Lab Manual

For

CAD/CAM using Pro/Engineer

Wildfire 5.0

Lecture 10- Milling Operations (Continued)

Prepared by:

Nabeel Nisar, SE

Table of Contents

1. Volume Milling............................................................................................................................................. 3

2. Profile Milling .............................................................................................................................................. 6

3. Local Milling ................................................................................................................................................ 9

4. Holemaking ................................................................................................................................................ 13

1. Volume Milling

A Volume milling NC sequence removes the material inside a Milling Volume slice-by-slice. All slices are

parallel to the retract plane; the axial depth of cut (slice depth) is defined by the combination of

STEP_DEPTH and WALL_SCALLOP_HGT parameters. The first slice is generated at slice depth below

the top of the mill volume. In case the mill volume extends above the top of the workpiece, the first slice is

generated at slice depth below the top of the workpiece, to avoid air machining. All planar surfaces inside

the volume that are normal to the Z-axis of the NC Sequence coordinate system produce additional slices

across the whole volume; use the MIN_STEP_DEPTH parameter to control the minimum acceptable

distance between slices. The step-over distance inside a slice can be controlled by the following parameters:

STEP_OVER, NUMBER_PASSES, BOTTOM_SCALLOP_HGT, and STEPOVER_ADJUST.

Some typical applications for Volume milling are:

● Facing down the workpiece

● General material removal on the outside of the workpiece

● Rough milling of a vertical slot or cut, or a blind slot with islands

To Create a Volume Milling Sequence

1. Select File > New, select Type Manufacturing and sub-type NC Assembly. Type the name of your

assembly (for example vol_mill_1).

2. Uncheck the option ‘use default template’, click OK, select ‘mmns_mfg_nc’ in next diolag box and

click OK.

3. Assemble the Reference Model vol_mill_1.prt, then create a Workpiece as discussed in previous

sequence.

4. Create a new coordinate system as shown in figure. Click OK.

5. Select Steps > Operation from the Menu bar. Select in front of NC machine. Make sure that

machine type is Mill and number of axes are 3. Click OK.

6. Select Machine Zero in Reference box. Select the coordinate system created in step 4.

7. Select Surface in Retract box, set value equal to 5. Click OK twice.

8. Select Mill Window on the Mfg Geometry Features toolbar. NC Manufacturing activates the

Mill Window dashboard. Click the silhouette window type ( ). Select Placement > Window

Plane and select top surface of the part, as shown in figure. Click the Depth slide-up panel to specify

the depth of the Mill Window. Create a new datum plane by selecting the edges of the lower surface,

as shown in figure. Click OK and complete the Mill Window feature.

9. For Volume Milling, click on the toolbar or click Steps ▶ Volume Rough. Retain the default

settings and click OK.

10. In the tools setup, set the diameter of tool = 10, click OK.

11. Select the Mill Window created in step 8.

12. Edit the parameters as shown in figure. Click OK.

13. Click Playpath > Screenplay. In Playpath window, click play button to view the toolpath of the

sequence.

14. Click Playpath > NC Check. Play the simulation of metal cutting in vericut.

15. Practice the sequence by using other reference models.

Parameters in Volume Milling

CUT_FEED

ARC_FEED

FREE_FEED

RETRACT_FEED

TRAVERSE_FEED

PLUNGE_FEED

STEP_DEPTH

TOLERANCE

STEP_OVER

PROF_STOCK_ALLOW

ROUGH_STOCK_ALLOW

BOTTOM_STOCK_ALLOW

CUT_ANGLE

SCAN_TYPE

CUT_TYPE

ROUGH_OPTION

CLEAR_DIST

SPINDLE_SPEED

COOLANT_OPTION

2. Profile Milling

Profile milling is used to rough or finish mill vertical or slanted surfaces. The surfaces selected must allow

for a continuous tool path. The depth of the cut is defined by the depth of the selected surfaces.

