Key Tips for Improving Technical Drawing

8 Key Tips for Improving Engineering Drawing.

The following hints will assist the way to enhance your engineering drawing skills. This way, production engineers can without problems recognize the necessities of your additives.

 

Tip 1: Include Dimensions of Only Critical and Measurable Features.

In CNC machining, the 3-D version regularly includes all dimensions wished for production. Therefore, you ought to best encompass crucial threading records and crucial inspection dimensions in your mechanical drawing.

 

Tip 2: Add Hole Tapping Needs to Your Drawing.

It is regularly difficult to degree thread intensity exactly. Therefore, you ought to constantly tread the intensity call-out as a minimum.

 

Tip 3: Consolidate Call-Outs.

If there are multiples of the equal characteristic in a view, deliver a measurement of the best one of these functions. You can then label the measurement as “#X DIM”. This method that the characteristic exists with-inside the view X wide variety of instances. For example, in the “5X 10-38 TAP” method that there are five 10-38 threaded holes in that view.

 

Tip 4: Communicate Assembly Intent of Crucial Features.

If the manufacturing includes the machining of a whole meeting, you ought to encompass a meeting practice on your engineering drawing. Also, you may offer element numbers to your machinists to appearance up. This is specifically vital if you’re putting in off-the-shelf hardware yourself.

 

Tip 5: Part Numbers are Very Important.

In a case in which hardware setup is wished, the dealer and element-wide variety ought to be furnished at the drawing. Just noting “press-healthy M4 dowel” does now no longer deliver fabric records or system store dowel length.

 

Tip 6: No Need to Include Optional Secondary Operation Call-Outs.

For non-crucial operations along with sprucing and anodizing, you may go away from your mechanical drawing. It’s regularly fine to request rates and lead instances for those operations separately. This way, you may understand the extra fee and time. You also can go away the fabric from the drawing if you’re uncertain of the sort of fabric to use. This will assist save you confusion on exceptional levels.

 

Tip 7: Avoid Over-Dimension or Over-Tolerance on Your Designs.

Usually, only a few of the functions of additives are vital to their function. Therefore, you'll need the machinist to recognition greater on those functions. Over-measurement may want to lose crucial functions with-inside the noise. It is, therefore, vital to assign tolerances to best function-crucial functions.

 

Tip 8: Tolerance Must Fall Within Standard Accuracy Levels.

It is vital that you deliver the proper degree of tolerance to your fabric. Do now no longer require tolerance that falls underneath the accuracy abilities of popular hand metrology tools. Therefore, you ought to study the commenced measurements used at your selected system store. This will assist you are making knowledgeable decisions.

 

Conclusion

 

Engineering drawing stays a large issue of a machinist’s job. These drawings make a contribution of as much as 20% of layout work time. This allows us to absolutely seize all of the geometric capabilities of products and their components. That way, you could ensure that producers can produce components that meet precise needs.

At Rapid Direct, we are trying to find to save time with the aid of using automating 3-D model studying for manufacturing purposes. This leaves engineers with the obligation to provide GD&T and meeting drawings only. The intention of this technique is to assist our consciousness of the production of higher products.

We boast strong production talents with offerings in an effort to meet your custom-designed requirements. We assist optimize your component layout and the usage of the maximum sturdy equipment to be had. All you need to do is upload your layout file, and you’ll get an immediate quote. These and lots of greater ones are to be had at competitive prices.

 

Geometric Dimension and Tolerance

Geometric Dimension and Tolerance (GD&T)

is a framework for characterizing and imparting designing resistances. It utilizes emblematic language on designing drawings and PC created three-dimensional strong models that unequivocally depict ostensible math and its reasonable variety. It tells the assembling staff and machines what level of exactness and accuracy is required on each controlled component of the part. GD&T is utilized to characterize the ostensible (hypothetically great) math of parts and congregations, to characterize the suitable variety in structure and conceivable size of individual highlights, and to characterize the permissible variety between highlights.

• Measurement details characterize the ostensible, as-displayed or as-expected math. One model is a fundamental measurement.

