Using Surfcam to Produce a Numeric Control (NC) Program

1. Using Surfcam to Produce a Numeric Control (NC) Program An Introduction to the CAD/CAM Process Instructions for 3 Axis Programming Using the D&M CNC Milling Machine Production processes for the plastic key fob project

2. The CAD/CAM process consists of the following steps: • The production of a drawing using a CAD program. • The identification of the types of cuts to be made and the sequence of the cuts (NC). • The Post Processing that converts the tool path sequences into G-Codes for use by the machine. • Making the part on the machine.

3. To produce the key fob for this exercise you will need to follow these general procedures: Create a 2d drawing using SolidWorks. Save the drawing as a .DXF file. Save the .DXF file on a flash drive. Open the file on a computer running the Surfcam software.

4. Surfcam Instructions Open Surfcam from the desktop on the computer. Insert the flash drive into the computer. Open the file that you need to have converted to G-code by selecting the location, file and file type.

5. Once the file is open you will need to make the following settings for converting the 2d .DXF data to Surfcam data.

6. The converted data will appear as shown below. However, the drawing data will need to be attached to the program origin which may not be visible. To find the origin select; “Display” and “Zoom Out”.

7. Select “Zoom Out” multiple times until the origin and the drawing data is shown on the screen together. Program Origin

8. The extra drawing data (added text) will need to be removed prior to attaching the drawing data to the origin. To do this select; “Edit” & “Delete”.

9. Select “Within” and drag a box around the text as shown below. After the text has been removed, select “Back”.

10. To move the drawing data, select; “Edit”, “Transform” & “Move”. Next, select “Location”. Then, select “Within”.

11. Click, drag and surround the drawing data as shown below.

12. Select “Sketch”, click on the lower left-hand corner of the drawing data and then click directly on the origin point.

13. The drawing data will now be attached to the origin and the diagram will need to be resized to fit the screen. To do this select “Display” & “Fit”.

14. The drawing data will now be fit to the screen. Select “Cancel” to return to the main menu to begin the NC process.

15. Select “NC”, “2 Axis” & “Contour” to begin. Even though you are using a 3 axis machine for the actual work, the layout for the process only requires 2 axis . “Contour” means cutting directly on the line.

16. Select the inner most lines for cutting first. Use “Single” to select individual lines, arcs or points by clicking on them. Use “Chain” to select groups of contiguous lines and arcs. Click near the beginning of the group you wish to “chain” and then again near the end of the group. Selected items will be highlighted in yellow. Select “Done” when you have selected all of the items to be included in this process.

17. After selecting “Done” the “Tool Information” dialog box will appear. Select “Select Tool” to identify the type and diameter of cutter to be used. In the dialogue box that appears select a 1/16” diameter, 2 flute end mill – this will be the tool used for the cutting of the material in this exercise After selecting the cutting tool, enter the feed and plunge rates for the process. For this exercise use a feed rate of 15 ipm and 5 ipm for the plunge rate. The material selection will be made next.

18. Select “Select Material” and choose “Mahogany”. Even though you are cutting plastic, the material properties are similar. Do not exit the 2 Axis Contour dialogue box yet! Select “Cut Control” to set the remaining features.

19. To control the cuts for this exercise, set all of the parameters as shown to the right. The “In Z” data includes 2 critical numbers. The “Amount To Remove” is the total depth of the cut. The “Rough Spacing” is the amount of material that should be removed in one pass of the cutter. It is the same number for this exercise. Once these parameters are set, select “OK” to exit the 2 Axis Contour dialogue boxes. The NC parameters for the cutting of the letters on the key fob are now complete. .25

20. The tool paths for the NC program have now been identified. Red lines will be seen on the 2d drawing indicating cutter travel in the G00 (Rapid Move)mode.

21. To see the all of the tool paths that have been produced, select “View”. In the View dialogue box double click on “Isometric view”. White lines represent the original drawing data, red lines the rapid (G00) tool movement and green lines the actual contour cuts (G01, G02 & G03).

22. Select “View” again and then “Top” (double click) to return to the top view of the drawing data. The next NC process will now need to be addressed. Following the concept that interior elements need to be cut first, select “NC”, “2 Axis” & “Contour”. Select the small circle using the “Single” tool. At the “2 Axis Contour” dialogue box, leave the tool and material information as previously set. Select “Cut Control” and change the information as shown on the next slide.

23. These settings represent the total depth of cut (.06) to go through the .55” material and .03 to be removed in a single pass. It will then require 2 passes to cut the entire way through the material. There will be two sets of green lines (contour cuts) shown on the diagram. .25

24. Repeat this exact same set of procedures to develop the NC data for the outside “slot” component of the drawing. All contour information will be the same as it was for the small hole (both the Tool Information” and the “Cut Control”) . When finished identifying the NC data for the 3 processes the drawing data will appear as shown below.

25. Once you have the NC process data in place, “Save” your file to the flash drive. Up until now you have been running the the “demonstration mode”. At this point you will need to insert the “software key” so that you may continue your work using the full capabilities of the software.

26. Next, select “Operations Manager” from the menu. The “Operations Manager“ screen will appear.

27. The “Operations Manager” outline is set up to show the following items for this project: The overall NC Project The project Setup The 1st process (the cutting of the letters) The 2nd process (the cutting of the hole) The 3rd process (the cutting of the slot) 1. 2. 3. 4. 5.

28. The material size data will now need to be entered. Right click on “NC Project” in the “Operations Manager” outline. In the sub-menu that appears select “Edit Setup Information”.

29. In the “Section Information” dialogue box select “Stock”. “Corner 1” is the lower, front, left corner of the material. “Corner 2” is the top, back, right corner of the material. Enter the data shown to the right for this project. Be sure to indicate the “Z” data for “Corner 1” as a negative number. Once the data is entered, select “Add” and then “OK”.

30. Save the program at this point. Select “Toolpath Verification” to inspect the program that has been created.

31. The “Toolpath Verification” screen will appear. Move the “speed control” slider to the left (slow)and then select “Play” to verify the accuracy of your program. If it appears correct, exit the screen and save your program. If there are errors, see the instructor. If the program is accurate, the material will be shown in blue. The letters will be shown in grey indicating that the material has been cut into – but not all the way through. The hole and the slot will show through to the background indicating they have been cut all the way through. Exit the “Toolpath Verification” screen and return to the “Operations Manager” .

32. The next step will be to run the “Post” to create the G- code. Set the “axis type” and the “post” as shown below. Be sure “NC” code is highlighted (blue). Select “Post” and the contour data will be processed into NC code (G-code) .

33. The “editNC” screen will appear. The code can be edited here, but we will make any necessary changes in the “Velocity 4CNC” software. Exit the screen and select “Done”. Save your file. You can now exit “Surfcam”. Your NC file should be saved on the flash drive with the name of your original DXF file , but with an NCC file extension . You are now ready to proceed to the mill to cut the plastic.

34. At the CNC milling machine: • Insert the flash drive into the computer • open the “Velocity 4CNC” software • select “File”, “Open NC Code” • Select your file (NCC file extension) • Run an emulation • Verify that the toolpath is accurate • secure your material on the mill • Turn on the mill • Zero the cutter to the material • Zero the software • Cut the material.