1. 2. 3. 4. 5. 6. 7. 8. 9.

10.

MasterCAM 2020 Step-by-Step Guide3 - Define Stock Size

Accurate Dimensions

MEASURE YOUR STOCK

MasterCAM will use the

3 - Define Stock Size

3 - Define Stock SizeAccurate Dimensions

3 - Define Stock Size1 - Open Template File

Material Based2 - Merge Geometry

Preparing Geometry in RhinoImporting from Rhino

3 - Verify Location and Orientation of Geometry

View Work Coordinate SystemVerify LocationVerify Orientation

4 - Define Stock SizeAccurate DimensionsEntering Stock Dimensions

5 - Roughing Operation(s)What is a Roughing Operation?

Contour 2D - Multi PassSurface Rough Parallel 

6 - Finishing Operation(s)What is a Finishing Operation? 

Surface Finish ParallelSurface Finish Contour Surface Finish Shallow Surface Finish Constant Scallop Pocket Contour 2D / 3DPeck Drill 

7 - Adjust Parameters

In order to use the large bed CNC routers at the GSD, students must submit a MasterCAM file to the online queue with geometry imported and operations assigned. CNC TA's are available during regular daily hours throughout the semester to answer questions , review submitted files, and run approved files on the mill. This page will enumerate the steps required to have an approvable MasterCAM files.

The GSD CNC lab is not full service. Staff and TA's are not available to set up users' files for them.

The FabLab has created material-specific to help alleviate common setup MasterCAM template filesissues. 

A basic workflow for successful MasterCAM setup is as follows:

Open template file (material appropriate)Merge geometry Verify location of geometry relative to file originDefine stock size (must match physical material to be milled)Assign geometry to roughing operation(s)Assign geometry to appropriate finishing operation(s)Adjust operation parameters (tool selection, machining heights, etc)Generate toolpathsVerify operations (ensure no collisions and desirable outcome)< repeat steps 4 thru 8 iteratively until successful verification >Submit file to online queue for approval and scheduling

Reference Pages

MasterCAM 2020 Reference > Managing Operations

Reference Pages

Please use this page in conjunction with the MasterCAM 2020 Reference.

Surface Rough ParallelSurface Finish ContourSurface Finish ShallowSurface Finish Constant ScallopPocketContour 2D/3DPeck Drill

8 - Generate ToolpathsDrawing the ToolpathsDirty OperationsUnused Operations

9 - Verify OperationsWhat is Verification?How to VerifySimulation PlaybackCollision CheckingRun Time Estimate

10 - File Approval + Scheduling Upload Files to GSD Server Complete the Online Form Edit Files if NecessarySchedule Milling Appointment Prepare Stock Material Attend Appointment 

1 - Open Template File

Material Based

The GSD FabLab provides   with and without example geometry, for both Foam and Wood projects. It is necessary to MasterCAM templatesseparate the two, because the material qualities and behaviors vary greatly and require different tooling and parameters for successful milling.

• The foam template should be used for all densities and types of foams, including extruded polystyrene, expanded polystyrene, and high density polyurethane.

Foam Context Model Milling Template - Without Sample Geometry (2020)

Foam Context Model Milling Template - With Sample Geometry (2020)

• The wood template should be used for all wood and wood products, including softwoods, hardwoods, plywood, oriented strand board, and medium density fiberboard. A special template is provided for milling flat stock materials, such as single sheets of plywood or MDF.

Wood Context Model Milling Template - Without Sample Geometry (2020)

Wood Context Model Milling Template - With Sample Geometry (2020)

Wood Flat Stock 2D Milling Template - With Sample Geometry (2020)

The GSD FabLab does not currently provide templates for less frequently machined materials, though we do maintain tooling to work with the following:

• Non-ferrous metals (aluminum, brass, copper)

• Plastics (Acrylic, HDPE, Corian, Pattern Board)

• Machinable Wax 

2 - Merge Geometry

Preparing Geometry in Rhino

Change Rhino file model space units to inches.

Scale geometry for milling.  

Move geometry to the origin and arrange in all positive space (+X, +Y, +Z).

Check that geometry fits within the maximum machinable extents of the intended CNC mill. 

Explode geometry and remove vertical surfaces.

Xmax Ymax Zmax

ONSRUD 48" 96" 6"

Reference Pages

MasterCAM 2020 Reference > > Managing Geometry Merge Geometry

Rhino File Preparation

AXYZ 96" 48" 4"

ROLAND 12" 12" 3"

Note that machinable Z height decreases for tougher materials. 

