The Goal of Exercise Four - Term Paper Example

 Table of Contents Introduction The goal of Exercise #4 was to gain familiarity with generating G-codes using SURFCAM CAD-CAM software and understanding the HASS 3-Axis CNC machine. Upon the completion of this exercise, we as Mechanical Engineers shall have a decent understanding of how this machine works.We created a rectangular block with three geometrical shaped pockets and 26 holes on the top surface. The designof this piece required five stages. The first stage wasdesigningthe part usingSolidWorks. This stage starts by drawing and dimensioning a sketch handed out in classby Dr. Sanchez using SolidWorks. A fewcalculations were requiredfor making this piece in SolidWorks. The second stage used SURFCAM to define the stock size, shaping tools, feeds and speeds.The SURFCAMsoftware also definedeach tool path. The third stage involved generating the G-code for machine the piece. During the fourth stage, the G-code was transferred to the HAAS machine using the GibbsCAM software in the machine shop. The final stage included loading the tools, selecting the zero points for each tool with the stock and running the machine to build the block. Prepared by: Binh Dao Design To start, a new file was open with a sketch on the front plane. Drawing from the origin, a center rectangle was drawn with dimensions of six in. on the x-axis and four in. on the y-axis. Fully defined, a fillet was then made with the radius of 0.250 in. on all corners. Following that, the rectangle was extrudedwith a one in. depth. After the extrusion, the upper portion of holes to be drilled was worked on next. The first hole, which was drawn for a linear pattern, was placed at the top left corner with a 0.250 in. diameter and an extruded cut depth of 0.250 in.The distance on the x-axis from the left edge to the center of the circle right, had a dimension of 0.500 in. indention. From the topof the rectangle to the center of the circle down, a dimension of 0.500 in. was also added. From here, a linear pattern was used to generate six holes by patterning with the x-axis with a distance of 0.43 in. from the center of one circle to the next. The step that proceeded with the drilling of the upper portion of the holes came to an extruded cut of a filleted rectangle with dimensions of 1.25 in. on the y-axis and 2.250 in. on the x-axis with an extruded cut of 0.250 in.This rectangle was to be positioned at the bottom left corner of the part with a dimension from the bottom edge of the part up to the bottom of the rectangle of 0.38 in.This same dimension was to be added to the left edge of the part towards the right direction to the left edge of the rectangle. From here, we moved to the next circular extruded cut. This circular extrusion started with a circle with a diameter of 2.00 in.and an extruded cut of 0.250 in.From the bottom of the part up to the center of the circle, a 1.250 in. dimension was set. From the right edge of the part, left to the center of the circle, a 1.500 in. dimension was also set to fully define the part. The next step that followed was to sketch on the base of the circle (extruded part) and draw eight evenly spaced circles within the circle. First, a reference circle was drawn from the center of the circle out with a dimension of 1.500 in. From here, a 0.250 in. circle was drawn at the top of the reference circle with an extrusion of 0.250 in. This then led to the use of a circular pattern using that little circle that was just extruded and the reference circle as the two need parts to create this pattern. By having the circles evenly spaced with a total of eight circles, this part of the drilling of holes within the circle was complete. After this, the drilling of holes around the previous rectangle that was drawn came next. The beginning hole with a diameter of 0.250 in. and a depth of 0.250 in., started at the left corner of the part with dimension from the left edge of the part right, of 0.230 in. This dimension was the same for the distance of the center of the circle down to the bottom edge of the part. A linear pattern was then used with the first direction being parallel to the y-axis with a distance of 1.560 in. from holes with a total of two holes. The second direction was the bottom edge of the part which was parallel to the x-axis with a distance of 0.870 in. between holes with a total of four circles. After having done this, we then calculated two more holes that would be drilled between the top row and bottom row of the previously drilled holes. The dimension of the circle itself as well as the extrusion remained equal to the top and bottom row. The distance from the left edge of the part to the center of the circle right, was a distance of 0.230 in. The distance of the bottom edge to the center of the circle up, was a distance of 1.010 in. A linear pattern was then used to find the other holes location in relation to its surrounding holes by picking the direction that was parallel to the x-axis and with a distance of 2.610 in. from one circle to another with a total of two circles. The last and final extruded cut on this part first began by drawing a circle with a diameter of 0.630 in. From here, a 3.00 in. distance from the left edge of the part to the center circle right was measured. Then from the bottom edge of the part to the center of the circle up, a measurement of 2.500 in.was inserted. From there, a circle of 0.630 in. diameter was drawn 2.380 in. to the left of the circle drawn before. This circle was tilted up 15 degrees from the bottom edge of the part up giving the second a slight vertical rise. From here, two lines were drawn to connect the two circles together. They were parallel to each other and were tangent to the circles. After, we trimmed the inner circle of both circles with the trim entities button. This then left a pill capsule shape which was then extruded cut downwards with a dimension of 0.250 in. After completing this step, the block part in Figure 1 is complete. Figure 1: Exercise #4 SolidWorks design. Prepared by: Ray Packingham Manufacturing Process: Generate G-Code SURFCAM CAD-CAD programming was used to set the G&M codes in order to manufacture the block design. SURFCAM is a computer-aided design (CAD) program and a computer-aided manufacturing (CAM) program. The SolidWorks design part was inserted directly into SURFCAM to create the tool path for machining that block.SURFCAM defines the boundary conditions for each tool path and the tools speeds for the selected material. Thepart origin was re-located to the upper left corner of the stock. This defined the starting point for the tool in the x-y-z plane. A stock size