SolidWorks 2011 Assemblies Bible - Matt Lombard [178]
FIGURE 21.1
Visualizing the goal of the Parting Surface feature splitting a cavity/core block
The SolidWorks Mold Tools are intended to help you create cavity and core blocks for molds. The tools and process are generic enough that you could use them to create casts, forging dies, powder metal dies, and tooling for most plastic forming processes. SolidWorks does not provide libraries or functionality for building the entire mold or mold components. Mold Tools require you to follow a semiautomatic process, with the tools appearing on the toolbar in the order in which they are intended to be used, from left to right.
Mold Tools rely heavily on surfacing, and require a fair amount of manual intervention for certain types of parts. The first half of this chapter deals with the semiautomatic process — the way it is supposed to work. The last half of the chapter deals with the manual side of the process — the way things really work with day-to-day models.
The general workflow for using Mold Tools to create cavity and core blocks for a mold is as follows:
1. Create split lines to add draft where needed.
2. Create draft as needed (you can use Move Face to angle faces much like the Draft feature).
3. Scale the part up to compensate for shrinkage during molding.
4. Identify the parting lines that separate cavity faces from core faces.
5. Create shut-off faces, which are surfaces that close any through holes (windows or pass-throughs) in the part and represent places where the steel from the cavity side of the mold directly touches steel from the core side of the mold. These openings in the part are capped by surface features.
6. Create parting surfaces. These are the faces outside the part where the steel from opposite sides of the mold touch.
7. Create the tooling split. The Tooling Split feature uses the faces of the shut-offs and parting surfaces and the faces of either the cavity or the core side to split a block into two sides.
8. Create any core features. In SolidWorks, the word core refers to the material used to make core pins, side action, slide, lifter, or pull in a mold.
With the formal SolidWorks process, you start in the part file with just the final plastic part in it, and then build both the cavity and core blocks around the plastic part. You also build any side actions or core pins within the part file.
Figure 21.2 shows the part of the Mold Tools toolbar that identifies the process. This toolbar also includes many surfacing and plastics analysis tools, but only the tools directly related to the Mold Tools process are shown in Figure 21.2.
FIGURE 21.2
The Mold Tools
Mold Tools are really meant for tooling engineers, but part designers often use the first part of the process to apply draft to parts. Tooling engineers often need to add or correct draft to plastic parts they receive from part designers when these parts are without draft or are not designed with any process in mind.
If you were to create a mold with manual modeling functions, you might go through roughly the same steps in the same order. The SolidWorks process often runs into problems in the automated surface modeling areas, such as shut-offs and parting surfaces. You may need to intervene in the process manually for these steps. Fortunately, the SolidWorks process is flexible enough to allow for manual modeling as needed.
Each one of these process steps may have several steps of its own. Cavity and core creation is far from a push-button operation, but when you understand the overall process, the detailed steps become clearer.