Organize geometry in Rhino by layer, such that each layer will receive similar treatment in MasterCAM (e.g. Building Tops, Draped Surface, etc).

Avoid using Yellow and Black as layer colors due to MasterCAM interface conflicts. 

Importing from Rhino

Click in the ribbon menu, and choose to open the file picker window. Change the file extension filter to Rhino 3D Files (*.3dm). Select file mergethe .3dm that contains your geometry. 

Click , and the geometry appears in the MasterCAM model space. open

Select the radio button for "Merged File Levels" in the Levels dropdown of the File Merge dialog pane.

Select and then de-select an option from the bottom "Settings' of the Merge Dialog

Press Enter or click the green checkmark. 

3 - Verify Location and Orientation of GeometryBecause the origin of the file typically corresponds to the origin used on the machine, it is important that your geometry be located relative to the origin such that it is appropriately located on the machine. Working far from the World Top Plane Origin in Rhino or similar applications will often cause the geometry to be located far from the origin in MasterCAM, so it's best to catch this issue early, before getting too far along in MasterCAM.

View Work Coordinate System

From the View Tab, choose "Show Axes" and "Show Gnomons"

Excessive Import Time

Large / complex surfaces or meshes can cause MasterCAM to become unresponsive during merging. This slowdown can be avoided by changing Visibility from to prior to merging. This prevents MasterCAM from "Tessellating", increasing responsiveness.shaded wireframe

Verify Location

Your geometry should be located within the X, Y, and Z quadrants, with the stock modeled such that it has a corner located at 0,0,0. positiveThe gnomon and axes visible on the screen should help to verify whether the geometry needs to move in order to satisfy this condition.

Verify Orientation

Machine dimensions vary, as do the lengths of their respective axes of travel. Make sure your geometry fits within the dimensions of the machine you intend to use.

Xmax Ymax

ONSRUD 48" 96"

AXYZ 96" 48"

ROLAND 12" 12"

4 - Define Stock Size

Reference Pages

MasterCAM 2020 Reference > Managing Operations

Accurate Dimensions

MEASURE YOUR STOCK

MasterCAM will use the input stock size when simulating, so it is vital to ensure that dimensions are true to the physical material that will be placed on the milling table. 

Entering Stock Dimensions

In the toolpath manager pane, expand the subgroup. properties

Choose , and the machine group properties window opens. The stock box is represented by a dashed red rectangular prism. stock setup

Set the coordinates to 0,0,0. stock origin

Click the lower left corner of the stock box. 

Enter the as-measured dimensions of your stock into the X, Y, Z fields. Default units are inches. 

Tick the checkbox to show stock box in MasterCAM model space.  display

Press ENTER or click  OK to accept the changes. 

Update Machining Heights

sers MUST manually update machining heights to reflect the stock thickness for each operation After defining stock dimensions, uindividually. MasterCAM will not auto-update these values. Inaccurate values cause collisions during verification.

5 - Roughing Operation(s)

What is a Roughing Operation?

A roughing operation is used to remove large amounts of material rapidly and to produce a part geometry close to the desired shape. 3D geometry will typically need to include one as the first operation, while 2D geometry may not. A roughing operation uses large diameter tools and coarse settings, and should not cut all the way down to the drive surface(s), instead leaving a small offset for the finishing operations to clean up afterwards. 

Contour 2D - Multi Pass

When stock thickness exceeds the shoulder length of the tools, the surrounding uncut stock may interfere with toolpaths drawn on the perimeter of the part, causing collisions. In this circumstance, it is necessary to partially clear away the stock outside the part perimeter before proceeding to the finishing operations. 

The Contour 2D operation may be used for roughing as follows:

Assign a part perimeter chain as the input geometry.Choose an appropriate tool for clearing a lot of material. Typically 3/4" Flat Upcut EndmillAdjust Compensation such that the toolpath is drawn outside the part.Enable Multi Passes in the operation parameters.Set Parameters > Multi Passes > Rough > Number = 3Set Parameters > Multi Passes > Rough > Spacing = 50% of tool diameter.Set Parameters > Linking Parameters > Depth to = 50% stock thickness.Set Parameters > Cut Depths > Max Rough Step to = 50% flute length

Reference Pages

MasterCAM 2020 Reference > Managing Operations

MasterCAM 2020 Reference > Assigning Geometry

Check for Gouging

Note that operation is not context-aware. Nearby parts may be gouged if there are multiple parts being machined from a  the Contour 2Dsingle stock.

