Challenge

Week 10 - Challenge 1- Attachment Feature Creation (Ribs & Screw Boss)

PPaventhan S28 Jul 2023

Attachment Feature Creation (Ribs & Screw Boss)

AIM

Create the component through the given Class-A surface.

the tooling axis for the given Class-A Surface should be created meeting the requirements of the draft angle and at the end perform the Draft analysis on the model. Create the rib and screw boss as by considering the design rules

CLASS A SURFACE

In automotive design, a class A surface is any of a set of free form surfaces of high efficiency and quality. It gives the aesthetic of the component which is created by the styling team and gives to the part design engineer to create the part with all engineering aspects.

TOOLING AXIS

TOOLING AXIS is created by bisecting the axis created on two intersections .

the best tooling direction for the class-A surface is along y-axis direction.

Flat surface on the center part is extracted for creating the tooling axis in y direction

Then created a with the point and direction along y axis.

TOOLING AXIS of the part is created

DRAFT ANGLE

When developing parts for plastic injection molding, applying a draft (or a taper) to the faces of the part is critical to improving the moldability of your part. Without it, parts run the risk of poor cosmetic finishes and may bend, break, or warp due to molding stresses caused by plastic cooling. Equally important, an absence of draft may prevent parts from ejecting from the mold, damaging not only the parts but possibly the mold itself—a costly and time-consuming detour.

DRAFT ANALYSIS OF CLASS A SURFACE

draft analysis is done using featured draft analysis tool

Use the compass fucnction to aling the compass to the tooling direction and lock the direction using lock function in the draft analysis tool bar

the surface is showing green colour so that the surface clears the minimum draft angle of 3 degree

By using the analyses under the running pointwe can check draft angle on the individual faces. It shows how much draft on specific points when we move the cursor point.

Green colour - above 3 degree positive draft

Red colour -between 3 and 0

blue colour- below 0 degree

CLASS B SURFACE

Class-B surface means the thickness of a part it is not visible and is inside part. In other words, the Class-B surface is a surface below a certain thickness from the class-A surface. This is the surface that contains engineering aspects of a model.The Class B finish is a quality finish with only minimal imperfections. A Class B finish is the most common finish for exterior surfaces. It is normally specified on surfaces such as external covers, panels, and parts that are fairly prominent.

B SURFACE is created by Offseting the class-A surface to 3mm inward direction.

patches are created while offsetting the surface. Rework on the patches using the features like extract, multi-extract, sweep, trim, extrapolate.

the boundary command is used to identify and highlight the patches

CLASS B SURFACE IS CREATED

CLASS C SURFACE

The surface that joins class-A and class-B surfaces are class-C surfaces. Class C is often specified for interior surfaces not readily visible, surfaces that will be covered by another part when assembledThe Class C finish allows more imperfections than Class A or B. Class C is often specified for interior surfaces not readily visible, surfaces that will be covered by another part when assembled, or surfaces which the Customer feels do not need to meet a high cosmetic finish.

The method used for class c surface is sweep feature

Since it is a complex class-A surface, we cannot create the class-A boundary curve and sweep in a single stretch .

small sections are created using multi-extract command and then create sweep of 90 degree with reference to the surface option.

S.OLID SURFACE

CLASS A and CLASS C is trim together

CLASS B is trimmed with CLASS A AND C

SOLID SURFACE FORMED

PART BODY

Close Surface feature usedto make a solid body from the surface

RIB DESIGN

sketch is created for ribs

extruded and created the surface according to the height of ribs in design rules

height - <=5t (thickness of part)

thicken the surface using thicken surface

thickness = 0.4t (thickness of part)

rib draft >= .5degree

fillet .25mm

part is timmed with main component

SCREW BOSS

sketch is created the diameter taken (m6 bolt) 5.2mm

the outer diameter

Thickness - Typically 40%* of the nominal wall at the base in one side

40% of 2.5 =1 mm one side =7.2

paded the sketch for height

Height to Diameter Ratio - 3

Draft - 0.5 degrees on the walls of boss

Radii - 0.25mm maximum radii.

COMPONENT

DRAFT ANALYSISOF COMPONEN

draft analysis is done using featured draft analysis tool

Use the compass fucnction to aling the compass to the tooling direction and lock the direction using lock function in the draft analysis tool bar

the surface is showing green colour so that the surface clears the minimum draft angle of 3 degree

By using the analyses under the running pointwe can check draft angle on the individual faces. It shows how much draft on specific points when we move the cursor point.