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best practices for manufacturing (individual operation) models and drawings

best practices for manufacturing (individual operation) models and drawings

best practices for manufacturing (individual operation) models and drawings

(OP)
This will likely be a very broad question, but any detail you might be able to help me with would be greatly appreciated. If there are already well-written tutorials out there that can answer my questions, please point me in that direction and I'll add them to my research.

First off, I'm in a new role with a different company, and I'm transitioning from Solidworks to NX10. I have little difficulty creating individual models (it's all just arcs and lines, right?), but I'm trying to create individual models now that are specific to the manufacturing operations that they correspond to. Traditionally (in SW), I would have 1 model file (sldprt) with multiple configurations; one for each machining operation (OP10, OP20, etc.). Using this method, each configuration would "add-on" to the previous configuration. At my new place of business, they prefer to have individual models for each operation so that they can be edited (if necessary) without affecting all other models. The idea behind wave linking is very alien to me; I think I understand the concept, but I don't know how to implement.

Most of the parts I deal with are castings / forgings. We (usually) receive a finished part model from the customer and maybe a casting model; sometimes we need to create both...I have no issues there. From there, I'd like to make an "assembly" of the cast model with the finished model (inside of the cast model; constrained as necessary), and then carve away the needed material for that operation (using the finished model's geometry for simplicity) and then save that partially-machined model as whatever operation it is (ex: OP10).

I want to get rid of as much "bloat" as possible with this method.

Side Note: The guy who created all the MOT's before me no longer works here. Most of the rest of the team are either NC programmers or they create shop routers. Since no one else currently working here normally makes MOT's (operation-level models and drawings), there's no established "one best way" and everyone has a different opinion on how they need to be created and look. The only definite guideline is that each operation must have its own model (individual prt files).

For example, I was tossed in the middle of an MOT for a part with many operations. Individual models have already been created for each operation. The MOT (prt that contains all the op-level drawings) takes FOREVER to manipulate (save, update, etc.). I think the reason for that is because each drawing somehow references EVERY model that came before it. Let's see if I can describe it:

Let's say there's 20 manufacturing operations (1-20). The OP20 drawing references the OP20 assembly model. The OP20 model references the OP19 model (via linked body), the OP19 model references the OP18 model (again, via linked body), etc., etc. So, for 20 operations, that particular MOT is referencing a minimum of 210 models...even if they're just linked bodies.

Can someone point me in the direction of a tutorial illustrating a simpler method of accomplishing the same thing? I'd even settle for a tutorial on how to accomplish it the difficult way at this point... While the other guys here are willing to help, they each have their own work to do, and they all have a different way of approaching this problem.

If anyone is REALLY bored or feeling generous, I've attached a couple of basic models; a cast part and the finished part. I'd like to create a tutorial for myself (and anyone that might follow me with the same level of confusion) on how to use this method. This part should have 4 machining operations:

OP10: face bottom of block and .250 up on each wall (to provide a machined surface to clamp in a Kurt vise)
OP20: finish machining sides, pocket and pocket radii
OP30: drill & counterbore hole on one side (whichever)
OP40: drill & counterbore hole on adjacent side

For visualization purposes, this will be done on a standard VMC with a Kurt vise. I'm not looking for manufacturing files (I don't program); just individual model files and a MOT file for the drawings.

Thanks for anything you might be able to help with!

-WRM

RE: best practices for manufacturing (individual operation) models and drawings

(OP)
What a difference a few hours make...

So, I've learned how to use WAVE geometry linker, and I've (somewhat) learned how to use "promote body" and "assembly cut." But so far, none of the 3 seem to be able to allow to do what I want.

I want to be able to make an assy. out of 2 solids; 1 inside the other...a "finished" model inside of a cast model. I can get that far. Then, I want to be able to select the finished model's geometry for features like an extruded cut.

Example:

I may know that the finished model is perfectly centered inside of the cast model, and that there's .100 stock all around. But, I don't want to create my sketch and make an extruded cut to a depth of .100 for a facing operation; I want to be able to select the face of the finished model (probably via static wireframe) and then make an extruded cut "until selected" or "until next."