Surface Rough Parallel 

Used to remove material from all surfaces quickly. 

The Surface Rough Parallel operation moves the tool in equally spaced parallel passes in the XY plane across the surface, cutting down incrementally in multiple steps. The toolpath can be drawn as One Way (best for anisotropic materials with grain direction, slower) or Zigzag (best for isotropic materials, faster).

Note that all surfaces except stock extents are assigned as Drive surfaces in a typical MasterCAM file.

6 - Finishing Operation(s)

What is a Finishing Operation? 

A finishing operation follows roughing and is used to achieve the final geometry and surface finish. Most MasterCAM files need at least one and frequently several separate finishing operations to produce an acceptable part. Finishing operations clean up the extra material purposefully left behind by the roughing operation. Finishing operations must be employed on a case-by-case basis, as the utility of each operation type varies from one file (and geometry) to the next. 

See reference pages (linked above) for a detailed explanation of concepts and usage that are common across all operation types. 

Commonly used finishing operations are listed below. Users must review them and determine which operations are appropriate for their geometry.

Surface Finish Parallel

The Surface Finish Parallel operation moves the tool in equally spaced parallel passes in the XY plane across the surface. The toolpath can be drawn in any angle relative to the XY origin. 

Reference Pages

MasterCAM 2020 Reference > Managing Operations

MasterCAM 2020 Reference > Assigning Geometry

This operation is often used with varying stepovers and machining angles to create surface patterns on site models. 

Surface Finish Contour 

Used primarily to clear material from vertical or steep features. 

The Surface Finish Contour operation cuts geometry by offsetting toolpaths away from the drive surface at incremental heights. As sloped geometry becomes steeper, the toolpaths get closer together; as that geometry becomes more shallow, the toolpaths are spaced farther apart. 

This operation is often paired with a flat endmill for use on vertical building faces. Note that the horizontal surface (building top) is the Drive surface.

Surface Finish Shallow 

 Used primarily to clear flat areas, such as stepped terrain or building tops.

The Surface Finish Shallow operation cuts geometry whose slope angle does not exceed a threshold (users can set maximum). 

This operation is often paired with a flat endmill for use on stepped topography and building tops. Users can dramatically reduce machining time by strategically using larger diameter tools to cut open areas, while targeting small diameter tools to narrower channels.

Surface Finish Constant Scallop 

Used primarily to clear sloped areas, such as rolling topography.

The Surface Finish Constant Scallop operation cuts geometry by dynamically adjusting stepover (users can set maximum) as a function of the slope angle for any given point along the drive surface. This method maintains a uniform scallop height across variable relief, and thus uniform smoothness. 

This operation is often paired with a ball endmill for use on rolling topography and gentle slopes. Users can achieve a smoother finish by increasing tool diameter (at the cost of decreasing resolution in narrow channels) and/or decreasing maximum stepover (at the cost of dramatically increasing machining time).

Pocket 

Used to cut flat-bottomed holes, such as building footprints.

The Pocket operation removes material from within a closed chain, creating recesses with flat bottoms. Pockets require closed 2D curves, all in planes parallel to the World Top CPlane. Note that the Pocket operation includes its own internal Roughing and Finishing stages within the parameters. 

This operation is often paired with a flat endmill to cut building footprints. Pockets are preferred over Surface Finish Shallow for cutting deep, flat-bottomed recesses due to their incorporation of incremental .depth cuts

Contour 2D / 3D

Used to trace linear features, such as final perimeter cut-out. 

The Contour operation cuts along a chain or series of chains. The cut may be compensated to the left or right of the chain(s), or on center if compensation is turned off. The chain may be 2D (planar) or 3D. The depth of cut can be absolute (2D only), or incremental (2D and 3D). 

Peck Drill 

Used to create precisely located holes.

The Drill operation creates holes using points as input geometry. Although it is possible to use endmills in a drilling operation, it is preferable to use drill bits. The ONSRUD can accept drill bits of all sizes up to 5/8", while the AXYZ and ROLAND can only accept drill bits in exact collet sizes. 

7 - Adjust Parameters

Surface Rough Parallel

Toolpath Parameters (First Tab)

Planes

In most cases, select TOP as work coordinate system, tool plane, and construction plane.

