Monday, May 4, 2020

Cad/Cam free essay sample

Midterm Project Report Project Goals The goal of this project was to help students become familiar with a program created by the company Siemens called NX, specifically versions 8. 0 and 8. 5. Somewhat similar to the program SolidWORKS, NX allows the user to create sketches of simple and complex objects, and then create a 3-D model of the object. Also, an assembly of these models can be made by assigning constraints to create an overall 3-D assembly model. This project was made to utilize NX in order to create an assembly model of a skateboard, made of 6 different parts: The Bearing, The Board, The Bushing, The Connection, The Shaft, and The Wheel. Some parts were easier than others, such as the Shaft, which just required a sketch of a circle to be extruded to a certain length. Others required much more commands, such as the Connection and the Bearing, which required a sweep and many other constraints. Before the project was assigned, students were given many homework assignments that required them to create a part using NX, which didn’t require many commands. Over time, these assignments became more and more challenging, requiring more and more commands. After these parts were modeled, students were taught how to create an assembly using the parts modeled, which use constraints to keep them together such as Concentric, Touch Align, and Center. In order to model the 6 parts of the Skateboard Assembly, students were given IGS files as a reference. These files allowed students to open them in NX and use the Drafting environment to infer dimensions to recreate the part on their own. Dimensions in the sketches were the most important, especially when putting the board together, as dimensions that were not proportional to one another could cause an error in the assembly environment when assigning constraints. Background The following parts were used in the overall skateboard assembly: The Bearing, The Board, The Bushing, The Connection, The Shaft, and The Wheel. The Board is the main part of the assembly, which the rest of the parts are built top down. On the bottom of the board, the connections are placed in line with the holes and attached to the skateboard. The connection allows the Bearing and the Bushing to be placed into the assembly. After the connection is in place, the bushing is placed into the appropriate space, where it keeps the bearing at a horizontal angle. The Bearing is then placed into the opposite space of the connection, where it is inserted until the bottom of the bearing is touching the bushing. The Bearing allows for the Shaft to be put into place. When the bearing is put into place, the shaft is inserted making the opposite ends equidistant from the center of the bearing. By making the centers of the Bearing and the Shaft aligned with each other, the wheels are placed at an equal distance, which allows for motion of the Board, completing the assembly of the Skateboard. Solid CAD Model The Board Figure 1a To start off the skateboard, the top half of the sketch (above the XC axis) was created, and then mirrored across the XC axis, shown in Figure 1a. The Concentric tool was used to make sure the circles shown were of equal radius, and a rectangle (not shown) was drawn to ensure the distances were correct. Figure 1b After the sketch is created, it is then extruded to a depth of 0. inches. No Boolean operation is necessary since the board is being extruded out of the sketch. It is important that there is no protruding lines or open areas in your sketch, as it will make the sketch unable to extrude. The Bushing Figure 2a To start off the bushing part, a carefully constrained sketch was made in the X-Y plane as shown in Figure 1a. Figure 2b After making the sketch, the revolve too was used to revolve the sketch using the Y-Plane as the Centerline axis, and it was revolved 360 degrees as shown above in Figure 1b. Figure 2c After the revolution is complete, here is the bushing halfway finished. By sketching is the way shown in Figure 1a, an Edge Blend at the top edge is not necessary at this time. Figure 2d Next, a sketch of a circle with a 0. 