Sunday, June 27, 2010

CATIA Tutorial for beginners

Here is the CATIA video tutorial for beginners

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CAD/CAM Related Career Paths

The following career paths are also pursued by persons interested
the field of CAD/CAM technology:

. Engineering
. Animation
. CAD/CAM software development
. CAD/CAM hardware development
. CAD/CAM software maintenance and troubleshooting
. CAD/CAM consulting services
. CAD/CAM instruction services
. CAD/CAM marketing and sales
. Simulation technology
. Robotics
. Digital art and advertising
. Internet development and consulting
. Cutting tool designer
. Architectural designer
. Rehabilitation technology
. Medical imaging systems
. Digital gaming and amusement systems

Wednesday, June 23, 2010

What Does a CAD/CAM Operator Do?

What Does a CAD/CAM Operator Do?

CAD operators are in demand in virtually every area of design.
A CAD operator with a backround in architectural design, for example,
would find employment in a firm that is involved in either residential or
commercial construction.
The operator would generate construction drawings on CAD from sketches and
specifications from the architect. All modifications, schedules and 3D
presentation models would also be created in CAD and plotted for the office and
the client.
The CAM operator, works with the production engineer to develop a process
plan or plan to manufacture a part. The operator then utilizes CAM software to
generate a set of instructions to the computer controlled manufacturing
machines. The operator takes care the process plan is adhered to when
generating the instructions. The CAM operator and production engineer
select the machine(s) and cutting tool(s) to be used in production

What Must a CAD/CAM Operator Know?

A CAD/CAM operator should be able to read and write well. A basic knowledge
of college level algebra , trigonometry, manual drafting practices, the Windows
operating system , 2D and 3D CAD, manual shop practices, production
processes, manual programming of computer controlled production machines as
well as using CNC software to program such machines is recommended.

How Does One Become a CAD/CAM Operator?

The optimum path to becoming a CAD/CAM operator is to seek the best
available training. Upon graduation from high school, students are encouraged to
enroll in a two year associate degree program with a concentration in CAD/CAM
technology. Graduates can then seek direct employment experience in the field
or go on to pursue a four year degree at a senior institution. They can also opt to
obtain work experience while they pursue a four year degree part time. Many
employers pay part of the expense for college level courses aimed at an employee’s
continued development.

Tuesday, June 15, 2010

CNC mill cutting a turbine blade



Milling the model turbine airfoil using homemade CNC machine with A axis. Its material is urethane foam.

Tuesday, June 8, 2010

Bench-top cnc machine image

5-axis machining

5 Axis Machining - For incredibly demanding machining of complex designs to execute a very accurate component. From Optical Switch to CT and MRI Scanner components. True 5 axis machining. CNC Machining - 3, 4 Axis machining services for close tolerance applications. While specialising in 5 Axis work, 4 Axis Milling for the truly discriminating needs of aerospace and fibre industries is offered. Precision Machining - Exacting tolerances of .00004” to .004” (one to one hundred microns). Unfortunately machining services for the automotive industry is not offered. Only ultra precision work. Wire EDM - The wire EDM department offers .001” dia wire cut with .0015” corner radii and a positional accuracy of ½ of a micron. (0.00002” or twenty millionths). Machine Shop - Machine shop is for precision machining but small parts only. Work Envelope Size: X:24", Y:14", Z:12" maximum. Micro Machining - Production of miniature components with micron tolerances is well within machining capabilities.


http://www.cncmachining.org/

Saturday, June 5, 2010

LATHE RELATED OPERATIONS

Boring.

Boring always involves the enlarging of an existing hole, which may have been made by a drill or may be the result of a core in a casting. An equally important, and concurrent, purpose of boring may be to make the hole concentric with the axis of rotation of the workpiece and thus correct any eccentricity that may have resulted from the drill's having drifted off the center line. Concentricity is an important attribute of bored holes. When boring is done in a lathe, the work usually is held in a chuck or on a face plate. Holes may be bored straight, tapered, or to irregular contours. Boring is essentially internal turning while feeding the tool parallel to the rotation axis of the workpiece.


Facing.

Facing is the producing of a flat surface as the result of a tool's being fed across the end of the rotating workpiece. Unless the work is held on a mandrel, if both ends of the work are to be faced, it must be turned end for end after the first end is completed and the facing operation repeated. The cutting speed should be determined from the largest diameter of the surface to be faced. Facing may be done either from the outside inward or from the center outward. In either case, the point of the tool must be set exactly at the height of the center of rotation. because the cutting force tends to push the tool away from the work, it is usually desirable to clamp the carriage to the lathe bed during each facing cut to prevent it from moving slightly and thus producing a surface that is not flat. In the facing of casting or other materials that have a hard surface, the depth of the first cut should be sufficient to penetrate the hard material to avoid excessive tool wear.




