Week 8 - Challenge 2 - Base Bracket Design

DESIGN OF BASE BRACKET

OBJECTIVE: The main objective of this challenge is to performe draft analysis on given class A surface and to develop a final solid base bracket part and perform the draft analysis on the solid part by using CATIA v5 software. A report has to be prepared by explaining about what is draft analysis and tooling axis and add all the relevant images to the report.

DRAFT ANALYSIS

Draft analysis is a analysis which is performed on the objects or bodies in order to check the draft angle of various faces in a particular direction which is tooling direction.

Every part like sheet metal parts which are generated from a Press Tool or some forming tools, may be the plastic parts which generally come out from the plastic moulds and maybe the casting parts, all such kind of parts required some drafted face on the surfaces which are parallel to the tooling direction. If we don't provide drafts on the surface then it will stick to the mould surface and whenever the mould is in motion they will destroy the surfaces or also reduced the finishing of surfaces.

The Tooling Direction is basically the direction that the mold pulls apart. The mold is built in two separate pieces, basically. You have a Cavity side and you have the Core side. The Core pulls apart from the Cavity and that's the Dyeline or the Tooling Direction.

And the axis which represents the tooling direction is called tooling axis and selection of this is axis is a crucial step while performing the draft analysis.

CLASS A SURFACE:

In automotive sector, a class A surface is any of a set of freeform surfaces of high efficiency and quality. Although, strictly, it is nothing more than saying the surfaces have curvature and tangency alignment – to ideal aesthetical reflection quality, many people interpret class A surfaces to have G2 (or even G3) curvature continuity to one another.

Class A surfacing is done using CAD applications. Class A surface modellers are also called "digital sculptors" in the industry. Industrial designers develop their design styling through the A-Surface, the physical surface the end user can feel, touch, see etc.

In general CLASS A surfaces are crated using autodesk alias software.

CLASS B SURFACE: Class B surfaces are the secondary surfaces that you can see sometimes, but are less important, such as the inside of your glovebox, ash tray, etc.. These must be smooth and "error-free" as well, but are not held to the standards that class A surfaces are.

CLASS C SUFACE: The 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.

CREATION OF TOOLING AXIS

Seeing from all direction we can clearly say that Z direction is the best possible direction for drafting the given part. so we create a tooling axis in Z direction. The steps for creating a tooling axis in Z direction are specified below

1. Create a point at the centre of circle bu using point command.

2.Now create a dummy tooling axis by using line command in Z direction which is passing through the point which we previously created.

3.Now create a plane which is parallel through point and by taking YZ plane as reference.

4.Now by using intersect command by selecting plane and the class A surface and create a intersection curve.

5.Now create two lines which passes through the faces as shown in below figure

6.Now create a line by using bisect line command and select the two lines , the line which is created now is the final tooling axis.

DRAFT ANALYSIS ON CLASS A SURFACE

Steps for performing draft analysis on the class A surface are explained below,

1.open the draft analysis command or feature.

2.click on the compass icon in the dialogue box and drag the red coloured point and make sure it will coincide withe the tooling axis which we have created earlier.

3.cliick on the lock symbol and click on the surface and click ok. now the draft analysis is finished for the class A surface.

3D VIEWS OF FINAL DRAFT ANALYSIS ON CLASS A SURFACE OF BASE BRACKET:

GIVEN CLASS A SURFACE:

ISOMETRIC VIEW:

FRONT VIEW:

SIDE VIEW:

TOP VIEW:

CREATION OF CLASS B SURFACE

The class B surface contains majorly three components, they are

• RIB 1
• RIB 2
• BASE SURFACE

CREATION OF RIB 1:

1.Extract the faces of RIB 1

2.Now untrim the extracted surfaces

3.Extrapolate the three surfaces by using curvature continuity and point continuity as propagation mode for a lenght of 10 milli meters

4.Now finally trim the surface and offset the surfaces with a value of 2.5 mm in the downward direction.

CREATION OF RIB 2:

Repeat the same procedure which is followed for RIB 1 and offset it to 2.5 milli meters in downward direction.

CREATION OF BASE SURFACE:

1.Extract the two surface of the base.

2. Now untrim the two surfaces and offset them by 2.5 milli meters distance.

3.Extrapolate base surfaces similar to the rib surfaces.

4.Now trim the surfaces and apply edge fillets to the surfaces with a value of 5.5 milli meters and rename the final edge fillet as class B surface

CREATION OF CLASS C

The class C surface is created by creating boundary on class A surfac and sweeping the boundary with a draft angle of 3 degrees by selecting proper direction and tooling axis.

similarly sweep the two holes and join class A surface and class C surface anf holes that we have created,

Now trim the final join with the class B surface which we have created earlier and it is the final base bracket surface

NOW use close surface command and hide the surface commands,

FINAL VIEWS OF SOLID BASE BRACKET

ISOMETRIC VIEW:

FRONT VIEW:

SIDE VIEW:

TOP VIEW:

DRAFT ANALYSIS ON SOLID BASE BRACKET

Similar to the draft analysis performed on the class A surface here also do the similar thing but insted of class A surface select the solid base bracket body.

1.ISOMETRIC VIEW

2.FRONT VIEW

3.SIDE VIEW:

4.TOP VIEW:

PART NAVIGATOR

CONCLUSSION

And hence, we are conluding that a base bracket has been created using given class A surface in CATIA V5 software. draft analysis is performed on both class A SURFACE AND solid base bracket which we have created. A report has been prepared by explaining all the procedures we have followed and all the require images to the report are attached properly and successfully.