• Resistance details characterize the reasonable variety for the structure and perhaps the size of individual highlights, and the admissible variety in direction and area between highlights. Two models are direct measurements and highlight control outlines utilizing a datum reference (both appeared previously).

There are several standards available worldwide that describe the symbols and define the rules used in GD&T. One such standard is American Society of Mechanical Engineers (ASME) Y14.5. This article is based on that standard, but other standards, such as those from the International Organization for Standardization (ISO), may vary slightly. The Y14.5 standard has the advantage of providing a fairly complete set of standards for GD&T in one document. The ISO standards, in comparison, typically only address a single topic at a time. There are separate standards that provide the details for each of the major symbols and topics below (e.g. position, flatness, profile, etc.).

Standard NC Programming Codes

 NC Programming Code

G00                       Rapid traverse

G01                       Linear interpolation

G02/G03               Circular interpolation

G04                       Dwell

G07                       Tangential circle interpolation

G08/G09               Path control mode (ramp at block transitions) and "Adaptive Look ahead" function
G10/G11               Block per-processing control

G12/G13               Circular interpolation with radius input

G17-G20               Plane selection

G33                       Thread cutting/rigid tapping

G36/G37               Programmable feed rate limitation

G38/G39               Mirror image

G40-G44               Tool radius compensation

G50                       Scaling

G51/G52               Part rotation

G53-G59               Zero offsets

G63/G66               Programmable feed rate/spindle speed override

G70/G71               Inch/metric dimension

G72/G73               Interpolation with in position stop

G74                       Home position

G80-G89               Canned cycles

G90/G91               Absolute/incremental programming

G92                       Position register preset

G94/G95               Feed rate

G160-G164           ART learning function

G186                     Programmable tolerance band

M00                       Program stop

M01                       Optional stop

M02/M30               End of program

M03/M04/M05       Spindle control (cw/ccw/stop)

M06                       Tool change (M-code depends on PLC)

M19                       Spindle orientation

M40-M46               Spindle gear transmission steps

All of the machine-specific functions have the M-code value configured in the PLC application.  Some of the M-codes, like M06 for a tool change and M07-M09 for coolant control, have typical assignments in many controls.  However this control does not require specific assignments.  Therefore, a machine function like the tool change does not have to be M06. The spindle control M-codes (3-5, 19, 40-46) also have configurable assignments.

Riveted Joints

Rivets are a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the buck-tail. On installation the rivet is placed in a punched or drilled hole, and the tail is upset, or bucked (i.e., deformed), so that it expands to about 1.5 times the original shaft diameter, holding the rivet in place. To distinguish between the two ends of the rivet, the original head is called the factory head and the deformed end is called the shop head or buck-tail.

 

Because there is effectively a head on each end of an installed rivet, it can support tension loads (loads parallel to the axis of the shaft); however, it is much more capable of supporting shear loads (loads perpendicular to the axis of the shaft). Bolts and screws are better suited for tension applications.

Fastenings used in traditional wooden boat building, such as copper nails and clinch bolts, work on the same principle as the rivet but were in use long before the term rivet was introduced and, where they are remembered, are usually classified among nails and bolts respectively.

Advantages And Disadvantages Of CNC

CNC Computer Numerical Control machines are widely used in manufacturing industry. Traditional machines such as vertical millers, center lathes, shaping machines, routers etc.... operated by a trained engineer have, in many cases, been replaced by computer control machines

