Parting Surface Sheets Wont Knit?
7 months ago

Hi all,


I've been working on a mold for a part for quite a while and I've been stuck since it keeps giving me the same rebuild error (cant knit sheets) when I try to make the tooling split. I've made some molds before but I have never run into this problem and I would appreciate some help. I just cant see why it would be giving me this error since I've done a geometry analysis and it shows nothing that would need to be knitted and just 4 knife vertices.

The mold will be used for a composite layup and neither the top nor bottom of it work so I've attached the part in multiple formats below and I would appreciate tips or help because I really don't want to use the cavity tool in an assembly since I believe it would be too complex with the geometry I have.



Categories: Modeling and Assemblies, Plastics and Mold Design

Last comment By: Doug Seibel   Mon, 27 Nov 2017 14:26:30 GMT
Re: Parting Surface Sheets Wont Knit?

I have found that the mold tool functions can not work on complex geometry, especially parting surfaces.

A good work around (which I personally prefer to mold tools anyway) is to use the already created core and cavity surfaces. Take a copy of the parting surface so there is 2. Use the knit command to knit the cavity surface to the parting surface, do the same with the core and the copied parting surface.

Now we can create planes for both halves of the tool and simply extrude up to the knitted surfaces we have created.


Thanks, Kyle

By: Kyle Mitchell  Tue, 21 Nov 2017 10:13:15 GMT
Re: Parting Surface Sheets Wont Knit?

I agree with you Kyle Mitchell. It is interesting in this case that the Parting surface will not knit completely with the Core surface.

There is a gap in the red area witch can not be handled by Gap Control. Is the part 100% symmetrical? Anyway you will have to tweek the Parting surface to get good results.

Disclaimer: I have not tried the Cavity Surface and I have not viewed the Iges-file.

By: Thomas Voetmann  Tue, 21 Nov 2017 12:42:53 GMT
Re: Parting Surface Sheets Wont Knit?

Thank you Thomas Voetmann.


Please see image of my attempt. I have had to use a combination of delete faces and surface fills.

I would upload the file but i am new here and don't know how to!


By: Kyle Mitchell  Tue, 21 Nov 2017 13:49:45 GMT
Re: Parting Surface Sheets Wont Knit?

Just figured it out! Don't reply from inbox...

By: Kyle Mitchell  Tue, 21 Nov 2017 14:10:09 GMT
Re: Parting Surface Sheets Wont Knit?

The part is 100% symmetrical (created using a mirror) and I spent a good hour and a half using the manual option with the parting surface to no avail. Apparently complex geometry like this is not possible to mold using default tools. 

By: Diego Toral  Tue, 21 Nov 2017 18:08:46 GMT
Re: Parting Surface Sheets Wont Knit?

I'm kind of sad that the default tools that are supposed to work for molds don't work in my case since to the naked eye it looks like SOLIDWORKS should be able to do what I am asking it to do. I see that you already completed the part below and I am really grateful but ill try to give it a shot using this new info and method. Thank you so much for your help.

By: Diego Toral  Tue, 21 Nov 2017 18:06:55 GMT
Re: Parting Surface Sheets Wont Knit?

Hi Guys,

This is the reason we developed SplitWorks in order to create core/cavity separation for complex parts which are not handled very well within the regular SOLIDWORKS environment.

SplitWorks also helps the creation of side cores and sub  inserts.


Anyone interested should check out our web site Online Demos | R&B we offer a 30 day evaluation version which can be requested from the same web site.


George Berold


By: George Berold  Sun, 26 Nov 2017 09:43:06 GMT
Re: Parting Surface Sheets Wont Knit?

The Parting Surface tool in Solidworks is nothing more than ONE of the many surface creation tool at your disposal in Solidworks.  Don't get stuck thinking that it is the ONLY option at your isn't.










Familiarize yourself with the full suite of surface creation tools.  Especially Boundary & Ruled, they are 2 of the most useful tools for creating parting surfaces.

By: Doug Seibel  Mon, 27 Nov 2017 14:26:30 GMT
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