Door Applique Design with Engineering Features

OBJECTIVE

Design the Driver Door Right Hand Applique with Locators and Fixtures to assemble it onto the main inner door panel.

LOCATION PRINCIPLE

• The 3-2-1 or 6 Point Location principle is used to constrain the movement of the workpiece (to be machined/fixed) along the 3 axes XX, YY, and ZZ.
• It is achieved by providing 6 pin locations:
  • 3 on Base plane.
  • 2 on Vertical plane.
  • 1 on the plane perpendicular to the first two planes.
• Every object has 12 DOFs and a minimum of 11 should be fixed/arrested.

HEAT STAKING

It is a plastic welding process that joins 2 dissimilar materials (Plastic-Plastic/Plastic-Metal) by controlled melting and reforming.

• The plastic stud protrudes through the hole of the parent that is to be locked with.
• The heated thermal tip contacts the top of the stud at constant pressure and melts it.
• The melted stud fills the volume of the tip cavity to produce the head for locking.

Note: The right combination of Heat and Pressure is required.

Advantages

• Simplification of Machinery.
• Reduces cost of Machinery.
• Multiple fastening points.
• Higher weld density, compared to Hot air Cold form welding or Ultrasonic welding.

PROCEDURE

STEP 1: CHECK CONNECTIVITY

We have to ensure that the Class A Surface is connected as one single profile. We can do that with 2 options:

Visually	Using the Join option. This option is efficient but not effective.
Manually	Extracting the Boundary of the Class A surface. This option confirms better.

APPLIQUE	COUNTERPART

STEP 2: FIND THE TOOLING AXIS

• Tooling Axis is the direction in which the Mold(Core-Cavity) Perpendicular lines always.
• Place the component on each plane (XY/YZ/ZX) and find the desirable tooling direction.

[Note: The plausible tooling axis is perpendicular to a Hole or large flat surface so look for those features when selecting.]

• So we need to create a midpoint on the plane perpendicular to the tooling axis.

Holes	Use Multiple extracts to get the Boundary and define a midpoint using the "Curve/Circle" option.
Flat Surfaces	Extract the surface and then create a mid-point using the "On Surface" option.

• Now, introduce an Axis system at the Midpoint. This will act as a reference coordinate system.

STEP 4: DRAW THE TOOLING/DRAFTING AXIS

• We employ the Compass method to determine the Tooling axis as it serves to the the most efficient, by saving us time and effort.
  • Use the "Measure Inertia" tool to get the Centre of gravity and the co-ordinate system of the selected surface.
  • Extend a Line along the Axis that is perpendicular to the surface, that will be our Tooling axis.

STEP 5: DRAFT ANALYSIS FOR CLASS A

Insert > Analysis > Feature Draft Analysis

Note: Ensure you have the Material view mode ON.

• Define the Draft direction using the "Compass" option.
  • Drag the Axis system representation close to the model and align it along the tooling axis.
• "Lock" the Draft direction.
• Set the Colour scale

Colour	Description	Value
Green	Core Side	Above 3 degrees
Blue	Parting Line	0 degrees
Red	Cavity Side	Below 0 degrees

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Method 1: Manual Selection	Method 2: Visual Selection
Analyze each feature manually. Place the Arrow icon on each feature to check if it passes the minimum draft angle. We can distinguish each feature's angle using the colour scale.	Directly choosing the plane (XY/YZ/ZX), that would pose fewer problems for tooling. This also ensures that the features (fillets) are captured on that plane. Analyze the entire geometry at one go.

Method 2 is more efficient as it gives us an overall result of the draft analysis without manually picking any feature.

STEP 6: B SURFACE CREATION

Note: Depending on the geometry, the extraction and offset of the fillets might generate non-uniform thickness. So it is advisable to extract only the flat surfaces and then apply fillets at the end of Class B formation.

Perform the following operations in the order:

EXTRACT	Choose the respective A surface and extract with no propagation option.
UNTRIM	The extracted surface will possess the specific trimmed. Untrim to get the basic geometry.
EXTRAPOLATE	The surfaces have to overlap each other in order to facilitate trimming therefore extrapolate it up to the required dimension.
TRIM	Trim the surfaces according to the required geometry.
OFFSET	Now, Offset the Trimmed geometry by the value of the thickness of the component. This Offset is our B Surface.
FILLET	Extract the Fillet surface from Class A. Untrim to get the basic Geometric shape. Measure the uniform radius of the surface. Apply Fillet to the respective edges to get the desired finish.

Note: The fillet radius of the Class B offset is altered to maintain the uniform thickness throughout the geometry.

Offset direction	Fillet Radius
Inward	Initial Radius - Thickness
Outward	initial Radius + Thickness

APPLIQUE	COUNTERPART

STEP 7: C SURFACE CREATION

C surface is the part of the geometry that connects Class A with B surface.

Rules to be followed. for C surface creation:

• A minimum draft of 3 degrees should be provided to facilitate the Ejection of the Molded component.
• The parting line should be on the B surface. This means that the draft should sweep outwards, from the C surface.

Perform the following operations in the order:

MULTIPLE EXTRACT	Extract only the Boundary by Tangential selection.
CURVE SMOOTH	We need minimum Parting lines as possibles, so smoothen the extracted boundary.
SWEEP	Based on the Geometry of the Coin Holder, the C surface is perpendicular to the tooling axis. Therefore, we Sweep with Reference Surface: Profile: Select the Smoothened Curve Reference Surface: Select the adjacent surface Draft Angle: 3 Degrees
MULTI-SECTIONS SURFACE	In places like Fillets where the Sweep option doesn't work, we can fill in the gap using MSS. Choose the Sections. Then choose the Guide Curve(extracted profile of the boundary) along which we can drag the profile.
EXTRAPOLATE	The Edges of the Swept C surface need to overlap in order to trim the adjacent surfaces at the corners. So give minimum extrapolation so that they can overlap and accessible for trimming.
TRIM	To get a clean edge/corner we have to Trim the overlapping edges.
JOIN	For our future reference, we can Join all the C surface sweeps as one single entity.

