Week 9 - Project 1 - Door Applique Design with Engineering Features

AIM:
Create the Door Applique Plastic component through the given Class-A surface. To begin with, the tooling axis for the
given Class-A Surface should be created meeting the requirements of the draft angle and at the end perform the Draft
analysis on the model.
Create the Heat Stakes and the locators considering the design rules mentioned in the video for the door applique.
CREATING A TOOLING AXIS :
tooling axis is created by class A surface

Door appliqué surface:

Door attachment surface:

Theory:

Heat stakes:

In manufacturing products with thermoplastic components, it is often necessary to join a thermoplastic to a part of dissimilar material, whether it to be metal, a dissimilar plastic, or other material.

Thermal staking is an assembly method that uses the controlled melting & reforming of a plastic stud or boss to capture or lock another plastic or metal component of an assembly in place. The plastic stud protrudes through a hole in the component to be locked in place. The heated thermal tip contacts the top of the studs, which melts & fills the volume of the tip cavity to produce a head, locking the component in place

3-2-1 Principle of Location-

The 3-2-1 principle of location (six-point location principle) is used to constrain the movement of the workpiece along the three axes XX, YY, and ZZ. This is achieved by providing six locating points, 3 pins in the base plate, 2 pins in the vertical plane, and 1 pin in a plane that is perpendicular to the first two planes.

The degree of freedom defines as the capability of a body to move. Consider a rectangular box, in space the box is capable of moving in twelve different directions (six rotational and six axial). Each direction of movement is counted as one degree of freedom.

i.e. a body in space has twelve degrees of freedom.

The above figure shows a body in space and its possible direction of movement. The body can move in two directions along each axis of three mutually perpendicular axes; also can rotate about this axis either clockwise or anticlockwise. There are twelve degrees of freedom for a body in space.

In the machining process, in order to attain specific results, the degree of freedom is constrained by using work holding devices, jigs, and fixtures and locating devices.

M method followed:

1. Checking continuity of class A
2. Decidingfeasible tooling direction & creating tooling
3. Performingdraft analysis on class A
4. Creating class B surface from given class A
5. Creating class C surface to join A & B class
6. Creating solid features by using closed
7. Creating4 way & 2 way
8. Creating heat
9. Creatingclearance holes for locators & heat stakes on the attachment part

10 Performing draft analysis on the final component

1. Checking continuity of class A

We have to check the continuity of the given class A surface to ensure the class A surface is properly joined or no discontinuity is present. This can be done by using the join or boundary command. By looking visually below the image we see that surface has continuously connected boundaries as highlighted by green.

2. Creating tooling axis direction:

The tooling axis is created by bisecting method. First, analyze the model. Check tool clearing direction i.e. X, Y, or Z. Perpendicular faces to tooling direction will not create a problem. we have to look for inclined faces. Take the intersection of inclined faces with the respective plane. Create line on that inclined face. Finally, make the bisecting line between the inclined lines.

But in this door applique, class A has most of the flat surface. So we have to create a tooling direction perpendicular to it i.e. in the Y direction. Create a point at the center of class A surface by using the point command & create a line passing through that point in the Y direction & publish it as a tolling axis.

3. Performing draft analysis on class A surface:

To perform draft analysis. Go to insert < Analysis< Feature draft analysis.

Switch customize view parameter mode to

Click on the compass icon & align it with the tooling axis & click on the surface, we will get our results.

Color scale variant of draft analysis:

From the below image it is seen that surface in green color has a 2.5 draft which is most required for tooling feasibility. Also, see the color variant display box. we provided all green color surfaces have +ve draft value also blue color surfaces show 0° draft whereas surfaces in red color have a draft.

4. Creating class B surface from given class-A surface.

Dividing class A surfaces in two as shown by different colors & extract them separately.

Offset it by 2.5mm as the thickness of the component.

Extrapolate both surfaces 5mm with tangent continuity so these surfaces intersects with each other.

