Core & Cavity III

This the third page that discusses the core and cavity functions of Mold Design Advisor. Here we look at parting and fill surfaces and creating forms.

• Parting and Filling Surfaces
• Form Creation: Cores, Cavities, Sliders

Exercises:

• 1. Creating Fill Surfaces
• 2. Creating Sliders
• 3. Creating the Parting Surface
• 4. Dealing with the Undercuts
• 5. Creating Forms

Parting and Filling Surfaces

A parting surface is created from the parting line and pull direction of a molded part, and is extended to the mold block. You can specify one of six modes - perpendicular, parallel, anti-parallel, normal, tangent and constant - to create the parting surface, although individual edges of the parting line can be given a different mode.

A filling surface is created by specifying a feature having edges defining an open loop, or by selecting those edges manually. If there are multiple open loops on the selected feature, you must select the correct loops for the fill surface.

For example, the following shows a mold part within the mold block, showing fill surfaces and the parting surface:

Form Creation: Cores, Cavities, Sliders

You can create a solid part from its core or cavity feature, parting surface, and fill surface. The resulting solid is the union of the respective faces trimmed at the mold block.

Sliders are created by specifying the slider feature (defined by manual part-splitting), the direction of the slider and the fill surface. Again, the slider is trimmed at the mold block.

The following graphic shows a part (middle), with its cavity (above, in green), core (below, in blue) and two sliders (left, in magenta):

Exercise 1: Creating Fill Surfaces

In the following exercises, you will create two fill surfaces in our part, followed by four sliders, then a parting surface, and finally the core and cavity forms.

Create the fill surfaces for the slider:

• Use the part from the previous (part splitting) exercise. You can also load the package TUT90-MDA-coring-ex3.pkg from the Parts directory, which contains the part already prepared for this exercise.
• Open the Fill Surface menu (click Core/Cavity in the main menu, and click Fill).
• By Feat is active by default: Click a face belonging to one of the slider features on the part.
• The Specified Items table opens, listing the features available at that face, which should be an undercut and a slider feature. Double-click the slider feature.
  
  
  
• There are two open loops on the feature:
  
  You need to specify the inside loop for the filling surface. Click Loops and click the inside loop on the feature.
• Click OK to create the fill surface:
  

Repeat the above procedure to create another filling surface in the other undercut containing two slider features:

Exercise 2: Creating Sliders

Create four sliders:

• Open the Create Slider menu (click Slider in the Core & Cavity menu).
• Click a face belonging to one of the four slider features.
• Select the slider feature from the Specified Items table.
• Click Fill Surface and click the relevant fill surface on the slider feature.
• Click OK to create the slider:
  

Repeat the above steps on the other three slider features, using each fill surface twice, to create a total of four sliders. They are pictured here copper-colored and slid out of the part:

Exercise 3: Creating the Parting Surface

Create the parting surface:

• Open the Parting Surface menu (click Parting in the Core & Cavity menu).
• Click a face belonging to the core feature.
• Select Normal from the Default Mode list.
• Select Right from the Ref Face list.
• Click OK to create the parting surface:
  

Exercise 4: Dealing with the Undercuts

Before you can create core and cavity forms, you must deal with the two undercuts in the part. You can follow one of two possible methods:

• Assign the undercut faces to the core.
  Hint: Use manual part splitting and add the faces to the existing core feature! It is probably called Core1, and you enter this name in the Feat Name box after selecting Core from the Type list. Then you click to add faces by Feature, and select an undercut feature from the table. Repeat this to add the other undercut to the core:
  
• Create four fill surfaces to cover the undercut holes.
  Hint: Use the By Feat selection method in the Fill Surface menu, and click the undercut features in turn:
  

Exercise 5: Creating Forms

Create the core form:

• Open the Create Core menu (click Core in the Core & Cavity menu).
• Click a face belonging to the core feature.
• Specify the parting surface. If you created four fill surfaces to cover the undercuts (see above), you would also select these at the same time as the parting surface. If you assigned the undercuts to the core feature, you need do nothing extra here.
• Click OK to create the core:
  

Create the cavity form in the same way, clicking a face belonging to the cavity feature: