İbrahim İLGÜZ 030040113 (5th week)

Hydraulic automation
Hydraulic systems have a significant advantage over pneumatic systems in their ability to handle higher loads and torques. Hydraulic oil is also practically incompressible. Hydraulic systems operate at significantly higher pressures ranging from 35 Mpa to 200 or more Mpa. This reduces the size of the actuators. Hydraulic systems require a power pack to supply pressurized oil of adequate quantity. As in pneumatic systems, the actuators are either motors or cylinders. The muscle power of hydraulic systems combined with the flexibility and ease of electrical and electronic control makes electro hydraulic systems an obvious choice even for very demanding applications. Industrial hydraulic systems use a wide variety of components like cylinders, rotary actuators, pumps, valves for the control of flow direction, volume, pressure etc, accumulators, filters and tubing.
( CAD/CAM/CIM, P. Radhakrishnan S. Subramanian V. Raju,p359)

POLLING (DATA TRANSFER TECHNIQUE)
A parallel interface is one that moves information 8 bits or more at a time. Centronics printer interface is a standard parallel interface. This interface allows data to be transferred to a printer, 8 bits at a time. Fig. 4.4 shows the timing diagram of a Centronics parallel interface. When the computer sends a byte of data to the printer it also sends a pulse down the strobe line. When the printer has read the data byte and is ready to accept another, it acknowledges that fact by sending back a pulse on the ACKNLG Line. IBM PC typically uses the BUSY line for handshaking in a polled mode. Polling means that computer hangs in a little loop, testing the line until the desired condition occurs. As soon as the BUSY Line goes low the PC’s ROM BIOS routine pulses the STROBE line low, telling the printer that a new byte is ready.
( CAD/CAM/CIM, P. Radhakrishnan S. Subramanian V. Raju,p84)

PUNCH PRESS(TURRET)
CNC has become very popular with punching and nibbling machine used for sheet
metal work. Many of these machines are equipped with a turret head. Such machines
are called turret punch presses. This machine is widely used in press shops. Main
application of the turret punch press is to cut various types of holes/openings in sheet metal for manufacturing machine frames or control cabinets out of sheet metal. Modular tooling systems available simplify tooling. Interactive programming facilities are available with the machine controls. Off line programming and simulation are adopted to utilize the machine fully and to obtain correct workpiece. Some of the turret punch presses have an additional plasma arc or a laser cutting head to generate contoured patterns. Some of the latest machines have automatic work handling, automatic tool change and automatic measuring systems interfaced with the machine. CNC has also been applied to other forming machines such as plate bending, tube bending, flow turning and stretch forming as well.
( CAD/CAM/CIM, P. Radhakrishnan S. Subramanian V. Raju,p369)

Parting Line
Sand casting can be used to make virtually any size part, and it basically involves making a pattern out of a suitable material (e.g., foam, wood, or metal) and packing sand around it. Parting lines are used to allow the sand mold components to be disassembled from around the pattern and then reassembled after the part is removed. Sand cores are often inserted into the mold to form cavities inside the mold (e.g., the cylinders of an engine casting). Regardless of the design of the part, one must also consider that as the metal cools it shrinks (on the order of 5 to 10% for most metals), and that in order to remove the part from the mold without breaking the mold, a taper (draft) of about 1:10 is required. In addition, extra metal should be added to surfaces that will have to be machined (a machining allowance), and locating surfaces should be added so that the part can be fixtured to facilitate machining. Thus in order to specify a casting, there are a few basic guidelines one needs to know in order to minimize the work that a professional mold design engineer has to do to clean up your design. These guidelines are discussed below.
(Mechanical Engineering Handbook, Ed. Frank Kreith Boca Raton: CRC Press LLC, 1999,sec11, p68)