Hayden
Mechanical
- Jul 31, 2002
- 121
We have some fairly complex machined components that are made up of fairly complex plates welded together. Our product designers design these weird and wonderful shapes (created in Pro E) that are used for vaccum moulding.
What we do is weld up an aluminium box with special weld prep nice and deep to make sure there is still material (weld) holding the the thing together for nice big radii on the corners of the machined part. These weld preps are machined in many cases as they have to be quite specific. We also machine swept cuts into the pre welded plates for heating water pipes to run in.
Here's what we do from a CAD perspective:
A. Welded fabrication:
1. Design fabrication part with 2 configs, one with weld preps and all the plates as seperate bodies, one with all the weld preps turned off and the bodies combined to give a completed welded fabrication.
2. Perform a 'save bodies' on all of the bodies in the fabrication and give them all seperate part numbers to eneble them to go through our workshop routing. As part of the save bodies feature you have the ability to create an assembly of all the bodies, we use this.
3. Create part drawings for all of the seperate plates for machining of weld preps and waterways and an assembly drawing for fabrication.
A. Finished machined part:
1. Import solid only STEP files from Pro E (Part A)
2. Apply scaling to the new SW model for shrinkage.
3. Insert part A into another part model (Split part).
4. Perform surface work on the split part to create stationary inserts for some protrusions and sliding inserts for protrusions creating undercuts. We use consume bodies for the inserts and save them out with their own part number. This leaves behind the bulk of the part geometry for the final part.
5. Create a machined part and for the first feature insert the split part from above.
6. Insert the single body config of the fabrication part.
7. Combine the bodies created by the previous 2 operations using 'common' as the combine type. By doing this we have an accurate representation of what the final machined mould will look like.
Now, we have a few problems pop up with this, most of which we live with, one which we have quite some difficulty living with though is:
When the product designers make a change to the product (can even be a fairly minor change) and we re-import the STEP files the split part pretty much always falls into a crumbling heap. The surfaces edges and vertexes we have used to define sketch planes, sketch profiles and feature depths all change and reorder. What we have to do is pretty much redefine all of our split features completely. But wait, there's more, we pretty much have to redefine features in the final machined part as well as most of these fall over too.
Is there anyone out there that does a similar thing or has done in the past with some degree of stability?
Thanks in advance,
Hayden
What we do is weld up an aluminium box with special weld prep nice and deep to make sure there is still material (weld) holding the the thing together for nice big radii on the corners of the machined part. These weld preps are machined in many cases as they have to be quite specific. We also machine swept cuts into the pre welded plates for heating water pipes to run in.
Here's what we do from a CAD perspective:
A. Welded fabrication:
1. Design fabrication part with 2 configs, one with weld preps and all the plates as seperate bodies, one with all the weld preps turned off and the bodies combined to give a completed welded fabrication.
2. Perform a 'save bodies' on all of the bodies in the fabrication and give them all seperate part numbers to eneble them to go through our workshop routing. As part of the save bodies feature you have the ability to create an assembly of all the bodies, we use this.
3. Create part drawings for all of the seperate plates for machining of weld preps and waterways and an assembly drawing for fabrication.
A. Finished machined part:
1. Import solid only STEP files from Pro E (Part A)
2. Apply scaling to the new SW model for shrinkage.
3. Insert part A into another part model (Split part).
4. Perform surface work on the split part to create stationary inserts for some protrusions and sliding inserts for protrusions creating undercuts. We use consume bodies for the inserts and save them out with their own part number. This leaves behind the bulk of the part geometry for the final part.
5. Create a machined part and for the first feature insert the split part from above.
6. Insert the single body config of the fabrication part.
7. Combine the bodies created by the previous 2 operations using 'common' as the combine type. By doing this we have an accurate representation of what the final machined mould will look like.
Now, we have a few problems pop up with this, most of which we live with, one which we have quite some difficulty living with though is:
When the product designers make a change to the product (can even be a fairly minor change) and we re-import the STEP files the split part pretty much always falls into a crumbling heap. The surfaces edges and vertexes we have used to define sketch planes, sketch profiles and feature depths all change and reorder. What we have to do is pretty much redefine all of our split features completely. But wait, there's more, we pretty much have to redefine features in the final machined part as well as most of these fall over too.
Is there anyone out there that does a similar thing or has done in the past with some degree of stability?
Thanks in advance,
Hayden