4 inch diameter is made on the top of the extrude about the center to create the hole in the bushing, as shown in Figure 1d. Figure 2e When the sketch is finished, the circle is extruded a little past the actual length of the bushing to ensure it goes all the way through. Material is subtracted under Boolean to create the hole, shown above in Figure 1e. Figure 2f Here is the finished bushing after the hole is extruded, as shown above in Figure 1f. Not much commands involved in making this part, being one of the simplest part to model. The Shaft Figure 3a To create the shaft, first a circle of 0. 3 diameter was made about the origin as shown above in Figure 2a. Figure 3b After sketching the circle, it was extruded to a length of 5. 6 inches as shown in Figure 2b. Figure 3c Here is the finished shaft part, comprised of just one sketch extruded. This was the simplest part to model in that there was not much commands involved in creating it The Wheel Figure 4a The next part modeled is the wheel of the skateboard. First, start off with a Sketch and create a Circle about the origin with a diameter of 1. 97 inches, shown above in Figure 4a. Figure 4b Next, we want to extrude that circle to a distance of 1. 18 inches, but no Boolean operations are required for this extrude, since it is a normal extrude, shown in Figure 4b. Figure 4c After the extrude, you should have a basic cylindrical drum, which is the overall outline of the part, shown above in Figure 4c. Figure 4d Next, the rounds for the wheel must be created. Using the Edge Blend tool, we select both the top circular edge and the bottom circular edge, and give them a radius of 0. inches, as shown in Figure 4d. Figure 4e After the edge blend is complete, the overall figure of the wheel should look like the one shown above in Figure 4e. Figure 4f Next, a sketch needs to be created on the top surface of the wheel. Do this by hitting the sketch tool, and place it on the top surface of the wheel. After that, use the Circle tool to create a circ le about the origin (middle of the wheel) to a diameter of 0. 89 inches. Figure 4g Now, an extrude must be done of the previous sketch created on the top plane. Use the Extrude tool, and select the previous circular sketch. The extrude needs to take material away to create an indent into the part, so a subtraction Boolean must be used to subtract material. The depth of the extrude will be 0. 16 inches, shown above in Figure 4g. Figure 4h After the extrude, the part should look like this, a wheel with rounds and an small indentation, shown above in Figure 4h. Figure 4i Next, another extrude on the bottom surface of the wheel is required, but first, a sketch must be created. First, hit the Sketch tool, and then select the bottom surface of the wheel. Next, use the Circle tool to create a circle with a 0. diameter about the origin, shown above in Figure 4i. Figure 4j After creating the sketch, we want to extrude it all the way through the material to create a hole from one side to the other. Use the Extrude tool and select the previous sketch, and under Boolean, select subtract. The distance will be 1. 18 inches, as the extrude in Figure 4b was also done to 1. 18 inches. Figure 4k After the extrude is comp lete, the part should now look like the one shown in Figure 4k, with a hole through the entire part. Figure 4l Finally, an extrude on the bottom of the wheel is required to finish the part. Start off by using the Sketch tool, and place it on the bottom plane, where the previous extrude was created. Next, use the Circle tool to make a circle about the origin, with a diameter of 0. 89 inches, as shown above in Figure 4l. Figure 4m Now, use the Extrude tool and select the sketch that was just drawn. Extrude it to a depth of 0. 12 inches, and since material must be taken away, use the Subtract feature under Boolean to subtract the material. Figure 4n Here is the finished wheel part, shown above in Figure 4n. Both sides of the wheel should look the same, two extrudes inward, and 1 hole through the middle. The Connection Figure 5a To start off the first of two complex parts, a carefully constrained sketch of the base is made, as shown above in Figure 5a. The top half was created first (above the XC plane) and the Mirror tool was used to create the bottom half (the XC axis was used as a Centerline) Figure 5b Next, using the Extrude tool, extrude the sketch to a distance of 0. 3 inches, as shown above in Figure 5b. No Boolean operation required, just a simple extrude. Figure 5c After the extrude is complete, the part should look like the one shown above in Figure 5c. Figure 4d Next, insert a datum plane on the top of the surface of the extruded part, as shown above in Figure 4d. The next Extrude will be placed on top of this plane. Figure 4e Next, use the Sketch tool and place it on top of the previously created Datum Plane. Then create two circles and lines tangent to the surface of the extrude, as shown above in Figure 4e. Figure 5f Next, use the Extrude tool to extrude the previous sketch to a distance of 0. 