Week 8 - Challenge 1 - Draft Analysis on a Fan Cover

OBJECTUVE: TO PERFORM DRAFT ANALYSIS TO CHECK IF PARTS HAS GIVEN DRAFT ON ITS ALL FACESANF FINDING TOOLING AXIS.

Draft : It is a tool used in CATIA to make the faces taper with respect to tooling axis.

Tooling axis : Tooling axis is the direction of mold part enjection.

draft is the amount of taper for MILDED parts perpendicular to the parting line. It can be measured in dgree or mm/mm (in/in).

why draft is necessary?

The functional part of injection molding has to draft facing both cavity and core sides to reduce the risk of damage to the parts and ensure ejection. As the molten plastics flows into the close die and fills the cavity the material shrinks inside the mold upon the cooling and as a result grips the core. Without any paper, the part would come out scratched while increasing wear and tear on the mold and shortening the tool life.

Draft angle recommendation

• 5 degrees on all vertical faces is strongly advised.
• 1 to 2 degrees works very well in most situations.
• 3 degrees is minimum for a shutoff (metal sliding on metal).
• 3 degrees is required for light texture.
• 5 or more degrees is required for heavy texture.

Steps involved in draft analysis

STEP 1.

All surfaces should be connected and there is no gap between lines and we can check it by using boundary command.If there is gap then green line should be appear. by using this method we can check is all surface are joined or not.

step 2.

Now we can analysis best possible tooling direction using the X/Y/Z planes.

step 3.

Now we can create tooling clearence along X/Y direction using the intersection of planes with class A surface.

We intersect Class A surface with XY/YZ/ZX planes and create the refrence lines onthe surface with might face problem during tool ejection.

by following simillar method we can make tooling direction in X axis.

Bisecting line

With the help of refrence lines we can make bisecting line which is on the same plane as the refrence lines but are in normal direction. They are the either or horizontal lines at the pointof intersection of refrence lines.

step 4.

Tooling direction line

When we get the tooling direction in both X and Y direction then we use bisecting line to generate the tooling axis

Step 5.

Publish the tooling line and class A surface .

Draft Analysis

First change the view parameters into customise mode with material checked.

Click on insert toolber then draft analysis icon.

now draft analysis tool will appear on the screen .

It gives information about colour coding mode, Display and direction.

mode: This option gives detials about colour coding and with help of this we can set the parameters of draft analysis.

Display option: first option is used to hide and show the color scale.

second option is used for analysis under point. It gives the value of draft with respect to tooling axis selected at given point of circle indicating plane tangent to surface.

Direction:In this we set the compass on tooling direction once the compass is set on tooling axis we lock it so that it does not change.

Also we can flip the direction of the tooling if the compass direction is not as per our tooling direction.

Final draft analysis

All surface are in green color this indicates that all surfaces have draft more then 2 deegres along the tooling direction indicating that our part can be easily ejected along this tooling direction.

ISO VIEW