Week 9 - Project 1 - Door Trim Lower with Engineering Features

DOOR TRIM LOWER WITH ENGINEERING FEATURES

AIM :

• Create the Door Trim Lower 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.

DESIGN PROCEDURE :

• Checking Class A input for imperfections

The input class A surface is checked for discontinuities and joined together to get complete class A surface as one.

• TOOLING AXIS :

The tool axis is the parameter which decides whether the tool enters into mould or not as as it denotes the draft clearance angle where a moulded part is easily removed from the mould.

Procedure for creating tooling axis

• Firstly we will be given with a class A surface which is looked as a asthetic and a smooth finish which is created with a Alias software workbench which is also known as a free imagination surface.
• For that class A surface we need to check a boundaries first to check any unattached faces is present in that surface.
• The below is the image of a class A surface which is given as a input.
• So next we need to take a dummy tool axis to get a real tool axis.
• Next we take inclined lines to the surfaces we assume that draft is required.
• Then we intersect the both the lines and the bisecting line will be the tooling axis.

• DRAFT ANALYSIS OF GIVEN CLASS A

• No parts can be ejected from the tool if it is having a straight 90 degree profile from its base surface. A small draft angle is provided to each and every area of the component in order to get an easy removal of the component from the tool.
• Draft analysis technique is used to analyze whether our part model created in cad is manufacturable based on the draft condition applied. Here the part should get easily removed from the panel dies (in case of Sheet metal part) or Mold (in case of plastic).
• Here we are providing a direction in which components should eject inorder to get an easy removal of components from the tool. In other words it also lets us know whether the model is having a draft angle and how much is the draft angle from the tool direction.

• B surface creation

As usual, B surface is created using standard procedure by extract, untrim, extrapolate and offset commands. B surface of this coin holder is divided as base, side walls, top wall and outer surface. B surfaces of all these sub parts are created and trimmed together to join as single surface.

The offset distance is kept 2.5mm as component thickness is 2.5mm

• Class C surface creation

Class C surface for this component is created using sweep command. All the ends of component surface are facing downwards, so the C surface will be created perpendicular to B surface.

To create C surface, boundary of class A surface and surfaces adjacent to boundary are extracted. Then sweep with reference surface command is used and surface is created at 90 degree.

• Creating final closed volume, converting in solid body and draft analysis.

Once all surfaces are created, Class A, B and C surfaces are joined together to get the final closed volume. This closed volume is then converted into solid body using closed volume command in part design work bench.

• Draft analysis of final closed body

Draft analysis is done on final component to check manufacturing ability. The walls of the bin are having zero draft angle with tooling axis. This will be ignored since it is given in class A surface.

B-SIDE FEATURES

Creations of the Heat Stakes and the locators considering the design rules

INTRODUCTION -

3-2-1 Principle:

Locating Process: In order to completely specify the position in space of a three-dimensional object (such as the cube that’s shown), we refer to six coordinates with total 12 degrees of freedom.

1. Translational position along the X-axis
2. Translational position along the Y-axis
3. Translational position along the Z-axis
4. Rotational position about the X-axis
5. Rotational position about the Y-axis
6. Rotational position about the Z-axis

These six coordinates are known as the six degrees of freedom of a three-dimensional object. As the double-headed arrows indicate, the translational and rotational positions can vary in either direction with respect to each of the three axes. To completely prevent movement, all six degrees of freedom must be restricted.

LOCATORS -

Primary locator - First the 3 locators or support are placed in the workpiece. It will be positioned on the primary locating surface also known as datum. It will resist 5 degrees of freedom.

Secondary Locator -The next two locator are normally placed on the secondary surface restricting 3 degrees of freedom.

Teritry Locator - This locator is positioned at the end of the part. It resists 1 degree of freedom.

2-Way Locators :

These are the locators which arrests 2 degrees of freedom by a single rib.

- Iso-constrained sketch :

- Part Body :

- Draft Analysis Of 2 Way Locators with 0.5 degree :

4-Way Locators :

These are the locators which arrests the 4 degrees of freedom by four ribs junctional together. These are of following type especially used for mold designs.

- Iso-constrained sketch:

- Part Body :

- Draft Analysis Of 4 Way Locators with 0.5 degree :

HEAT STAKING -

Heat Staking is a pulsed-heat process to join two or more parts out of which one at least is made of plastic. The process is to deform the plastic material using heat and force at a set process time. The bond is made by partially de-forming the plastic part in order to fix the other. Heat Staking makes it easy to bond metal to plastic and is commonly used in high volume/low cost applications such as automotive, IT and consumer appliances.

Shaping Plastic Using Heat and Pressure :

The plastic is deformed by heating it to a temperature above the glass transition temperature. Super-heated air or a thermode is used for this. Pressure is then applied to create the stake. After the stake has been formed, the plastic should be cooled down again below the glass transition temperature. Cooling is performed under constant pressure to ensure good fixation of the parts. Compressed air can be applied for cooling when a thermode is used. Heat is used to facilitate the creation of the stake. Heat control is critical, especially for glass-filled plastics which often have a process window of less than 10 degrees Celsius. When the temperature is too high, the glass fibres come out of the plastic which leads to a rough surface and adhesion to the thermode. If the temperature is too low, the plastic will crack due to cold deformation.

Heat staking Benefits :

1. Similar and dissimilar materials may be joined: metal to metal, plastic to plastic, metal to plastic
2. Accurate control operating within a small process window
3. Local heating resulting in no damage to surrounding materials
4. Processing of glass-filled materials
5. No mechanical vibration
6. Many heat-stake shapes possible through custom designed tools

Heat Stakes Design :

• First, extract the class 'A' boundary and use parallel curve commapnd to offset the extracted curves.
• Use point and plane repitation command for points on the curves.
• Create sketch by taking door attachment class 'A' surface as refrance.
• Pad the sketch upto certain limit and use design rules as per Screw boss design.
• Use 0.5 degree draft with pulling direction as tooling axis.
• Give Fillate
• Union Trim with Door Applique.
• Use Translet command for number of same locators.

- Iso-constrained sketch :

- Part Body :

- Draft Analysis Of Heat Stakes with 0.5 degree :

FINAL COMPONENT DOOR TRIM LOWER WITH ENGINEERING FEATURES (HEAT STAKES & LOCATORS)

-- DRAFT ANALYSIS ON THE FINAL COMPONENT :