Evrim Berk 030060161 2nd Week

1-) Ice Blasting (Method)

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Deburring of complex components is subject to formidable efforts in terms of time and expenses. In order to ensure quality and due to lack of operational alternatives, these efforts are inevitable. As a result, even in times of continuous automation components must often be deburred manually. In order to counteract this trend and keep up with heightened requirements of production, implementation of a new and innovative deburring procedure, which will be presented here, needs to be promoted. The procedure is referred to as ice blasting or ice deburring.
The procedure investigated here is essentially a blasting method using a solid blast medium. The innovative idea at the foundation of this endeavour lies in the use of ordinary ice as a blast medium. The advantage of ice is its property to not leave any solid residue behind and in that it is consequently applicable to the blasting treatment of complex component geometries, as shown in Fig. 1. In this current case the diameter of hole is 5 mm and the position of burr in hole is 30 mm distant from access.

(B. Karpuschewski, M. Petzel, “Ice Blasting – An Innovative Concept for the Problem-Oriented Deburring of Workpieces”, Burrs - Analysis, Control and Removal 2010, Part 6, page 197)

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Ice blasting is an excellent way to clean molds without removing the mold from the press. The concept of this process is similar to sand blasting, except the media used is small particles off dry ice. A block of dry ice is placed into a canisterand the apparatus shaves a layer of ice which is carried into the path of pressurized air and through a nozzle. The nozzle is pointed at a mold surface and the dry ice particles are cast with high pressure aire against the mold surface to aggressively remove stubborn deposits. The ice particles quickly dissolve into atmosphere with no residual harm to the environment and no clean up. Dry ice sublimates - transitions directly from a solid to a gas - at 109 F and at a rate of five to ten pounds every 24 hours.

Drawbacks to the method include the fact that the unit is extremely loud and requires ear protection. It is cumbersome to use because the hoses are large, making the nozzly difficult to articulate, and can be ineffective in deep undercuts and blind pockets.

(Stritzke B., Custom Molding of Thermoset Elastomers: A comprehensive approach to Materials, Mold Design and Processing, p. 81)

2-) Open Loop Control (control system)

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Every control system, including CNC systems, may be designed as either an open or a closed loop control system. Open-loop systems provide no check or measurement to modify orthat a specific position has actually been reached. No feed back information is passed from the machine tool back to the controller. Stepping motor-driven systems are examples of open-loop NC control. Open loop control provides relatively cheap solution to NC control systems, while closed-loop control is especially suited for varying load conditions and contouring control systems.

(Niebel B., Draper A., Wysk R., Modern Manufacturing Process Engineering,1989 ,p. 860)

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An open loop control system is one in which the control action is independent of the desired output. The actuating signal depends only on the input command and output has no control over it.

Two elements of an open loop control system can be usually divided into the following two parts.

i) Controller

ii) Controlled Process

An input signal or command is applied to the controller, whose output acts as the actuating signal, the actuating signal then controls the controlled process, so that the controlled variable will perform according to prescribed standarts.

In simple cases, the controller can be amplifier, mechanical linkage, filter or other control element, depending on the nature of the system. In more sophisticated cases the controller can be a computer such as a microprocessor.

Because of simplicity and economy of open-loop control systems we find this type of system in many non-critical applications.

(Rajput R.K., Manufacturing Technology ( Manufacturing Processes), p. 8)

3-) Production Flow Analysis (method)

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Production flow analysis lead an approach that is, parts also maybe classified by studying their production flow during the manufacturing cycle

(Kalpakjian S., Schmid S.R.,Manufacturing engineering and technology, 5th Edition, p 1211)

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Production Flow Analysis is a method for identifiying part families and associated groupings of machine tools. ıt does not use a classification and coding system and it does not use part drawings to identifiy families. Instead, PFA is used to analyze the operation sequence and machine routing for the parts produced in the given shop. It groups parts with identical or similiar routings together.

PFA Procedure:

1- Data Collection

2- Sorting of process routings.

