MasterCAM version Mill9.1

Tutorial chapters:1. Importing IGES file into MasterCAM2. Tool path setup

a. Setting job parameters: stock boundaries, creating a bounding box, selecting the stock origin.

3. Surface toolpaths:a. Rough cutb. Finish cut

4. Setting toolpath parametersa. Creating a new tool

5. Preparing for machining; post processinga. Checking toolpaths for collisions and gouges

6. NC file upload7. Router Functions

Routing is an effective method for machining materials such as wood (or wood byproducts), plastics, and rigid or high-density foam. The tutorial chapters will enable you to generate g-code .NC files from an imported 3-D model to be machined by the AXYZ4008 router at the GSD.

1. Importing IGES file into MasterCAM

Surface and solid models can be imported into MasterCAM from environments that create watertight models. The Rhinoceros platform is successful for exporting watertight .igs or .iges models. (Note: FormZ is not suited to producing these models.)

Exporting your model from Rhinoceros

1. Prior to exporting your surfaces the entire Rhino model needs to be located in the Cartesian positive X- and Y-axes and the negative Z axis.

2. In Rhinoceros select File / Export Selected (follow the

Command prompt instructions and select the appropriate surfaces.) An Export dialogue box will appear: create file name and save as an IGES *.igs, *.iges.

3. An IGES Export Options dialogue box will appear: scroll through the IGES types, select Mastercam and select OK.

Importing your IGES file into MasterCAM

1. Open the MasterCAM Mill9.1 icon.2. Using the prompts at the top left of the screen select: File /

Converters / IGES / Read File.3. Browse to find your file and open it.4. A dialogue bow will appear, accept defaults and click OK.

An addition dialogue box will appear, asking, “Delete the Current Part?” Click Yes. Your model should now appear.

5. Press F9 to toggle on/off the X, Y, Z-axes. The MasterCAM location of your model will correspond to the Rhinoceros exported position. To view your model obliquely, Right-click for “dynamic spin” options.

Verify Surface Viability

1. Any initial machining problems can be identified by the following sequence.

2. First, testing the normals: select Main Menu / Analyze / Surfaces / Test Norms / All / Surfaces / Done. A pop-up window will then appear informing you of your model’s integrity. If you have reversed normals, follow the onscreen prompts to adjust the surfaces of rebuild your model and re-import.

3. Second, testing the model for sharp internal corners that may not be machinable: select Main Menu / Analyze / Surfaces / Check Model / All / Surfaces / Done. A tolerance will be shown at the bottom left of the screen, select Enter to accept

4. A pop-up window will appear with diagnostics of your model. Click OK. If you had internal sharp corners, MasterCAM will ask you if you wish to draw the internal sharp curves. We recommend that you say no and either proceed knowing that the machine may not be able to reproduce your model as precisely as you have drawn it or to redraw your model in the original modeling program avoiding sharp internal corners and re-import. Take note of the location of the curves that MasterCAM indicates contain sharp internal corners before proceeding. And also understand that you may be able to set parameters that will minimize the differential between what is modeled and what the machine is capable of cutting. See below for details

2. Tool path setup

Setting Job Parameters: stock boundaries

The stock boundaries help you visualize the part you are machining during the toolpath verification.

1. Choose: Main Menu / Toolpaths / Job setup2. Choose: Select corners3. Select one corner of the stock using the Point Entry

system and then select the opposite corner. The system automatically fills in the X, Y, and Z fields based on the geometry you selected.

4. Choose OK if you accept.Note: you can only set up rectangular stock

Setting Job Parameters: creating a bounding box

A bounding box defines the stock limits by finding the extents of the selected geometry.

1. Choose: Main Menu / Toolpaths / Job setup2. Choose: Bounding box3. Select the entities around which the bounding box is

defined.4. Choose: Done

Setting Job Parameters: selecting the stock origin

The stock origin adjusts the position of the stock. You can set the stock origin to any corner of your model.

1. Choose: Main Menu / Toolpaths / Job setup2. Choose: Select origin3. Select a point in the graphics window. The system returns

to the Job Setup dialog box and fills in the stock origin X, Y, and Z-coordinate based on the point you selected.

