Week 8 - Challenge 1 - Base Bracket Design
AIM: Create the Base Bracket 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.
REPORT ON DRAFT ANALYSIS
Draft
- Draft is a taper applied to the faces of the part that prevent them from being parallel to the motion of the mold opening. This keeps the part from being damaged due to the scraping as the part is ejected out of the mold.
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When developing parts for plastic injection molding, applying a draft (or a taper) to the faces of the part is critical to improving the moldability of your part. Without it, parts run the risk of poor cosmetic finishes and may bend, break, or warp due to molding stresses caused by plastic cooling.
When designing a part, apply as much draft angle as possible—a general rule of thumb is 1 degree of draft per 1 inch of cavity depth, but that can change with the aforementioned factors. Try following these general guidelines:
- 0.5 degrees on all vertical faces is strongly advised.
- 1 to 2 degrees works very well in most situations.
- 3 degrees is the minimum for a shutoff (metal sliding on metal).
- 3 degrees is required for light texture (PM-T1).
- 5 or more degrees is required for heavy texture (PM-T2).
Tooling Direction
The Tooling Direction is basically the direction that the mold pulls apart. The mold is built in two separate pieces, basically. You have a Cavity side and you have the Core side.
- In Molding machine arrangement is given to open the mold along a direction which is known as Tooling Direction.
- In other words. The mold is built from two separate halves (Core and Cavity) and tooling direction basically define the direction of mold pulls apart.
- Tooling direction is known as primary direction.
Case Study
Given Class A Surface:
STEP 1: Check the connectivity of the Class A Surface
Ensure that there is no gap between the component, using join command.
We can visually check it or by clicking boundary command.
It has 3 boundaries one outer and two inner circle boundaries.
Therefore first check completed.
STEP 2: Find the tooling axis of the component. The tooling axis is nothing but the mold & cavity opens.
Check visaully which is the best possible tooling axis.
Check all three axis.
Along x it possible but expensive and y is not possible.
z is the best possible tooling axis.
Creating a dummy Tooling axis along z:
Therefore the main tooling axis is along z-axis.
Now perform the Draft analysis using the Featured Draft Analysis tool in the tools.
Then after opening the draft analysis toolbox go for the compass and place the compass aligned to tooling axis and click on the lock symbol after alinging and further click on the surface.
Bisecting Method
In our case study to creat the tooling Direction we use Bisecting Method it is basically use to find the proper tooling axis using the dummy tooling axis. In Bisecting method, bisecting line is used which either bisect the two line or it will show error which means the two lines are parallel to each other. In order to know whether the particular surface is tool able or not we intersect the surface with the respective plane and get a sketch which consist of two lines and with the help of bisecting line option we bisect the line which creates a line at the mid point of the two lines. Like wise we create tooling clearing axis for x and y which will be used to create the main tooling axis using the bisecting line option in in the line comand
Class B Surface
Intially extracting the right side rib using extract option from Class A surface.
Then perform Extrapolate inorder to increase the length
Now trim the surfaces to required surfaces
Then Offset the surface inorder to get the required thickness
Similary create the left side rib
Now Similarly get the slanted as well as the flat surface and offset it to desired value
And now trim inorder to get the required surface
Now fillet the surface to required amount
Class C Surface:
Useing the Boundary command on outer surface a and swpet it with 3 Degree And also swpet the 2 hole whitch present in surface A and joind the surface A and c with those 2 hole
For final surface we triam surface A and C with surface B
Converting to surface to solid We use Close Surface command
Draft Analysis
To check Draft Analysis With a Proper angle (max 3 degree)
Draft analysis for Class A Surface (Input) Plastic Component
Draft analysis for Final Plastic Component
Tree Stracture
Drawing view
Final ABC Surface
Part Body
Isometric View
Frount view
Side View
1.Left side view
2. Right side view
Top View