When machining the underside of a two-sided job (flip milling), select FLIP as work coordinate system, tool plane, and construction plane. FLIP plane must be defined in Plane Manager.

 Tool Selection

Select largest diameter flat upcut endmill to remove material quickly. Harder materials require shorter tools.

Special tools are available for roughing solid wood, plywood, and mdf.

Surface Parameters (Second Tab)

 Stock to Leave

Input a positive offset for both Drive and Check surfaces. Default is 0.125" for both values.

Machining Heights

Input values appropriate for stock thickness.

Clearance = Stock Thickness + 0.5"

Retract = Stock Thickness + 0.25"

Feed Plane = Stock Thickness + 0.1"

Top of Stock = Stock Thickness

Rough Parallel Parameters (Third Tab)

Cutting Method

Select One Way if stock material is non-uniform (wood, other materials with grain), or Zigzag if stock material is uniform (foam, plastics, mdf)

Stepdown

Value should not exceed flute length of tool, and must be appropriate for stock material. Harder materials require smaller stepdown.

Stepover

Value should not exceed tool diameter, and must be appropriate for stock material. Harder materials require smaller stepover.

Reference Pages

MasterCAM 2020 Reference > Defining Parameters

Selecting a Stepover

("Cut Depths")Depth Limits

Select Absolute

Minimum Depth = Stock Thickness - Stepdown

Maximum Depth = Height of deepest desired cut relative to origin. If plunging, should not exceed Stock Thickness - Shoulder Length of Tool. Value should never be negative.

Machining Angle

Change value to match grain direction of stock if cutting method is One Way and stock material is non-uniform.

Surface Finish Contour

Toolpath Parameters (First Tab)

Planes

In most cases, select TOP as work coordinate system, tool plane, and construction plane.

When machining the underside of a two-sided job (flip milling), select FLIP as work coordinate system, tool plane, and construction plane. FLIP plane must be defined in Plane Manager.

Tool Selection

Select largest diameter flat endmill that can maneuver completely around input geometry while producing desired resolution. Harder materials require shorter tools.

Select upcut endmill for soft, uniform materials (foams), and downcut endmills for hard non-uniform materials (wood, plywood, mdf).

Surface Parameters (Second Tab)

Machining Heights

Input values appropriate for stock thickness.

Clearance = Stock Thickness + 0.5"

Retract = Stock Thickness + 0.25"

Feed Plane = Stock Thickness + 0.1"

Top of Stock = Stock Thickness

Finish Contour Parameters (Third Tab)

Stepdown

Value should not exceed flute length of tool, and must be appropriate for stock material. Harder materials require smaller stepdown.

("Cut Depths")Depth Limits

Select Absolute

Minimum Depth = Stock Thickness - Stepdown

Maximum Depth = Height of deepest desired cut relative to origin. If plunging, should not exceed Stock Thickness - Shoulder Length of Tool. Value should never be negative.

Surface Finish Shallow

Toolpath Parameters (First Tab)

Planes

In most cases, select TOP as work coordinate system, tool plane, and construction plane.

When machining the underside of a two-sided job (flip milling), select FLIP as work coordinate system, tool plane, and construction plane. FLIP plane must be defined in Plane Manager.

Tool Selection

Select largest diameter flat upcut endmill that can maneuver completely across input geometry while producing desired resolution. Harder materials require shorter tools.

Surface Parameters (Second Tab)

Machining Heights

Input values appropriate for stock thickness.

Clearance = Stock Thickness + 0.5"

Retract = Stock Thickness + 0.25"

Feed Plane = Stock Thickness + 0.1"

Top of Stock = Stock Thickness

Finish Shallow Parameters (Third Tab)

Cutting Method

Select One Way if stock material is non-uniform (wood, other materials with grain), or 3DCollapse if stock material is uniform (foam, plastics, mdf).

Stepover

Value should not exceed tool diameter, and must be appropriate for stock material. Harder materials require smaller stepover.

Depth Limits

Minimum Depth = Stock Thickness

Maximum Depth = Height of deepest desired cut relative to origin. If plunging, should not exceed Stock Thickness - Shoulder Length of Tool. Value should never be negative.

Machining Angle

Change value to match grain direction of stock if cutting method is One Way and stock material is non-uniform.

Surface Finish Constant Scallop

Toolpath Parameters (First Tab)

Planes

In most cases, select TOP as work coordinate system, tool plane, and construction plane.