Apply bi-tangent fillet to these surfaces. Measure class A surface fillet. It is 13.5 mm. so keep the fillet value 11mm (class A surface fillet – thickness of component).

Extrapolate filleted surface over all boundaries at value 5 mm to have an intersection with class A & C later. This is B class surface. Now publish it.

5. Creating class C surface to join class A & B surface

Extract the boundary of the class A surface in two separate curves. To do this we have to give limiting points in the boundary command pop-up box.

Then sweep these curves along the main tooling direction with a 3° draft. So we get two surfaces.

But we observe the gap between these two surfaces that these surfaces do not intersect with each other. So we have to extrapolate these surfaces at both ends to intersect with each other.

Trim these together to get the final C class surface.

TRIM Class A & C surface together

Then trim this join with B class surface to obtain a closed surface.

6. Creating solid features by using a closed surface.

A solid model is created from a closed surface in the part workbench by using the close surface command.

7. Creating 4-way & 2-way locators for fixing appliqué.

Now we have to fix this door appliqué with the given door attachment. To fix this we need locators & heat stake.

Assign 2 mm thickness to attachment surface in part workbench by thick surface command.

4 way & 2-way locators:

Create a point on the attachment surface in the middle by using the point command.

Create a plane parallel to the ZX plane & passing through the center point. This plane we used to create profiles of locators.

Make a profile of a 4-way locator. Draw a positioned sketch on the plane.

Pad this profile with thick feature & assign 1.3 mm thickness. Keep profile as neutral fiber while assigning thickness to get equal thickness on both sides.

Add 0.5° draft to the faces of the locator with pulling direction as tooling axis base as a neutral element.

Give entry chamfer 3*45° & also give 3mm fillets to chamfered edges.

Give 0.25 mm fillet to all other edges.

Create a copy of the 4-way locator body in the main part. Copy locator body & past special as result with a link.

Translate copied body to the desired position by use of coordinate within door appliqué area. Make sure both locators should be at the same height.

Use Boolean operation. Union trim locator body with door appliqué.

Similarly, follow the above same procedure & create 2-way locator.

8. Creating heat stakes.

Extract class-A surface & offset it to 2.5mm. Extract the boundaries of class A surface with tangent continuity in two separate curves.

Create parallel curves for both boundaries at 15mm on the respective surfaces.

Create multiple points on two parallel curves by the point & plane repetition command. These points represent center of heat stakes. Make sure there is sufficient distance between heat stake & locator. To do this, adjust point instances accordingly.

Make a heat stake profile. Draw a positioned sketch at any one point.

Pad this sketch & add 0.5° draft to faces. While padding makes sure the heat stake height should be less than the locator height. The door appliqué must be located properly in place then it should be screwed.

Provide 0.25 mm fillet at the top outer edge of heat stake.

Now we have to make heat stake at every point on parallel curves. So, Copy this body & paste special as result with the link in the main part. Create no. of the body equals no. of points.

Give point-to-point reference & translate heat stake to all created points.

Assemble all heat stake bodies. Use Boolean operation & union trim all heat stakes with door appliqué.

Add 0.25mm fillet at the base to all locators & heat stakes.

9. Creating clearance holes for locators & heat stakes on the attachment part

Door appliqué is an ornamental part of the door & to locate it with the door we need clearance holes on the counterpart. Provide 0.1mm clearance for locator & 0.5mm for heat stake.

Clearance hole for locator:

To create a clearance hole make a cylindrical body & remove it from the attachment body.

A clearance hole should be created at the same reference as the locator. Use the same locator sketch by copying & paste. Make another element as construction & draw a new circle at the center.

Use Boolean operation & remove form counterpart. Hence we get a clearance hole for 4-way locator.

Create another instance by using copy & paste. Translate it to other locator positions by using coordinate. Use Boolean operation to remove from counterpart.

Ensure clearance is around 0.1mm. If it is not around 0.1 then change the pad value or modify the sketch accordingly. A little deviation is accepted.

Images of the solid model with the proper color code of the draft angle in various orientations