Challenge

Door Arm Rest Week 8 Challenge

Door arm rest from Class A as Input – Automotive plastic component

Aim: Creation of Door arm rest and add thickness to It.

Objectives:

Create a class B and class C surface for the door arm rest using the given class A surface.
Use the given Class-A For reference
Use the close surface feature to make a solid body from the surface.
Use the publication option and use the class-A, class-B, class-C surfaces and the tooling axis.

Procedure:

Step 1: Design Check (Pre check) on received class-A:

After receiving the class-A for the Door arm rest Check for the connectivity of the surfaces on it.
Use boundary operation and disassemble.
Check for Discontinuous surfaces.
The check is over if any discontinuities do not arise.

Step-2: Determine the Tooling axis:

Extract a plain surface and create a point on its center for axis system creation.
In this case Z axis can be a possible Tooling Axis direction.
Create a Sketch on the XZ plane of the axis system and use intersect 3D to plane option to get the sketch.
This line is used for tooling axis for X.
Do similar steps for YZ plane.
The tooling created here is Y tooling.
Then use Bisecting line option to bisect both the tool clearing axis and pass the bisecting line through the origin.
This line created here is the main tooling axis.

Step 3 Draft analysis on class-A and possible creation of side tooling axis:

Change View Mode Customization to material mode.
Go to INSERT> ANALYSIS> FEATURE DRAFT ANALYSIS and move the compass to the tooling axis.
The input Class-A also has walls having negative angle to the tooling axis.
This can be an issue while manufacturing the component as it would be very difficult to draw from the molds.
So, the design needs to consider various Side tooling options.
The minimum draft angle is 3 deg, here red is zero, Green is above Zero deg, blue is below zero. So, try to keep that draft angle in positive.

Class A Draft analysis:

Final Draft analysis:

Step 4 Creating Class-B surface

First extract all the necessary flat surfaces from the class-A surface.
Then untrim these surfaces to get intersection for surfaces so that 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.
Then offset all the surfaces by thickness of 2.5mm as given to obtain B-surface.
One surface where you wont able to extract the surface because of the fillet in that case extract the boundary of that surface and create a guide line taking one boundary as tangent curve reference in line command and sweep it.
Next surface trim is used to get class-B surface.
Lastly measure the fillets from class-A surface and give to the surface according to the formula.

Fillet:

(If it is inward A surface then: Radius = A surface fillet radius – Thickness of the component (2.5mm))

(If it is Toward B surface; Radius = A surface fillet radius + Thickness of the component)

Step 5 Creating Class-C surface

Class-C surface is where the thickness of the component lies, it is joining surface Between Class-A And Class-B.
For creating Class-C surface we are using Sweep command most of the cases and for that the boundary lines are obtained from the class-A surface.
All boundary lines are sweep with draft direction since all the surfaces must have a draft angle of minimum 3 deg so that component eject easily from molding. Also, the tool axis is used as the direction of the sweep.
But for some cases like complicated curves, we use muti-section surface command
Next the swept surfaces joined with the Class-A surface to a complete A and C surface, (Note- Merging distance kept at 0.003mm to avoid any gaps)
Still if there is any one, we can do extrapolate A surface by 0.5mm and trim with the Class-C.