To Create a Profile Milling NC Sequence

1. Repeat steps 1-8 of volume milling sequence, but select the Reference Model prof_mill_1.prt.

2. For Profile Milling, click on the toolbar or click Steps ▶ Profile Milling. The MACH AXES

menu appears with the required options for Profile Milling selected. Go with defaults and click OK.

3. In the tools setup, change the diameter of the endmill to 5. Click OK.

4. Edit the parameters as shown in figure. Click OK.

5. In the Surface panel, select the surfaces to which you want to profile cut. Select ‘Reference Model

Surface’ from selection filter, and select the surfaces as shown in figure.

6. Click Playpath > Screenplay. In Playpath window, click play button to view the toolpath of the

sequence.

7. Click Playpath > NC Check. Play the simulation of material removal in vericut, as shown in figure.

8. Practice the sequence by using another reference model.

Parameters in Profile Milling

CUT_FEED

ARC_FEED

FREE_FEED

RETRACT_FEED

PLUNGE_FEED

STEP_DEPTH

TOLERANCE

PROF_STOCK_ALLOW

CHK_SRF_STOCK_ALLOW

WALL_SCALLOP_HGT

CUT_TYPE

CLEAR_DIST

SPINDLE_SPEED

COOLANT_OPTION

3. Local Milling

There are four types of Local Milling:

● Prev NC Seq—Remove material left after a Volume, Profile, or another Local Milling NC sequence,

usually with a smaller tool.

● Corner Edges—Specify one or more corners to clean up by selecting edges.

● By Prev Tool—Calculates the remainder material on specified surfaces after being machined by a larger

tool; then removes this material by the current (smaller) tool.

● Pencil Tracing—Cleans up edges of selected surfaces by creating a single-pass tool path along the

corners.

Local Milling by Referencing a Previous NC Sequence

This type of Local Milling NC sequence removes material left after a Volume, Profile, or another Local

Milling NC sequence, usually with a smaller tool. When you create such a Local milling NC sequence, you

will be prompted to select a reference NC sequence. The system will then compute the material left by the

reference NC sequence and machine away this material only. After a Volume or Profile NC sequence, you

can do region-by-region milling. The following illustration shows Local Milling by reference.

1 Volume milling performed with a large tool

2 Local milling removes the leftover material

To Create a Local Milling NC Sequence by Referencing a Previous Sequence

1. Create new manufacturing file, local_mill_prev_seq. Assemble the reference model having same

name.

2. Setup the milling operation as before. First remove the material from inner cavity using Volume

Milling sequence, Ø12 mm end mill cutter. Use either Mill Window or Mill Volume for this

sequence.

3. After completing Volume Milling, select Steps > Local Milling > Previous Step as shown in figure.

4. Select reference milling operation for which you want local milling. In this case, select NC

SEQUENCE > Volume Milling > CUT MTN#1

5. Select Tool and Parameters from the Options menu. Select Ø3 mm end mill cutter. Enter the

parameters as shown in figure.

6. Local milling is completed.

7. Practice the sequence using another reference model.

Local Milling by Using Corner Edges

In this type of Local Milling NC sequence, you specify one or more corners to clean up by selecting edges.

The amount of material to remove will be calculated by the system based on the value of the

CORNER_OFFSET parameter that you supply. The following illustration shows Local milling using Corner

Edges.

1 Select corner

2 CORNER_OFFSET

3 This material will be removed

To Create Local Milling NC Sequence by Using Corner Edges

8. Create new manufacturing file, local_mill_corner_edge. Assemble the reference model having same

name.

9. Setup the milling operation as before. First remove the material from inner cavity using Volume

Milling sequence, Ø10 mm end mill cutter. Use either Mill Window or Mill Volume for this

sequence.