691 inches, and use the Unite option under the Boolean toolbar, to unite the extrude with the first extrude, making one part. Figure 5g After the extrude is complete, here is the updated part, shown above in Figure g. Figure 5h Use the Drafting tool to draft down the previously created extrude, using an angle of 10 degrees, as shown above in Figure 5h Figure 5i After the Draft is complete, here is the updated part, shown above in Figure 5i. Figure 5j Next, use the Sketch tool, and sketch the shape shown above on the bottom surface of the part, as shown above in Figure 5j. Figure 5k Using the Extrude tool, extrude the previous sketch to a distance of 0. 2 inches. Since material must be removed, use the Subtract option under the Boolean Bar. Figure 5l Here is the updated part after the Extrude is complete, as shown above in Figure 5l. Figure 5m Using the Sketch Tool, place the sketch on the bottom surface of the part, and create a circle with a diameter of 0. 6 inches about the centerline, and the center of circle 0. 47 inches away from the side of the previous extrude. Figure 5n Using the Extrude tool, extrude the previous sketch to a depth of 0. 2 inches, and select the Unite option under the Boolean toolbar, to unite the extrude with the overall part. Figure 5o After the Extrude is complete, here is the updated part, shown above in Figure 5o. Figure 5p Using the Sketch tool, create a . 22 x . 44 inch rectangle that is . 076 inches off of the bottom plane extrude, as shown above in Figure 5p. Figure 5q Insert a datum plane, on the left (or right) side of the part, using an offset of 5 inches away from the center of the part, as shown above in Figure 5q. Figure 5r Using the Sketch tool, create a sketch on the previously created datum plane and use the dimensions shown above in Figure 5r. Figure 5s Using the Extrude tool, extrude the previously created sketch and extrude it to a value that goes past the part completely (I used 10 inches for safe measure), and under Boolean choose the Intersect option to create an extrude of the shape. Figure 5t After the extrude is complete, the updated part is shown above in Figure 5t. Note the shape has now taken form of the sketch created on the datum plane. Figure 5u Use the sketch tool to create a sketch on the right side of the line of separation, specifically a circle of diameter of . 45 inches, the center a distance of 0. 381 inches away from the line of separation, and a distance of 0. 33 inches from the centerline. Figure 5v Using the Extrude tool, extrude the previous sketch to a distance of 0. 7 inches, using the subtract option under the Boolean toolbar, since material must be taken away to create a hole, shown above in Figure 5v. Figure 5w Figure 5w shows the updated part after the extrude, including the hole just created from the extrude. Figure 5x Using the Sketch tool, sketch a circle on the surface of the opposite side of where the previous extrude was placed. The diameter of the circle is 0. 95 inches, and the offset off of the YC plane is 0. 506 inches, as shown above in Figure 5x. Figure 5y Using the Extrude tool, extrude the previously created sketch to a distance of 0. 12 inches, using the Subtract option under the Boolean toolbar, since material must be taken away, as shown in Figure 5y. Figure 5z Here is the updated part after the extrude is complete, as shown above in Figure 5z. Figure 5aa Using the Sketch tool, create a sketch where the previous extrude was made, and using the same center point as the last extrude, create a circle with a diameter of 0.. 4 inches, as shown above in Figure 5aa. Figure 5ab Using the Extrude tool, extrude the previously created sketch to a depth of 0. 1 inches, using the Subtract option under the Boolean Toolbar, since material must be subtracted, as shown in Figure 5ab. Figure 5ac Here is the updated part after the previous extrude, showing the new hole created, as shown above in Figure 5ac. Figure 5ad Insert a datum plane relative to the face of the last extrude, and offset it to 0. 