Advantages

1. CNC machines can be used continuously 24 hours a day, 365 days a year and only need to be switched off for occasional maintenance.
2. CNC machines are programmed with a design which can then be manufactured hundreds or even thousands of times. Each manufactured product will be exactly the same.
3. Less skilled/trained people can operate CNCs unlike manual lathes / milling machines etc.. which need skilled engineers.
4. CNC machines can be updated by improving the software used to drive the machines.
5. Training in the use of CNCs is available through the use of ‘virtual software’. This is software that allows the operator to practice using the CNC machine on the screen of a computer. The software is similar to a computer game.
6. CNC machines can be programmed by advanced design software such as Pro/DESKTOP^®, enabling the manufacture of products that cannot be made by manual machines, even those used by skilled designers / engineers.
7. Modern design software allows the designer to simulate the manufacture of his/her idea. There is no need to make a prototype or a model. This saves time and money.
8. One person can supervise many CNC machines as once they are programmed they can usually be left to work by themselves. Sometimes only the cutting tools need replacing occasionally.
9. A skilled engineer can make the same component many times. However, if each component is carefully studied, each one will vary slightly. A CNC machine will manufacture each component as an exact match.

Disadvantages

1. CNC machines are more expensive than manually operated machines, although costs are slowly coming down.
2. The CNC machine operator only needs basic training and skills, enough to supervise several machines. In years gone by, engineers needed years of training to operate centre lathes, milling machines and other manually operated machines. This means many of the old skills are been lost.
3. Less workers are required to operate CNC machines compared to manually operated machines. Investment in CNC machines can lead to unemployment.
4. Many countries no longer teach pupils / students how to use manually operated lathes / milling machines etc... Pupils / students no longer develop the detailed skills required by engineers of the past. These include mathematical and engineering skills.

CNC G Code

G-Codes Simple Definition

G00     Rapid traverse
G01     Linear interpolation with feedrate
G02     Circular interpolation (clockwise)
G03     Circular interpolation (counter clockwise)
G2/G3   Helical interpolation
G04     Dwell time in milliseconds
G05     Spline definition
G06     Spline interpolation
G07     Tangential circular interpolation / Helix interpolation / Polygon interpolation /             Feedrate interpolation
G08     Ramping function at block transition / Look ahead "off"
G09     No ramping function at block transition / Look ahead "on"
G10     Stop dynamic block preprocessing
G11     Stop interpolation during block preprocessing
G12     Circular interpolation (cw) with radius
G13     Circular interpolation (ccw) with radius
G14     Polar coordinate programming, absolute
G15     Polar coordinate programming, relative
G16     Definition of the pole point of the polar coordinate system
G17     Selection of the X, Y plane
G18     Selection of the Z, X plane
G19     Selection of the Y, Z plane
G20     Selection of a freely definable plane
G21     Parallel axes "on"
G22     Parallel axes "off"
G24     Safe zone programming; lower limit values
G25     Safe zone programming; upper limit values
G26     Safe zone programming "off"
G27     Safe zone programming "on"
G33     Thread cutting with constant pitch
G34     Thread cutting with dynamic pitch
G35     Oscillation configuration
G38     Mirror imaging "on"
G39     Mirror imaging "off"
G40     Path compensations "off"
G41     Path compensation left of the work piece contour
G42     Path compensation right of the work piece contour
G43     Path compensation left of the work piece contour with altered approach
G44     Path compensation right of the work piece contour with altered approach
G50     Scaling
G51     Part rotation; programming in degrees
G52     Part rotation; programming in radians
G53     Zero offset off
G54     Zero offset #1
G55     Zero offset #2
G56     Zero offset #3
G57     Zero offset #4
G58     Zero offset #5
G59     Zero offset #6
G63     Feed / spindle override not active
G66     Feed / spindle override active
G70     Inch format active
G71     Metric format active
G72     Interpolation with precision stop "off"
G73     Interpolation with precision stop "on"
G74     Move to home position
G75     Curvature function activation
G76     Curvature acceleration limit
G78     Normalcy function "on" (rotational axis orientation)
G79     Normalcy function "off"

G80 - G89 for milling applications:
G80     Canned cycle "off"
G81     Drilling to final depth canned cycle
G82     Spot facing with dwell time canned cycle
G83     Deep hole drilling canned cycle
G84     Tapping or Thread cutting with balanced chuck canned cycle
G85     Reaming canned cycle
G86     Boring canned cycle
G87     Reaming with measuring stop canned cycle
G88     Boring with spindle stop canned cycle
G89     Boring with intermediate stop canned cycle

