12 Replies Latest reply on Dec 1, 2015 6:15 AM by Chris Brooking

Mates error in assembly keep coming back

Jano Reyneke Apr 4, 2014 8:50 AM

Hello

I have a problem with mates in certain assemblies , we use solidworks proffessional 2014 and PDM at the office and I have a number of assemblies where the mates are marked red and when I fix it , it goes normal , but as soon as I click update it turns red again , I have even gone as far as deleting all the mates and entered them again from scratch ,then they also turn normal again , but even after I have saved that , as soon as I close the model and reopen it again , all the same mates are red again.

Have deleted the mates about 5 times and still nothing changes , it is also not on my licence , the other draughtsman in our office (who works on her own license) is experiencing the same problem with these certain assemblies.

has anyone seen this before?

Re: Mates error in assembly keep coming back

Glenn Schroeder Apr 4, 2014 9:08 AM (in response to Jano Reyneke)

Hello Jano,

Welcome to the forum. There can be so many causes for mate errors that it's very difficult to say what could be causing the problem without having the assembly with it's parts to look at. Is there any chance you can post it here? (Click on "Use advanced editor" just above the right corner of the text box to post files.)

It could be conflicting mates, too many mates, or any one of several other issues. There may be nothing wrong and a Ctrl+Q rebuild will fix it.

One thing that I learned the hard way is that SW doesn't like mating to components brought in with a Linear Pattern, Mirror, etc. That will cause errors quite often. It's pretty much always better to mate to reference geometry or sketch entities belonging to the assembly, or to parts that were inserted and mated instead. Once in a while I'll do it anyway, but when I do I'm prepared to reach for Ctrl+Q on a regular basis.
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- Re: Mates error in assembly keep coming back
  
  Jano Reyneke Apr 4, 2014 9:27 AM (in response to Glenn Schroeder)
  
  Hi Glenn
  Thank you for your reply.
  That is what I thought s well , but I have assemblies with much more mates than these , its just this one range of machine that we sell that does this , have never seen it on any of the other assemblies and w have well over 3000 assemblies that work on our different machines.
  Unfortunately I am not allowed to post an assembly of this size on a public site due to company regulations , but I can tell you that it I have also experienced the mate problem with patterns , mirror etc... so I am also inserting parts one by one and even that doesnt help.
  and as for the Ctrl+Q update , everything is fine , all the mates appear regular , but as soon as I use that update all the mates go red again. and there are only straight forward , distance , coincident and cocentric mates involved.
  I have heard of mates going mad when saved folders are different in one assembly , for instance when some of the parts are saved on a server and some on desktop , but we use PDM so all our parts and assemblies used by all of the draughtsmen are checked into the vault and which is on a server , so I do not know where to start searching for the problem ...
  
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Re: Mates error in assembly keep coming back

Alin Vargatu Apr 4, 2014 9:13 AM (in response to Jano Reyneke)

Do you have any in-context relations or assembly features in your assembly? Have you deleted any in-place mates?
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- Re: Mates error in assembly keep coming back
  
  Jano Reyneke Apr 4, 2014 9:35 AM (in response to Alin Vargatu)
  
  Hi Alin
  
  I have deleted all mates in the assembly and added them again and still the same thing happens , but it wasn`t always like this , these machines are almost 10 yeasr old and this is the first time it has happened.
  
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  - Re: Mates error in assembly keep coming back
    
    Alin Vargatu Apr 4, 2014 10:00 AM (in response to Jano Reyneke)
    
    Jano, if you deleted the in-place mates, without breaking the references, you will get these issues.
    
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    - Re: Mates error in assembly keep coming back
      
      Jano Reyneke Apr 4, 2014 10:23 AM (in response to Alin Vargatu)
      
      I dont use in-place mates at all , every part in the assembly is a part with its own code (name) , we only have parts and make assemblies from the different parts , we dont use weldments or in place mates at all , because all parts are manufactured by our own factory.
      
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      - Re: Mates error in assembly keep coming back
        
        Alin Vargatu Apr 4, 2014 11:28 AM (in response to Jano Reyneke)
        
        Do you have assembly features?
        
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      - Re: Mates error in assembly keep coming back
        
        Fredrik Karlsson Apr 7, 2014 4:24 AM (in response to Jano Reyneke)
        
        Be careful when using concentric,
        combined with locking it´s rotation with a plane-plane (or surface) coincident.
        (it will make it mathematically overdefined. SW often ignore this, but not always..)
        Try a parallel mate for locking rotation instead.
        
        Good luck / Fredrik
        
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        Re: Mates error in assembly keep coming back
        
        Chris Brooking Dec 1, 2015 6:15 AM (in response to Fredrik Karlsson)
        
        Hi fredrik karlsson,
        
        I'd be interested in seeing an example of this, as you shouldn't see the issue you describe. Can you provide a simple example?
        
        Best regards,
        Chris
        
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  - Re: Mates error in assembly keep coming back
    
    Jerry Steiger Apr 17, 2014 4:31 PM (in response to Jano Reyneke)
    
    Jano,
    
    I am guessing that you have some over-defining degrees of freedom, as others have mentioned. The newer version of SolidWorks is probably checking the degrees of freedom more stringently than previous versions. You probably need to be more careful about making sure you don't have redundant mates.
    
    In theory, when you mate two planes, you have taken out 3 of your 6 degrees of freedom. If you mate two lines, that removes two more degrees of freedom. If you mate two points, you have taken out the last degree of freedom. Any additional mates may cause problems. Mating two planes, then two lines, then another two lines (meaning you now have one redundant degree of freedom) might work, or it might not. Mating two planes, then two planes, then two planes theoretically gives you three redundant degrees of freedom. That gives you even more chances for problems.
    
    Jerry S.
    
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    - Re: Mates error in assembly keep coming back
      
      Qinghai Jin Apr 17, 2014 4:42 PM (in response to Jerry Steiger)
      
      I experienced the problem of too overdefined mates inside assembly.
      
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Re: Mates error in assembly keep coming back

Steve B. Nov 30, 2015 3:55 PM (in response to Jano Reyneke)

I ran into the same/ a similar problem. I had mates that were completely fine when being added but caused errors as soon as I rebuilt/saved/reopened the assembly. Turned out I had used entities from the main assembly as references for a sketch on a new part (I was trying to match profiles for a cable tie and used two vertices from the main assembly to line up the sketch for the cable tie). Deleted the references and all was back to normal.
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