actuators used in industrial automation. Support with at least one figure.

Figure 4.2 SensorA sensor is a transducer whose purpose is to sense or to detect some characteristic of its environs. It detects events or changes in quantities and provides a corresponding output, generally as an electrical or optical signal. Sensors are the first link between the typical automated system and the conventional process. Sensors convey information from the manufacturing process equipment, the piece part or product being manufactured, and from the human operator, if any. It may seen strange that the automated system senses the human operator, but this is without doubt the most important link between the automated system and the real world. The first sensor we shall examine is in that vital link. Vision sensors are particularly helpful when multiple features must be inspected on the product.There is usually some degree of tolerance for each article.Vision sensors are considerably quicker and more accurate than humans employed for the same task. A smart transducer is either a sensor or an actuator that is instrumented or integrated with signal conditioning and conversion and a microcontroller or microprocessor to provide intelligent functions. Its output is migrating from an analog to a digital format for added capability to communicate with a host or a network.

Figure 4.3 ActuatorsOne of the examples sensors is limit switches. This switch is actuated mechanically, but it also automatic inputs from the manufacturing process, the material or the automated system itself, without intervention by the operator. The reason for this is that limit switches must be designed to be exactly correct in size, lever travel, force of actuation, and ruggedness for the specific automation application desired out of the myriad of automation applications that might be feasible. Limit switches are used in a variety of applications and environments because of their ruggedness, ease of installation, and reliability of operation. They can determine the presence or absence, passing, positioning, and end of travel of an object. Limit switches are actuated by levers, toggles, push buttons, plungers, rollers, and just about anything else the inventor can device to make an automation application feasible. Limit switches can be used to limit the travel of a robot arm on any of its axes of motionActuator is a type of motor that is responsible for moving or controlling a mechanism or system. It is operated by a source of energy, typically electric current, hydraulic fluid pressure, or pneumatic pressure, and converts that energy into motion. An actuator is the mechanism by which a control system acts upon an environment. The control system can be simple (a fixed mechanical or electronic system), software-based for example a printer driver, robot control system, a human, or any other input.In a manufacturing system, actuation may be a direct physical action upon the process, such as a sweep bar that sweeps items off a conveyor belt at the command of a computer or other analyzer. In other cases, an actuator is simply a physical making of an electrical circuit, which in turn has a direct effect upon the process. An example would be an actuator (relay) that turns on power to an electric furnace heating circuit. Relay is the most popular solenoid of all is used to switch an electrical circuit. Switching-type circuits usually operate at lower voltages and especially at lower amperage than power circuits. The output of the switching logic network than can be used to trip one or more relays to close or open a power circuit. A relay can be described as either "latching" or "non-latching".

Figure 4.4 Using relays to automatically switch power circuits. In circuit (a), both sensors A and B must supply voltage to their respective relays to close the power circuit. In circuit (b), a voltage at either sensor is sufficient to close the power circuit.

c) Differentiate between cylinders and solenoids. Support your differentiation with at least one figure.

Figure 4.5 SolenoidSolenoid valve which is an integrated device containing electromechanical solenoid which actuate either a pneumatic or hydraulic valve, or a solenoid switch, which is a specific type of relay that internally uses an electromechanical solenoid to operate an electrical switch. An electrical solenoid is a logical selection when a small, light, quick linear motion is desired in an automated system. The principle of the solenoid operation is a long, thin loop wire were wrapped around metallic core then produce a uniform magnetic field in a volume space when an electric current is passed through. The stroke motion of a solenoid is not very controlled in comparison, for example, with a hydraulic cylinder, but many automation applications require only a short, quick, discrete action, not a smooth, controlled stroke.While for the cylinder, it is a linear and quick movement in an automation application. The most popular are the pneumatic cylinder. This is due to the convenience of piping compressed air throughout a manufacturing plant. When manufacturing process require forces to be applied in excess 200pounds, the suitable cylinder is hydraulic cylinder because it is more accurate compare to pneumatic cylinder.

Figure 4 Pneumatic cylinder

Figure 5 Hydraulic cylinder