Unit - 1 Basic Design
Unit - 1 Basic Design
Unit - 1 Basic Design
UNIT – II 2D DRAFTING 9
Projection views – Orthographic view, Axillary view, Full & Half Section
views, Broken Section view, Offset Section view – Title Block creation – BOM
Creation – Notes creation – Ballooning of 2D drawing and its features for
Inspection reporting
UNIT – V CAM 9
Basics of CNC Machining – 3, 4 & 5 Axis machines - CNC and Part
Programing, CAM programing 2D & 3D. Elements of CAM Orientation,
Boundary Creation, Cutter Path Selection, Cutter Compensation –Machining
Stocks, Roughing, Re-roughing, Semi Finishing & Finishing - Tool Path
Generation, Isl and Milling Programing. Machining program simulation,
integration of program with machine; Estimation of CNC Cycle time. – Post
Process NC Code conversion and Setup Sheet Preparation.
TOTAL : 45 PERIODS
UNIT – I BASICS OF DESIGNS 9
If the distance from the observer to the object is infinite, then the projection
lines are assumed to be parallel, and the projection is called a parallel
projection. Parallel projection is orthographic if the plane of projection is
placed between the observer and the object, and the plane is perpendicular
to the parallel lines of sight.
You can use parallel projection technique to create both multiview and
pictorial (isometric and oblique) views.
1. In multiview orthographic projection (see details below), the object
surface and the projection plane are parallel, and you can see only two
dimensions.
2. In isometric view (orthographic) the surface is no longer parallel to
the projection plane, but the latter is perpendicular to the lines of sight,
with three dimensions being seen.
3. In oblique projection (non-orthographic) the object surface and the
projection plane are also parallel, but the lines of sights are not
perpendicular to the projection plane, and you can see again three
dimensions.
If the distance from the observer to the object is finite, then the projection
lines are not parallel (since all lines of sight start at a single point), and the
drawing is classified as a perspective projection. In perspective view the
object surface and projection plane can be also parallel.
Multiview projection
By changing position of the object relative to the line of sight you can create
different views of the same object. Drawing more than one face of an object
by rotating the object relative to your line of sight helps in understanding
the 3D form. Having several views on one drawing you use the concept
of multi-view projection, which is based on the orthographic (parallel)
projection technique where
Positions of the other views relative to the principal view in the drawing
depend on the projection method.
SCALES
Scale in architecture refers to the ratio between a model of a building or
structure and the real-life version.
The 1:100 scale means that 1 unit on the model represents 100 units in real
life.
For example, a room that is 1 inch on a 1:100 scale model would be 100
inches, or 8.3 feet, in real life. But I’m no fan of inches; show me something in
metric.
Using the metric system, 1 meter on a 1:100 scale is equivalent to 100 meters
in real life.
The 1:100 scale may not seem like a big difference, but in the real world, it
is.
Combined, the feature control frame provides all the information you need
to measure the geometric tolerance of the features of the part and
determine if the part is in spec.
LeaderArrow
This points to the feature that the geometric control is placed on. If the
arrow points to a diametric dimension, then the axis is controlled by
GD&T. If the arrow points to a surface, then the surface is controlled by
GD&T. The arrow is optional and may not be present on some drawings.
GeometricCharacteristicSymbol
This is where geometric control is specified. Download our free GD&T
Symbol Reference Guide and Font for more information.
Tolerance
The numerical value defines the tolerance zone. The unit of measure is the
same for the whole drawing and will be defined in the title block.
ModifierfortheTolerance
This is max material condition or a projected tolerance in the feature
control frame. See the Modifiers section of the GD&T Symbols Guide for
more information on these features.
PrimaryDatum(ifrequired)
If a datum is required, this is the main datum used for GD&T. The letter
corresponds to a feature somewhere on the part which will be marked with
the same letter. This is the datum that must be constrained first when
measuring the part. The order of the datum is important for measurement
of the part. The primary datum is usually in 3 places to fix 3 degrees of
freedom.
SecondaryDatum (ifrequired)
When a secondary datum is required it will be to the right of the primary
datum in the feature control frame. Like the primary datum the letter
corresponds to a feature somewhere on the part which will be marked with
the same letter. During measurement this datum is fixated after the
primary datum.
TertiaryDatum(ifrequired)
When a tertiary datum is required it is to the right of the secondary datum
in the feature control frame. During measurement, this datum is fixated
last.
TITLE BLOCK
The title block found at the bottom right-hand corner of the drawing. There
are other information blocks like it, but the title block serves as the context
in which the drawing should be perceived.
Note that any information in the notes outside the title block that conflicts
with the information in the title block should be considered as the right
information and supersede the title block information
Revision block
The revision block, located in the upper right hand corner, shows details
about the changes that were made to roll the revision. The Revision Block
includes the revision, the description of what changes were made, the date
of the revision, and approval of the revision.
Located usually either just above the title block or in the upper left-hand
corner, the Bill of Materials block (also known as a BOM, Schedule or Parts
List) contains a list of all the items and quantities that are required for the
project or assembly. This is used for parts that either require assembly or
when hardware should be added to the part.
REVISION / ECN STATUS OF DRAWINGS
1. Typographical changes
These types of changes are all about spelling corrections and typographical
errors. There are no physical changes that occur to any of the components,
and therefore no effect on the system’s form, fit, or function.
2. Alternative manufacturers
Sourcing from another manufacturer or supplier should not affect the
operation of existing equipment. These changes usually seek to improve
the procurement process by reducing lead times or costs. For this type, it is
important to ensure that only the source of supply changes, and not the
specifications of the part itself.
3. Obsolete component
As much as possible, replacing a manufacturer-discontinued part does not
intend to change the characteristics of existing components. However, since
an entirely new component is being introduced, more thorough
compatibility reviews are necessary.
A typical ECO process for existing equipment within the plant may
resemble the following diagram:
What are the signs of an ECN/ECO bottleneck?
A process “bottleneck” is regarded as an activity that contributes most to
the lead time of a particular operation. In other words, bottlenecks are
constraints within a process that cause delays. Change management
processes can take a lot of time and effort to complete. For that reason,
organizations need to be aware if their queues are getting out of hand.
When overlooked, delayed ECN/ECO implementation can cause
devastating blows to production and safety objectives.
Here are some signs that your ECN/ECO queue is causing constraints to
the rest of your operations: