SolidWorks 2011 Parts Bible - Matt Lombard [251]
I recognize that this description of how I made the part is a lot to follow. The point is not to show in detail how the parts were built, but to demonstrate how you can get to a part with 1,200 features or more. It is precisely on parts with this level of complexity that you need to think about modeling the part in this modular fashion — build each part separately and bring each separate section of the part together as individual bodies.
Figure 19.11 shows two of the separate pull direction parts being separated from one another in the same way that the mouse part was shown exploded in the previous example. Here the frame is also modeled as a separate part, again because it was not so intimately related to the other parts and was easily separated out.
Once this was complete for each direction, the separate parts were put together as bodies into a single part and again joined together using the Combine feature. Having all those features in separate parts enables you to segment the rebuild time. This is the opposite of building all the parts of an assembly in a single part, where you are simply compounding your rebuild time. Figure 19.12 shows bodies joined together as a single body.
This is probably a technique that you will not use very often, but when you do, it can save you a lot of rebuild time. I use it whenever I have a model that takes more than 20 to 30 seconds to rebuild and I know that I am going to be working on it a lot; it must also lend itself to segmenting in the way that this one did, with easily definable areas.
FIGURE 19.11
A complex model created as separate parts and brought together as bodies in a single part
FIGURE 19.12
Bodies all joined together as a single body
Bridging between solids
Often when modeling, you “build what you know” and “fill in as you go.” An example of this would be modeling a duct between end connections that are well defined. The duct in between is defined only by the ends, which must exist first. Another example is a connecting rod where you know the diameter of each end and the distance between the ends, and the connection between them is of secondary importance.
Figure 19.13 shows a connecting rod made in this way. In this case, the bearing seat at one end was created, and the other end was created by copying the body of the first one. From there, the link between bearing seats was created, which joined the separate bodies together into a single solid body.
FIGURE 19.13
Connecting disjoint bodies
This part contains some interesting features. First is the Thin Feature extrude that is used to make the first bearing seat, which is combined with a Mid-plane extrude to make it symmetrical at the same time. Then comes the Move/Copy Bodies feature, which copies the body in the same way that the feature in previous examples has moved bodies. Next is the use of the Extrude From option, which extrudes from a face, and then the use of the end condition Up To Next, which ends the feature neatly. The part also incorporates fillets that use faces and features to form the selection.
If you are not familiar with these options, I recommend that you open up the part from the DVD and have a look at it. It is a simple part that takes advantage of nice but simple productivity-enhancing options that have been available for some time in the SolidWorks software. The part filename is Chapter 19 – Bridge.sldprt.
By default, Solid features have the Merge option selected, and they automatically combine with any bodies that they touch. At the same time, they do not display errors if the Merge option is selected but the new body does not touch any existing bodies.
Modeling for undetermined manufacturing methods
Sometimes you must start a design before you know exactly how the product will be manufactured. This is an example of where the geometry of the finished product exists first and is then broken up into manufacturable parts. The initial model, shown in the image at the top in Figure 19.14, is created as a single part as a result of input from marketing, but