While I was working with a group of students last week we got on the discussion about Design Intent and why it is important when creating files in SolidWorks. Design Intent as defined in the SolidWorks Help is “Design intent is how your model behaves when dimensions are modified”, but Design Intent goes much further than that.
The case that me and my students were talking about was the part show below and we were talking about the Counter Bored holes and the channel in the lower portion of the part.
For creating the model the choice of features used to create the part was fairly simple, a Hole Wizard feature, Linear Pattern and a Mirror for the Holes and a Simple Cut Extrude for the channel.
The real issue came when it was time to create a Detail Drawing for the part as to how to put in the Hole Callouts for the Counter Bored Holes. You would think that for a Hole Callout the answer would be simple but there are several different ways that we could define the callouts and while modeling the part our choice was pretty simple it was not as simple for the detail drawing. We needed to look at several different items:
1. The Hole Callouts
a. We could do a Hole Callout on each side of the part.
b. We could put a Hole Callout on one side with a Thru Hole for the small diameter hole and Counter Bore only for the other two holes.
Before we decided how to put in the Hole Callout we need to answer the questions of
2. How will the part manufactured
a. Was this machined from a single block, if so when would the center channel be added.
b. Was the part a cast part and the center channel already in the part.
c. How or What type of machine will the part be made on, weather it is a simple Bridgeport a multi-axis milling machine.
d. What is the overall size of the part and can items like the center hole be completed in one operation.
3. The application the finished part will be used in
a. The center holes need to perfectly in line with each other.
b. The holes independent of each other and alignment not a critical factor.
Each scenario is that we run thru has a different outcome and different set of ramifications from time to manufacture to overall cost of that part. If the incorrect Hole Callout is added to the part the part could easily take twice as long to produce or cost twice as much to manufacture.
An example of this is we choose the end application of 3b and the part was manufactured with 2b we would want to use Hole Callout 1a. If we used hole call out 1b it would greatly increase the time and cost to add the holes, because with the center slot already in the part it would be almost impossible to drill a thru hole in part and not have it step out of alignment in that process.
As we can see Design Intent is not just as simple as the definition of “how your model behaves when dimensions are modified”. Design Intent is much involved and it is important to pay attention to pay attention to all the small details and work with all Departments and Vendors to fully understand the entire scope of a project before completing it.
Josh Altergott, CATI Support Manager
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