Week 9 - Project - A pillar Design with Master Section

 AIM

Create the component through the given Class-A surface. 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 Dog House with side core tooling axis considering the master section provided

REPORT

Trims are the plastic parts installed on the inside and outside of a car. The interior trims are usually used for giving the aesthetic look to the interior of the car. There are various types of trims used in automobilesFunctionality and aesthetically pleasing trim applications are crucial factors for a perfect interior experience and successful vehicle sales. The selection, design, and processing of plastics solutions for interior trim components are very important for consumers when making their purchase decisions.

The A-pillar trim is attached to the A-pillar and improves the aesthetic look of the car. Mostly the trims are manufactured by the injection molding process. The design of the B-pillar is carefully done to make the part manufacturable and usable in the interior. While manufacturing a part through injection molding a lot of defects can occur on the plastic part which will destroy the look of the panel. The design has to made in such a way that all the errors can be rectified.

CLASS A SURFACE

In automotive design, a class A surface is any of a set of free form surfaces of high efficiency and quality.  It gives the aesthetic of the component which is created by the styling team and gives to the part design engineer to create the part with all engineering aspects.

CREATING THE CLASS A SURFACE

We have been given the Class-A surface and the first thing to do is to make sure that the given surface has no gap in between them. We can check it visually and also with help of Join or boundary commands.

 

MASTER SECTION

Master sections are the guides for design requirements which decide the component packaging after technical (Styling, Concept or Class-A) surfaces. Creating this master section should need 5 to 6 years of experience. This helps you to decide the feasibility, clearance, the packaging and the fixation strategy before working it on a 3D.

TOOLING AXIS

Tooling axis is the direction in which the core and cavity opens. If we are using proper tooling axis, we can avoid adding side cores thus the cost of manufacturing the component can be reduced.It is defined as the direction in which the mould/core and cavity open. Selection of the direction of the tooling axis depends on the ease at which components can be easily ejected.Generally tooling axis is decided from the natural axis of the design, that is, tooling axis is analysed with the x, y and z axis of the system. If the axis doesn’t clear the draft analysis, the next step is to look for the surface in which the drafting axis can be created in such a way that the axis is normal to the surface taken. These are the methods of deciding tooling axis. Bisecting method is the least used method.

MAIN TOOLING AXIS

BISECTING METHOD

It is a method used to create tooling axis. The sides of the surfaces are chosen in such a way that the edges which is almost parallel to the dummy tooling axis are taken as the input for the creation of tooling axis. the bisecting line is created to the lines formed at the edges for creating the tooling axis

Here, tooling axis is created using the reference from the master section. As there is a doghouse present in the B side, the sides of the doghouse is taken to created the tooling axis.

Two lines are drawn from the edges of doghouse

bisecting line drawn from these two lines is the tooling axis

DRAFT ANGLE

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. Equally important, an absence of draft may prevent parts from ejecting from the mold, damaging not only the parts but possibly the mold itself—a costly and time-consuming detour.

DRAFT ANALYSIS OF CLASS A SURFACE

Change the view to material mode for draft anlysis

draft analysis is done using featured draft analysis tool

Use the compass fucnction to aling the compass to the tooling direction and lock the direction using lock function in the draft analysis tool bar

Green colour - above 3 degree positive draft

Red colour -between 3 and 0

blue colour- below 0 degree

the surface is showing green colour so that the surface clears the minimum draft angle of 3 degree except below mentioned area 

By using the analyses under the running pointwe can check  draft angle  on the individual faces. It shows how much draft on specific points when we move the cursor point.

 the surface clear the 2 degree draft angle

 

CLASS B SURFACE

Class-B surface means the thickness of a part it is not visible and is inside part. In other words, the Class-B surface is a surface below a certain thickness from the class-A surface. This is the surface that contains engineering aspects of a model.The Class B finish is a quality finish with only minimal imperfections. A Class B finish is the most common finish for exterior surfaces. It is normally specified on surfaces such as external covers, panels, and parts that are fairly prominent.

B SURFACE is created by  Offseting  the class-A surface to 2.5mm inward direction.

patches are created while offsetting the surface. Rework on the patches using the features like extract, multi-extract, sweep, multi-section surfaces, extrapolate.

 the boundary command is used to identify and highlight the patches

CLASS B SURFACE IS CREATED

 

 

small sections are created  using multi-extract command and then create sweep with draft direction .

 

SOLID SURFACE

 

CLASS A and CLASS C is JOIN together

 

CLASS B is trimmed with CLASS A AND C

SOLID SURFACE FORMED

TREE STRUCTURE

 

PART BODY

Close Surface feature usedto make a solid body from the surface

DOG HOUSE

Dog house is an engineering feature used in plastic trim design. Dog houses are used as supporting feature. Sometimes other engineering features like snaps; locators etc. are mounded on them to increase their strength. Dog houses are subjected to draft analysis to prevent breakage of the component during ejection from mould cavity. Dog house and other engineering components are built on B-surfac

Dog house is an engineering feature used in plastic trim design. Dog houses are used as supporting feature. Sometimes other engineering features like snaps; locators etc. are mounded on them to increase their strength

"C" is where the doghouse contacts the backside of the surface

•  Doghouse wall thickness at the intersection of the part wall ( C ) should be 40% or less than the main wall stock ( T ). 

• The height of  ( B ) should be between 3.0 – 6.0 mm 

The sketch for dog house iscreated with reference to master section 

the inside surface is created using extrude

the front and back limit is extracted from master section

surface is created for trimming

surface is formed for thickening

the surface is thickened to the tickness provided  in the master section 

the front portion is split  by using surface

sketch for upper cut out is created

 the surface isformed and split from component 

the doghouse is created

draft is provided  

surfaceis extracted for creating the contact section

offst for 5 mm

contact section is created as per design rules

sketch is created to form rib section

trimmed with dog house

SIDE CORE AXIS

side core axis is created

draft is provided with respect to side core axis

the dog house is created

dog house trimmed with main component

DRAFT ANALYSIS OF COMPONENT

Change the view to material mode for draft anlysis

draft analysis is done using featured draft analysis tool

Use the compass fucnction to aling the compass to the tooling direction and lock the direction using lock function in the draft analysis tool bar

Green colour - above 3 degree positive draft

Red colour -between 3 and 0

blue colour- below 0 degree

MAIN TOOLING AXIS

the surface is showing green colour so that the surface clears the minimum draft angle of 3 degree except the below mentioned section

By using the analyses under the running pointwe can check  draft angle  on the individual faces. It shows how much draft on specific points when we move the cursor point.

SIDE CORE AXIS

draft analysis of dog house inside section is done along side core axis

the surface is showing green colour so that the surface clears the minimum draft angle of 0.45 degree

CONCLUSION

• TOOLING AXIS for the CLASS A SURFACE and MODEL is created
• CLASS B AND CLASS C surfaceis created from CLASS A surface
• SURFACE MODEL is created using CLASS A,B & C surface 
• SOLID BODY is created from SURFACE MODEL using close surface
• DOG HOUSE are created considering the design rules
• SIDECORE AXIS is created for DOG HOUSE
• DRAFT ANALYSIS is done on CLASS A SURFACE
• DRAFT ANALYSIS is done on SOLID BODY along MAIN TOOLING AXIS and SIDE CORE AXIS
• Publications: Use the publication option published the following
  • Tooling Axis
  • side core axis
  • Class A, B, and C surface
  • SURFACE MODEL
  • SOLID BODY