Week 9 - Attachment Feature Creation (Ribs & Screw Boss) - Challenge 1

Aim:

Create the rib for the Drill Handle considering the design rules

Condition:

Thickness of the component = 2.5 mm

Draft angle = 3°

Input:

The following surface is given as the input for the component creation.

Input checking:

The given input surface is checked using boundary comment the boundary of the surface is are fully closed or not. If there is any open boundary make sure close it properly.

The given input has one boundary with fully closed condition. So there no problem in creating class B surface.

Creation of Tooling Axis:

Tooling axis is the line represents the mold open and close direction at the time of component manufacturing.

If a component has flat surfaces, then the tooling axis identified by visually, otherwise intersection method is used to find the tooling axis of component.

Here, given surface has inclined walls so intersection method is used to create tooling axis.

The flat surface is extracted from class A and created point center of component. Then axis system created for tooling axis creation.

In axis system XY plane sketch created in the both extreme edge of class A and then intersecting these two line tooling axis line 1 is created.

Tooling axis line 2 is also created by same method in YZ plane.

Tooling axis for mold open and close is created by Bisecting Tooling line 1 and 2 shown as per below image.

Draft Analysis of Class A surface:

Drafting analysis shows that when component ejected from the mold die whether the component removed smoothly without creating any damage or scratch on the surface of the component.

The minimum draft angle applied on the component is 0.5°. But it need high precision and it increases cost of the mold.

In industry 3° draft angle is used for optimal solution for component ejection.

Here, draft analysis is done with respect to 3° angle.

The draft analysis of class A surface shows that class A is not clearing the condition for creating component.

The green color shows the given input class A surface has good positive draft effect. The red color shows surfaces are not clearing mold ejection condition that means the given class A need modification for mold ejection.

Where modification of class A surface need to consider with customers.

In this challenge after considering faculty further process done.

Creation of Class B:

The Drill Handle has many curved surfaces. So, here direct offset used to create the class B surface and done some patching work to complete the class B surface.

After offsetting the class A surface 2.5mm, the patching work is done by using the multisection command.

Patching needed area

After patching work done all the surfaces are joined together an created into single surface shown like below.

Class C surface:

• For creating class C surface, we have extracted the boundary of Class A using multi-extract and then converted to smooth curve.
• Now this smooth curve is swept along the draft direction with a 90deg perpendicular to CLASS A surface.
• In some places not smooth class C surfaces not formed, In those places multisection command used create the surface.
• Finally, the sweep surface and multisection surfaces are joined into single surface by join command.

Class A + Class C

By, joining the class A and class C this surface formed for the final trim operation.

Class A + Class B + Class C

For this we have trimmed the Class B surface with Class A+C surface using trim feature. Then the fully closed surface is formed.

Design rules:

Rib calculation:

Wall Thickness = 2.5mm

Rib thickness = 0.4*t =0.4*2.5

=1mm

Rib Height =5t=5*2.5

=12.5mm

Rib fillet radius =0.125*t=0.125*2.5

=0.3125mm

Draft angle =0.5°

Distance B/W rib =2t=2*2.5

=5mm

Rib creation:

Rib sketch created and extruded along tooling direction and used thicken applied 1mm thicken

Then unitrim used trim unwanted face to remove with respect to main body and then 0.5° draft applied to ribs with respect to tooling axis.

Boss calculation:

Wall Thickness = 2.5mm

Screw boss thick =0.6*t=0.6*2.5

=1.5mm

Height : Diameter =3:1

H:5.2 =3:1

H =3*5.2

=15.6mm

Screw Boss creation:

Screw boss inner diameter assumed=5.2mm.

Screw boss sketch created and extruded along tooling direction and used thicken applied 1.5mm thicken.

Then unitrim used trim unwanted face to remove with respect to main body and then 0.5° draft applied to ribs with respect to tooling axis.

Solid body draft analysis:

Drafting analysis shows that when component removed from mold smoothly without creating any damage or scratch on the component.

The minimum draft angle applied on the component is 0.5°. But it need high precision and it increases cost of the mold.

In industry 3° draft angle is used for optimal solution for component ejection.

Here, draft analysis is done with respect to 3° angle.

From the above shown image the draft angle of final component has some surfaces not achieved 3°. So, need to modify the component for mold opening.

The draft angle is modified to 2.9° which is nearly equal to three degree.

The rib and screw boss are clearing the condition of mold ejection.

ISOMETRIC VIEW

FRONT VIEW

TOP VIEW

RIGHT SIDE VIEW

LEFT SIDE VIEW