This part:
demonstrates the Subtract tool
previews the procedure to unite a linked patch body in core or cavity
to compensate for geometry removed by Solid Patch Step 1 Create a project for mdp_cap.
First Part .../cap/mdp_cap Units default (Inch) Proj Name default (mdp_cap) Mold Csys default
Shrinkage Scale Factor 1.008 Work Piece default Layout Auto Center
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Step 2 Prepare the part for tooling design.
This part has 12 windows that must be patched before we can trim core and cavity inserts. The window edges are shared between multiple faces, therefore the face cannot be patched with Surface Patch.
Auto Patch works, using edge patches, but it tedious to repeat the face confirmation process twelve times.
In this case, Solid Patch is an efficient method to use.
Choose Tools. Choose Create Box.
Use the default value for Allowance. (Ignore the Allowance
text input window.)
Select, and confirm if necessary:
the inner face containing the window openings . . . À the small inner face nearest the top of the cap. . . . Á
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Choose OK to end selection.
A block is created surrounding the material volume defined by the faces you selected.
The patch block can be trimmed in one or two areas, but there are several concentric faces with opposing directions.
With multiple faces and complex geometry it is a lot faster to use a Boolean subtract to shape the patch body using Subtract in the Split Method section of the Tools dialog.
The current topology presents a problem. A Subtract at this stage would divide the patch block into more than one piece. When Subtract divides a body into multiple pieces, it causes all parameters to be removed. In our scenario, we specify full
associativity, thus, we need an approach that retains parameters. We can avoid trouble by trimming the rectangular patch body to the largest inside diameter of the part before we subtract.
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Step 3 Trim the patch block to the interior shape of the pen cap.
Choose Surface Split.
Select and confirm the block you just created as the solid to
be split.
Remove the outer material by selecting the inner face
containing the windows. (The same face you used to define the patch block.)
Choose Trim.
The enlarge sheet dialog appears.
Do NOT change U.
Expand in the V direction to approximately 400%, until the
cone extends past both ends of the block.
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Step 4 Use Subtract to complete the patch body.
From Tools, in the Split Method section, choose Subtract.
NOTE The order of selection is very important. Watch the Cue!
Select and confirm the smaller, green patch body as target. Choose the larger, cyan parting body as tool.
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Step 5 Use the patch body to create shut off faces in the windows.
Choose Solid Patch.
Select the larger, outer pen cap body as target solid, and the
smaller interior patch body as tool.
Choose OK or Cancel to dismiss the selection dialog.
The unite operation performed by Solid Patch removes several faces from the core region of the parting part. These removed faces will not appear in the core tooling when it is initially created. You must plan to compensate.
MoldWizard will make linked copies of the original patch body, now in layer 25, in the core and cavity parts. You can use this knowledge to complete your plan to replace the removed faces.
The following steps give you a preview of the actions necessary to replace the missing faces in the core workpiece. This will help you to fully understand what you accomplish by uniting a patch body.
Step 6 Create a Parting Curve and Face.
Choose the Parting icon.
Enable the Auto Process toggle. Choose Parting Lines.
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MoldWizard identifies the correct parting loop . . . Á
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Once the parting loop has been identified, the Product Design Advisor becomes available.
Auto Patch remains grayed out, an indication that Solid Patch successfully removed all holes from the part.
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Product Design Advisor tells you at a glance that there are no vertical faces, one potential undercut area, and 65 Small Angle Faces with a Draft Angle less than 3°.
Choose the Undercut Areas radio button to verify what the
system has found.
The bottom face of the patch body, remaining after Solid Patch, is highlighted. In wireframe mode, you might be able to discover a reason for such a face being highlighted, perhaps a small gap caused by tolerance issues. There will be no problem with this part; however, it shows the value of the Product Design Advisor
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We know there are no Vertical Faces, because that radio button remains grayed. We can use the Product Design Advisor to quickly investigate the minimum draft on the product.