Parting.

Parting is the operation by which one section of a workpiece is severed from the remainder by means of a cutoff tool. Because cutting tools are quite thin and must have considerable overhang, this process is less accurate and more difficult. The tool should be set exactly at the height of the axis of rotation, be kept sharp, have proper clearance angles, and be fed into the workpiece at a proper and uniform feed rate.


Adjustable cutting factors in Machining

Speed, always refers to the spindle and the workpiece. When it is stated in revolutions per minute(rpm) it tells their rotating speed. But the important figure for a particular turning operation is the surface speed, or the speed at which the workpeece material is moving past the cutting tool. It is simply the product of the rotating speed times the circumference (in feet) of the workpiece before the cut is started. It is expressed in surface feet per minute (sfpm), and it refers only to the workpiece. Every different diameter on a workpiece will have a different cutting speed, even though the rotating speed remains the same.

Feed, always refers to the cutting tool, and it is the rate at which the tool advances along its cutting path. On most power-fed lathes, the feed rate is directly related to the spindle speed and is expressed in inches (of tool advance) per revolution ( of the spindle), or ipr. The figure, by the way, is usually much less than an inch and is shown as decimal amount.

Depth of Cut, is practically self explanatory. It is the thickness of the layer being removed from the workpiece or the distance from the uncut surface of the work to the cut surface, expressed in inches. It is important to note, though, that the diameter of the workpiece is reduced by two times the depth of cut because this layer is being removed from both sides of the work.


source : http://www.mfg.mtu.edu/marc/primers/index.html

What is Numerical Control ?

Numerical control (NC) is the operation of a machine tool by a series of coded
instructions consisting of numbers, letters of the alphabet, and symbols that the machine control
unit (MCU) can understand. These instructions are changed into electrical pulses of current that
the machine's motors and controls follow to carry out manufacturing operations on a workpiece.
The numbers, letters, and symbols are coded instructions that refer to specific distances,
positions, functions, or motions, that the machine tool can understand as it machines the
workpiece.

History

A form of NC was used in the early days of the industrial revolution, as early as 1725,
when knitting machines in England used punched cards to form various patterns in cloth. Even
earlier than this, rotating drums with prepositioned pins were used to control the chimes in
European cathedrals and some American churches. In 1863, the first player piano was patented;
it used punched paper rolls, through which air passed to automatically control the order in which
the keys were played.

The principle of mass production (interchangeable manufacture), developed by Eli
Whitney, transferred many operations and functions originally performed by skilled artisans to
the machine tool. As better and more precise machine tools were developed, the system of
interchangeable manufacture was quickly adopted by industry in order to produce large
quantities of identical parts. In the second half of the nineteenth century, a wide range of
machine tools were developed for the basic metal-cutting operations, such as turning, drilling,
milling, and grinding. As better hydraulic, pneumatic, and electronic controls were developed,
better control over the movement of machine slides became possible.

NC Evolves

In 1947, the U.S. Air Force found that the complex designs and shapes of aircraft parts
such as helicopter rotor blades and missile components were causing problems for
manufacturers, who could not keep up to projected production schedules. At this time, John
Parsons, of the Parsons Corporation, of Traverse City, Michigan, began experimenting with the
idea of making a machine tool generate a “thru-axis curve" by using numerical data to control
the machine tool motions. In 1949, the U.S. Air Material Command awarded Parsons a contract
to develop NC and in turn speed up production methods. Parsons subcontracted this study to the Servomechanism Laboratory of the Massachusetts Institute of Technology (MIT), which in 1952 successfully demonstrated a vertical spindle Cincinnati Hydrotel, which made parts through simultaneous three-axis cutting tool movements. In a very short period of time, almost all machine tool manufacturers were producing machines with NC.
At the 1960 Machine Tool Show in Chicago, over a hundred NC machines were
displayed. Most of these machines had relatively simple point-to-point positioning, but the
principle of NC was now firmly established. From this point, NC improved rapidly as the
electronics industry developed new products. At first, miniature electronic tubes were
developed, but the controls were big, bulky, and not very reliable. Then solid-state circuitry and,
eventually, modular, or integrated circuits were developed. The control unit became smaller,
more reliable, and less expensive. The development of even better machine tools and control
units helped spread the use of NC from the machine tool industry to all facets of manufacturing.

