ITEC 103-1
assembly drawings
- shows how each part of a design is put together - can be pictorial drawing or orthographic drawings - can be exploded or not
cutting plane line
- thick, dark line composed of a long dash, two short dashes and a long dash - optional cutting plane line can be used - short perpendicular lines with arrowheads pointing away from the line are added to each end to indicate the viewing direction or line of sight -arrows should point away from the view sectioned
detail drawings
-each nonstandard part will receive a detail drawing showing how the part looks when completed - it completely describes the part giving everything one needs to make it, including shape, size, material, finish - the part number followed by the part name is given below each detail drawing - detail drawings are not needed for standard parts such as screws, threaded fasteners, bushing, bearings
Lettering(Drawing)
.13" or 1/8"
Lettering(Title)
.25" or 1/4"
Characteristics of good sketching
1. Neat 2. Dark 3. Proportionate 4. Complete Data Labeling
Steps for Successful Freehand Sketching
1. Pencil-in lightly main overall shape 2. Pencil-in lightly main detail locations 3. Refine/darken details 4. Darken all important lines (clean the sketch) 5. Add dimension lines, supporting text, symbols, etc.
Dodecagon
12 sided, 15 degrees
oblique
2D rolled out to 3D. 45 degrees (one direction) circles and arcs are truly circular in the frontal view
EQ Triangle
3 sided, 120 degrees
Partial auxiliary
3 view with 4th view coming off the incline in the front view (90 degrees from surface)
isometric
3D 30 degrees (both direction) ellipses are used
Square
4 sided, 90 degrees
Pentagon
5 sided, 72 degrees
Hexagon
6 sided, 60 degrees
Octagon
8 sided, 45 degrees
Regular Polygon
A figure with 3 or more equal sides and equal angles on the corners
modify
A generic term used for changing your objects
panels
A grouping of commands/tools on the ribbon
Visable line
A heavy line that shows the form of an object. Also called an object line. (a wide solid line)
block
A pre-drawn image you can insert in your drawing to save time and make your file size smaller.
tabs
A series of Tabs make up the Ribbon (Home, Insert, Manage, etc) and organize the Tools into common groups.
limits
A setting to impose an 'artificial' boundary on your drawing that sets the area of the grid, and when turned on, limits you to drawing in the grid area.
Alphabet of lines
A system if lines of various thickness, appearance, and darkness, each having a specific meaning on technical sketches and drawings
Border line
A very heavy line that frames the drawing (a wide solid line)
Cutting Plane line
A very heavy line that shows where a line cuts through an object to show how the inside looks (a very heavy broken line, long dash 1", short dash 1/4", spaces 1/8")
Absolute coordinates
A way of inputting points based on AutoCAD's origin.
relative coordinates
A way of inputting points based on a starting point.
polar coordinates
A way of inputting points based on distance and angle.
layer
All objects are drawn on a layer. You can group objects (such as electrical) on a single layer and organize your drawing.
linetype
All objects are drawn with a particular linetype. Examples would be solid, center, dashed, etc.
plot
Also known as print. To make a hard copy of your drawing.
Tangents
An absolute correct point of intersection between line and circle, circle and arc, etc.
object
Any item that is in the AutoCAD database. Also known as an entity.
property
Any specific characteristic of an object such as layer, scale, linetype, start point, etc.
explode
Breaks a compound object into its component objects. Explodes a compound object when you want to modify its components separately. Objects that can be exploded include blocks, polylines, and regions, among others.
fillet command
Connects two lines, arcs or circles by means of a smoothly fitted arc of specified radius.
offset
Constructs an entity parallel to the specified one, either through a given point or at a given distance.
mirror
Create objects that represent half of a drawing, select them, and mirror them across a specified line to create the other half. The two specified points become the endpoints of a line about which the selected objects are mirrored.
dimension style manager
Creates new styles, sets the current style, modifies styles, sets overrides on the current style, and compares styles.
linetype scale
Determines how the linetype is displayed and plotted. To change it, type in LTSCALE (LTS) and try different values to get the look you want.
extend
Extends an object until it meets another object.
styles
Formatting that defines the look of text, dimensions, etc.
lineweight
How wide lines on an object are displayed on the screen and when printed.
where sketching is usually done
In remote places, thus it usually involves very little tools or instruments
Drafting
Language of industry
divide
Lets you divide an entity into several equal-length parts, placing markers along the object at the dividing points.
measure
Measures an entity and places markers at specified intervals.
erase
Permanently removes specified objects.