4. Click OK and leave the remaining defaults as they are set.

3. Surface Tool paths

Rough Cut

Rough toolpaths remove large amounts of material from surfaces as rapidly as possible. A rough cut is not required for milling foam. A rough cut is required when removing wood. Note: be sure to leave 1/16” of material for your finish cut.

1. Choose: Main Menu / Toolpaths / Surface / 2. Ensure that the Surface settings shown at the top left of the

interface are as follows:a. Drive: Sb. CAD file: Nc. Check: Nd. Contain: N

3. click / Rough4. Select the “surface roughing.” Choose from a number of

preset paths that the tool will take (i.e., parallel, radial, flowline, contour, etc.) These are all options for the direction or manner in which the tool will make its cuts over the surface of the object. To learn more about the differences at this point, click on the help button.

5. If you choose parallel cut you will be prompted to tell MasterCam whether you are cutting a boss or a cavity. Do so accordingly (Boss is a positive, cavity is a negative. If you have both or a complex form, choose unspecified)

6. You will now be prompted to select the surfaces for machining. Select all surfaces feature by clicking All and then Surfaces. Do not worry if this automatically selects an underside. You will verify that the machining is only cutting the desired surfaces in the next steps. Click Done.

7. If you wish to select only specific surfaces rather than clicking All as described above, use the pointer and click on each desired surface. When finished selecting, click Done. You may use the unselect button at the top left if you accidentally choose a surface you didn’t intend to.

8. Again, once your surfaces have been selected, click Done.

9. A Toolpath Parameters Dialog Box will open. Follow the directions in Chapter 4: Setting Toolpath Parameters to set the parameters of your rough-cut, prior to setting the Finish Cut parameters.

Finish Cut

Surface finish toolpaths are used to create precise surfaces after roughing.

1. Choose: Main Menu / Toolpaths / Surface / 2. Ensure that the Surface settings shown at the top left of the

interface are as follows:a. Drive: Sb. CAD file: Nc. Check: Nd. Contain: N

3. click / Finish4. Select the Surface Finishing. This is the manner in which

the tool will make its cuts over the surface of the object. To learn more about the differences at this point, click on the help button.

5. You will now be prompted to select the surfaces for machining. Select all surfaces feature by clicking All and then Surfaces. Do not worry if this automatically selects an underside. You will verify that the machining is only cutting the desired surfaces in the next steps. Click Done.

6. If you wish to select only specific surfaces, rather than clicking All as described above use the pointer and click on each desired surface. When finished selecting, click Done. You may use the unselect button at the top left.

7. Again, once your surfaces have been selected, click Done

4. Setting toolpath parameters

Creating a new tool

1. After the defaults are set, a dialogue box will appear.2. Under the “Tool Parameter” tab, in the Parameters dialog

box, right-click in the tool list area and choose Create new tool.

3. Enter your bit parameters in the Define Tool dialog box.4. Choose OK.

5. Set the following parameters for your tool:a. Feed Rate: 25 (for wood), 200 (FOR FOAM

ONLY!!!)b. Plunge Rate: 10 (for wood), 200 (FOR FOAM

ONLY!!!)c. Retract Rates: 200d. Coolant: offe. Accept all other defaults

6. Click on the Surface Parameters Tab and adjust the following parameters according to the specifics of your project.

(NOTE: BE SURE ALL MEASUREMENTS ARE SET TO INCREMENTAL)

a. Clearance: This is how high the tip of the bit will be raised off of the top of the material block when the arm travels during initial and final non-cutting movements. It will be important to forecast the height of any bracing or clamps used to hold down your material on the router bed when calculating this figure. THE TIP OF THE ROUTER MUST BE HIGH ENOUGH SO THAT IT WON’T HIT ANY OF THEM.

b. Retract: This is the height the tip of the bit will be raised off of the top of the material block in between cutting movements.

c. Feed Plane: This is distance off of the machined material to which the feed rate will continue and after which the Plunge Rate will begin. In other words, the tool will move very quickly when it is above this height, and will move at the feed rate when it is below this height.

d. Tip comp: This is the point on the bit from which the cutting measurements are drawn. You do not want to use center comp.