3- PFA Chart

4- Analysis.

(Groover M.P., Automation, Production Systems, And Computer-Integrated Manufacturing, p 445)

4-) Flexible Fixturing (manufacturing)

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In describing workholding devices for the manufacturing operations throughout this book, the words clamp,jig, adn fixture often were used interchangeably and sometimes in pairs such as in jigs and fixtures.Clamps are simple multifunctional workholding devices and jigs have various reference surfaces and points for accurate alignment of parts or tools.Fixtures generally are designed for specific purposes.Other workholding devices also include chucks, collets, and mandrels, many of which usually are operated manually. Workholding devices are also are designed and operated at various levels of mechanization and automation and are driven by mechanical hydraulic or electrical means.Workholding devices generally have specific ranges of capacity.For example a particular collet can accomodate bars only within a certain range of diameters; four-jaw chucks can accomodate square or prismatic workpieces having certain dimensions; various other devices and fixtures are designed and made for specific workpiece shapes and dimensionsan for specific tasks called dedicated fixtures.If the part has curved surfaces, it is possible to shape the contacting surfaces of the jaws themselves by machining them to comfort to the workpiece surfaces.The emergence of flexible manufacturing systems has necessitated the design and use of workholding devices and fixtures which have built in flexibility.There are several methods of flexible fixturing based on different principles that also are called intelligent fixturing systems.These devices are capable of quickly accomodating a range of part shapes and dimensions without the necessity of extensive changes adjustments or requiring operator interventions both of which would affect productivity adversely.

(Serope Kalpakjian- Steven R. Schmid p:1176)

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In a manufacturing system, it is desirable that fixtures be flexible so that the turn -around time can be reduced. Flexible fixturing involves a design that allows rapid conversion of existing fixture designs into those that meet new production requirements with little changes of hardware and without extensive testing. Therefore, flexible fixturing may include flexible fixture hardware and fixture design and analysis software. The hardware may include modularized fixture systems for part families in customized mass productionand modular fixture systems for small volume production.

(Rong Y., Huang S.H., Hou Z., Advanced Computer Aided Fixture Design, p 94)

5-) End Effector (part)

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The end of wrist in a robot is equipped with an end effector which also is called end-of-arm tooling.Depending on the type of operation, conventional end effectors may be equipped with any of the following.
-Grippers, hooks, scoops, electromagnets, vacuum cups, and adhesive fingers for material handling.
-Spray guns for painting
-Attachments for spot and arc welding and for arc cutting
-Power tools ( such as drills, nut drivers, and burrs)
-Measuring instruments
End effectors generally are custom-made to meet specific handling requirements.Mechanical grippers are used to most commonly and are equipped with two or more fingers.Compliant end effectors are used to handle fragile materials or to facilitate assembly.These end effectors can use elastic mechanisms to limit the force which can be applied to the workpiece, or they can be designed with desired stiffness.



(Kalpakjian S., Schmid S.R.,Manufacturing engineering and technology, 1166)

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An End Effector is defined as the special device that attaches to the manipulator's wrist to enable the robot to accomplish a specific task. Because of the wide variations in tasks that are performed by industrial robots, the end effector must usually be custom engineered and fabricated for a specified job. In the case of a gripper the part shape and size will vary for different applications; this will influence the design of the gripper.

Tools and grippers are two general catagories of end effectors used in robotics. Tools are used in applications where the robot must perform some processing operation on the work part. Examples of the tools used as end effectors by robots to perform processing applications include:

Spot welding gun

Arc welding tool

Spray painting gun

Rotating spindle for drilling, routing, grinding, etc.

Assembly tool

Heating torch

Water-jet cutting tool

In each case the robot must not only control the relative position of the tool with respect to the work as a function of time, it must also control the operation of the tool. For this purpose, the robot must be able to transmit control signals to the tool for starting, stopping, and otherwise regulating its actions.

(Groover M.P., Automation, Production Systems, And Computer-Integrated Manufacturing, p 314)