Door Arm Rest Design

AIM:

Creation of the door arm rest and add thickness to it

Objective :

• Creating the B and C surface
• Creating the tooling axis
• Performing the draft analysis on both A surface and final Door armrest and draft analysis must show the positive value and color.

Procedure :

Creating the tooling axis :

The tooling direction is used to find the direction in which the part is ejected out of the mold. The draft on the part should be positive in order to manufacture the part easily. The draft angle should be positive with respect to the tooling direction.

• To create the tooling axis, we need the proper orientation or view that gives the correct features and draft available in the component.
• So here the component view from the Z direction gives the proper view for the tool to see the features present in the geometry.

Fig - Z direction will be the tooling axis

• To create the tooling axis from the Z direction we need the tooling axis from the other X direction since it gives the draft available at the slanted part.
• The tooling axis created from the X direction by following steps

1. The base surface is extracted.
2. Then the center point is created using the point > on the surface at 0
3. At the point created the axis system is created

1. After that switching the view of the model to the X direction and creating the tooling axis.

Using the intersect in ZY plane to get the boundary lines.

Then the lines are created along the slant surfaces.

Then these two lines are bisected to get the tooling axis for the X or the final

1. Next, switching in the Y direction and intersecting the switch bezel part in ZX direction to get the intersecting lines.
2. Using the axis center point, a line is drawn in sketch mode and it is constrained at the angle of 2 degrees. (this angle value is an arbitrary value and can be changed to get the final tooling axis that provides a positive draft )
3. At last, both the lines are bisected to get the final tooling axis.

Class B surface creation:

The input of the product designer is in the form of the A-class surface. The job of the product designer is to create the B and C surfaces keeping all the aspects for the mold.

Class A is

1.Visible surface and aesthetic look

2.surface with textures

3.Surfaces provided by customer(OEM)

4.Don't have any features like(rib, snap, bosses, etc) on class A surface.

5.Class A surface is made from scanned data with different software like alias etc.

6.Surfaces which are having CURVATURE CONTINUITY IS CALLED class-A.

Class B surface:

1.invisible Surfaces.

2.Surface mostly don't have textures

3.Surface needs to be created according to the class-A surface.

4.having all features(Rib,boss,snap etc) in B-side surface only.

5.Surfaces which is having TANGENT CONTINUITY IS CALLED class-B

The process for the B class is as follows :

• First, extract all the surfaces for the inclined portion of the base plate.
• Then these surfaces are first untrimmed to get the intersection for surfaces so that a replica can be created.

• If the surfaces are not intersected, then extrapolate by point continuity propagation is used to make these surfaces have an intersection between them
• Lastly, the surface trim is used to get the replica for the inclined surface.
• Now, the thickness of the final component is 2.5mm so this obtained surface is offset below by 2.5mm.

• Like that the rest of the region is extracted and trimmed to get the final B surface.

• Now, the fillets assigned in the B class surface will be 17-2.5 mm = 14.5mm. This is to have the uniform thickness between the A and B classes.

Note : If the fillets in b surface are contracting then fillet value is reduced by thickness otherwise it increases by thickness value.

The whole component B surface is created in small parts, then joined using the trimmed option and then the final fillets are assigned.

C surface :

C class is where the thickness of the component can be seen.

The process for C-class surface is as follows :

• The C class surface will be created using the sweep command and for that, the Boundary lines are obtained from the A-class surface.

• The curve part is then smooth by some value for ease in sweeping.

• Then, all boundary lines are sweep with draft direction since all the surfaces must have a draft angle of 3 degrees. Also, the tooling axis is used as the direction of the sweep.

• Next, the swept surfaces are joined with the A-class to form a complete A and C surface.(note merging distance is kept at 0.003mm to avoid any gaps)

• Lastly, the A and C is trimmed with the B surface to get the final baseplate component. This obtained surface is then thickened in part design.

Draft analysis :

• To perform the draft analysis the view parameters are first set to material mode.
• Then go to Insert >>analysis>>feature draft analysis.

• First, select the axis system and drag the axis system to align and coincide with the tooling axis and lock the orientation. This axis system defines the draft direction according to the tooling axis.

• Switch on the color scale and set the minimum draft value. Here it is set to 3 degrees and it will be displayed in green color. Any draft angle below 3 degrees will be shown in red color.
• Here, the compass direction is rotated to have the positive direction in the maximum portion of the part. Then the compass is locked in the orientation and a new tooling axis is created using the compass as the direction.

• Now select the running point tool to measure the draft angle at the various locations and then if all surfaces pass the draft analysis switch on the light effect that will show the component in green color if the component has the required draft angle.
• The bin portion of the armrest has a negative draft because the model is not accurate and has some inappropriate surface that creates the problem in the final drafting. To overcome this problem we will need another tooling axis or sliding axis that will clear this region properly in ejection.

Results :

The Door arm rest B and C class surface is created with the draft angle of 3 degrees and then a solid component is formed.

Door armrest :

Draft analysis:

Tree structure :