Assignment 02

Assignment no.2

ROOH UL AMIN

REG NO: A1EWT-216005

SUBJECT: “PRODUCTION AUTOMATION”

PROGRAMM: B.TECH (Mech) 4 YEAR (WEEKEND)

SEMESTER: SUMMER 2016

PIMSAT KARACHI

Application of CNC in automation industry

“Two discussions”

What is the CNC?

CNC Machining is a process used in the manufacturing sector that involves the use of computers to control machine tools.

Tools that can be controlled in this manner include lathes, mills, routers and grinders. The CNC in CNC Machining stands for Computer Numerical Control.  Industrial automation and the control of its tools are provided by Computer Numerical Controls (CNC). CNC provides fast, precise and reliable manufacturing methods – a requirement that has grown proportionately with the rising complexity of modern industrial fabrication. Even common consumer gadgets such as smartphones and home computers require a level of sophistication to manufacture not seen a few decades ago.

CNC Control MechanismCNC machines require programmed instructions in order for them to

function. These highly –automated instructions for the manufacturing process are made using Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) software. The instructions are then loaded into the CNC machine and govern its control.

The motions of a CNC machine are moved along at least two axes, vertically (Y) and horizontally(X). A tool spindle provides depth of movement called the Z-axis. Movement is provided by Stepper motors or servo motors. Stepper motors function through powerful electromagnets. When a Direct-Current (DC) charge is pulsed the motor’s electromagnets turn on the magnets pull on the gears, moving it. CNC-controlled machines are very precise and reliable. They are used in a wide variety of industrial automation solutions including welding, laser cutting, friction stir welding, ultrasonic welding, flame and plasma cutting, spinning, bending, gluing, fabric cutting, tape and fiber placement, routing, picking and placing, sawing, hole-punching, pinning, sewing and picking and placing.

Types of CNC Machines

CNC Milling machine

CNC Lathes

CNC Plasma Cutters

Electrical Discharge Machining (EDM)

Water Jet Cutter etc.

CNC milling machineCNC milling is a specific form of computer numerical controlled (CNC)

machining. Milling itself is a machining process similar to both drilling and cutting, and able to achieve many of the operations performed by cutting and drilling machines. Like drilling, milling uses a rotating cylindrical cutting tool.However, the cutter in a milling machine is able to move along multiple axes, and can create a variety of shapes, slots and holes. In addition, the work-piece is often moved across the milling tool in different directions, unlike the single axis motion of a drill.

CNC milling devices are the most widely used type of CNC machine. Typically, they are grouped by the number of axes on which they operate, which are labeled with various letters.

1. X and Y Group2. Z Group3. W Group

1. X and Y Group

X and Y designate horizontal movement of the work-piece.

(Forward-and-back and side-to-side on a flat plane).

2. Z Group

Z represents vertical, or up-and-down, movement.

3. W Group

W represents diagonal movement across a vertical plane.

Most machines offer from 3 to 5 axes, providing performance along at least the X, Y and Z axes. Advanced machines, such as 5-axis milling centers, require CAM programming for optimal performance due to the incredibly complex geometries involved in the machining process. These devices are extremely useful because they are able to produce shapes that would be nearly impossible using manual tooling methods. Most CNC milling machines also integrate a device for pumping cutting fluid to the cutting tool during machining.

Virtually every type of material that can be drilled or cut can be machined by a CNC mill, although most of the work performed is done in metal. As with drilling and cutting, the proper machine tools must be selected for each material in order to avert potential problems. The hardness of the work-piece material, as well as the rotation of the cutting tool must all be factored before beginning the machining process.

CNC milling machine

CNC lathe / CNC turning center

What Is Lathe?

A lathe machine is a mechanical device in which the work piece is rotated against a suitable cutting tool for producing cylindrical forms in the metal, wood or any other machinable material.

Or

Lathe is a machine that helps in shaping several material pieces in the desired shapes. A lathe is a machine that rotates the piece on the axis in order to perform various operations like cutting, facing, knurling, deformation and more. Metal spinning, thermal spraying, woodturning and metalworking are the common operations performed with a lathe machine.

Computer numerical controlled (CNC) lathes are rapidly replacing the older production lathes (multispindle, etc.) due to their ease of setting, operation, repeatability and accuracy. They are designed to use modern carbide tooling and fully use modern processes. The part may be designed and the tool paths programmed by the CAD/CAM process or manually by the programmer and the resulting file uploaded to the machine, and once set and trailed the machine will continue to turn out parts under the occasional supervision of an operator.

The machine is controlled electronically via a computer menu style interface; the program may be modified and displayed at the machine, along with a simulated view of the process.

The setter/operator needs a high level of skill to perform the process, however the knowledge base is broader compared to the older production machines where intimate knowledge of each machine was considered essential. These machines are often set and operated by the same person, where the operator will supervise a small number of machines.

The design of a CNC lathe varies with different manufacturers, but they all have some common elements.

1. The turret2. The spindle

1. The turretThe turret holds the tool holders and indexes them as needed,

2. The spindle The spindle holds the workpiece and there are slides that let the turret

move in multiple axes simultaneously.

The machines are often totally enclosed, due in large part to occupational health and safety (OH&S) issues.

With rapid growth in this industry, different CNC lathe manufacturers use different user interfaces which sometimes make it difficult for operators as they have to be acquainted with them. With the advent of cheap computers, free operating systems such as Linux, and open source CNC software, the entry price of CNC machines has plummeted.

CNC lathe / CNC turning center