G81 - G88 for cylindrical grinding applications:

G81     Reciprocation without plunge
G82     Incremental face grinding
G83     Incremental plunge grinding
G84     Multi-pass face grinding
G85     Multi-pass diameter grinding
G86     Shoulder grinding
G87     Shoulder grinding with face plunge
G88     Shoulder grinding with diameter plunge
G90     Absolute programming
G91     Incremental programming
G92     Position preset
G93     Constant tool circumference velocity "on" (grinding wheel)
G94     Feed in mm / min (or inch / min)
G95     Feed per revolution (mm / rev or inch / rev)
G96     Constant cutting speed "on"
G97     Constant cutting speed "off"
G98     Positioning axis signal to PLC
G99     Axis offset
G100   Polar transformation "off"
G101   Polar transformation "on"
G102   Cylinder barrel transformation "on"; cartesian coordinate system
G103   Cylinder barrel transformation "on," with real-time-radius compensation         (RRC)
G104   Cylinder barrel transformation with center line migration (CLM) and RRC
G105   Polar transformation "on" with polar axis selections
G106   Cylinder barrel transformation "on" polar-/cylinder-coordinates
G107   Cylinder barrel transformation "on" polar-/cylinder-coordinates with RRC
G108   Cylinder barrel transformation polar-/cylinder-coordinates with CLM and         RRC
G109   Axis transformation programming of the tool depth
G110   Power control axis selection/channel 1
G111   Power control pre-selection V1, F1, T1/channel 1 (Voltage, Frequency, Time)
G112   Power control pre-selection V2, F2, T2/channel 1
G113   Power control pre-selection V3, F3, T3/channel 1
G114   Power control pre-selection T4/channel 1
G115   Power control pre-selection T5/channel 1
G116   Power control pre-selection T6/pulsing output
G117   Power control pre-selection T7/pulsing output
G120   Axis transformation; orientation changing of the linear interpolation rotary     axis
G121   Axis transformation; orientation change in a plane
G125   Electronic gear box; plain teeth
G126   Electronic gear box; helical gearing, axial
G127   Electronic gear box; helical gearing, tangential
G128   Electronic gear box; helical gearing, diagonal
G130   Axis transformation; programming of the type of the orientation change
G131   Axis transformation; programming of the type of the orientation change
G132   Axis transformation; programming of the type of the orientation change
G133   Zero lag thread cutting "on"
G134   Zero lag thread cutting "off"
G140   Axis transformation; orientation designation work piece fixed coordinates
G141   Axis transformation; orientation designation active coordinates
G160   ART activation
G161   ART learning function for velocity factors "on"
G162   ART learning function deactivation
G163   ART learning function for acceleration factors
G164   ART learning function for acceleration changing
G165   Command filter "on"
G166   Command filter "off"
G170   Digital measuring signals; block transfer with hard stop
G171   Digital measuring signals; block transfer without hard stop
G172   Digital measuring signals; block transfer with smooth stop
G175   SERCOS-identification number "write"
G176   SERCOS-identification number "read"
G180   Axis transformation "off"
G181   Axis transformation "on" with not rotated coordinate system
G182   Axis transformation "on" with rotated / displaced coordinate system
G183   Axis transformation; definition of the coordinate system
G184   Axis transformation; programming tool dimensions
G186   Look ahead; corner acceleration; circle tolerance
G188   Activation of the positioning axes
G190   Diameter programming deactivation
G191   Diameter programming "on" and display of the contact point
G192   Diameter programming; only display contact point diameter
G193   Diameter programming; only display contact point actual axes center point
G200   Corner smoothing "off"
G201   Corner smoothing "on" with defined radius
G202   Corner smoothing "on" with defined corner tolerance
G203   Corner smoothing with defined radius up to maximum tolerance
G210   Power control axis selection/Channel 2
G211   Power control pre-selection V1, F1, T1/Channel 2
G212   Power control pre-selection V2, F2, T2/Channel 2
G213   Power control pre-selection V3, F3, T3/Channel 2
G214   Power control pre-selection T4/Channel 2
G215   Power control pre-selection T5/Channel 2
G216   Power control pre-selection T6/pulsing output/Channel 2
G217   Power control pre-selection T7/pulsing output/Channel 2
G220   Angled wheel transformation "off"
G221   Angled wheel transformation "on"
G222   Angled wheel transformation "on" but angled wheel moves before others
G223   Angled wheel transformation "on" but angled wheel moves after others
G265   Distance regulation – axis selection
G270   Turning finishing cycle
G271   Stock removal in turning
G272   Stock removal in facing
G274   Peck finishing cycle
G275   Outer diameter / internal diameter turning cycle
G276   Multiple pass threading cycle
G310   Power control axes selection /channel 3
G311   Power control pre-selection V1, F1, T1/channel 3
G312   Power control pre-selection V2, F2, T2/channel 3
G313   Power control pre-selection V3, F3, T3/channel 3
G314   Power control pre-selection T4/channel 3
G315   Power control pre-selection T5/channel 3