When machining the underside of a two-sided job (flip milling), select FLIP as work coordinate system, tool plane, and construction plane. FLIP plane must be defined in Plane Manager.

Tool Selection

Select largest diameter ball endmill that can maneuver completely across input geometry while producing desired resolution. Harder materials require shorter tools.

Surface Parameters (Second Tab)

Machining Heights

Input values appropriate for stock thickness.

Clearance = Stock Thickness + 0.5"

Retract = Stock Thickness + 0.25"

Feed Plane = Stock Thickness + 0.1"

Top of Stock = Stock Thickness

Finish Constant Scallop Parameters (Third Tab)

Depth Limits

Minimum Depth = Stock Thickness

Maximum Depth = Height of deepest desired cut relative to origin. If plunging, should not exceed Stock Thickness - Shoulder Length of Tool. Value should never be negative.

Stepover

Value should not exceed tool diameter, and must be appropriate for stock material. Harder materials require smaller stepover.

Smaller values reduce scallop height, thus increasing smoothness, while also increasing machining time.

Pocket

Tool

Tool Selection

Select largest diameter flat endmill that can maneuver completely within input geometry while producing desired resolution. Harder materials require shorter tools.

Select upcut endmill for roughing and finishing if cutting soft uniform material (foam)

Select upcut endmill for roughing, and downcut endmill for finishing if cutting hard non-uniform materials (wood, plywood, mdf). This requires two separate Pocket operations - the first with only roughing enabled, and the second with only finishing enabled.

Cut Parameters

 Stock to Leave

User may input an offset for both walls and floors. Default is 0 for both values. Overlaps with Parameters > Linking Parameters > Depth, as well as Parameters > Cut Parameters > Break Through

Cut Parameters > Roughing

Cutting Method

Select One Way if stock material is non-uniform (wood, other materials with grain), or Zigzag if stock material is uniform (foam, plastics, mdf)

Stepover

Value entered as either a percentage of tool diameter, or an absolute distance. Value should not exceed tool diameter, and must be appropriate for stock material. Harder materials require smaller stepover.

Machining Angle

Change value to match grain direction of stock if cutting method is One Way and stock material is non-uniform.

Cut Parameters > Roughing > Entry Motion

Entry Motion

Choose Helix for ONSRUD, or Ramp for AXYZ.

Users may input plunge angle value in degrees. An increase in plunge angle corresponds with a decrease in machining time. Value should not exceed 30 degrees, and must be appropriate for stock material. Harder materials require smaller plunge angle.

Cut Parameters > Finishing

Enable Finishing

Set Passes to 1

Enable "Machine Passes only at Final Depth" if pocket depth relative to adjacent geometry is equal to or less than the tool flute length.

Cut Parameters > Finishing > Lead In / Lead Out

Lead In / Lead Out

Enable Lead In / Lead Out

Cut Parameters > Depth Cuts

("Max Rough Step")Stepdown

Value should not exceed flute length of tool, and must be appropriate for stock material. Harder materials require smaller stepdown.

Linking Parameters

Machining Heights

Input values appropriate for stock thickness.

Clearance = Stock Thickness + 0.5"

Retract = Stock Thickness + 0.25"

Feed Plane = Stock Thickness + 0.1"

Top of Stock = Stock Thickness

Depth = Desired depth of deepest cut. Value should never be negative. Overlaps with Parameters > Cut Parameters > Stock to Leave (on floor), as well as Parameters > Cut Parameters > Break Through

Planes

Planes

In most cases, select TOP as work coordinate system, tool plane, and construction plane.

When machining the underside of a two-sided job (flip milling), select FLIP as work coordinate system, tool plane, and construction plane. FLIP plane must be defined in Plane Manager.

Contour 2D/3D

Tool

Tool Selection

Select largest diameter flat endmill that can maneuver completely within input geometry while producing desired resolution. Harder materials require shorter tools.

Cut Parameters

 Stock to Leave

User may input an offset for both walls and floors. Default is 0 for both values. Overlaps with Parameters > Linking Parameters > Depth, as well as Parameters > Cut Parameters > Break Through

Compensation

Toggle between Left and Right depending on whether the tool should offset outside or inside the assigned chains.

Turn off compensation if the assigned chains are intended as cut centerlines.

Cut Parameters > Depth Cuts

("Max Rough Step")Stepdown

Value should not exceed flute length of tool, and must be appropriate for stock material. Harder materials require smaller stepdown.

