SOLIDWORKS Mate Best Practice #2: Don’t Mate Your Relations

Article by Jim Peltier, CSWE updated May 15, 2013


Welcome back, fellow SOLIDWORKS users for another installment of our SOLIDWORKS Mate Best Practice series.

Last time, we looked at Rule #1: Mate before you relate. After the video, I suggested such a terrifying possibility: That a hole in a plate with a sketch relation to another hole on a different part might be wrongly used to apply a concentric mate as well, resulting in a circular reference. I can tell you’re cringing just thinking about it! Still, as perfect an example as that may be, it wasn’t as visually striking as what you’re about to see. Next up is Rule #2: Don’t Mate Your Relations:

Something worth explaining in greater detail is exactly what was going on with my path sketch. Why is it that it rebuilt and the hose going into the valve was not in line with the fitting as I thought I sketched it? In fact, I did not sketch it to be in-line with the fitting at all! That’s what I’m getting at. I sketched it to be in-line with the Z-axis of my part. When I started rotating my part the Z-axis of the part rotated with it, and the hose followed accordingly. Some other things that could have caused instability: If I had mated the hose to the fitting on the valve and then moved my valve vertically (along the Y-axis). There would have been conflicting mates for sure!

You might also note that I broke rule #1: Mate before you relate (I applied sketch relations to the valve while it was not mated). That’s partially what caused the instability towards the end.

As you can see, I ended up in quite a mess. When I tried to change the mates so that I was mating to the valve rather than the air cylinder, I ended up in even more trouble. I had mates that were over-defining my assembly, since I was fixing my valve which already had mates applied to it. In a rush, I actually suppressed the wrong mates, but I still made my point and also lead very nicely into Rule #3: Don’t fight with your mates (tune in next time).

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Jim Peltier, CSWE

Jim has been using SolidWorks since 2001, and has spent most of that time working in the design of industrial automated manufacturing equipment. He has been working as an Applications Expert at Javelin Technologies in Oakville, Ontario since July 2012 and is a Certified SolidWorks Expert (CSWE).