Sketching
Rough draft for drawings
Irregular Polygons
Some side lengths or angles different from the other
units
The basic drawing unit set for your drawing. For example, you can use inches or millimeters depending on your needs. You can also set the precision you want displayed, such nearest 1/4", 1/2" 1/64", etc.
selection set
The current group of objects selected for modifying.
entexts
The outer boundaries of the objects you have drawn.
Inscribed Polygon
The polygon fits inside of a base circle- the pats of the polygon touch the base circle
Circumscribed Polygon
The polygon fits on the outside of a base circle--the side are tangent or touch the base circle
drafting
The use of sketches, instrument drawings, CAD, to produce technical diagrams, supported by text.
tools
These are the icons that start the commands you use to draw, modify, etc.
drawings spaces
These is where you draw your designs.
status bar
This allows to see and change different modes of drawing such as Ortho, Osnaps, Grid, Otrack, etc. You can right click this area to toggle between icons and text for this area.
APPLICATION BUTTON
This button displays commands for printing, saving, drawing utilities and other non-drawing tools.
ortho mode
This is a drawing mode that allows you to draw only perpendicular lines. It is toggled on and off by pressing the F8 key.
snap
This is a drawing mode that allows you to snap your cursor to precise points laid out in a grid pattern. Toggle with the F9 key.
object snap
This is a method of 'snapping' to certain, precise points on an object. (Osnap)
quick access toolbar
This is for quick access to common commands like New, Open, Save, Plot
grid
This is pattern of dots displayed on the screen to guide you. It can be toggled on and off by pressing the F7 key
crosshairs
This is your cursor when it is in the drawing space.
chamfer command
Trims two intersecting lines a specified distance from the intersection and connects the trimmed ends with a new line segment.
trim
Used to trim objects such that they end exactly at cutting edges defined by other intersecting objects.
command line
When you type a command, you will see it here. AutoCAD uses this space to 'prompt' you for information.
cursor
Your cursor will change depending on what function it is performing in the program.
Short break line
a heavy wavy line it cuts off a narrow long object. (A wide line)
view
a particular area of your drawing
Hidden line
a thin line that has broken dashes. It shows a hidden edge also called an "invisible line". (dashes are 1/8" long with 1/32" space)
Section line
a thin line that shows a solid surface when a cutting plane line passes through it. Also called cross-hatching lines. (thin line normally drawn at a 45 degree angle)
Extension line
a thin line used to extend the size of the object being drawn so the dimension can be placed near the view. (a thin line that projects from an object)
Leader
a thin line with an arrowhead on one end. On the other end is a dimension or not. should not be 0 or 90 degrees. (A thin line used to show the parts related to the note or dimension)
Dimension line
a thin line with arrowheads on each end that touch the extension line. It is opened for the dimension. (A thin line the length of each dimension)
Center line
a thin line with long and short dashes. It shows the center of objects. (dashes are 1" long and the short dash is 1/8" with !/8" spaces)
Long break line
a thin line with several freehand zig-zags. It cuts off a wide object. (A thin line with zig-zags every inch or two)
major components of working drawings
a. assembly drawing b. detail drawing c. bill of material d. title block
section lining or cross hatching
added to the section view to distinguish the solid portions from the hollow areas of an object and can also be used to indicate the type of material that was used to make the object
section lining
always bound by visible lines
Ellipses
an oval shape
most descriptive view
apply dims to the
spokes and ribs
are not sectioned
hidden lines
are omitted from section views
zone
between the views
extension lines
can cross each other
Eccentric
circles that do not share the same center although the centers of each circle are all contained in a least one of the circles
Concentic
circles with common center
Sketching
clarify thoughts in a technical discussion, and record ideas quickly.
