Week 9 - Project - A pillar Design with Master Section

A pillar Design with Master Section

Objectives

• Creation of proper tooling direction
• Draft analysis to check the feasibility of class A surface
• Creation of class A surface and class B surface
• Creation of doghous

Tooling direction

• 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.
• For given master section tooling direction is created with bisection method

Draft analysis

• For molded or cast parts, the draft angle is the amount of taper perpendicular to the parting line. It is measurable in degrees. Because plastic shrinks and sticks on molding surfaces as it cools, we draft the walls of the plastic part so that it ejects or breaks free from the molding surfaces more easily and without dragging. To reduce the risk of damage to the parts and ensure ejection, a functional injection molding part must have drafts on both the cavity and core sides.
• Nominal values for Draft angles.
• 3 Degrees is a nominal draft angle.
• 5 Degrees can also be manufactured. Increasing the manufacturing cost.
• Reduces the possibility of part damage due to friction during the release.
• Reduces mold wear and tear.
• Ensures a uniform, smooth, unscratched finish.
• Ensures the integrity and uniformity of other surface finishes and textures.
• Reduces overall cooling time by reducing or eliminating the need for unusual ejection steps.

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 Draft angle is applied.
• Running point analysis is used to display permissible draft angle.

Creation of class B surface and class C surface

• Class B
• To create the class B surface, offset the class A surface inside as per our thickness requirement (here the thickness is 3mm, so I offset the class A to 3mm inside).
• Once the offset is created, we can observe some patches on the offset surface by taking the boundary for the offset surface, those patches are formed due to the fillets on the class A surface.
• We covered the patches by using the different surface commands multi sections surface in the Generative Shape Design workbench.

• Class C
• To create the class C surface concerning the boundary of the class A surface, I used the sweep command. Initially, I extracted the boundary of the class A surface with tangent continuity, and I sweep the extracted boundary concerning the surface at 90deg (for draft angle) for 4mm to intersect properly with the class B surface.
• Once we sweep all the surface boundaries of class A, extrapolate the swept surfaces until both surfaces got intersected properly, and trim them to remove extended extrapolated surfaces to get a proper sweep boundary throughout the entire surface, including the centre hole of the bumper.
• Now, join both class A and sweep boundary to get the complete class C surface.
• Now Class A surface and Class C surface is joined.
• Now Class B surface is also trimmed with the obtained surface to get the closed surface.
• Boundary check is done to check for any Class C
• To create the class C surface concerning the boundary of the class A surface, I used the sweep command. Initially, I extracted the boundary of the class A surface with tangent continuity, and I sweep the extracted boundary concerning the surface at 90deg (for draft angle) for 4mm to intersect properly with the class B surface.
• Once we sweep all the surface boundaries of class A, extrapolate the swept surfaces until both surfaces got intersected properly, and trim them to remove extended extrapolated surfaces to get a proper sweep boundary throughout the entire surface, including the center hole of the bumper.
• Now, join both class A and sweep boundary to get the complete class C surface.
• Now Class A surface and Class C surface is joined.
• Now Class B surface is also trimmed with the obtained surface to get the closed surface.
• Boundary check is done to check for any open boundaries in the part. The closed surface then obtained moved to part design and close surface tool is used to obtain the part. open boundaries in the part. The closed surface then obtained moved to part design and close surface tool is used to obtain the part.

Creation of doghouse

• Doghouses are created by following the design rules. For this, the sketch is created from the master section provided. It is then made into a closed body and is made into a part model.
• Shell operation is performed to get a hollow structure and then coring is done in order to avoid sink marks on the class A surface. Drafts are given for the surfaces as per design rules and proper fillets are also provided. As per the given master section, ribs and supporting features are also added to the doghouse.
• Then, the doghouse is added to the main body. All the sketches used are iso-constraint.
• The height of ( B ) should be between 3.0 – 6.0 mm
• Extract the base of Class A Surface and offset it with a part thickness of 2.5 mm.
• Draw a sketch of the open rectangle and extrude the rectangle at some height of 30 mm.
• Close the upper surface face by offsetting the below-extracted surface and then after trimmed it.
• applying part thickness as 2 mm.
• Give the draft to the inside surface of 0.5 degrees.
• Doghouse wall thickness at the intersection of the part wall ( C ) should be 40% or less than the main wall stock ( T ).
• Now to create the C and B sections as shown in the design rules, offset the base surface between 3 to 6 mm.