Week 12- Final project
AIM: To design the Door Trim panel along with it's Dog Houses through the given Class-A surfaces and Master Sections. 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 panel from 'Close Surface' through given Class-A surface and Master Sections 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 Dog House considering the design rules mentioned in 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.
Flanges: It is an engineering feature used in plastic design which are used as fixing two parts to each other with the help of heat stake or without it. Other engineering features like snaps, locators, push pins and screw bosses are mounted on them to increase their strength. Flanges are subjected to draft analysis to prevent breakage of the component during ejection from the mould cavity. Flanges and other engineering components are built on the B-surface.
Dog House: It is an engineering feature used in plastic design which are used as support feature. Other engineering features like snaps, locators, and screw bosses are mounted on them to increase their strength. Dog houses are subjected to draft analysis to prevent breakage of the component during ejection from the mould cavity. Dog house 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 considering the master sections and drawing) and later a vertical surface CLASS C. Then the three surfaces were trimmed to obtain the required part.
Push pins: It is an mechanical design which are used for joining one component to another. These are basically attached to the dog house.
PROCEDURE:
Class A Surface:
1) Open CATIA V5.
2) Open the downloaded 'MASTER_SECTION_DEVELOPMENT_SEPERATED_MODEL.stp' in CATIA.V5 having the CLASS A SURFACE.
3) The CLASS A SURFACE's was given it's shape and was saved as a .CATPart with name MASTER_SECTION_DEVELOPMENT_SEPERATED_MODEL.CATPart to MASTER_SECTION_DEVELOPMENT_SEPERATED_MODEL_Part_4.CATPart and Part5.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.
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 a distance of 2.5mm considering the master sections.
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, a fillets of radius of 45mm was given and with rest operations like extrapolations and that extrapolated part was named as 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 and CLASS A+C SURFACE.
Final trimming:
1) All the surfaces made i.e. Class A, B and C for all four parts 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(T).
Dog House:
1) The lines from the master section was extracted to create a point.
2) Now considering three points, two from the master section and one created, a plane is made.
3) The point where plane is made and that point are used for drawing a positioned sketch.
4) Then the ISO-constrained sketch was extended with Pad command.
5) A slight taper was given according to the master section.
6) Then the entire part was hollowed front and below through Shell command.
7) To make the inside part, the sketch was drawn along the same point and plane and then extended through Pad command.
8) To make the below taken out part, the inside of the hollowed part was extracted.
9) Then that extracted part was ofsetted till 1mm and from the top, a surface was extracted and extrapolated and offsetted till 17+1+6mm=24mm.
10) After trimming and joining the surfaces, a closed surface was obtained and that surface was used to cut out the solid hollowed surface in Part Design.
11) The inside part was extended with Pad command following the second sketch and with the third sketch, a keyhole was pocketed with Pocket command.
12) The inside teeth and the hollow part was then trimmed to get absolute Dog House. Then at last that dog house was trimmed with the main body to get final design.
Flanges:
1) Measure the thickness of the flanges from the master sections given.
2) Draw lines perpendicular to each other that can guide the surface for making flanges.
3) Select the curve from the edge which can guide the surface along the curve.
4) Through sweep, extrude and trim command, the required surface is achieved.
5) The required surface is then thickened and a hole was made using Thickened command and Pocket command.
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 2.8 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.
Assembly of Push Pins:
1) Select Existing Components from there select the 'MASTER SECTION' and the part Push Pin.CATPart.
2) Fix the pins and the part where the pins to be aligned.
3) Select the Coincidence Constraints and select the axis of both dog house and pin and then click Update.
4) Then select the face of the dog houce and the pin and also the alignments where it must be placed and then click Update.
5) Do the same for the second pin on the second dog house.
OUTPUT:
The outputs are given below in the form of screenshots of .CATPart as instructed above in the question for the completed model from Week 12 - Final Project:
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 all the .CATPart's along with it's .CATProduct of combined parts were attached below and the entire report is submitted.