Will any of these features (promote body, assembly cut or wave linker) allow me to do this? I can't seem to get anything to work for me.

-WRM

RE: best practices for manufacturing (individual operation) models and drawings

I can perhaps answer a couple of your questions but not all of them.

We do some casting and machining parts here. The way we do it is to make the casting part, and then add that part as a component in the machining part, as an assembly. I can't speak for Promote Body because I've never used it, but I've mostly read that using Linked Bodies is a better way to do this. Searching for Promote Body you will find some threads that will provide more info.

Once the casting part is added use the WAVE linker to make an associated Linked Body of the casting. Now you want to "turn off" the casting part, otherwise you will see both parts on top of each other and you won't see your cuts or holes or whatever when you make them. There are probably a few ways to do this. We make the Reference Set for the casting part set to Empty. You could also put it on a separate layer and blank that layer.

Now you make whatever features you need to make your machined part. You can play around with reference sets and features like points or datums from your casting to help you locate your machined features.

Production parts that will go through our plants need to be broken down into separate parts and drawings for each different setup. For instance the part will be clamped into one machine; that's one 'operation'. When it's changed to another machine for making cuts from another direction or whatever that's another 'operation'. And so on. Each of these operation parts will get a different dash number based off of the same base number.

For example:

Casting - 12345-000
Machining final machining - 12346-000 (i.e. final machining operations)
Machining 1st op - 12346-001 (i.e. bore a crosshole)
Machining 2nd op - 12346-002 (i.e. machining top and bottom flat and bore hole in one flat surface)

This got long-winded in a hurry, but it should give you a good idea of one way of accomplishing what you want to do. I'm sure others will have different opinions.

Good luck.

Mike

RE: best practices for manufacturing (individual operation) models and drawings

(OP)
Thanks for the reply Mike; I appreciate it. Our process is very much like yours, but our naming conventions are a bit different.

If I understood your post correctly, you're adding both components (finished and cast) to an assembly and then wave linking the cast model (and then turning off the original cast model so that you don't see 2 of the same). I'll have to do some more research on reference sets though, as I haven't had the opportunity to use them yet. I also need to find out how the "until selected" end condition works for the extrude command; I haven't been able to get it work like I would expect it to. For whatever reason, I've been using "until extended" for extruded cuts (when my finished model is "inside" the cast model), but I usually have difficulty selecting the hidden geometry of the finished model. I'm wondering if making a wave-linked copy of the finished model as well as the cast model would help my being able to select geometry?

-WRM

RE: best practices for manufacturing (individual operation) models and drawings

The casting model is a part by itself. It is added as a component to the machining model, making the machining model an assembly. The point of making the linked body for machining is so if you make changes to the casting they will update in your machining model. If you made a separate model for both the casting and machined part you would have to make any changes to both parts separately.

Think of it like doing actual machining to an actual cast part. You're making cuts and drilling holes and such in the casting, but the casting part still 'exists' because there is a bin full of more castings to choose from. I don't know if that helps.

It's worth noting that, IMO, 'assembly' is kind of a grey area in NX. Any model can be termed an assembly if you create your new model as a Product Assembly under File/New. If you only create features and never add anything as a component it is still technically an assembly. This is different than other CAD programs I've used. I used to think that you had to create a Product Assembly instead of a Product Model to be able to add components to it, but I think I remember being told that's not necessarily true.

I've also not had much luck with Until Selected or Until Next and the like so I just don't use them. Through All works well though so I use it. I don't think the fact that the model is a linked body will make much of a difference, but you may find otherwise.

Mike

RE: best practices for manufacturing (individual operation) models and drawings

Intresting topic, we are currently working on separating our cast parts into separate cast and machined part files (we currently let the foundry patch/rebuild the machined model into something suitable for casting). The motivation for us is to have a part frozen as it was when it was sent for casting, and to keep the machined model tree lighter (Larger models containing castinng & maching features are approx 3000-7000 features)

I took a crack at it see included zip file, thought I broke it down to reference sets rather than separate parts for each operation as in the image below.

And on part level

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