Week 9 - Attachment Feature Creation - Challenge 2

AIM:

To Create the screw boss and dog house on coin holder as per the given design rules. and also carry out the ceating the toolingaxis and performing the draft analysis of the final component component.

SCREW BOSS:

Boss features 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.The most common variety consists of cylindrical projections with holes designed to receive screws, threaded inserts, or other types of fastening hardware. Under service

PROCEDURE FOR CRATING THE SCREW BOSS:

FIRST TO EXTRACT THE BASE AND CREATE THE SKETCH ON IT.

Considering the diameter value of 5, the outer circle will be 5+(2* 0.6*2.5)= 8.

Then, these circles are padded along the tooling direction. Using the 3:1 height to diameter ratio.

The thickened ribs later on drafted by 0.5 degrees and the pulling direction is taken as the upper face of the ribs.

The screw boss is not made alone, they are coupled with the stiffener or ribs to provide structural stability.

Then, they are extruded to a height of 12.5 and thickened to 1 mm.

Later, ribs are also drafted to 0.5 degrees.

The screw boss and ribs are then union trimmed to form a single part.

Now, the final screw boss is assembled to the main coin holder component and provided with the fillets or 0.25mm radius.

DOG HOUSE:

The Dog house is an engineering feature used in plastic design. Doghouses are used as supporting features. Sometimes other engineering features like snaps; locators supported by the doh houde. and dog house 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-surface.

DOG HOUSE PROCEDURE FOR CREATION:

First, the screw boss is translated to someplace, and keeping a reference of this, the dog house is created on the base extracted and a C shape sketch is drawn for the dog house.

That sketch is swept with a drafting direction of 1.5 degrees.

This box needs to be packed from the top, so the base surface is offset to a height that intersects with the top, and then they are trimmed to close the top of the box.

Then the extended portion is again trimmed with the surface to form the proper box and the edges are given the fillets of 1mm.

The above surface is then thickened to 2mm in the part workbench.

For the lower part of the dog house, the inner walls of the box are extracted and offset by 1mm to the outer side in a shape generative workbench.

C= 0.4*2.5 = 1mm

The offset face is then extrapolated by point continuity by 10mm and another face is from the base is offset by a distance of 6.5 mm such that the distance B should be around 4-5 mm as per the design rule.

The two offset faces are trimmed together to get the lower cut section of the house and later they are trimmed with the solid box to form the final dog house.

Lastly, the dog house is assembled with the main coin holder body and the screw bode is translated and positioned on the top of the dog house.

TOOLING AXIS:

The purpose of toolin axis is basically the direction that the mold opens. The mold is built in two separate pieces, these are core and cavity. The Core and cavity moves along the Tooling Direction. There are different methods to find out the tooling direction. Here we are using bisecting method to find out tooling direction. We can use any method. but our main aim is to reduce the cost of manufacturing by reducing the complicity in manufacturing the component.

PROCEDURE:-

Here i am using bisect method to find out the tooling axis for fan cover. then we perform the draft analysis on the fan cover.

CREATING THE TOOLING AXIS USING BISECT METHOD:-

• The first thing to do is finding out the possible tooling direction by visually checking the part. Rotate the part in all direction and find out the possible direction for tooling axis. Here in this case viewing from Z direction we can clear the face in tooling.
• Then we create a point on the surface of the part, we can create the point anywhere on the surface.
• most of the cases we create the point in holes and pocket of the part.because the holes and pockets is to create a problems when we do the draft analysis.so we create a point in mid of the hole. to create a line on this point along z direction. named as side tooling axis. because the main tooling axis doesent clear the all the faces of the dog house.
• so the side tooling axis should clear the inner faces of the dog house.

DRAFT ANALYSIS:-

The Draft Analysis command enables to detect if the part you drafted will be easily removed from the core and cavity. This type of analysis is performed based on color ranges identifying zones on the analyzed element where the deviation from the draft direction at any point, corresponds to specified values.In Draft Analysis, the Class C surface side walls are checked for draft. A minimum 3 degrees draft is expected on the component to make it manufacturable without any damage to the product. and it is eaisily withdrawl from the core and cavity after manfacturing.the draft analysis gave a report whether the tooling axis can clear the all faces of the parts.some times it cant cler the all faces due to complexity of the part. so side tooling axis are used to clear that face.for that a side cores are used to manfacturing the compopnent.

PROCEDURE:-

• To perform the draft analysis the view parameters are first set to material mode.
• Then go to Insert >>analysis>>feature draft analysis.the fallowing window will be appread

• First, select the axis system and drag the axis system to the tooling axis and lock the orientation. This axis system defines the draft direction according to the tooling axis.
• Switch on the color scale and set the draft value 3.5 using colour scale. and it will be displayed in green color. Any draft angle below 3 degrees will be shown in red color.
• drag the compass to the side tooling axis.
• Now select the running point tool to measure the draft angle at the various locations and then if all surfaces pass the draft analysis switch on the light effect that will show the component in green color if the component has the required draft angle.

the above draft analysis shows the negative draft for the inside feature, we need to create the side core tooling axis to properly extract the dog house properly. so we create the side tooling axis to clear the inner faces of the dog house

Result:

The Screw Boss and Dog House for the coin holder has been screated as per the design rules and the draft analysis also done for the final component.