Data Processing

NC data processing (with numbers, letters, and symbols) is done in a computer or
machine control unit (MCU) by adding, subtracting, multiplying, dividing, and comparing. The
computer can be programmed to recognize an A command before a B command, an item 1
before an item 2, or any other elements in their sequential order. It is capable of handling
numbers very quickly; the addition of two simple numbers may take only one billionth of a
second (a nanosecond).

Thursday, June 3, 2010

Easy steps to program a cnc machine

7 Easy Steps to CNC Programming





as

Machine controller in CNC



MACHINE CONTROLLER converts the G CODES in to action , The controller interprets the signal from the Control Computer and instructs the machine to move using STEPPER MOTORS and/or SERVO MOTORS . MACHINE CONTROLLERS are build up off Micr-controllers, OP-AMPS, I/O PORTS etc.

Learn Basics of CNC programing - Video Tutorial

Learn Basics of CNC programing

CNC Programing Sample Problems

1.Write a part program to cut as shown in FIG-1




Ans :

N010 G90; PUT IN ABSOLUTE MODE

N011 G01 X1 Y2; MOVE TO (1.2)

N012 G01 X2 Y2; MOVE TO (2.2)

N013 G91; PUT IN INCREMENTAL MODE

N014 G01 X1; MOVE TO (3.2)

N015 G92 X2 Y2; SET NEW ORIGIN

N016 G01 X1 Y2; MOVE TO (3,3) ABSOLUTE

N017 G92 X0 Y0 Z0; RESET TO ZERO


refer G CODES

M CODES used in CNC

# M00 - program stop
# M01 - optional stop using stop button
# M02 - end of program
# M03 - spindle on CW
# M04 - spindle on CCW
# M05 - spindle off
# M06 - tool change
# M07 - flood with coolant
# M08 - mist with coolant
# M08 - turn on accessory #1 (120VAC outlet) (Prolight Mill)
# M09 - coolant off
# M09 - turn off accessory #1 (120VAC outlet) (Prolight Mill)
# M10 - turn on accessory #2 (120VAC outlet) (Prolight Mill)
# M11 - turn off accessory #2 (120VAC outlet) (Prolight Mill) or tool change
# M17 - subroutine end
# M20 - tailstock back (EMCO Lathe)
# M20 - Chain to next program (Prolight Mill)
# M21 - tailstock forward (EMCO Lathe)
# M22 - Write current position to data file (Prolight Mill)
# M25 - open chuck (EMCO Lathe)
# M25 - set output #1 off (Prolight Mill)
# M26 - close chuck (EMCO Lathe)
# M26 - set output #1 on (Prolight Mill)
# M30 - end of tape (rewind)
# M35 - set output #2 off (Prolight Mill)
# M36 - set output #2 on (Prolight Mill)
# M38 - put stepper motors on low power standby (Prolight Mill)
# M47 - restart a program continuously, or a fixed number of times (Prolight Mill)
# M71 - puff blowing on (EMCO Lathe)
# M72 - puff blowing off (EMCO Lathe)
# M96 - compensate for rounded external curves
# M97 - compensate for sharp external curves
# M98 - subprogram call
# M99 - return from subprogram, jump instruction
# M101 - move x-axis home (Prolight Mill)
# M102 - move y-axis home (Prolight Mill)
# M103 - move z-axis home (Prolight Mill)

