PM 06 Corner Finishing

7/28/2019 PM 06 Corner Finishing

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PowerMILL 6. Corner Machining

Issue PMILL 6 93

6. Corner Finishing

Introduction.Corner Machining includes 5 different types of strategy: Pencil, Multi Pencil, Stitch

Corner, Automatic Corner andAlong Corner.One of the strategies creates 'single pass'

machining along sharp internal corners (Pencil) while the other four perform local machining

of areas inaccessible to a larger tool (Rest Milling).

All Corner Finishing strategies allow a Threshold Angle to be specified. PowerMILL limits

the toolpath to either side of this angle the idea being to solve the potential problems

associated with the tool running up or down steep slopes. For instance the user could apply a

stitch strategy to track across the steep areas and parallel strategy for shallow areas. Also a

higher feed rate could be used on the shallow areas and a lower feed rate on the steep areas,

which if applied first is more likely to be taking a heavy cut.

Pencil FinishingThis option produces single pass tool tracks along the intersection between sharp internal

corners of the component surface.

Select Delete Al l from the File menu and Reset forms from the Toolsmenu.

FromFile > Examples open the model cowling.dgk

Calculate the Block.

Create a Ball nosed dia 10 tool and name it as bn10.

Select an Iso2 view.


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6. Corner Machining PowerMILL

94 Issue PMILL 6

From the Toolpath s trategies form, select Corner Pencil Finishing

Keep the thresholdangle of30 degrees.

Selecting both will produce the

steep and shallow toolpath.

Apply the toolpath andCancel.


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Issue PMILL 6 95

The toolpath is split where the steep areas where the

slope exceeds the specifiedThreshold Angle

separately.

Animate the toolpath. Rename thetoolpath as pencil_both.

Right click over the toolpath in the explorerand select Settings.

Select the Copy Toolpath icon from the form.

Change the Output option fromBoth to Shallow.

SelectApply to generate the Shallow slope machining only.

The toolpath is produced. The steep area is no

longer machined.

Animate the toolpath. Rename the toolpath as pencil_shallow.

Right click over the toolpath in the explorer and select Settings.

Select the copy toolpath icon from the form.

Change the Output option fromShallow to Steep.


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96 Issue PMILL 6

Generate a steep pencil machining toolpath.

Only the steep area is machined.

Animate the toolpath. Rename the toolpath as pencil_steep.

Save the project inC:\temp as train-corner.

Corner Along Finishing

All the Corner Finishing

strategies, (except forPencil) are

based on machining the area

between the Reference tool (2) and

the Active tool (1).

In this example the main finishing

tool is a 12 Ball nose (reference) to

be Corner finished with a diameter

5 Ball-nose.

From the Toolpath s trategies form, select Corner Along Finishing.

Define a dia 5 ball nose toolnamed bn5.

In the Reference Area, select the tool bn10.

Change Output to Shallow.

SetCusp to 0.03.

Check Direction is set to Climb.


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Issue PMILL 6 97

Apply the toolpath andCancel.

Animate the toolpath and note that

it has machined the shallow areas

from outside to inwards in a Climb

milling direction.

The leads and links need to be

improved

Set all the Links to Skim


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98 Issue PMILL 6

Select the Lead In tab

Select Vertical Arc and fill

in the values shown.

Click Copy to Lead out

Apply andAccept

The Vertical Arc leadprovides a smoother

transition onto the work

piece with the tool already

moving at the specified

cutting feed rate.

Open the Leads and Links form and change the Lead In/out fromVertical Arc back to None as the next toolpath to be created doesntrequire them.

Corner Stitch Finishing

From the Toolpath s trategies form, select Corner Stitch Finishing.

The previously used values are in the form.

Change Output to Steep


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Issue PMILL 6 99

Apply the toolpath andCancel

The steep area has been machined.

If required, it is possible to change the Direction and/or

order of individual tool tracks via the Toolpath - Edit

options.

Right click on the toolpath and select Edit >Reorder.


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100 Issue PMILL 6

SelectAl ternate direct ions.

In Leads and Links select CircularArc

The steep areas now run in a zig-zag

direction rather than one way and this

time the Short links are defined as a

Circular Arc.


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Issue PMILL 6

101

Corner MultiPencil Finishing

From the Toolpath s trategies form, select Corner MultiPencil Finishing

Change Output backtoShallow

Apply the toolpath andCancel


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Change theThreshold Angle to90

This has the effect of

creatingan unlimited

Shallow machining area for

the toolpath. Using these

setting the same strategy

would be created if the

Output- Both is applied. IfOutput - Steep is applied no

toolpath would be created.

Apply the toolpath and Cancel


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Issue PMILL 6

103

Corner Automatic Finishing

From the Toolpath s trategies form, select Corner Automatic Finishing

Change Output toBoth

Change thethreshold angleback to 30

Apply the toolpathand Cancel

This strategy automatically uses

Along for the Shallow areas and

Stitch for the Steep areas.

However, due to it being all one

toolpath, it is not so easy to controlthe Leads and Links or the

Reordering.


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104 Issue PMILL 6

Documents

PM 06 Corner Finishing