G316   Power control pre-selection T6/pulsing output/Channel 3
G317   Power control pre-selection T7/pulsing output/Channel 3

Note that some of the above G-codes are not standard. Specific control features, such as laser power control, enable those optional codes. 

CNC ALPHABET

• A

Absolute or incremental position of A axis (rotational axis around X axis)

• B

Absolute or incremental position of B axis (rotational axis around Y axis)

• C

Absolute or incremental position of C axis (rotational axis around Z axis)

• D

Defines diameter or radial offset used for cutter compensation. D is used for depth of cut on lathes.

• E

Precision feedrate for threading on lathes

• F

Defines feed rate Common units are distance per time for mills (inches per minute, IPM, or millimetres per minute, mm/min) and distance per revolution for lathes (inches per revolution, IPR, or millimetres per revolution, mm/rev)

• G

Address for preparatory commands G commands often tell the control what kind of motion is wanted (e.g., rapid positioning, linear feed, circular feed, fixed cycle) or what offset value to use.

• H

Defines tool length offset; Incremental axis corresponding to C axis (e.g., on a turn-mill)

• I

Defines arc center in X axis for G02 or G03 arc commands. Also used as a parameter within some fixed cycles.

• J

Defines arc center in Y axis for G02 or G03 arc commands. Also used as a parameter within some fixed cycles.

• K

Defines arc center in Z axis for G02 or G03 arc commands. Also used as a parameter within some fixed cycles, equal to L address.

• L

Fixed cycle loop count; Specification of what register to edit using G10 Fixed cycle loop count: Defines number of repetitions ("loops") of a fixed cycle at each position. Assumed to be 1 unless programmed with another integer. Sometimes the K address is used instead of L. With incremental positioning ( G91), a series of equally spaced holes can be programmed as a loop rather than as individual positions. G10 use: Specification of what register to edit (work offsets, tool radius offsets, tool length offsets, etc.).

• M

Miscellaneous function Action code, auxiliary command; descriptions vary. Many M-codes call for machine functions, which is why people often say that the "M" stands for "machine", although it was not intended to.

• N

Line (block) number in program; System parameter number to be changed using G10 Line (block) numbers: Optional, so often omitted. Necessary for certain tasks, such as M99 P address (to tell the control which block of the program to return to if not the default one) or G.T. statements (if the control supports those). N numbering need not increment by 1 (for example, it can increment by 10, 20, or 1000) and can be used on every block or only in certain spots throughout a program. System parameter number: G10 allows changing of system parameters under program control.

• O

Program name For example, O4501. For many years it was common for CNC control displays to use slashed zero glyphs to ensure effortless distinction of letter "O" from digit "0". Today's GUI controls often have a choice of fonts, like a PC does.

• P

Serves as parameter address for various G and M codes With G04, defines dwell time value. Also serves as a parameter in some canned cycles, representing dwell times or other variables. Also used in the calling and termination of subprograms. (With M98 , it specifies which subprogram to call; with M99, it specifies which block number of the main program to return to.)

