Week 10 - Challenge 2- Attachment Feature Creation (Dog House)
Attachment Feature Creation - Challenge 2
AIM
Create the Dog House for the Door Trim considering the design rules
INTRODUCTION
DOG HOUSE
Dog house is an engineering feature used in plastic design. Dog houses are used as support feature. Sometimes other engineering features like snaps, locators, screw bosses are mounted on them to increase their strength.
Dog houses are subjected to draft analysis to prevent breakage of the component during ejection from the mould cavity. Dog house and oher engineering components are built on the B-surface.
OBJECTIVE
- Create Tooling axis for the given CLASS -A surface.
- Create the CLASS B and C surfaces of door trim using the given CLASS-A surface.
- Create final surface model and convert it into solid body using close surface command in the part design workbench.
- Create side core axis for the dog house
- Create Dog house on the B surface by considering the design rules.
- Perform draft analysis for both Class-A surface and Final part body.
CLASS A
TOOLING AXIS
In injection molding, the Class A surface is first analyzed to determine the axis or tooling direction that separates the molds. Tooling direction is critical for plastic product design because it determines mold direction
Steps followed for Draft Analysis
- The created part must be changed to the material mode in the display frame
- Compass is enabled and placed in the direction of the Tooling Axis
- The lock command is then used to fix the compass along the tooling axis
- Color codes are classified and a Draft angle is applied
- Running point analysis is used to display permissible draft angle
which stands for 'Use the Compass to define the new current draft direction'.
CLASS B SURFACE
It is the offset surface of the Class A Surface the offset value depends on the thickness of the material, here the offset value is 2.5mm
CLASS C SURFACE
The surface that Joins both Class A and Class B surfaces is considered to be Class C Surface
CLASS A & C SURFACE
FINAL SOLID BODY
Using Solid Command, we convert the closed surface to a solid surface in the Part model
Creating B Surface Attachment Feature Dog House
Creating Dog House on B Surface
Dog houses are designed to avoid Sink marks 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 of the tooling direction.
The 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.
DOG HOUSE CREATION
RULES
Side Core Axis or Lifter Axis
The side core axis is also a type of Tooling Axis, we can say it is an additional tooling axis for sub-elements on our part body in different axis.
Here we used the axis for inside clearance for the dog house part.
Inside walls of the dog house was drafted with those side core axis at 0.5 degrees draft angle with a pilling direction of the same.
CHECKING DOG HOUSE
"C" is where the doghouse contacts the backside of the surface
Doghouse wall thickness at the intersection of the part wall (C) should be 40% or less than the main wall stock (T).
The height of (B) should be between 3.0 – 6.0 mm
C 40 % of T or ≤ T
B 3 - 6 mm
Width ≥12 mm
Width to Height Ratio 3:1
Draft 1.5
DRAFT ANALYSIS
Analysis shows the drafted walls of Attachment Feature Creation (Dog House) are 1.45 degrees which are permissible for manufacturing in injection molding
Conclusion
Creating the Attachment Feature Creation (Dog House) Plastic component through the given Class-A surface, Draft Analysis, Dog House is successfully completed.