Cut Parameters > Lead In / Lead Out

Lead In / Lead Out

Enable Lead In / Lead Out

Cut Parameters > Multi Passes

Multi Passes

Enable if operation is intended for roughing, disable otherwise.

Cut Parameters > Tabs

Tabs

Enable for when vacuum hold down is used. (stock is held by air pressure to CNC table)small parts

Enable for when mechanical hold down is used. (stock is screwed to CNC table)all parts

User may select Automatic or Manual tab placement. Automatic works well for most situations, with minimum 4 tabs recommended.

Linking Parameters

Machining Heights

Input values appropriate for stock thickness.

Clearance = Stock Thickness + 0.5"

Retract = Stock Thickness + 0.25"

Feed Plane = Stock Thickness + 0.1"

Top of Stock = Stock Thickness

Depth = Desired depth of deepest cut. Value should never be negative. Overlaps with Parameters > Cut Parameters > Stock to Leave (on floor), as well as Parameters > Cut Parameters > Break Through

Planes

Planes

In most cases, select TOP as work coordinate system, tool plane, and construction plane.

When machining the underside of a two-sided job (flip milling), select FLIP as work coordinate system, tool plane, and construction plane. FLIP plane must be defined in Plane Manager.

Peck Drill

Tool

Tool Selection

Select appropriate diameter drill tool

Cut Parameters

Cycle

Select Peck Drill

Set First Peck value = Diameter of tool

Set Subsequent Peck value = 2x Diameter of tool

Set Peck Clearance = 2x Diameter of tool

Linking Parameters

Machining Heights

Input values appropriate for stock thickness.

Clearance = Stock Thickness + 0.5"

Retract = Stock Thickness + 0.25"

Top of Stock = Stock Thickness

Depth = Desired depth of deepest cut. Value should never be negative. Overlaps with Parameters > Cut Parameters > Stock to Leave (on floor), as well as Parameters > Cut Parameters > Break Through

Planes

Planes

In most cases, select TOP as work coordinate system, tool plane, and construction plane.

When machining the underside of a two-sided job (flip milling), select FLIP as work coordinate system, tool plane, and construction plane. FLIP plane must be defined in Plane Manager.

Absolute vs Incremental

Contour 2D operations may be set up with a Linking Parameters > Depth in or units.Absolute Incremental

Contour 3D operations may only be set up with Linking Parameters > Depth in units.Incremental

8 - Generate Toolpaths

Drawing the Toolpaths

Once operations have been chosen, geometry has been assigned, and parameters have been adjusted, the next step is to generate toolpaths. Toolpaths are visualized in the modeling space as Blue and Yellow lines that are drawn across the input geometry.

Select the operation(s) that is(are) being used, then g  enerate the selected operation by clicking dirty operations by , or regenerate all

clicking  .

Dirty Operations

In most cases, MasterCAM will not automatically generate the toolpath for a selected operation after its parameters and geometry have been assigned.

If the operation lacks assigned geometry, or has had any changes made to the geometry assignment, parameters, or tool definitions, then the

operation is considered "dirty" and the   toolpath icon will instead display  . 

The toolpaths for a dirty operation will disappear from the modeling space until regenerated.

If an attempt to verify dirty operations is made, MasterCAM will prompt the user to regenerate with a pop-up dialogue. Verification using dirty operations is inaccurate and should be avoided.

Unused Operations

Delete unused operations to avoid verification mistakes and  

Select the unused operation(s) , then right click > delete. 

Reference Pages

MasterCAM 2020 Reference > > Managing Operations Toolpath Generation

Failure to Generate

Toolpath generation may fail for a number of reasons. Common causes include:

Drive mesh / surface too complex (MasterCAM draws only partial toolpath or takes excessive (15+ minutes) amount of time for generation)Geometry too far from origin (also causes graphical glitches)Tool diameter too large for assigned closed chain ( )Cutter Compensation Not SuccessfulDepth limits set incorrectly ( )No Cuts Found

Complex or corrupted geometry may cause toolpath generation to fail. In this situation, the problem geometry should be deleted from MasterCAM (a prompt will warn the user that any operations that reference the problem geometry will be affected). The geometry can then be edited or recreated in Rhino, exported as a new .3dm while maintaining the same origin, and merged back into the MasterCAM file.