APPLIQUE	COUNTERPART

STEP 8: TRIM THE SURFACES A, B & C

• First Trim/Join Class A with Class C.
• Then Trim with Class B and keep the respective surfaces.

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STEP 9: CLOSED BODY

• Switch to Part Workbench.
• Define the part body.
• Select the closed surface trim to fill it with volume.
• Now we have a solid body with a certain volume and density (depending on the material we give).

STEP 10: CLOSED BODY DRAFT ANALYSIS

All the 3 class surfaces must pass in this analysis.

Insert > Analysis > Feature Draft Analysis

Note: Ensure you have the Material view mode ON.

• Define the Draft direction using the "Compass" option.
  • Drag the Axis system representation close to the model and align it along the tooling axis.
• "Lock" the Draft direction.
• Set the Colour scale

Colour	Description	Value
Green	Core Side	Above 3 degrees
Blue	Parting Line	0 degrees
Red	Cavity Side	Below 0 degrees

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• Place the Analysis Tool (Arrow Icon) anywhere on the model and review the colours on the feature.
• If any feature (especially C surface) is showing Blue/Red then choose the same option again (It will switch to Analysis under Running point) and place on the respective feature to review the deviation of the sweep angle from the Tooling Axis.

STEP 11: OPERATIONS PERFORMED

Extrude	Create a straight line sketch using the surface as support. In the Surface workbench, Extrude the line in the direction of the Tooling axis.
Thickness	Go to the Part workbench and add Thickness to the extruded surface. We now have a solid rib of definite volume and density.
Draft	Give Draft of 0.5 degrees on all the vertical faces of the rib. This is done for easy ejection of the Core and to avoid any damage to the molded component.
Boolean	Boolean Add/Union Trim the Rib to the Coin holder body.
Fillet	We provide rounded corners at edges to facilitate easy flow rate and avoid Flowlines.

11.1 LOCATORS

• We have to design the 3-2-1 location principle to arrest the applique onto the inner door panel.
• Therefore, we employ:

Type of Locator	Quantity
4 Way Pin	2
2 way Pin	1

• No. of DOFs arrested = 11.

11.1.1 DESIGN GUIDELINES FOR 4 WAY AND 2 WAY LOCATORS

Draft	0.5-1.5 Degrees If it is more, then the rib will be too narrow at the top and mold wouldn't fully fill the rib.
Thickness	(0.4-0.5) T at the base of the rib. The larger the area of the base of the rib, the more heat retained. Retained heat causes more shrinkage. This leads to Sink marks as well. Minimum 0.75mm at the Tip of the Rib. Molten material won't reach any further.
Fillet	Maximum radius = 0.25 mm. Due to the less thickness of the rib we need to maintain a small fillet radius, or else we'll get ribbon formation.
Height	Height `<=` 5T Taller ribs are prone to buckling.
Base Rib Root Dia	D `<=`30% of Deviation from Thickness. Greater than that causes Sinkmark.
Spacing between Ribs	Heigh t: Weight = Y : X 3:1 is allowable. 2:1 is preferred.

4 WAY LOCATOR	2 WAY LOCATOR

11.2 HEAT STAKES

The guidelines for Heat stakes are given below:

Diameter	There are no standards for Dia, it depends on the manufacturer. The dimension is altered in such way that sink marks are avoided.
Thickness	There is no standard for thickness as well, but keep it lesser than the part thickness. Minimum 0.75mm at the Tip of the Rib. Molten material won't reach any further.
Height	Height of Heatstake < Height of Locator Since Fixing occurs after Locating.
Draft	0.5 degree.
Flat plate	Dia of Flat Plate = 2.5 x (Dia of Heat Stake).
Clearance	0.1mm to accommodate for clearance.
Spacing	50-100 mm

HEAT STAKE	FLAT PLATE

STEP 12: FINAL DRAFT ANALYSIS

All the Heatstakes, 2 way and 4 way pins must pass the draft analysis.

Insert > Analysis > Feature Draft Analysis

Note: Ensure you have the Material view mode ON.

• Define the Draft direction using the "Compass" option.
  • Drag the Axis system representation close to the model and align it along the tooling axis.
• "Lock" the Draft direction.
• Set the Colour scale

Colour	Description	Value
Green	Core Side	Above 0.5 degrees
Blue	Parting Line	0 degrees
Red	Cavity Side	Below 0 degrees

• Place the Analysis Tool (Arrow Icon) anywhere on the model and review the colours on the feature.
• If any feature is showing Blue/Red then choose the same option again (It will switch to Analysis under Running point) and place on the respective feature to review the deviation of the sweep angle from the Tooling Axis.

APPLIQUE	COUNTERPART

RESULT

• The Driver Door Right Hand Applique is designed with the features listed below, following the design guidelines:
  • 4 way locators
  • 2 way locator
  • Heatstakes
• The DOFs are arrested in 11 directions, allowing the applique to assemble onto the inner door panel.

APPLIQUE: FIRST ANGLE PROJECTION
COUNTERPART: FIRST ANGLE PROJECTION
TREE STRUCTURE: PART WORKBENCH OPERATIONS
TREE STRUCTURE: SURFACE WORKBENCH OPERATIONS