Week 8 - Challenge 4 - Coin Holder Design

DESIGN OF COIN HOLDER

OBJECTIVE: The main objective of this challenge is to performe draft analysis on given class A surface and to develop a final solid of a coin holder 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

The step to create a proper tooling axis for surface are explained below:

1. First extract the base surface of the class A

2. create a point at the centre of the surface by giving 0 value.

3. Now with the help of the point create an axis system and intersect the class A surface with the axis system.

4. Now we can observe that the intersection is far away from the centre so that we can create our tooling axis at the centre of the surface by taking point as a reference.

DRAFT ANALYSIS ON CLASS A SURFACE

1. Click on insert >> analysis>> feature draft analysis or else click on the draft analysis feature command which is on the catia screen.

2. Now click on the compass and align it with the tooling axis which we have created in a proper manner.

3. Then click on the lock symbol and then just tap on the class A surface and observe the colour codes. the enlarged values of coloir codes are as shown in below picture,

4. The different views of draft analysis on class A surface are as shown in below pictures.

1. ISOMETRIC VIEW

2.FRONT VIEW

3.SIDE VIEW

4.TOP VIEW

CREATION OF CLASS B SURFACE

We have divided class B surface into four segments, the four segments are namely

• SIDE WALLS
• BASE
• TOP WALL
• OUTER FLANGE

CONSTRUCTION OF SIDE WALL:

1. First extract the surfaces of side walls from class A surface

2. Untrin the extracted faces of side walls

3. Extrapolate the untrimmed surfaces of side walls and make sure they intersect with each other properly

4. Now trim the exprolated surfaces of the side walls make it like a closed rectangular box.

5. Offset the side walls to a distance of 2.5 milli meters in proper directions.

6. Finally apply edge fillets to the side walls and rename the last edge fillet as final side walls

CONSTRUCTION OF BASE:

1. Extract the base surfaces of the class A surface

2. Untrim the extracted surfaces of the base

3. Now extrapolate the base surfaces to the required dimensions for proper intersection of the surfaces

4. Offset the two surfaces for a distance of 2.5 mm in proper direction

5. Now trim the offsetted faces

6. We have a small triangular shaped rib like structure on the base so we have to create that. To create that we have to extract the faces and untrim, extrapolate them.

7. Finally trim the surfaces and offset it for ad istance of 2.5 milli meters.

8. Finally trim it with base surface what we have previously

CONSTRUCTION OF TOP WALL:

1. Extract the surfaces of top wall from the input CLASS A surface

2. Extrapolate the top wall to a required distance

3. Now offset it to 2.5 milli meters distance

4. First trim side wall surface with base surface

5. Trim the above trim with the top walls and we get the required the shape

CONSTRUCTION OF OUTER FLANGE:

1. Extract the outer flange surfaces from the given class A surface

2. Extrapolate the outer flange to make the two surfaces intersect properly.

3. Offset the two surfaces to required distance and make sure the direction is proper or not

4. Trim the two offsetted surfaces to get the required shape

5. Trim the previois trim with the trim of top wall and side wall- base.

6.Apply edge fillets wherever required and give it a nice colour and rename it as class B surface.

CREATION OF CLASS C SURFACE

1. First create a boundary by using class A surface as shown in below figure

2. By using multiple extrat command extract all the faces which are in contact with the boundary.

3. Sweep the surface and boundary in order to create main part of CLASS c surface.

4. Similarly create a boundary for hole and by using multiple extrat command extract all the faces which are in contact with the boundary.

5. Similar to the main class C surface sweep the hole and surfaces and we will get the required class C surface for the hole.

6. Now trim class C surface with class B surface.

7.Now join the previous trim with class A surface.

8. Finally trim the join with class c hole and a closed surface is formed. rename the surface as coin holder.

CREATION OF SOLID FROM CLOSED SURFACE:

The closed suface of coin holder is converted into the solid by using close surface command in part workbench of catia. Various views of solid coin holder part are as shown in below pictures,

ISOMETRIC VIEW:

FRONT VIEW

SIDE VIEW

TOP VIEW

DRAFT ANALYSIS ON SOLID COIN HOLDER

Similar to the draft analysis performed on the claa A surface perform draft analysis here alos and observe the colours what we have obtained. the draft analysis views of solid coin holder are attached below

ISOMETRIC VIEW:

FRONT VIEW:

SIDE VIEW:

TOP VIEW:

PART NAVIGATOR

CONCLUSSION

Hence we have created a complete surface of a coin holder and thickened it and made it into solid body and draft analysis is performed on both class A surface as well as final solid body of coin holder. A detailed report has been prepared by attaching all the relavat images successfully.