• Q

Peck increment in canned cycles. For example, G73 , G83 (peck drilling cycles)

• R

Defines size of arc radius, or defines retract height in milling canned cycles For radiuses, not all controls support the R address for G02 and G03, in which case IJK vectors are used. For retract height, the "R level", as it's called, is returned to if G99 is programmed.

• S

Defines speed , either spindle speed or surface speed depending on mode Data type = integer. In G97 mode (which is usually the default), an integer after S is interpreted as a number of rev/min (rpm). In G96 mode (CSS), an integer after S is interpreted as surface speed —sfm ( G20 ) or m/min (G21 ). See also Speeds and feeds . On multifunction (turn-mill or mill-turn) machines, which spindle gets the input (main spindle or subspindles) is determined by other M codes.

• T

Tool selection To understand how the T address works and how it interacts (or not) with M06 , one must study the various methods, such as lathe turret programming, ATC fixed tool selection, ATC random memory tool selection, the concept of "next tool waiting", and empty tools. Programming on any particular machine tool requires knowing which method that machine uses. Ways of obtaining this training are mentioned in the comments for M06.

• U

Incremental axis corresponding to X axis (typically only lathe group A controls) Also defines dwell time on some machines (instead of " P " or " X "). In these controls, X and U obviate G90 and G91 , respectively. On these lathes, G90 is instead a fixed cycle address for roughing .

• V

Incremental axis corresponding to Y axis Until the 2000s, the V address was very rarely used, because most lathes that used U and W didn't have a Y- axis, so they didn't use V. (Green et al. 1996 did not even list V in their table of addresses.) That is still often the case, although the proliferation of live lathe tooling and turn-mill machining has made V address usage less rare than it used to be. See also G18 .

• W

Incremental axis corresponding to Z axis (typically only lathe group A controls) In these controls, Z and W obviate G90 and G91 , respectively. On these lathes, G90 is instead a fixed cycle address for roughing .

• X

Absolute or incremental position of X axis. Also defines dwell time on some machines (instead of " P " or " U ").

• Y

Absolute or incremental position of Y axis

• Z

Absolute or incremental position of Z axis The main spindle's axis of rotation often determines which axis of a machine tool is labeled as Z.

Computer Aided Drafting And Design (CADD)

Definition

Computer Aided Drafting And Design (CADD) is the computer process of making engineering drawing and technical documents more closely related to drafting.

• What is CADD ?

Computer Aided Drawing is a technique where engineering drawings are produced with the assistance of computer and, as with manual drawing, is only the graphical means of representing a design.
Computer Aided Design, however, is a technique where the attributes of the computer and those of the designer are blended together into a problem solving term.

• Two Dimensional (2D) CAD

Computer drawing is the representation of an object in the single view format which shows two of the three object dimensions or the multi view format where each view reveals two dimensions.

 

• Three Dimensional (3D) CAD

Computer drawing is the coordinate format. Three dimensional computer aided drawing allows the production of geometric models of a component or product for spatial and visual analysis.

• Advantages Of CADD

• Drafting Stage

1. Increased accuracy
2. Increased drawing speed
3. Easy to revise
4. Availability of drawing libraries
5. Constant drawing quality
6. Multicolor drawing
7. Built in several analysis tools
8. Better presentation (Easy To Visualize)-Pan, Rotate, Animate, Shade, Texture
9. Save on repetition

• CADD Capability

1. Draw
2. Modify
3. Dimension
4. Object snap
5. Layer concept

• Concepts In Working Drawing Creation

2-D CADD

• Draw a group of line that are connected and present

- Orthographic multiview

- Pictorial view

Solid Modeling

• Draw a closed contour and convert to surface.
• Modify this surface to solid object.
• Create an orthographic view from a solid object.

• Limitation Of CADD

Good engineering drawing must have the following characteristics.

• Part or product information is completely given.
• Information is clearly presented.
• Information can be used in manufacturing of part.

Always remind yourself that

"Good drawing cannot be created by using CADD software alone without understanding the drawing concept." 