10. After completing Volume Milling, select Steps > Local Milling > Corners as shown in figure.

11. Select Tool, Parameters, Surfaces and Corner Edges from the Options menu. Select Ø3 mm end mill

cutter. In edit parameters, select ‘ALL’ tab instead of ‘BASIC’. Enter CUT FEED = 30, STEP

DEPTH = 1, STEP OVER = 1, CLEAR DIST = 1, SPINDLE SPEED = 500

12. Set CORNER OFFSET = Diameter of Larger tool – Diameter of Smaller Tool. So in this case, it will

be 10 – 3 = 7

13. In surface pick drop-down menu, select Model > Done. Now select the surfaces whose intersections

give the required corners (i.e. select all inner surfaces in this case). Select OK, then

DONE/RETURN. Now select SUGGEST to view the required corners. If satisfied, click SELECT

ALL, then click DONE/RETURN.

14. Local milling sequence is completed. Click Playpath > Screenplay or NC check to review it.

4. Holemaking

A Holemaking NC sequence is created by selecting the cycle type and specifying the holes to drill by

defining the Hole Set(s). The order of machining the holes is defined by the SCAN_TYPE parameter value.

A Hole Set includes one or more holes to be drilled; each Hole Set has a drilling depth specification or

countersink diameter value associated with it. You can include more than one Hole Set in a single

Holemaking NC sequence; this allows drilling of holes with different depth specifications, as well as having

multiple countersink diameter values, within a single NC sequence.

There are various methods of selecting the holes to be included in a Hole Set:

● By selecting individual hole axes

● By including all holes on a specified surface

● By including all holes of a specified diameter

● By including all holes with a certain value of a feature parameter

● By including all holes with chamfers machinable by the current tool (for countersinking)

● By selecting individual datum points to mark the drill locations

● By including all datum points on a specified surface

If you need to perform a series of Holemaking NC sequences on the same group of holes, you can define a

Drill Group using the techniques above, and then reference this Drill Group when defining Hole Sets. This

simplifies the selection process; you can also parametrically update all the NC sequences b y modifying the

Drill Group.

To Create a Holemaking NC Sequence

1. Create new manufacturing file DRILL_1.asm. Assemble the reference model DRILL_1.prt in it. Also

create automatic workpiece as well as machine coordinate systems as discussed in earlier sequences.

2. Create new operation, select milling machine.

3. Select Steps > Drilling > Standard for holemaking sequence as shown in figure.

4. Select tools, parameters and holes in menu manager.

5. Create Ø7 mm basic drill, click OK. In parameters, enter cut feed = 50, clear dist = 1 and spindle speed =

500. In hole set, select DETAILS in front of select diameters, then select Ø7 in available and send it to

selected ( holes of Ø7mm will be selected). Click done, again done.

6. Repeat steps 3-5 for Ø5 mm holes, using Ø5 basic drill.

7. Sequence is completed. Review it using playpath.

To Define Depth

All Hole Sets (except for Countersink and Web drilling), require specifying the drill depth type. To define

the depth type and references, click Depth in the HoleSet dialog box. The Hole Set Depth dialog box opens.

Select one of the following Hole Depth icons to specify the depth or surface for drilling:

● (Blind)—Drill from the start surface to specified depth. Specify the Start and End surfaces. If you

select the checkbox next to the Use breakout distance option, the system adds the

BREAKOUT_DISTANCE parameter value when calculating depth.

● (Auto)—Depth of drilling is determined automatically, by referencing hole geometry. If the selected

axis is associated with several coaxial hole features, the maximum depth will be selected as long as the

tool fits inside the hole diameter.

● (Thru All)—Drill a through hole, from the retract surface all the way through the workpiece(s) or

reference part(s) that the hole intersects. By default, all the reference parts and workpieces are used for

depth calculation. You can unselect some of the parts or explicitly select parts, by using the Models

collector of the Options tab in the Hole Set Depth dialog box. The All Models option selects all the

reference parts and workpieces.

● —Drill from the start surface to the depth of the selected reference. Surfaces and datum planes are

selected by default.