CHAPTER 4 AUTOMATION SYSTEM DAE 32503 – ROBOTICS & AUTOMATION SYSTEM By: Nor Faezah Adan

Introduction to Automation Automation in Manufacturing Automation strategies Designing for Automation

4.1 Introduction to Automation Automation can be defined as a technology concerned with the application of mechanical, electronic and computer based systems to operate. Therefore, an automated machine is composed of: A mechanical part including the actuators/drives and sensors. An electronic circuit i.e the hardware. A control system that represents the intelligence of the system.

4.1.1 Automatic vs Autonomous Example: The automatic toaster Bread is put in the toaster, a lever is pushed down, and when the toast is done, it shuts off and pops up automatically  The toaster is automatic, but not autonomous. Autonomous toaster  would have a more flexible capability. It would have a way of knowing what kind of bread was in it and how well done the user wants the toast, so it could adjust the heat accordingly. It would be able to monitor the toasting process so the toast would always be fully done and never burned.

4.1.1 Automatic vs Autonomous Example 2: The traffic light Human presses button at traffic light when they want to cross the street. Even if the traffic light work automatically without any buttons are pressed, it is still an automatic system because the input (e.g. time to change the lights) is provided  Automatic traffic light. Autonomous traffic light  if the traffic light uses a camera and moves its camera to detect people who want to cross the street and change its light accordingly, it is then an autonomous system.

Program of instructions 4.1.2 Basic elements Power Process Control System Program of instructions Power: To accomplish the process and operate the system. A program of instruction to direct the process. A control system to actuate the instructions.

4.1.3 Benefits of Automation Increase labour output Example: Addition of a robot to handle material or use of PLC to control manual process. Each is intended to free up the worker from a task, thereby enabling him or her to produce more. Increase production output Increase the amount of product made over a specific period of time. Robot is fast and consistent.

4.1.3 Benefits of Automation Reduce or eliminate effects of labour shortages If the manufacturing process is particularly labour intensive, lack of workers can result in machine downtime, less product and overtime for the current workforce. Making the process labour intensive through automation allows it to better withstand periods of labour shortages.

4.1.3 Benefits of Automation Improve worker safety Example: Utilization of a robot to remove parts from an injecting press. For a worker to remove parts from the mould, the press door must be opened, which activates the mechanical interlocks that prevent the mould from closing as the worker removes the parts. But if a robot removes the parts, the worker is no longer required to reach the press, thus removing him from the dangerous environment. Injecting press Auto injecting press

4.1.3 Benefits of Automation Reduce labour cost Example: Labour cost reduction include any type of automation that reduces the number of workers or the time each worker spend in production. Improve product quality Robot has higher accuracy and consistent.

4.1.3 Benefits of Automation The existence of processes that simply cannot be done manually Some processes may require too high of a degree of precision or be too small for the human hand to effect or have too complex a geometry. Example:Manufacturing of computer chips. In 2008, INTEL announced a new computer chip containing 2 billion transistors. Obviously, this can only be produced with the aid of automated machines.

4.2 Automation in Manufacturing Examples of automated manufacturing system: Automated machine tools that process machine parts. Transfer lines that perform a series of machining operations. Automatic inspection system for quality control. Manufacturing systems that use industrial robots to perform processing or assembly operations. Automatic material handling and storage systems to integrate manufacturing operations. Automated assembly systems. Inspection

4.2 Automation in Manufacturing Automated manufacturing systems can be classified into three standard types: Manufacturing automation Fixed automation Programmable automation Flexible automation

4.2.1 Fixed Automation Fixed automation is a system in which the sequence of processing (or assembly) operations is fixed by the equipment configuration. This is also called hard automation. Used when the volume of production is very high, therefore, appropriate to design specialized equipment to process products at high rates and low cost. Examples: Machining transfer lines, Automated assembly machines.

4.2.1 Fixed Automation Example: Automobile industry, where highly integrated transfer lines are used to perform machining operations on engine and transmission components. The economics of fixed automation is such that the cost of the special equipment can be divided over a large number of units produced, so that the resulting unit costs can be lower relative to alternative methods of production. Transfer line Assembly

4.2.1 Fixed Automation The risk: Initial investment cost is high and if the volume of production turns out to be lower than anticipated, then the unit costs become greater. The equipment is specially design to produce only one product, and after that product’s cycle life is finished, the equipment is likely to become obsolete. Therefore, for products with short life cycles, fixed automation is not economical.