G-CODES used in cnc

1. G00 - Rapid move (not cutting)
2. G01 - Linear move
3. G02 - Clockwise circular motion
4. G03 - Counterclockwise circular motion
5. G04 - Dwell
6. G05 - Pause (for operator intervention)
7. G08 - Acceleration
8. G09 - Deceleration
9. G17 - x-y plane for circular interpolation
10. G18 - z-x plane for circular interpolation
11. G19 - y-z plane for circular interpolation
12. G20 - turning cycle or inch data specification
13. G21 - thread cutting cycle or metric data specification
14. G24 - face turning cycle
15. G25 - wait for input #1 to go low (Prolight Mill)
16. G26 - wait for input #1 to go high (Prolight Mill)
17. G28 - return to reference point
18. G29 - return from reference point
19. G31 - Stop on input (INROB1 is high) (Prolight Mill)
20. G33-35 - thread cutting functions (Emco Lathe)
21. G35 - wait for input #2 to go low (Prolight Mill)
22. G36 - wait for input #2 to go high (Prolight Mill)
23. G40 - cutter compensation cancel
24. G41 - cutter compensation to the left
25. G42 - cutter compensation to the right
26. G43 - tool length compensation, positive
27. G44 - tool length compensation, negative
28. G50 - Preset position
29. G70 - set inch based units or finishing cycle
30. G71 - set metric units or stock removal
31. G72 - indicate finishing cycle (EMCO Lathe)
32. G72 - 3D circular interpolation clockwise (Prolight Mill)
33. G73 - turning cycle contour (EMCO Lathe)
34. G73 - 3D circular interpolation counter clockwise (Prolight Mill)
35. G74 - facing cycle contour (Emco Lathe)
36. G74.1 - disable 360 deg arcs (Prolight Mill)
37. G75 - pattern repeating (Emco Lathe)
38. G75.1 - enable 360 degree arcs (Prolight Mill)
39. G76 - deep hole drilling, cut cycle in z-axis
40. G77 - cut-in cycle in x-axis
41. G78 - multiple threading cycle
42. G80 - fixed cycle cancel
43. G81-89 - fixed cycles specified by machine tool manufacturers
44. G81 - drilling cycle (Prolight Mill)
45. G82 - straight drilling cycle with dwell (Prolight Mill)
46. G83 - drilling cycle (EMCO Lathe)
47. G83 - peck drilling cycle (Prolight Mill)
48. G84 - taping cycle (EMCO Lathe)
49. G85 - reaming cycle (EMCO Lathe)
50. G85 - boring cycle (Prolight mill)
51. G86 - boring with spindle off and dwell cycle (Prolight Mill)
52. G89 - boring cycle with dwell (Prolight Mill)
53. G90 - absolute dimension program
54. G91 - incremental dimensions
55. G92 - Spindle speed limit
56. G93 - Coordinate system setting
57. G94 - Feed rate in ipm (EMCO Lathe)
58. G95 - Feed rate in ipr (EMCO Lathe)
59. G96 - Surface cutting speed (EMCO Lathe)
60. G97 - Rotational speed rpm (EMCO Lathe)
61. G98 - withdraw the tool to the starting point or feed per minute
62. G99 - withdraw the tool to a safe plane or feed per revolution
63. G101 - Spline interpolation (Prolight Mill)

Computer Numerical Control

A computer controller is used to drive an NC machine directly. (more on Numerical Control ),

The need of CNC program is be able to direct the position of the cutting tool. As the tool moves we will cut metal (or perform other processes). I we plan to indicate positions we will need to coordinate systems. The coordinates are almost exclusively cartesian and the origin is on the workpiece.


Cartesian Coordinate System

Primitive people used their 10 fingers and 10 toes to count numbers and from this
evolved our present decimal, or Arabic system where "base ten," or the power of 10, is used to
signify a numerical value. Computers and MCUs, in contrast, use the binary or base 2 system to
recognize numerical values. Knowledge of the binary system is not essential for the programmer or operator since both the computer and the MCU can recognize standard decimal system and
convert it to binary data.

Almost everything that can be produced on a conventional machine tool can be produced
on a computer numerical control machine tool, with its many advantages. The machine tool
movements used in producing a product are of two basic types: point-to-point (straight-line
movements) and continuous path (contouring movements).

The mathematician and philosopher Rene Descartes invented the Cartesian or rectangular
coordinate system. With this system, any point can be located in mathematical terms from any
other point along three perpendicular axes. CNC systems use rectangular coordinates because
the programmer can locate every point on a job precisely and independently from each other.

Eg :-

1.



For a lathe, the infeed/radial axis is the x-axis, the carriage/length axis is the z-axis. There is no need for a y-axis because the tool moves in a plane through the rotational center of the work. Coordinates on the work piece shown below are relative to the work.

2.



For a tool with a vertical spindle the x-axis is the cross feed, the y-axis is the in-feed, and the z-axis is parallel to the tool axis (perpendicular to the table). Coordinates on the work piece shown below relative to the work.

3.



For a tool with a horizontal spindle the x-axis is across the table, the y-axis is down, and the z-axis is out. Coordinates on the work piece shown below relative to the work.



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The advantages of CNC machines are

1. They are located very close to machine tool

2. CNC allows storage/retrieval/entry of NC programs without preprocessing of NC code

3. CNC program is only entered into memory once, so it is more reliable

4. The programs can be tested and altered at the machine

5. Increased flexibility and control options on the local computer

6. Easy to integrate into FMS systems

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