(NOTE: BE SURE ALL MEASUREMENTS ARE SET TO INCREMENTAL)

7. Click on the Finish Parallel Parameters Tab to adjust tolerance, max stepover, cutting method, and machining angle.

a. The Tolerence will help determine how accurate the bit interpolates your surface curvature. The smaller the number, the more accurate and longer the cut-time. Most jobs will be fine accepting the default of 0.001

b. The Max Stepover determines the distance the bit will move over for the next parallel cut. This will affect the “smoothness” of your final surface Here a larger number will result in more “stepping” (if using a flat-end bit) or “scalloping” (if using a rounded bit). Consider the width of your bit and some fraction of that width as a Max Stepover.

c. Cutting Method: select “zig-zag” to allow the machine to cut while traversing both positive and negative directions or “one-way” to restrict cutting to a single direction. The most efficient is “zig-zag.”

d. Machining Angle: this will allow you to dictate which angle the parallel lines are cut.

8. Select OK and the lines of your toolpath will appear along the surface of your object/model along with an Operations Manager Dialog Box. Fron this dialog box you will be able to complete the final steps to Verify and Post your file.

CHAPTER 5. Preparing for machining; post processing

A post processor is a program that converts a toolpath, which contains all information necessary to machine a part, into an NC program, which is the code, required by a particular machine and control combination to machine the part.

Checking toolpaths for collisions and gouges

By checking your toolpaths for collisions and gouges, you can prevent future problems while machining a part. Collisions and gouges can cause damage to a part, tool, CNC machine, and the machine operator. A collision occurs when the tool contacts material during a rapid move. A gouge occurs when the tool removes more material than desired, usually during a linear or arc move. The system compares a surface toolpath to an STL file that represents the finished shape of the part to see where gouges have occurred.

You can check more than one toolpath for gouges and collisions at the same time if the toolpaths are all in the same tool plane. You can also set the color and level of the geometry that marks collisions and gouges. This function works with flat, bull, or ball endmills.

(NOTE: TOOL HOLDER COLLISIONS AND GOUGES ARE NOT REPORTED)

Verifying Toolpaths

The model created by Verify represents the surface finish, and shows collisions, if any exist the simulation will pause to identify the location, so that any program errors can be eliminated before they are sent to the router.

1. Verify your toolpath:a. If the Operations Manager Dialog Box is open,

select Verifyb. Or, select: Main Menu / NC utils / Verify

2. To preview multiple toolpaths highlight the name in the post box by holding the Ctrl and LMC.

3. To run the verify, click the play button.4. If you are unsatisfied for any reason, return to the

Operations Manager and click on the Parameters line to return to the tool parameters dialogue box. Make any necessary adjustments and say OK.

5. IMPORTANT: If you have altered the parameters, you must return to the Operations Manager and click Regen. This will regenerate the tool path. Then repeat the steps outlined above to re-verify the new tool path. Repeat these steps until you are satisfied with the tool path demonstrated in the verify.

6. If you are satisfied with the verify, close the verify bar by clicking on the X at the top right. This will reopen the Operations Manager. From within the Operations Manager, highlight the tool path in the window on the left and click on the Post button on the right.

7. This will open the Post Processing dialogue box. You

should use the AXYZ postprocessor (axyz_Harvard.pst). If it is not shown in the dialogue box, choose change post and choose it from the list (it will be the first one on the list). Click on save NCI, as well as save NC. You do not need to click the edit box. When prompted, save the file to your desired location.

8. Saving the file will cause your G-Code to be written.9. You now have a rough cut tool path ready for the uploading

to the mill/router.

6. NC file upload

Log on to the computer in L40d and transfer your file onto the desktop.

7. Router Functions

In L40d a laminated sheet titled AXYZ CNC Router Table – Instructions for Milling your Part is located with the bits. The sheet walks the operator through the simple Functions in machine operation.