NX 10 Mold Wizard (Part 3)
This 3-part article discusses a few of the commands within NX10 Mold Wizard functionality that are very impressive and indicate the level of sophistication of the cross-applicational software product. Part 3 discusses the steps that create the cavity and core inserts, which will contain the molded product part cavities, and how to slice it into the two halves. It also provides a rough overview of completing many of the steps in the process of building the parts and subassemblies of the complete mold assembly.
Defining the Workpiece In Your Mold Wizard Project
This step in the Mold Wizard CAD process can be implemented with several different approaches of how you might want to define the portion of the mold that actually shapes the molded product part.
The Part to Be Molded
As an example, we’ll work with a small injected molded part designed to rotate like a pump vane or maybe it’s a part in an industrial assembly machine that loads parts into position in an assembly…
You’ll see in the references that follow that the part is named “double_flipper”.
Reviewing the Mold Wizard Workflow Process
Mold and tool makers, machinists, programmers, or any user involved in designing tooling that fabricates parts and products using the multitude of molding processes can benefit from selected portions of this functionality or the entire integration of tasks (assuming the product part is modeled):
- Create Mold Wizard product assembly (initiate a project)
- Apply a shrink factor
- Define core and cavity regions within a product model
- Create patch up (shut off) geometry
- Create mold tooling inserts
- Use mold base libraries to choose a standard mold base
- Use standard part libraries to select and position common parts – including pockets, sub inserts, cooling channels, gates, and runners
- Create a bill of materials
- Begin mold assembly and component drawings
To reinforce these best practices, we’ll assume that some of the tasks we’ve already discussed in the previous 2 parts of this article have already been accomplished.
Normally, you would have already validated the part design for moldability – meaning, check for drafted surfaces, identify what surfaces are to be formed by what parts of the mold, and mold flow analysis
|1. Check wall thickness
|| 2. Check regions and pull direction
Drafted faces – 2° reference draft
|3. Define Region – cavity
||4. Define Region – core
Perform a mold flow analysis and display the results.
Here’s the one we did in Part of this series, “The Skinny on NX 10 Mold Wizardry“.
The next task would be to initiate the Mold Wizard project, an essential and critical step. If you remember from part 2 of this article, this command creates the entire mold assembly structure including subassemblies and many bottom level components that can accommodate optional parts and data that you may choose to include in this Mold Wizard process.
Although this task doesn’t really create the actual bodies of the parts in the mold, it does create the containers (the part files) for them. However, the project initiation process does use template parts that contain some geometry. For instance, making the “prod” assembly the Work Part and highlighting the “cavity” part shows us some stuff.
Making the “cavity” file the Work Part, we can see a solid block and a sheet body, both named and assigned the attributes/metadata necessary to make all the links work for you within the mold assembly.
Ok, enough of the preliminaries – let’s get on with the show!
One thing should be emphasized and strictly adhered to when working in Mold Wizard: every time you complete a step and close a Mold Wizard dialog, you should save all. Not just the Work Part, not just the higher level assembly, but from the “top” part of the mold project all the way through the structure. This needs to become a habit because one of the things NX does when it saves is to “clean up” for itself by updating features and geometry as well as interpart links and other information such as metadata, the Undo buffer, and many other things. You’ll find this tends to preserve the integrity of your Mold Wizard sessions too.
Assigning a Mold CSYS
Before moving forward in this Mold Wizard processes, you should also consider the possible situation that in its own part file the product part that we’re building a mold for is oriented in a way that is contrary to how we would want our mold to be oriented. But hypothetically, we might want to reverse the part orientation to be upside down or perhaps it sits in space all “catty-whompus”. (This is a high technical term that mean its location and orientation doesn’t line up with the ABS at all!)
Mold Wizard has a function called Mold CSYS, an icon in the Main group of the Ribbon Bar in the Mold Wizard application, that allows you to change the product part location and/or orientation within the mold assembly without affecting the model in the product part file. This is of particular importance when it comes to the parting surface or plane of the part. It is of great value to place the part in space where that parting line/plane is relative to the two halves of the mold.
In this “double_flipper” part file, orientation is acceptable, but we have to look at the plane where the cavity and core sides will part. Look at the hold in the middle and the coloration of the faces that the Check Regions function did for us. If the orange is the cavity side and the blue is the core side, we need to part the mold where the hole meets the counterbore.
But, if we look at the bigger picture, the entire side of the part down to the bottom will be formed by the cavity side. We need to part the mold at the plane on the bottom of the part. Fortunately, that plane happens to be at the X-Y plane of ABS. No problem!
We can just create core pins that “kiss” in the middle to form the hole, counterbore, slot, and countersink on the bottom as long as the possibility of a small amount of flash at that parting surface is acceptable. An acceptable amount might be .01″ or so if this part if just going to be stuck onto the end of a drive shaft or rotor. If you’re a mold designer, you hopefully know all about these kinds of considerations.
Adding Shrink to the Mold
At this time, it would be good to incorporate shrink into the definition, but we’ll keep the discussion short.
