Week 10 - Challenge 3 - Door Trim Lower with Engineering Features
AIM: To design the Door Trim component along with it's Heat Stakes and the locators considering the design rules mentioned in the video for the door applique. To start with the design, the tooling axis for the given Class-A Surface is created meeting the requirements of the draft angle and at the end perform the Draft analysis on the model.
OBJECTIVE: To design the Door Trim component design from 'Close Surface' through given Class-A surface given in .CATPart. This can be done by designing Class-B and Class-C surfaces then trimming both the surfaces to get the actual closed surface. Then designing the required Heat Stakes and the locators considering the design rules mentioned in the videos and in this question. The proper Tree Structure of the model is ensured. Publication is done by using the publication option by publishing the above Tooling Axis, Class A, B, and C surface from the Tree Structure. The sketches are Positioned Sketch and are ISO constriained.
DESCRIPTIONS:
Class A: It is the surface that is created by the concept sketches made by free hand sketchers. The finalised sketch is then fed to the computer and a 2D surface is created out of it by the use of a software like Alias. This computerized design is known as Class A surface.
Class B: It is a reference surface that is created by the design engineer and is a copy of the class A surface that is at a distance equal to the thickness of the part.
Class C: It is again a reference surface that is created by the design engineer to connect Class A and Class B surface also known as the side wall of the surface.
Heat Stakes and locators: It is an engineering feature used in plastic design which heat staking feature. Other engineering features like snaps and locators are mounted on them to increase their strength. Heat Stakes are subjected to draft analysis to prevent breakage of the component during ejection from the mould cavity. Heat Stakes and other engineering components are built on the B-surface.
The technique that is used to create the model is to initially create a CLASS B surface at a distance equal to thickness(2.5mm taken here) and later a vertical surface CLASS C surface. Then the three surfaces were trimmed to obtain the required part.
PROCEDURE:
Class A Surface:
1) Open CATIA V5.
2) Open the downloaded 'Door Trim - Heat Stake and Locator.CATPat' in CATIA.V5 having the CLASS A SURFACE.
3) The CLASS A SURFACE was given it's shape and was saved as a .CATPart.
Tooling Axis:
1) The surface where we want to make the tooling axis is extracted with Extract command.
2) Then a point was made at the middle of the extract.
3) A line was drawn out on the point perpendicular to the extract along Y-axis. That line was taken as dummy since it was showing negative clearance.
4) An intersection was made on the same point along X-axis on the entire part.
5) Then two lines alongside the sides of intersections are made for the perpose of making an actual tooling axis through Bisecting method.
6) Then a line between the two lines at that point is drawn through Bisecting method to get the actual tooling axis.
Class B Surface:
1) One of the outer surface of CLASS A SURFACE was extracted surface by surface.
2) The entire surface was the offsetted below CLASS A SURFACE at 2.5 mm distance.
3) The surface which was not offseted was later filled with Fill command.
4) The filled and offsetted part was joined with Join command.
5) The joined part was given boundary with help of Boundary command for furthur operations.
6) After the trim operations, give a fillets of radius of 6.9 mm and rest operations like extrapolations and that extrapolated part was named CLASS B SURFACE.
Class C Surface:
1) The boundary of each opening edges consisting of all four edges at the corners are obtained.
2) Then all those boundaries are subjected to swept operation with Swept command with different draft angle each.
3) Then the sides of all those swept components bounded are later extrapolated sideways.
4) Those extrapolated parts are then trimmed to each other to get a combined swept surface.
5) That combined swept surface is joined with CLASS A SURFACE and then we find something that we named as CLASS C SURFACE.
Final trimming:
1) All the surfaces made i.e. Class A, B and C were made visible for further operations and intersected to see any further non-intersections between those three.
2) Then the surfaces were trimmed to get a model of 2.5 mm thickness.
Heat Stakes and locators:
1) The point where the sketch should be made is considered for positioned sketch.
2) That sketch is then extruded with Pad command in Part Design till 15mm and 1 mm both sides.
3) The nessesary fillets, chamfer, draft etc., are given for this model.
4) When one model is complete, that model is copied and pasted in Main Tree.
5) That pasted body is then translated to next point given in the input.
6) Same thing is done for the straight supports around the edges as shown in the challenge above.
7) After the translation operation, all parts were trimmed with main body.
8) Same supports were trimmed with the main body to get the final product with Heat Stakes and locators.
Draft Analysis:
1) In plastic design, the draft analysis or angle that is considered in the OEMs (Original Equipment Manufacturer) is 3 degree.
2) First thing to carry out was to select the compass and set it on the tooling axis in upward direction.
3) By clicking on the surface, the whole part turned into green colour. If blue was visible that meant that the analysis was inversely done so just by flipping the direction, draft analysis.
4) Then the hollow part was lat er created into a solid body by going the part body option and then selecting close body surface.
5) We can see draft analysis on the solid part resulted in green colours.
6) The green region shows the part which is toolable or produceable by the molding machine and the draft angle is 3 degree.
7) Blue colour region states that the part can be allowed in some OEMs but still need to be improved for the other OEMs as the draft angle is more than 3 degrees.
8) Red colour which is there in this case states that the draft angle is less than 3 or 2.7 degree and cannot be produced or if produced would be faulty.
NOTE: The tooling axis was adjusted in such a way so that to mitigate the red colour fault as much as possible and get desired design to get the draft analysis correct.
OUTPUT:
The outputs are given below in the form of screenshots of .CATPart as instructed above in the question for the completed model from 14 - Week 10 - Challenge 2- Attachment Feature Creation (Dog House).CATPart:
a) 3D views:
b) Tree Structure:
INFERENCE: The design was achieved through the tooling axis and Class A, B and C surfaces and doing the nessesary operations to get the closed surface. Next the thickening surface was solidified through 'Closed Surface' command. After that it's .CATPart was attached below and the entire report is submitted.