Most drawings
consist of Geometric Shapes (it is important for the drafter to be able to identify and construct geometric entities)
parts list
consists of an itemized list of all the parts to assemble one complete unit
section lining
different marterials have different patterns of lines and spacing
visible lines
do not overdraw section lines beyond..
blind holes
does not go all of the way through
working drawings
drawing from which a design is built; legal contacts that document the design details and specifications
Chamfer
edge/end that is cut off at some angle
overall dimensions
for the height, width and depth. should be the farthermost out
ribbon
has most of the commands/tools that you will use while you are working. It runs across the top of the drawing space and contains panels - each panel has a group of associated tools. Switch to different panels by clicking on the tabs at the top of the ribbon.
2 point
human like diagram depth lines diminish to 2 vanishing points
1 point
human like diagram oblique with non-parallel depth lines depth lines are projected from the frontal plane and diminish at the distant vanishing point rear lines parallel to frontal
30 degrees
if section lines are drawn appropiately at a 45 degreee angle are or appear nealy parallel or perpendicular to a prominent visible outline, change the angle to
small dimensions
inside of the overall dimensions
uniformly space
lines in section linings
sectional views
located by creating a cutting plane line in a one view
location dimension
may be the length from the edge of an object to the center of a feature
size dimension
may be the overall width of a part or the diameter of a hole
fasteners
on assembly sections are not sectioned
avoid dimensioning
on sectioned areas and over section linings
basic tools of freehand sketching
paper, pencil, eraser, and grid paper (although sketches are rough drafts it be as neat and professional as possible)
Avoid
placing dims inside of the drawings
avoid
placing dims on hidden lines
working drawings
rely on orthographic projection and many other graphical techniques to communicate design information for production
section lining
remove ... in the areas where the dimensions appear
avoid
repeating dims
Good lettering
requires use of guidelines
Fillet
rounded edge
average section linings
should be approximately 3/32" apart
section lines
should be drawing at a 45 degree angle to the horizontal
dimension holes
should be marked with a "o" with a "/" through it. should be marked on the circular view, using an angular, radial leader
dimension arcs
should be marked with an "R" on their circular view, using an angular, radial leader
Lettering
should be neat,dark,professional looking and should be done in all capital single stroke gothic alphabet.
section lining
should be reversed or mirrored on adjoining parts when doing an assembly drawing
section lines
should be thinner than visible lines
section lines
should be uniformly thin, even in weigh and with good resolution
visible lines
should never pass through an area of section lining
dimension lines
should not cross any line
partial section view
similar to a broken-out but usually covers a larger area but less than a half section
1/16" to 1/8"
space section lines ... apart depending on the size of the drawing
working drawings
specialezed engineering drawings that provide information required to make the part or assembly of the final design
cylindrical objects
the dimensions should be put in the rectangular views
.38" .25"
the first row of dimensions should be how far from the object? succeeding ones?
Dimensions
the systems of size descriptors on mechanical drawings. should be done in a systematic method, typical for industry. clear, neat and not crowded
pick
to select an object by 'left-clicking' on it
notes
use ___ to dimension repetitive features
Sketches
used for manufacturing, constructing, modifying, repairing, illustrating items in industry
sectional views
used to clarify interior or hidden details on a multi-view drawing of an object
guide line
used to keep lettering uniform in height (very light)
construction lines
used to layout the object and all of its features (very light)
assembly section
used to show the arrangement and relationship of parts that makeup an obect
pictorial section
used to show the arrangement and relationship of parts that makeup an object in a three dimensional view with a quarter to half of the object removed
offset section
used to show the cutting plane stepped at one or more right angle bends, but will eventually cut through the whole object
broken-out section view
used to show the material thickness of a hollow object
Full section view
used to show the object as if one half of the object was removed
half section view
used to show the object as if one quarter of the object was removed
aligned section view
used to show the shape of features that do not align with the vertical and horizontal center lines of the object
revolved section view
used to show the uniform shape of the object from end to end
removed section view
used to show the variable shape of the object from end to end
sectional views
usually replaces one of the principle view (top, front and side) but may also be an additional view or series of supplemental views depending on the type
general purpose section lining
usually represents cast iron. uses medium, thick, lines drawn at a 45 degree angle and spaced 1/8" apart
opposing directions
when 2 or more parts in a section are adjacent, use section linings in
thru holes
where it is not clear that a hole goes through an object
section lines
within a sectioned area must be parallel
outline sectioning
you may limit drawing section lines to areas adjacent to outline of sectioned areas, called ..., providing the drawing remains clear