Weldment Part Problem

Discussion created by Ben Conners on Aug 7, 2008
Latest reply on Aug 7, 2008 by Ben Conners

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I have attempted to use a master sketch profile in an empty part to build my model. I need this pofile at various angles about a circle so this is why I placed it in a part to be inserted multiple times. The model is a weldment part, the empty part with master sketch is a regular part. I use lines in the sketch to locate the inserted parts (since there are no bodies). These constraints hold in the <As Machined> configuration. When in the <As Welded> configuration upon rebuild the inserted parts do not hold their location. Upon futher rebuilds it eventually goes back to the desired position (there is a rebuild loop). I know that in most cases using reference geometry should be avoided in the weldment environment, so I tried putting a dummy solid in the inserted part to locate. This also did not work. I have attached two files, both attempts (using ref. geometry and using solid faces and edges). Does anyone have any insight into this problem? Regards, C. Lawrence LOVAT Inc. SolidWorks Office Premium 2008 SP4.0

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1-6TXHTM Aug 6, 2008 6:09 PM
Ben

I would get away from using the angle in your location. To do this I create a master sketch in the part (not the inserted ones) to show the angles that you want. This would be easier to edit than editting the Move/Copy Body feature. Then I would mate to the sketch or create a planes from the sketch and mate to them. I tried to test my theory with your part but I can't because the weldment part is not in the zip file.

Lorne
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Ben Conners Aug 6, 2008 6:57 PM
Hi Lorne,

Thanks for the response.

The reason we attempted to insert a part containing nothing more than a sketch into another part is because this will be used multiple times at various angular locations within a weldment. We use this sketch part to locate various inserted parts that we bring into this weldment as well.

I wish solidworks was able to do a polar convert of a sketch onto another plane located at a specific angle to the original, it would make life so much easier. Then we could body locate to these sketches.

We also tried created blocks from a sketch and then insert these blocks onto various angular planes within the weldment. When we inserted the blocks we linked them back to the one stored in our vault, so that if we made changes to the one outside the weldment, all changes would populate into the weldment. The problem we found was that if the block was edited in anyway, all locational body moves in the weldment would have errors. I think this is because the particular ID or the entities in the block become lost upon editing. So as a result, we could not use this method as well.

We are really in a predicament here, as we would like to use the weldment environment, but are having difficulty locating inserted parts with body moves being constrained to inserted part sketches or to inserted blocks. All seem to blow-up on us.

Would you happen to have any other ideas we could try?

Thanks

Ben Conners
SW2008 SP 4.0
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1-6TXHTM Aug 6, 2008 7:19 PM
Ben

Can you zip the weldment part file and post it? I could then edit the master part to try a couple things.

Lorne
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Ben Conners Aug 7, 2008 11:38 AM
Hi Lorne,

I have attached the file. If you open file 225301old it contains some inserted parts and that master sketch part I was trying to utilize.

If you switch into the as welded configuration and inititiate several hard rebuilds (CTRL-Q) you will seen the blocks move around but in a specific routine.

I have a much larger part weldment that contains this file 225301old and it too is doing the same thing. Although it contains this file, it also has the master sketch inserted by itself. So rather than send the large file, I opted to send this, as this demonstrates the basic behaviour that is being experienced in all our weldments with the body move and master sketch parts.

I hope we can get over this hurdle, as the weldment environment would greatly reduce our output time to manufacturing in comparison to using assemblies and all individual parts. We have to take a number for all individual parts but for a weldment everything is reduced to one number for us by the way we have structured things.

Thanks for your help.

Ben Conners
Lovat Inc.
SW2008 SP 4.0
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David Stone Aug 7, 2008 12:09 PM
Ben

Looking at the parts/assemblies you uploaded, it appears you are not using weldments in the "normal" way (i.e. utilising standard profiles to generate a welded framework). As the parts/assemblies appear to be in a polar array I wonder if you'd be as well to make one part as a multibody part and then pattern the parts or sub-assemblies within a final assembly.

Alternatively you should be able to use sketches within the assembly to position items as required.

I have attached a (very) simple assembly illustrating positioning with a sketch in an assembly and a polar array.

Regards

David
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Ben Conners Aug 7, 2008 12:44 PM
Hi David,

Thanks for the reply.

We currently utilize the way you explained, but we have been trying to fine tune the engineering department by trying to use the weldment environment so we could have a quicker turn around time for production.

typically we generate assemblies of around 7,000 parts in asseblies, most repetitive but a large portion too being unique. For every unique part we require part numbers for as we use PDM and an MRP system. This means huge amounts of drawings for stupid things like plate and cut lengths of structural steel. We are trying to get away from creating all these part numbers and drawings.

We are attempting to use the weldments environment, where we could combine structural profiles to account for cut lengths, and could also do extrusions for plate to be flame cut. Our drawings for the weldments would be multisheet, which would include a sheet for welding and the cutlist, another for machining, and other for 1:1 scale burn templates and any rings that may have to be formed. As a result we are reduced to one part number for the entire weldment and all its bodies, and drawings are simplified and reduced because burn templates no longer require detailing.

The only thing holding us back at the moment is the case I stated above. I was hoping to try and resolve this.

It may come down to trying to figure out a combination of weldments with assemblies to try and get this thing to work as you stated.

Hopefully maybe there is just an instability in the body constraints that we can figure out to do in some other manner.

Thanks for your help.

Ben Conners
Lovat Inc.
SW2008 SP4.0
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1-6TXHTM Aug 7, 2008 3:06 PM
Ben

I can see what you are trying to do and it makes sence to me because I think that our companies have similar part number systems. Right now what we do is create a unique part number and drawing for everything. I am also trying to change this but have given up with SW2008 and am waiting till SW 2009 to impliment the change. The reason is that in SW 2009 you can create an assembly (which is esentially what you are doing) and a drawing of that assembly. The difference is that we will be able to pull up cutlist info in the drawing of the assembly BOM. THis way you can use the functionality of the assembly environment to mate etc but still do one drawing (and one part number). I am waiting because I know this will be a better solution than whatever I come up with in SW 2008.
I don't know if this will solve all your issues but I know for us it will increase our productivity and the stability of our models, tenfold.
I looked at your model and the only thing I can say is I hate Move/Copy Body feature, it always seems to screw up especially when you are trying to use it as much as you are.
Sorry for the no-answer.

Lorne
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Ben Conners Aug 7, 2008 4:26 PM
Hi Lorne,

I appreciate you looking into my model and understanding what we are trying to accomplish. At least I know there is someone else out there experiencing the same problems as us.

I am going to try and re-think some type of procedure but I too may give up until SW2009.

In the meantime I can still train employees here regarding weldments and the basics. Some other aspects of our machinery can still be handle somewhat using master sketches being in the main weldment. The example you saw was one from a more specialized department where we used these inserted part sketches to locate an abundance of tooling. Other departmentst don't deal with locating many items.

So I thank you very much for your efforts. I have sent this dilemma to our VAR and they have forwarded it on to Solidworks with a high importance priority (not that this means a whole lot since they have not developed weldments to its utmost potential thru all new releases).

Regards,

Ben Conners
Lovat Inc.
SW2008 SP 4.0
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Weldment Part Problem

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