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.).

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.

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

Paper Sizes

Paper size standards govern the size of sheets of paper used as writing paper, stationery, cards, and for some printed documents.

The ISO 216 standard, which includes the commonly used A4 size, is the international standard for paper size. It is used everywhere except in North America and parts of Latin America, where North American paper sizes such as "Letter" and "Legal" are used. The international standard for envelopes is the C series of ISO 269.

The standard for drawing sheet sizes is the A series. The basic size in this series is the A0 size (1189 mm x 841 mm) which has an area of about 1-m3. The sides of every size in the series are in the ratio Sq rt (2) = 1.414 : 1 and each size is half the area of the next larger size.

Drawing Sheet Size	Size in millimeters	Size in inches
A0	1189 x 841	46.81 x 33.11
A1	841 x 594	33.11 x 23.39
A2	594 x 420	23.39 x 16.55
A3	420 x 297	16.55 x 11.69
A4	297 x 210	11.69 x 8.27
A5	210 x 148	8.27 x 5.84
A6	148 x 105	5.84 x 4.13

Preferred Scales For Drawings...

The preferred scales are

1:1, 1:2, 1:5, 1:10, 1:20, 1:50, 1:100

• BS EN ISO 5457 Drawing Sheet Sizes

Designation	Trimmed Sheet		Drawing Space +/- 0.5 mm		Untrimmed Sheet +/- 2 mm
-	Width (mm)	Length (mm)	Width (mm)	Length (mm)	Width (mm)	Length (mm)
A0	841	1189	821	1159	880	1230
A1	594	841	574	811	625	880
A2	420	594	400	564	450	625
A3	297	420	277	390	330	450
A4	210	297	180	277	240	330