32 inches going into the part, as shown above in Figure 5ad. Figure 5ae Using the Extrude tool, extrude the sketch of the rectangle on the bottom face of the part, but do not use a distance as the end, use the Until Extended feature and select the previously created datum plane as the End. Use the Subtract feature under the Boolean toolbar to remove material, as shown above in Figure 5ae. Figure 5af Here is the finished Connection part, as shown above in Figure 5af. The Bearing Figure 6a First, to start the bearing, create a sketch and place it in the X-Y plane, using the dimensions given. The sketch shown above in Figure 6a was created by drawing the left side first, and then using the Mirror Curve tool to mirror it across a line that was drawn (now erased) to use as a centerline. Figure 6b Next, draw a line from the bottom of both ends of the first sketch, onnecting the two like the one shown in Figure 6b. This was done in order to avoid a problem with the Extrude that is about to be performed. Figure 6c After the sketch is finished, use the Extrude tool to extrude the sketch to a distance of 0. 325 inches. No Boolean Operation is necessary here as it is just a normal extrude. Figure 6d After the extrude is finished, use the Sketch tool to create a sketch, shown abov e in Figure 6d, and place it on the top plane. No Mirror was used here. Figure 6e Next, use the Extrude tool to extrude the sketch previously created to a distance of 0. 11 inches. Use the subtract option under the Boolean toolbar, since material here is being removed to make a hollow space. Figure 6f On the bottom plane, create a sketch like the one shown in Figure 6d using the sketch tool. Note that a mirror was not used in this sketch either. Figure 6g After creating the sketch, use the Extrude tool to extrude it to a distance of 0. 06 inches. Another Subtraction Boolean is necessary here, since material needs to be removed to create a hollow space, shown in Figure 6g. Figure 6h Once the extrude is complete, return to the top plane, and create a sketch oriented like the one shown above in Figure 6h. Figure 6i After the sketch is complete, use the extrude tool to extrude the sketch a distance of 0. 12 inches, using the Subtract option in the Boolean toolbar, shown above in Figure 6i. Figure 6j After the first extrude is complete, another extrude is done to make the hole completely hollow, like the one shown in Figure 6j. Figure 6k Once the extrude is complete, insert a datum plane in the middle of the sketch, but relative to the Y-Z plane, like the one shown in Figure 6k. Figure 6l Create a sketch on the recently inserted datum plane, specifically 2 concentric circles that are both 0. inches and 0. 65 inches in diameter. The centers of the circles are to be placed on the top edge of the sketch, as shown above in figure 6l. Figure 6m Next, use the Extrude tool to extrude the sketch created on the datum plane. Use the Symmetric Value option under End, and use the value of 3. 34/2, to give an exact extrude. Under Boolean, select the Unite option, to have the extrude united with the part. Figure 6n Once the extrude is complete, use the Edge Blend tool and select the edge of the top hollow extrude, shown above in Figure 6n. Give it a radius of 0. 02 inches. Figure 6o Next, create an edge blend on the bottom surface of the first hollow extrude, as shown in Figure 6o above. This is also a radius of 0. 02 inches. Figure 6p Next, use the Edge Blend tool and select the top and bottom outer edges, as shown in Figure 6p. Give these a radius of 0. 02 inches. Figure 6q Use the Edge Blend tool and switch to the bottom plane of the part. Select the bottom edge of the hollow extrude, shown above in Figure 6q. Give this a radius of 0. 02 inches. Figure 6r Next, use the Edge Blend tool and select the top edge of the hollow extrude, as shown above in Figure 6r. Make this a radius of 0. 02 inches also. Figure 6s Next, create a sketch on the bottom plane with the dimensions shown above in Figure 6s. No Mirror tool was used here. Figure 6t Now, we want to get rid of the protruding face inside the circular extrude. Hit the Delete Face tool and select that part, and click OK. Figure 6u Next, create a datum plane . 4 inches away from the bottom face of the part, as shown above in Figure 6u. Figure 6v Next, create a sketch on the previously created datum plane, using the dimensions shown above in Figure 6v. Figure 6w Create a line from the previous sketch and adjust the dimensions to match the dimensions shown above in Figure 6w. Figure 6x Now, use the Sweep tool to create a sweep that attaches to both the circle drawn on the datum plane shown, and the bottom of the part, shown above in Figure 6x. Figure 6y After the sweep is complete, use the Extrude tool to extrude the circle to a length of . 