Challenge

Week 9 - Attachment Feature Creation - Challenge 2

TTirupathi Rao Kolli9 Mar 2021

CREATE THE BOSA AND DOG HOUSE FOR THE CENTER CONSOLE COIN HOLDER

OBJECTIVE –

To create Screw Boss and Dog House on Coin Holder Based on the Design Consideration Using CATIA.

SCREW BOSS CREATION –

Boss feature are commonly found in injection molding designs.They are used to aid in the assembly of molded parts by providing a channel for a screw.Designing plastic screw bosses is fairly straight forword but there are a few considerations to ensure a strong connection between parts and mitigate cosmetic defects.

Design Criteria –

SREWBOSS CREATION IN CATIA -

First I created two circles in the sketch.

The inner circle diameter is 5.2 mm and outer circle diameter as per design criteria.Thickness of Screw boss should not be higher than the 40% of the bass.

Thikness of Coin Holder -2.5 mm

Diameter of outer circle is -7.2mm

As per the given parameters the draft angle and fillets are provided.

Dog house creation –

Dog house is an engineering feature used in plastic trim design. Doghouse are used as supporting features. Sometimes other engineering feature like snaps ,locators etc..are mounted on them to increase their strength.Dog house 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-Surface.

DOG HOUSE CREATION –

First I created rectangular sketch (one end made as construction )

Next I used to sweep command with draft angle 1.5 degree and height 12 mm

To adjust the height and bring it perfect dog house shape I used the command Surface Untrim, Offset and trim.

The draft angle of the inner side of dog house is 0.5 degree.

Edge fillet of inner side of the dog house is given a nominal diameter of 1mm.

The height of the dog house is given as 5mm whereas given design parameters is was indicated between 3-6 mm.

To achieve the C value in the Dog house as mentioned in the question, I have made an extract on the inner face of the dog house and made an offset for 1mm (0.4 *2.5 mm =1mm)

Fillets – Edge fillets were done on the inner side of dog house ( intersection of part wall C ) for a nominal 0.5 mm. This was done to achieve a proper Draft analysis result.