Week 12- Final project

AIM :- Creation of CAD model considering following inputs as like in OEM and tier1 companies.

OBJECTIVES :-

• To create individual tooling axis for the parts and perform draft analysis on the class A surface
• To create the class B and class C surfaces from the given class A surface
• To form a solid geometry by combining all the surfaces
• To decide an attachment strategy for the part and create engineering features in reference from the master section provided
• To perform draft analysis on the solid part model with all engineering features
• To assemble all the components togehter to obtain the final trim.

INTRODUCTION :- Next to the dashboard, the door trims are the interior parts that contain most of the controls and decorative parts the door trim comprises of various components such as the arm rest, map pocket, switch bezel, speaker and other electronic regulators and aesthetic trims designed in a way to enhance the user experience of the driver and the passenger. The plastic trim is attached to the sheet metal component which is the door inner with the help of various engineering features such as push clips, heat stakes etc.

METHODOLOGY :-

ARM REST :-

PRE-DESIGN CHECKS :-The class A surface of the arm rest received had a small opening near the edges as shown below. Join operation was used to close the opening in the surface.

IMPROVED CLASS A SURFACE :- With the help of extraxt, trim and spline command, repair the class A surface and make it smooth.

TOOLING AXIS :- Due to complexity of the surface was impossible to clear all the surfaces in a single tooling axis and hence two tooling axis where created as below.

SIDE CORE AXIS :-

DRAFT ANALYSIS OF IMPROVED CLASS A SURFACE :-

CLASS B SURFACE :- Class B surface is created by offseting class A surafce by 2.5 mm as per the mastersection. After offseting some area not get offseted , there patches formed. This patches are closed by surface creation features such as extract, boundary and multisection, etc.

CLASS C SURFACE :- C surface is the connecting surface of class A and class B surface. By using Sweep we created the class C surface. For that first we have to creat boundary and sweep and then with draft direction and with reference surface at angle 90 degree and 93 degree we have sweep the class A boundary and we get the Class C surface.

CLOSED BODY OF ARM REST :- By trimming join of class A ,C with class B surface we get close body.

SOLID BODY OF ARM REST :-

DRAFT :- The draft is something that allows the componenet to release or eject from the mold properly. The draft is required on all parts in the direction of mold movement in order to allow parts to release properly. Most parts or applications require a minimum of 1/2 to 1 degree, however 3 degrees is widely accepted as the norm but i use 2.8 degree. The draft is given in the direction of tooling direction or core cavity opening. If we don't give the draft to the component it strick to the mold and friction alos act so we get the damage in our part so to overcome this we give some draft angle to overcome this problem.

As mentioned above we have two tooling axis for Arm rest.

Following images give the idea about is it manufacturable or not.

ENGINEERING FEATURES :-

FLANGE :- Flanges were created on the arm rest with the reference dimensions from the master sketch provided. The purpose of the flange was to provide slots for the heat stakes and locator which are required to assemble the two components together and constraint the motion between them.

From above draft analysis we notice that given part is not as good to manufcature. There is lot of modification needed. We have to request styling team to improvement in class A at particular areas.

TREE STRUCTURE :-

MAP POCKET :-

PRE-DESIGN CHECKS :- The class A surface provided for the map pocket was checked for openings with the aid of boundary feature. There were no openings found in the class A surface and hence the same surface was used in future operations.

TOOLING AXIS :-

• First a dummy tooling axis is drawn along the Y direction with the axis system and the centre point as reference
• If the draft analysis is cleared with the dummy tooling axis then it is considered as our main tooling axis if not then the tooling axis is created with the help of bisecting method. In our case the dummy tooling axis was able to cover all the faces with the required draft angle and hence was taken as the main tooling axis.

SIDE CORE AXIS :-

DRAFT ANALYSIS OF CLASS A SURFACE :-

CLASS B SURFACE :- Class B surface is created by offseting class A surafce by 2.5 mm as per the mastersection. After offseting some area not get offseted , there patches formed. This patches are closed by surface creation features such as extract, boundary and multisection, etc.

CLASS C SURFACE :- C surface is the connecting surface of class A and class B surface. By using sweep we created the class C surface. For that first we have to creat boundary and sweep with reference surface at angle 90 degree get the Class C surface.

CLOSED BODY OF MAP POCKET :- By trimming join of class A ,C with class B surface we get close body.

SOLID BODY OF MAP POCKET :-

DRAFT ANALYSIS ON FINAL PART :-

ENGINEERING FEATURES :-

FLANGE :- Flanges were created on the map pocket with the reference dimensions from the master sketch provided. The purpose of the flange was to provide slots for the heat stakes and locator which are required to assemble the two components together and constraint the motion between them.

TREE STRUCTURE :-

BOTTLE HOLDER :-

PRE-DESIGN CHECKS :- The class A surface provided for the bottle holder was checked for openings with the aid of boundary feature. There were no openings found in the class A surface and hence the same surface was used in future operations.