Excessive toolpath generation times can sometimes be reduced by changing from Shaded to Wireframe. This prevents Visibility MasterCAM from "Tessellating", increasing responsiveness.

Trimmed surfaces with far-flung control points cause trouble when merged into MasterCAM. Sometimes these problems can be averted by running a few Rhino commands on the problem surface(s) prior to merging:

ShrinkTrimmedSrfRebuild

Large, complex meshes and surfaces occasionally cause problems in MasterCAM as well, depending on how they were generated. This issue is usually solved by recreating the mesh or surface in Rhino or Grasshopper. The FabLab provides a sample Grasshopper script that should produce usable geometry from the original problem geometry.

Grasshopper Script for Recreating Geometry

9 - Verify Operations

What is Verification?

Verification (aka Simulation) is the process of playing out the generated toolpaths in a virtual environment in order to check for errors and omissions.

Successful verification (accurate stock and tool definitions, no collisions found) is a necessary pre-requisite to performing any real CNC machining at the GSD.

Student submitted jobs will not be approved or scheduled until successful verification is demonstrated. 

How to Verify

Select all operations that have been configured and will be used. Operations will be verified in chronological order according to their order in the Toolpath Manager.

Click   verify selected operations in the Toolpath Manager to open the Mastercam Simulator window.

Simulation Playback

Toggle the simulation playback by pressing R or clicking the play/pause button.

Users can scrub backward and forward along the timeline by clicking and dragging the red slider, or incrementally by pressing B (backward) and S (forward).

Users may skip to the previous or next operation by pressing P (previous) and N (next).

Users may skip to the start or end of the job by pressing HOME (start) or SPACE (end). 

Collision Checking

Ensure that collision checking is activated before starting the simulation:  

Choose File > Options, then, under General and Collision Checking, check the following within Tool: Stock: Mill tool holder, Mill tool shank, Mill tool shoulder, mill tool cutting length

Reference Pages

MasterCAM 2020 Reference > Verification

Choose Home > Stop Conditions from the MasterCAM Simulator ribbon menu, and then check Collision.

Choose Home > Tool Components from the MasterCAM Simulator ribbon menu, and then check all items in the Milling field (Holder, Shank, Shoulder, Flute Length).

Choose Verify > Collision Checking, making sure it is highlighted in blue to enable this function before running the simulation.

During simulation playback, areas of the stock involved in a collision will be colored dark red. The type of collision can be identified in the Collision Report.

Run Time Estimate

MasterCAM Simulator provides an estimate of total run time for selected operations based on specified feed rates, stepover, stepdown, etc. This estimate is displayed in the Move List panel on the right. 

After playing through the simulation, check "Elapsed Time" for the time estimate. Often this estimate is too low by a factor of 2, so as a rule of thumb, double the MasterCAM Simulator time estimate when making a CNC appointment reservation.

10 - File Approval + Scheduling

Immediate Collision

An immediate collision upon simulating an operation (Flute Length - In Progress Stock) is typically the result of incorrectly defined Machining Heights within that operation.

Important Links

CNC Router Job Submission Form

CNC Router Queue

CNC TA Office Hours

Upload Files to GSD Server 

Create a folder in CNCtmp on the GSD server and include both your MasterCAM file as well as the original CAD geometry file (Rhino, or other). If you have more than one MasterCAM file, consider using separate sub-folders to organize the projects.

Complete the Online Form 

Submit a CNC Router Job request online. Be sure to let us know about any pertinent information related to the job such as material type, your deadline, stock size, or any questions or problems that you've had in making the MasterCAM file. 

Edit Files if Necessary

Once submitted, pay attention to emails that may come from   or any one of the TAs as your file is being reviewed. cncta@gsd.harvard.edu A TA may ask you to meet with them during office hours to discuss what you want to make; they might also ask you to make changes to your file. The

online queuestatus of your submitted file can be viewed through the  , along with those of others, but you should also receive emails as the job status changes.

Schedule Milling Appointment 

After the file is approved, you will be asked to schedule a milling appointment. Visit your job in the queue and choose the "Save Changes" button to be brought to the scheduler. Choose a block of time that corresponds to the estimated run time for your job, as indicated by the TA in the job request form.

Prepare Stock Material 

Make sure you purchase and prepare your material prior to your milling appointment (allow 24 hours for most adhesives to fully cure or dry).

Attend Appointment 

You must be present in L33 while the machine creates your part.

Fab Lab Store

During the Milling Appointment