In the Draft Angle < window, enter: 1.000 Choose Apply.
Type a value
Apply the change Interpret the result
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Small Angle Faces now displays 25 faces, 24 faces between the ribs" and one small conical face at the top of the part.
Change the Draft Angle < value to 0.5, Apply, then choose
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The small face at the top is no longer highlighted. It is drafted at least half a degree.
Change Draft Angle < to 0.49
Small Angle Faces are no longer found. The part has approximately 0.5° draft, within .01 degrees!
Choose OK to exit the Product Design Advisor.
Choose OK in the Search Parting Lines dialog to accept the
previously identified parting loop. (It is no longer highlighted.)
NOTE The parting curve (only one arc in this case) is displayed, colored green. The green color indicates that while
geometry has been chosen, the process is still incomplete. It is important not to dismiss the Parting Lines dialog by Cancel, or the system will not correctly identify your parting curve(s).
Choose OK in the Parting Lines dialog.
How Does it Work?
The parting curve should now change to a magenta color, and the Create Parting Surfaces dialog appears.
This magenta color was selected for class. The default color is green, the same as the default curve creation color. We edited our defaults file to make it easier to realize when the operation has been successfully completed, and, to recognize if it was not successfully completed.
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We will deal with the full set of choices that complete the identification of parting curves in a later lesson. At this point, you need to understand only that when you choose OK the process is completed properly. The arc you selected is moved to MW_PartingLinesLayer (26), category PartingLine
(MW_PartingLinesLayerName). Additionally the curve is colored MW_PartingLinesColor (magenta for the class) and added to a special group, UM_PARTING_LINES. The parting lines group is used when you create parting surfaces.
Step 7 Create the parting surface.
Enter 8.0 in the Distance window.
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Choose Create Parting Surfaces.
A Warning Message appears:
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Step 8 Define Core and Cavity regions.
Extract Regions appears because you selected Auto Process.
Parting Face
Fit the view to see the parting face.
The Extract Regions dialog is equipped with sliders to permit you to examine faces that MoldWizard has automatically
determined belong to core and cavity tooling. We will study the features of this dialog more completely in a later lesson.
Use the sliders to preview the cavity and core regions.
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Step 9 Complete the core and cavity bodies.
The Core & Cavity dialog appears because of Auto Process.
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We will learn the features of this dialog in a later lesson.
From the Core & Cavity dialog choose Create Core . . . À
The Select Sheets dialog appears:
In the Select Sheets dialog choose OK.
The View Parting Result dialog appears. The displayed part has been temporarily changed to mdp_cap_core. As with the other dialogs in this process, we will learn more later.
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Examine the body that was created as your core tool insert. Choose OK in the View Parting Result dialog to return to the
parting part.
The layer settings in the parting part were changed. The geometry you see now represents a sewn core trim sheet
containing the parting sheet, the core region, and a seed face".
How Does it Work?
The parting sheet and seed face are mutually trimmed. The seed face is oriented perpendicular to the main parting plane. This face has been in the part from the time you initiated the project. Its purpose is to act as the linking geometry between the parting part and the core tool. A similar face exists for the cavity tool. The vertical orientation of seed faces is a clever trick to be certain that they can be joined to your parting geometry no matter where in vertical space you might choose to locate them.
Make layer 1 the Work Layer, and optionally make layer 27
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The missing faces appear. You are seeing a Wave linked body that MoldWizard has automatically created and associated to the original patch block you created.
Core work piece
Linked patch body
If necessary choose Application → Modeling. Unite the two bodies:
Select the larger, lower, core body as the target.
Select the smaller, upper, green linked body as the tool.
This completes the plan you made to compensate for faces removed from the parting part by the patch body.
The core section is well suited to machine with a lathe. In a later lesson you will learn how to create a sub insert in a work piece. You may then, on your own, choose to return to this project to design an appropriate sub insert.
Step 11 Save your work.
From the Menu Bar choose File Close Save All and
Close.
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