TOOLING AXIS :-

• First a dummy tooling axis is drawn along the Y direction with the axis system and the centre point as reference
• If the draft analysis is cleared with the dummy tooling axis then it is considered as our main tooling axis if not then the tooling axis is created with the help of bisecting method. In our case the dummy tooling axis was able to cover all the faces with the required draft angle and hence was taken as the main tooling axis.

DRAFT ANALYSIS OF CLASS A SURFACE :-

• The class A surface provided had less or negative draft angle on certain surfaces. When trying to clear those faces the draft angle on other faces seemed to get compromised
• This could only be solved by the Class A designer by ensuring the minimum draft angle of 3 degrees is provided in the critical areas of the class A surface.

CLASS B SURFACE :- Class B surface is created by offseting class A surafce by 2.5 mm as per the mastersection.

CLASS C SURFACE :- C surface is the connecting surface of class A and class B surface. By using sweep we created the class C surface. For that first we have to creat boundary and sweep with reference surface at angle 90 degree get the Class C surface.

CLOSED BODY OF BOTTLE HOLDER :- By trimming join of class A ,C with class B surface we get close body.

SOLID BODY OF BOTTLE HOLDER :-

DRAFT ANALYSIS ON FINAL PART :-

ENGINEERING FEATURES :-

FLANGE :- Flanges were created on the bottle holder with the reference dimensions from the master sketch provided. The purpose of the flange was to provide slots for the heat stakes and locator which are required to assemble the two components together and constraint the motion between them.

TREE STRUCTURE :-

LOWER SUBSTRATES :-

PRE-DESIGN CHECKS :- The class A surface provided for the lower substrates was checked for openings with the aid of boundary feature. There were no openings found in the class A surface and hence the same surface was used in future operations.

TOOLING AXIS :-

• First a dummy tooling axis is drawn along the Y direction with the axis system and the centre point as reference
• If the draft analysis is cleared with the dummy tooling axis then it is considered as our main tooling axis if not then the tooling axis is created with the help of bisecting method. In our case the dummy tooling axis was able to cover all the faces with the required draft angle and hence was taken as the main tooling axis.

DOG HOUSE AXIS :-

DRAFT ANALYSIS OF CLASS A SURFACE :-

• The class A surface provided had less or negative draft angle on certain surfaces. When trying to clear those faces the draft angle on other faces seemed to get compromised
• This could only be solved by the Class A designer by ensuring the minimum draft angle of 3 degrees is provided in the critical areas of the class A surface.

CLASS B SURFACE :- Class B surface is created by offseting class A surafce by 2.5 mm as per the mastersection.

CLASS C SURFACE :- C surface is the connecting surface of class A and class B surface. By using sweep we created the class C surface. For that first we have to creat boundary and sweep with reference surface at angle 90 degree get the Class C surface.

CLOSED BODY OF LOWER SUBSTRATES :- By trimming join of class A ,C with class B surface we get close body.

SOLID BODY OF LOWER SUBSTRATES :-

DRAFT ANALYSIS ON FINAL PART :-

ENGINEERING FEATURES :-

DOG HOUSE DESIGN :- Dog house is an engineering feature used in the plastic trim design. Dog houses are used as supporting features. Sometimes other engineering features like snaps, locators, etc are mounded on them to increase their strength. Dog house and other engineering Features are built on B-surface.

DESIGN RULES FOR DOG HOUSE CREATION :-

• C thickness should be 40% of the main wall thickness T
• Minimum width of the dog house is 12 mm.
• Height of B should be 3-6 mm

HEAT STAKES :-

• Heat stakes are used in thermoplastics to assemble two parts together by locally heating and cooling the plastic material and allowing it to reform itself and act as a joint for the two materials.
• We have placed 15 heat stakes in the model based on the reference points created by estimation.
• One of the important factor to be considered while designing the heat skates is the height of the heat skates. It should always be less than the height of the locators.

LOCATORS :-

• The main purpose of locators is to facilitate proper locking of two components together while assembling and arrest the maximum degrees of freedom possible.
• These locators are similar to guide pins provided in mould.

From below image we can see the position of all heat stake, locators and dog house. This all feature created on lower substrate by considering position of its counter parts.

TREE STRUCTURE :-

FINAL ASSEMBLY :- For final assembly of door trim panel we have to constarin all parts together. Following image shows the assembly of push pin with dog house.

In the same way we have to constrain all the parts together.

Following tree structure shows the how all part are constrained.

CONCLUSION :- From this project I have leraned how to create CAD model for plastics parts by considering design rule by doing this project on Catia V5. I get very well familiar with part workbench, surface workbench, assembly workbench. Also I get confidence in handling different features of all workbenches. Along with this I get idea of how to design a part by considering manufacturing and assembly aspect.