• Limitation Of CADD (with in scope of drawing creation)

To create a good engineering drawings You must do the following tasks yourself.

1. Apply a proper line weight and style.
2. Select a necessary view.
3. Decide the appropriate places of dimensions.
4. Select an appropriate section techniques.

• Limitation Of CADD (with in scope of drawing interpretation)

No CADD software can create a pictorial view from an orthographic multiview.

Because they are frequently used technical document. Therefore,You must prepare your self for interpreting (or visualizing) them when you become an Engineer.

• Modern System In CADD

Tn modern system the light pen has been replaced by more effective pointing hardware, that is a digitizer tablet, a mouse.

CADD System And Hardware

1. The mainframe computer
2. The minicomputer
3. The Microcomputer

Input Devices

The input devices are used for making selections from a menu, which is a layout of a variety of commands and functions required to operate the system. Sending these command into the computer produces complete engineering drawing.

• Modern System In CADD

1. Impact printer (dot matrix)
2. Non-impact printer include electrostatic, ink-jet and laser
3. Flatbed plotters
4. Drum plotters

• User Interface

CAD systems may be considered as comprising a large number of functions for creating or manipulating the design model. Traditionally, there are two ways in which this is achieved:

Command-based systems

Command-based systems operate by reading a command and its parameters entered by the user, carrying out the required actions, then waiting for the next command.

• User Interface – Menu Driven

The menu-driven approach contrasts markedly with the command

approach. The basic principle is that the user is at any time

presented with a list or menu of the functions that are available

to be selected.

Rules

• The most important of these rules are:
• A clear, well presented screen layout.
• Easy function selection by a well-structured menu system.
• Meaningful function names.
• Meaningful and helpful prompts to the user.
• Easily accessible and clearly written help information.

• CADD Functionality

The main benefits of a computerized drafting and design system over those of manual methods is this ability to represent the design of a component or assembly in a geometrically accurate format so that the same model can be used for other modelling, analysis and manufacturing work.

The functions can be said to fall into three categories:

• Synthesis type functions are concerned mainly with the creation of geometric features and drawing details.
• Modification functions include those which allow for the deletion and editing of existing geometry or detail.
• Management functions are concerned with how the drawing is presented both on the screen and eventually on paper.

• CADD System Selection

There is a large variety of different CADD packages available on the market these days and the design manager is faced with the enormous problem of selecting a package to suit the demands

of the company and its product range. A lot of ease and efficiency has been obtained with the use of CADD systems. Among the more widely used CAD systems are AutoCAD, CATIA, SolidWorks, I-DEAS, and ProEngineer. Most of these packages have both a 2D and 3D component or have an integrated 2D and 3D modeling system. The newer versions of drawing software operate under a menu system which can be accessed through keyboard input or mouse manipulation.

• CADD System Selection

According to these factors, the system must have;

• Functional abilities: the abilities to perform memory circuits.
• Memory capacity : evaluation between main and branch memory circuits.
• Data transfer characteristics : when we consider data transfer between two computers, or a main computer and a station, we have to keep in mind the need to decrease computing time

• CADD System Selection

The size of the company and the amount of investment capital available will be one of the main deciding factors but there are many other questions to be considered:

Mainframe or PC/workstation platform?

Two dimensions or three? Lines, surfaces or solids?

Other analysis tools needed? Will the ability to transfer the

geometry to these modelling and analysis systems be needed?

Compatibility with other systems needed?

How good is the maintenance and support from the suppliers?

How much, how good and how long is the training?

How easy is it to expand the system?

• AutoCAD

AutoCAD is PCbased

CAD software products (late 1982).

System Requirements for AutoCAD

Windows NT or Windows 95/98/2000

Intel 486 or Pentium processor or compatible

32 MB of RAM

50 MB of hard disk space

64MB of disk swap space

2.5 MB of free disk space during installation only

CD-ROM drive

640 x 480 VGA video display (1024 x 768 recommended)

Windows-supported display adapter

Mouse or other pointing device