JAINIL N DESAI UFID: REVERSE ENGINEERING OF A PAPER PUNCH PROJECT REPORT COMPUTATIONAL METHODS FOR DESIGN AND MANUFACTURING EML5045

Transcription

1 JAINIL N DESAI UFID: REVERSE ENGINEERING OF A PAPER PUNCH PROJECT REPORT COMPUTATIONAL METHODS FOR DESIGN AND MANUFACTURING EML5045

2 A) Objective: The main purpose of this project is reverse engineering. Here, reverse engineering of a mechanical paper punch is done. A paper punch is used to make holes in paper so as to bind them in a file. This is a three hole punch and the hole locations are adjustable in size. The solid models of each component were done on Solid works. Vernier calipers were used to measure the dimension of each component. The punch was totally dissembled to take the measurements and find out the way assembly was done. Most of the punch is made of carbon steel material and made with sheet metal. Using Vernier calipers for measurements, the accuracy was 0.01 mm. After assembly is done, the interference test is supposed to be done to find out whether the assembly is actually good and that there is no interference between any of the components. B) Description: The paper punch works on the basic principle of a lever mechanism. The main parts of the punch are the base (1), spring(8), the puncher (4) and a press(6) to apply effort. The other supporting parts are the spring support (2), the screw to fix the slider (5), the slider guide (3) for spring support. Functional requirements of each part: 1. Base: It is the support for the entire assembly and basically bears all the load. 2. Spring support: This also acts as a guide to the path of the puncher. It maintains the horizontal path. Also they can move in vertical direction so as to vary the distance between the holes. 3. Slider: This is basically used to constrain the motion of the puncher assembly. 4. Puncher: It actually makes the hole in paper. It should have sharp edges and the edges should not wear out. Guide for spring support: This has a pathway that gives the horizontal motion to the puncher assembly. 5. Screw: The screw is used to fix the puncher assembly to the guide and also acts as a guide so as to constraint the horizontal motion of the assembly. 6. Press: This is a part through which the load is applied. It is hinged to the base. the protrusion under the surface of the press is used to push the puncher. 7. Pin: it is used to hinge the base and the press. 8. Springs: They are used to bring back the assembly to its original position after the work is done. Here, the numbers refer to the number of component in the bill of materials in the assembly drawing. Working: A single paper or a bunch of papers are placed in between the base and the puncher. The effort is applied with the help of press. This pushes the puncher down. The path of the puncher is guided by the spring support. It has holes in it and the protrusion out from the puncher prevents it from going away from the path. The springs are mounted concentric with the puncher and mounted in the spring support. Now as the pressure is applied via the press on the puncher pushes it down.

3 The puncher has sharp edges and as it comes in contact with the paper, the shearing of paper takes place. Now as the pressure is released, the springs push back the puncher and the press returns to its original position. The position of the holes can be varied. There is a screw provided and it fixes the position of the puncher and spring assembly to the slider. It guides the motion in the horizontal direction. The press has freeform surfaces. It is made with combining multiple splines together using the boundary blend feature in Solid works. First the actual surface was created. A reference plane was defined and the cross section of the material to be removed was drawn over it and it was used in the feature extruded cut. Now again a set of splines were used to define the geometry of the depression. Again surface blend feature was used to create the free form surface of the depression. Then all the surfaces were combined and were given thickness of 1 mm. Assembly process: Most of the components are pressed components. The base and the slider are first assembled together with welding them. The spring and the puncher are assembled and fitted in the spring support to make one entire assembly. This in turn is fixed with the slider with the help of the screw. Again the fit is such that the puncher is mated with the gap in the base. Then the press comes in the picture. It is also a sheet metal pressed component. It is hinged with the base with the help of the hinges and it is constrained by the geometry of the shape of the press itself. C) Results: Here the drawings of the entire assembly and each component in the assembly are shown. Here, the exploded view of the assembly is shown and also the detailed drawing of each component as well as the assembly drawing is shown. The assembly drawing also shows the bill of materials. In Solid works, after the assembly is done, there is an Interference tab in evaluation section. The interference of the assembly was checked using this and the result was that there was zero interference. The image from the software is shown that says no interference. Image showing no interference

4 Below is the exploded view of the assembly showing each component. Exploded View Here is the detailed drawing of the assembly with the Bill of Materials and the preceediung drawings are the detailed drawings of each single component.

5 D) Conclusion: The assembly is done on Solid works and the components were measured using Vernier calipers with a reasonable accuracy. Each component was studied for its working and functionality. The drawings are created for each component. The assembly is checked for interference and the results were ok. There was no interference. The component is reverse engineered with the best accuracy possible. The press is entirely made of free form geometries.