Door Arm Rest Week 8 Challenge
DOOR ARM REST DESIGN
The main objective is to create a tooling axis for a given Door Arm Rest by satisfying the construction of surfaces and to perform draft analysis to check if the part has given draft to the surfaces which are lying parallel to the tooling axis. Also, to create CLASS B and CLASS C surfaces from the given CLASS A surface of the door arm rest to create the solid part with proper draft standards.
DRAFT :
In engineering, draft is the amount of taper given to the surface of molded or cast parts perpendicular to the parting line.
The in build draft analysis tool used in CATIA to ensure that the faces are taper with the respect to the tooling axis. The tooling axis is the direction of mold part ejection.
The draft is provided on both core and cavity sides of the parts, which are produced using molding, to reduce damage to the surfaces during ejection.
Usually the draft angle should be 3 degrees.
CREATION OF TOOLING AXIS
STEP 1 - Create dummy tooling axis
When trying to create a point in the center of the sphere, it was generating more than one point as shown in the below figure
Create a three point rectangle in reference to the extracted surface and create a point at its center
Dummy tooling axis
STEP 2 - Create tooling axis for x-direction
Create an axis system at the reference point. Open a positioned sketch and intersect the XZ plane with the surface.
Extend the taper edges of the profile using line and create a bisecting line
Similarly, do the same for the taper on the hole
Create the bisecting line for the both x direction dummy lines, and that one is the tooling axis for x direction
STEP 3 - Create tooling axis for Y-direction
Create a line using positioned sketch and with reference to the surface as shown in the picture below
Also create extending lines for taper on holes and create bisecting line
Now bisect the both dummy axis of y direction
STEP 4 - Creating final tooling axis
Bisect both the x and y direction tooling axis to create the final tooling axis
DRAFT ANALYSIS
If we observe from the above picture, it is observed that some portions of the surface does not meet the standard drafting criteria.
This type of surface require SIDE CORE. So create the side core axis.
SIDE CORE
Create the side core axis in Y direction
Create the side core axis from both the dummy axis
Side core axis
SIDE CORE DRAFT ANALYSIS
By using side core, the effected zones are isolated
Therefore, tooling axis and side core axis created are valid.
CLASS B SURFACE
Take the point on the edge and insert an axis system. Now create a line on that edge as shown in the below picture
Extract the edge as shown in the picture and smooth the curve
Sweep the surface along guide curve
Extract the edge, un trim it and extrapolate on three edges
Combine both the ends of the surface using multisection surface. The guide used is extracted using multiple extract and the that curve is smoothed using smooth curve.
Join all three surface and create an offset surface at a distance of 2.5 mm because the thickness of the part is 2.5 mm
Extract the surface, un trim it and create an offset surface at a distance of 2.5 mm
Create an edge fillet
Trim the extra edges as shown
Extract the arm rest surface, un trim it and crate an offset surface
Do the same for other set of surfaces
Now trim the unwanted surface
To create the cup shaped surface, follow the process, extract the surface, un trim it, extrapolate the surface and offset the surface to 2.5 mm. Finally, trim the unwanted surfaces. The output after doing these are as shown in picture
Creating hole at the bottom, extract and un trim
Extrapolate the edges
join both and create an offset surface
Trim the unwanted surface
now trim the surfaces
All the required surfaces are created, Now apply the fillets. To find the fillet radius, use intersection curves
The final CLASS B surface
The final CLASS B surface
CLASS C SURFACE
Using the multiple extract feature, extract the edges of the given class A surface as shown
Smooth the curve and swept with the draft direction
Also do same for other surfaces
Join the open ends of the swept surfaces using multisection surface
Also do same on other side of the class A surface and swept the edge with the side core axis
Join both the class C edges with multisection surface
Also do same on the other side
Join all the edges to create a CLASS C surface
The final CLASS C surface
SOLID PLASTIC PART
Trim the unwanted edges
Also need to clear the hole at bottom
Sweep the surface along the circular profile
trim the unwanted edges
Final trim of the plastic part (no open boundaries found)
Adding material
DRAFT ANALYSIS ON PLASTIC PART
Draft analysis using tooling axis
Draft analysis using side core axis
From this analysis, it is concluded that, the surfaces which are not satisfying the tooling axis draft analysis are solved using the side core axis draft analysis.
Tree Structure :
Conclusion :
The draft analysis is done on the given class A surface of the Door Arm Rest, and it is found that the surfaces are having the minimum draft, and it is suitable for manufacturing. The class B and class C surfaces are created, and a solid part is created from the all surfaces.
Thank You