Week 9 - Attachment Feature Creation - Challenge 2

DRAFT ANALYSIS OF SCREW BOSSES & DOG HOUSE OF COIN HOLDER

Objectives:

To design SCREW BOSSES & DOG HOUSE of COIN HOLDER & add thickness to it.

To perform draft analysis on final component of COIN HOLDER part model.

Creation of SCREW BOSS on COIN HOLDER:

First, extract bottom surface of COIN HOLDER part model using EXTRACT option.

As per guideline of BOSSES, height to diameter ratio should be 3 : 1. Here height is 12 mm, so diameter will be (12/3) = 4 {Minimum value}. I have applied 5.2 mm for inside diameter of BOSS.

Now, draw two circles of diameter of 5.2 & 8.2 mm respectively as shown in figure.

EXTRUDE it upto 12 mm in direction of Z axis.

Give 0.5° draft around its circular face in Z direction.

Here this SCREW BOSS requires support around its periphery.

We need to create RIBS as shown in figure. Relations are given with these two lines.

Height of RIBS is 10 mm & thickness is 1 mm.

Give these RIBS draft about 0.5° and use UNION TRIM with cylindrical boss to remove inside cross body. Apply fillet of 0.25 mm all over this UNION TRIM.

Now, create center point of the BOSS by using extract and point.

Then create a new plane by referencing XY plane and newly created point. Use INTERSECTION to create an INTERSECTION CURVE with this SCREW BOSS.

One can see that RIBS around BOSS aren’t aligned with center. Here one must select neutral fiber option while creating RIBS.

Copy this final body of SCREW BOSS and TRANSLATE it as shown in figure. This way, 2 SCREW BOSSES are created.

Creation of DOG HOUSE on COIN HOLDER:

First, extract bottom surface of COIN HOLDER part with SCREW BOSS model using EXTRACT option.

Now, EXTRACT a center point from boss hole on this surface.

Create a new plane on center point of the TRIM and parallel to ZX plane.

Make a sketch for 3 WALLS of DOG HOUSE on the surface as shown in image.

Use SWEEP surface with draft direction option for this sketch. Apply 1.5° draft in TOOLING AXIS direction.

BOTTOM surface of CLASS-A is untrimmed & offset to upper side. Now, use TRIM to join this offset and sweep surface.

Apply 1 mm fillet on 2 surfaces of this TRIM. Add 2 mm thickness to outside of this TRIM.

Now, EXTRACT inside 3 surfaces from this solid body as well as OFFSET Class A surface upside further about 4 mm.

Again, OFFSET inside surfaces about 1 mm outside and EXTRAPOLATE them about 3 mm. Do untrim & extrapolate for OFFSET of Class A surface.

Do FINAL TRIM for WALLS surfaces and bottom Class A surface.

Use FINAL TRIM for splitting solid part body of DOG HOUSE WALLS.

Apply 0.5° draft on the split edge inside this solid body and also apply 0.5 mm fillet on both edges.

In this way, DOG HOUSE is created on COIN HOLDER.

Change length of 2 RIBS from earlier and Translate SCREW BOSS about 23 mm to place it over the DOG HOUSE & assemble it. This will be our FINAL OUTPUT.

In this way, SCREW BOSSES & DOG HOUSE are created on given part model according to guidelines.

Steps to do draft analysis on COIN HOLDER model:

Go to insert > analysis > feature draft analysis or directly click on Feature draft analysis icon from menu.

First select compass option from pop-up menu to set axis system coincide with tooling axis.

Here change position of TOOLING AXIS by moving compass location and use lock option to fix it to give every surface a proper draft.

Surface model will turn into green colour surface, which shows that draft for model is in limit upto 3 degrees. Here I have given green colour for 3 degree draft, light blue for 0 and red colour for negative draft.

Run quick analysis on model and if any draft angle is more than limit, then one can apply new value of it in pop up box.

Full analysis shows different draft angles with different colours as shown in figure.

Here is an example of INVERT DRAFT DIRECTION analysis.

Below image shows the different views of draft analysis of COIN HOLDER model.

Here are snaps of QUICK ANALYSIS, FULL ANALYSIS & INVERT DRAFT DIRECTION as well as different VIEWS in direction SIDE CORE AXIS:

Here are snaps of feature tree of this COIN HOLDER model:

Conclusion:

I have learned about creation of SCREW BOSSES & DOG HOUSE for COIN HOLDER model in this challenge.

Also, I understand the importance of SCREW BOSSES & DOG HOUSE design in terms of industry guidelines.