612 inches, shown above in Figure 6y. Figure 6z Use the Move Face Tool and select the bottom of the previous extrude, as shown above in Figure 6z. Rotate it at an angle of 330 degrees. Figure 6aa Next, use the Edge Blend tool and select the bottom face of the extrude that was just moved. Give it a radius of 0. 05 inches, as shown above in Figure 6aa. Figure 6ab After the Edge blend is complete, here is the finished bearing, as shown above in Figure 6ab, one of the two most complex parts modeled for the skateboard assembly. The Assembly Figure A1 Start off the assembly by opening an assembly file and uploading all the parts of the Skateboard (Bearing, Board, Bushing, Connection, Shaft, and Wheel) to the file, using the Add Component tool, as shown above in Figure A1. Figure A2 Next, start off with the base of the assembly, inserting the board into the assembly environment, as shown above in Figure A2. Figure A3 Next, use the Add Component tool to insert the Connection into the Assembly environment. Use the Move Component tool to adjust the placement of the Connection to just shy of the bottom plane of the Board, as shown above in Figure A3. Figure A4 Using the Assembly Constraints, use the Concentric Feature to align the ottom circles of the connection to the top circles of the bottom plane of the skateboard, and then use the Touch Align Constraint to unite the two components together, shown above in Figure A4. Repeat this for the other side of board as well. Figure A5 Next, use the Add Component tool to insert the Bushing into the Assembly Environment, and use the Move Component tool to create relative spacing for the Assembly Constraints to work. Next, use the Touch Align tool and select the bottom face of the bushing and the face of shallow in sert of the connection, shown above in Figure A5. Repeat for other side of board. Figure A6 Next, use the Add Component to add the Bearing to the Assembly Environment, and use the Move Component tool to make the bearing relatively close to the connection and bushing, creating adequate spacing from the bushing and in line with the hole of the Connection, as shown above in Figure A6. Repeat for other side. Figure A7 Next, use the Add Component to add the Shaft to the Assembly Environment. Use the Move Component tool to move the Shaft relatively close to the Bearing, and then use the Concentric Constraint to match the shaft end to the bearing end, shown above in Figure A7. Repeat for other side of board. Figure A8 Use the Center Constraint tool to make the Shaft centered through the bearing by selecting the two ends of the shaft, and then selecting the two end planes of the bearing, as shown above in Figure A8. Note: This can also be achieved by deleting the former concentric constraint and moving the shaft accordingly using the Move Component tool. Repeat this for other side of board. Figure A9 Insert the wheel into the Assembly Environment, and move it relatively close to the shaft by using the Move Component tool. Use the Concentric constraint and select the small circle of the wheel and the circle created by the intersection of the bearing and the shaft, as shown above in Figure A9. Repeat this for the 3 remaining wheels. Figure A10 Here is the final CAD assembly of the skateboard, live and in color, with all parts/components correctly assembled. Summary Overall, NX is a program that can create complex assemblies from modeled parts, such as the skateboard that was modeled and assembled from several parts. By using simple commands, complex and simple parts were made and constrained in one assembly to ensure the proper appearance and setup. Though the process of creating the parts and assembling them correctly was challenging, the prior knowledge of NX was just enough to create an accurate representation of the skateboard. By using the IGS files for references, simple sketches using the dimensions drafted were just drawn and extruded/rotated to create the parts, and several constraints were used to complete the assembly. Appendix Figure A: The Bearing IGS Figure B: The Board IGS Figure C: The Bushing IGS Figure D: The Connection IGS Figure E: The Shaft IGS Figure F: The Wheel

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