Week 10 - Challenge 1- Attachment Feature Creation (Ribs & Screw Boss)
REPORT ON DRAFT ANALYSIS OF CREATION OF CLOSED CLASS A SURFACE -DRILL HANDLE
1.Visual Inspection -
- The first step of the draft analysis is to determine whether the given class A surface contains any side core functionality that needs to be achieved in the component.
- This can be done by visually checking/insepecting the class A geometry completley step by step.
- Any basic geometrical features such as chamfer,fillets,holes are assumed to be cleared through the direction of tooling axis that are perpendicular to that of the tooling axis.
- Use Join/boundary command to check if all surface edges are closed.Use surface boundaries in Tools-options also to ensure proper enclosure of surface.
- In the given Drill handle class A surface,there is no side core requirement to produce the component with respect to tooling axis which can be assumed to be created perpendicular the given geometry in drill handle.
2.Understanding injection molding process -
- Any geometrical surface that are not aligned to perpendicular direction of the tooling axis needs a separate side core in the mold to create the injection molded component.
- Plastic injection molding process requires core and cavity to form a plastic component.Under injection of high pressure the plastic components is formed.The direction of movement of the core and cavity where it opens and closed is said to be the tooling axis.
- Apply nominal draft of upto 3 deg on both side i.e.. 1 1/2 deg each side to the surface,according to the design rules for plastic injection moulding component this allows for easier ejection and no defects after cooling.
3. Creation of Tooling axis -
- After the proccess of visual inspection,we know that for given Class A surface of drill handle does not require any side core for plastic component to be produced.The next step involves in deciding the tooling axis selection,this can be x,y or z direction.For drill handle,the tooling axis can be taken from y-axis as the geometry of drill handle is perpendicular to that of tooling axis.
X-axis
Y-axis
Z-axis
- The bisecting method is use to create a reference tooling axis by creating a point on surface by extract of the existing flat surface in y-axis in the given class A surface,then creating the bisecting line between the two lines of reference surfaces from the left and right using 3D project elements.
- After creation of Main tooling axis,perform draft analysis from Insert- Analysis - Feature draft analysis
- Enter 3 deg of color scale variant to control the nominal draft angle under which the surface needs to be formed.This color scale can be changed by double-click (or) to color scale mode from quick analysis to full analysis mode
- Then,use angle running point
for identifying angle of the surface which can measure abnormal angle in surfaces.
- Pick the Compass
and place it on the created tooling axis by clicking on the red dot and click to drag. - Use
Lock command to hold in place the compass. - Change direction of the draft
only if required .This changes the core and cavity side with respect to tooling axis. - Click ok to perform draft analysis to the given Class A surface.The result of the draft anlysis will be available under Free form analysis - Draft analysis tree structure.
RESULTS-
- The following result shows that the component requires an 2.222 deg & 1 deg angle to be manufactured in injection molding which does not apply to the nominal draft angle required for easier ejection of the part.Therefore,the manufacturing feasibility needs clarification with respect to design rules as the component deviates in certain areas of surfaces.This analysis is achieved with help of draft analysis tool.
- This concludes the report on draft analysis of the given class A surface drill handle.