was selected to meet the required dimensions for the part with anadequate thickness that would prevent a collision error with the HAASmill table or stock hold downs.Coordinates for the block design stock size are defined in Figure 2. Figure 2: Dimension selections for the stock material A 2-Axis contour was chosen as the first cutting operation inthe Operation Manager screen in Figure 3. Each proceeding toolpath operation was also defined. Figure 3: Operations Manager Dialog screen Next, the outside edge of theblock was selected, which highlighted most of the part. Selecting the opposite side completed the outside contour of the design. TheTool Informationscreen appeared anda 0.500 in. 2-flute end mill tool is designated for the outside contour. The three pockets in theblock design also used the same parameters and tool number as shown in Figure 4. Figure 4: Tool Selection parameters for the contour and pockets The Tool Number also calls out the tool position on the HAAS machine. Length Offset and Diameter Offset were also defined. The Coolant option was set to offsincethe part was made out of soft material called RenShape® molding board. Spindle Speed was set at 2500 rpm in the clockwise direction (CW), Feed Rate at 25.0 IPM (in. per minute), and Plunge Rate at 10.0. The Surface Speed,Feed Chip Load and Plunge Chip Loadwere calculated automatically. The final step was selecting a Program Number of 20124. The program number will define the file name that will be sent to the CNC control board. The Climb cutting method was selected on the Cut Control screento provide a smoother cut with the CW spindle rotation.Material selection, cutting tools, and cut rates determined the following values in Figure 5. Figure 5: Cut Control for 2-D contour The total amount removed in the Z-axis corresponded with the total height of the block design. A series of rough passes will remove the majority of the material, while a finish pass will remove the final 0.020 in. of material for a smoother finish. The Tool Center was selected to be On for the contour and pocket cuts in Figure 6. Figure 6: Contour Material tool center option On Contour and pocket tool paths have the same 2Axis Options screen settings in Figure 7.Side and Depth Roughing and Finishing step sizes were reduced to prevent large pieces of material from breaking off during the roughing pass. Figure 7: 2Axis Options screen settings Three pocket cuts were made using the same0.50 in. 2-flute end mill tooland cutting speeds. Each pocket boundary was selected in a similar fashion as the contour boundary method. On the Cut Control screen in Figure 8, the Pocket Cut Mode was set to the Spiral cut mode, which generated a tool path that followed the defined contour of the pocket until the material is removed. The depth of each pocket was set to cut in the Z-axis direction at a depth of 0.250 in. Figure 8: Pocket Cut Control settings The Material Selection and 2Axis Options for the pockets were the same as shown in Figure 6 and 7, respectfully. After selecting the2Axis Hole Process from the NC menu, the outer diameters of all 26 holes weredesignated. Each hole required two new tool callouts; a #2 center drill and a 0.250 in. drill bit. A cutting depth of 0.100 in. for the center drill placed a guide point for the drill bit operation to maintain a concentric hole. The Spindle Speed, Feed Rate and Program numbers for both tools are shown in Figure 9 and 10. Figure 9: Center Drill operation settings Figure 10: Drill bit operation settings The depth of each hole is 0.250 in. from the surface. SURFCAM acknowledgedeach hole inside the circular pocket started at a depth of 0.250 in. The final tool path for the block design is outlined Figure 11 from the top view. Figure 12 displays an isometric view of the block, which shows the depthof each pass and the suggested pattern for the drilling procedure. Figure 11: Top view of SURFCAM tool path Figure 12: Isometric view of SURFCAM tool path Posting the selected tools and paths for the G-code was done by selecting the HAAS machine and highlighting the NC Project at the top of the tree, then the Post button at the bottom of the Operations Manager screen shown in Figure 3. A SURFCAM license key was inserted into the USB port and the work offset number set at 54 shown in Figure 13. Figure 13: Work offset selection This generated the call out commands in x-y-z coordinates for the HAAS machine. The top line contains the Program Number beginning with the lettero. After changing this number to 20124, the information was saved as a text file for transfer to the HAAS machine. A portion of the G-code generated is included in Figure 14. Figure 14: Block design partial G-code In the machine shop, GibbsCAM software converted the G-code text file into the proper format for the HAAS CNC machine. After sending the file from the computer to the HAAS, the manufacturing process can begin. Prepared by: John Blair Manufacturing Process: Machining http://news.thomasnet.com Figure 15: HAAS 3-Axis CNC Mill Figure 16: RenShape®molding material Prepared by:Ibrahim Conclusion In summary, the paper has achieved the goal of Exercise #4, which was to gain familiarity with generating G-codes using SURFCAM CAD-CAM software and understanding the HASS 3-Axis CNC machine. Due to the successful completion of the exercise, we have gained a decent understanding as Mechanical Engineers, of how this machine works. In this exercise, we have created a rectangular block with three geometrical shaped pockets and 26 holes on the top surface. The design stage has also been completed in five stages. During the initial stage of the exercise, Solid Works was used to design the parts, in which there was a detailed drawing and dimensioning a sketch that was handed out in class by Dr. Sanchez using Solid Works. There were some aspects of calculations required for making this piece in Solid Works. The paper has also described the second stage which used SURFCAM in order to define the stock size, shaping tools, feeds and speeds. The software, SURFCAM was also used in defining each tool path. Finally, the paper detailed the third stage in which there was a generation of the G-code for machine. The transfer of the G-code to the HAAS machine in the fourth stage using the GibbsCAM software in the machine shop has also been illustrated in the paper. As shown in the paper, the last hole in the circular pocket was drilled to deep due to an error in the g-code generation. This was ascertained in order to effectively complete the exercise with no gross defaults in the g-code generation. Work Cited Figure 15 http://news.thomasnet.com http://www.surfcam.com/help/web/index Read More