Week 10 - Challenge 2- Attachment Feature Creation (Dog House)

Challenge 2- Attachment Feature Creation (Dog House)

Create the Dog House for the Door Trim considering the design rules mentioned in the video. Consider the thickness of the part to be 2.5 mm.

introdution:

DOG HOUSE DESIGN:

Dog house: Dog house is an engineering feature used in the plastic trim design. Dog houses are used as supporting features. Sometimes other engineering features like snaps; locators, etc. are mounded on them to increase their strength. Dog house and other engineering Features are built on B-surface.

Tooling Axis

Tooling Axis is the direction in which the mold or core and cavity opens and closes. While designing a component first thing is to define the tooling axis.

Procedure

• Check the connectivity of given Class A Surface i.e no gaps between the surfaces.
• Analyse the component along x,y,z direction and check which is the best possible tooling direction (Here Y)
• Create a point at flat surface by extracting it.
• Draw a line perpendicular to extracted flat surface through the point and that is the tooling axis.

Tooling Axis By Bisecting Method

• Check the connectivity of given Class A Surface i.e no gaps between the surfaces.
• Analyse the component along x,y,z direction and check which is the best possible tooling direction (Here Y)
• Create a point at base surface by extracting it.
• Create an axis system with that point as origin.
• Create an intersection of class A in xy axis
• Create two lines with reference of faces which we think will create problems.
• Create a bisecting line with the lines drawn, which will gives us the tooling axis.

Side Core Tooling Axis

Here while creating the Dog House inside part will not clear the draft with main tooling axis so in order to clear the draft direction we will introduce tooing axis from the side which is prependicular to the face that is not clearing the draft in main tooling axis direction

Draft Analysis

Draft analysis is used to analyze whether the part model created in CAD id manufacturable based on the draft condition applied.

Draft is required on all parts in the direction of mold movement in order to allow parts to release or eject from the mold properly. Most part or application require minimum 0.5o-1o">0.5o−1o0.5�-1� as draft angle, however 3o">3o3� is widely accepted as the norm.

Procedure

• First change the view to " Customize View Parameters" and select Material option.
• Select Feature Draft Analysis from the tool bar.
• Click on the direction, drag and drop the compass to the component such that it should coincide with the tooling axis.
• Lock the draft direction and click on the component.
• Green colour shows the positive draft, cyan as zero degree and red as negative draft

Class A Surface: Class A surface is any of a set of freeform surfaces of high efficiency and quality. In other words, Class A surface is the aesthetic surface.

Class B Surface: Class B surface is the thickened suface or engineering surface where all ribs, screw bosses, dog houses etc will come.

Class C Surface: It is the Surface which joins Class A and Class B surfaces.

CLASS A+C

3D MODEL SOLID PART

DOG HOUSE Creation

• Dog houses are designed to avoid SINK MARK created on the CLASS-A surface by screw bosses and to solve the length issues when giving screw bosses which need to be assembled to other components.
• It is also useful when perpendicular screw bosses are required on the part to the tooling direction.

• C thickness should be 40% of the main wall thickness T
• Height of B should be 3-6 mm

Procedure for creating the DOG HOUSE

• Create a side core axis.
• Chose the normal to-the-point method for creating the side core tooling axis.
• Create the dog house by creating a positioned sketch on the z-x plane. Using extrude or sweep method create dog hose outer walls.

Draft analysis

CONCLUSION:

the Door Trim was created with thickness of 3mm and dog house on the solid part was created with thickness of 2.5mm as per desgin consideration and draft anylisis was done.