4.2.2 Programmable Automation In programmable automation, the production equipment is designed with the capability to change the sequence of operations to accommodate different product configuration. The operation sequence is controlled by a program. New programs can be prepared and entered into the equipment to produce new products. Example, CNC lathe that produces a specific product in a certain product class according to the “input program”.

4.2.2 Programmable Automation The system must be reprogrammed with the set machine instructions that correspondent to the new product when a new batch of different product needs to be produced. Physical setup of the machine must be changed (this changeover procedure takes time): Tools must be loaded. Fixtures must be attached to the machine table. Required machine setting must be entered.

4.2.2 Programmable Automation In terms of economics: The cost of equipment can be spread over a large number of products even though the products are different. Because of the programming feature and the resulting adaptability of the equipment, many different and unique products can be processed economically in small batches.

4.2.2 Programmable Automation Typical features of programmable automation are: High investment in general purpose equipment. Lower production rates than fixed automation. Flexibility to deal with variations and changes in product configuration. Most suitable for batch production. Example: Numerically controlled (NC) machine tools. Industrial robots. Programmable logic controllers. CNC

4.2.3 Flexible Automation Flexible automation is most suitable for mid-volume production range. Flexible automation possesses some of the features of both fixed and programmable automation. It is also called soft-automation. Flexible automation typically consists of a series of workstations that are interconnected by material handling and storage equipment to process different product configurations at the same time on the same manufacturing system.

4.2.3 Flexible Automation A central computer is used to control the various activities that occur in the system, routing the various parts to the appropriate stations and controlling the programmed operations at the different stations. With flexible automation, different products can be made at the same time on the same system. This means that the products can be produced on a flexible system in batches, if desirable, or that several products can be mixed on the same system.

4.2.3 Flexible Automation The computational power of the control computer is what makes this versatility possible. However, the exorbitant cost of this system limits its use to high volume application. Example: Industrial robot. Flexible manufacturing system. Robot FMS

4.2.4 Automation comparison Consideration Advantages Disadvantages Fixed / Hard High demand volume Long product life cycle Maximum efficiency Low unit cost Automated material handling – fast and efficient movement of parts Large initial investment Inflexibility Programmable Batch production Products with different options Flexibility to deal with changes in product Low unit cost for large batches New product requires long set-up time High unit cost relative to fixed automation Flexible/Soft Low production rates Varying demand Short product life cycle Flexibility to deal with design variations Customized products High unit cost relative to fixed or programmable automation

4.2.4 Automation comparison

4.2.4 Automation Strategies A central computer is used to control the various activities that occur in the system, routing the various parts to the appropriate stations and controlling the programmed operations at the different stations. With flexible automation, different products can be made at the same time on the same system. This means that the products can be produced on a flexible system in batches, if desirable, or that several products can be mixed on the same system.

4.2.5 Designing for Automation Symmetry Both ends of the part were designed to be identical to make orientation unnecessary.

4.2.5 Designing for Automation Asymmetry Important features of each part are difficult to detect mechanically and solution to the problem is to remove symmetry. Disk and circular objects are particularly good candidates for asymmetric design features, because without locating features, they can assume an infinite number of rotational orientations. Rectangular shapes however, usually benefit from symmetry because they are only a few feasible orientations

4.2.5 Designing for Automation

4.2.5 Designing for Automation Parts tangling Parts often have both holes and projections in which the functions of these features are irrelevant to each other and the projections are not intended to enter the hole. The relationship between hole size and part projection dimensions for such parts is important to prevent projection from sticking into the hole and causing a tangle.

4.2.5 Designing for Automation

4.2.5 Designing for Automation

4.2.5 Designing for Automation Parts feeding Most of the machines for feeding parts utilize vibration or gravity, and force is transmitted from piece to piece as parts are pushed forward from the rear. If parts are too thin or if edges are beveled, the parts will tend to “shingle”. If parts end are not orthogonal to the direction of travel, the parts will tend to “wedge”.

4.2.5 Designing for Automation

4.2.5 Designing for Automation

4.2.5 Designing for Automation Design for insertion Even if parts are oriented correctly, when the tolerances are close, it is difficult to achieve the perfect alignment necessary to accomplish an insertion task with an industrial robot or other automatic machine. It is frequently possible to design the mating parts to make the insertion job easier.

4.2.5 Designing for Automation

4.2.5 Designing for Automation Fasteners There are assembly machines that are used for driving screws. Fundamentally, it is wise to avoid screws and fasteners because of the complexity they add to the assembly process. It is often possible to do this with no compromise in quality or integrity of the assembly.

4.2.5 Designing for Automation

4.2.5 Designing for Automation End of Lecture 10