If we incorporated the shrinkage right now, Mold Wizard would automatically make the “shrink” file the Work Part…
…and we would have some fairly simple options to choose from:
As you can see, there are only 3:
And Mold Wizard would default to the shrink factor identified when we first selected the material in the initiation of the project (1.0045). Based on the selected option, Mold Wizard would allow u to manually enter different values for the various directional elements as desired.
However, die to time constraints, you need to get done reading this and get back to work, so any more about shrink will have to be discussed at a later time.
So, that now brings us to the Workpiece task, finally, which essentially allows us to define the core and cavity insert as one homogenous part (subassembly). Mold Wizard uses that to – for example – calculate default mold base sizes, split into the individual regions using the parting geometry, modift with the various mold tools, (slides, lighters, gates and runners, cooling channels, pockets, etc). Most of these procedures are done without the user having to change Work or Displayed part – Mold Wizard does that automatically.
When you choose the Workpiece icon, NX changes the Displayed Part to be the “layout” part file and the Work Part to be the “workpiece” part file.
The dialog uses the default Workpiece Method of “User Defined Block”.
As soon as the Workpiece icon is selected, Mold Wizard reads the default settings and begins to create the geometry. When User Defined Block is the default Method and Sketch is the default Definition Type, it creates a rectangle in a Sketch that is larger than the product part by predefined Expression values already stored in the Mold Wizard definition. Notice the Distance values in the Limits fields highlighted above.
The Sketch has predefined Dimensional Constraints being driven by these built-in Expressions as well as some Geometric Constraints controlling the shape.
By activating the Sketch, using the Sketch Section icon in the dialog, we can see the actual expressions that result in those values and the Geometric Constraint symbols.
There are actually 4 options for the Workpiece Method:
The 3 involving the cavity or core offer options to select an existing solid or solids as the Workpiece(s) or you can select from the Workpiece Library.
When you select the Workpiece Library icon, the Reuse Library tab is opened in the Resource Bar and another dialog appears to aid in defining the Workpiece(s).
An alternate Define Workpiece option is the Definition Type of Reference Point which uses the ABS 0,0,0 position as a base point and allows the user to input positive and negative offset values manually.
And, by the way, you do need to be careful about clicking in the graphics area while this is in process – Mold Wizard will redefine the base point and mess things up a bit. Ooops!
If this happens, you can either use the Point Dialog option to reenter the base point values for ABS 0.0,0 or Reset the dialog, which will change all options and entered values back to the way the dialog was set when first opened.
Regardless of the options and values chosen, select OK to the Workpiece dialog and a result similar to this will appear:
NOTE: The Workpiece is translucent. If yours is not, you may need to turn on this option in your Visualization preferences.
In the Visualization Preferences dialog box, on the Visual page, select the Translucency checkbox.
Once that step was completed, Mold Wizard automatically returned the Work Part back to the “top” assembly file. And what you should do after completing that step in the process?
Save early, save often. Just like voting!
Now we’re ready to check regions again, which will have retained information from doing it earlier, and also defining the regions, a more definitive assignment of faces to be formed by cavity or core sides of the mold which will enable Mold Wizard to automatically identify a split between cavity and core sides of your Workpiece.
All of these functions are in the Parting Tools group on the Mold Wizard tab.
But before that, another step is necessary. Any planar regions where there aren’t faces of the product part body but where the cavity and core will need to meet face to face will need a separator face. These are called Patch surfaces and are easily created on a part like our “double_flipper”.
We could move on to the Define Regions step and full assign every face in the part to a region. The objective here is to make sure there are no “Undefined Faces” in the model by alternately selecting “Cavity region and Core region” nodes in the Region Name list and selecting faces of the model to add them in the desired region.
If necessary or desired, additional regions can be defined for side pulls, slides, lifters, etc. Just remember that all faces of the model have to be formed by steel in the mold and that steel exists in one part or another, whether it’s cavity, core, slide, etc.
“Apply” is then selected to complete the definition of regions and when everything is assigned, turn on the Create Regions and Create Parting Lines options and choose OK.
The next step you might complete is to design the parting surfaces. In this step, Mold Wizard creates continuous surfaces. In this step, Mold Wizard creates continuous surfaces that will cut through the Workpiece and divide it into cavity and core sides.
There are a lot of options here and – depending on the complexity of the shape on the product part being so simple, this is a piece of cake. As soon as the icon is selected, Mold Wizard builds a surface at the parting line of our part which has a cutout in it at the actual part geometry.
And then there’s a step to Define Cavity and Core. This is where Mold Wizard actually splits the Workpiece into two.
Upon choosing OK, the graphics area flashes a bit and then a preliminary result is displayed, waiting for your approval. Here’s our cavity insert, top/cavity side:
And the bottom/core side:
If all is well, choose OK in the View Parting Result dialog. Sometimes, the normal vectors can get reversed and the result might show the core side as the cavity side and vice versa, but this doesn’t happen often. If desired, you can reverse the normal just to check some things out.
Now that we’ve split our Workpiece into real cavity and core inserts, we’re ready for the big finish. (Well, we’re actually not even close to done with the mold, but we’re close to being done with this article!) Make the “top” assembly file the Work Part and here’s what she looks like:
And we haven’t created a single piece of geometry! Mold Wizard has done it all!
Building the Actual Mold Geometry
To say that we’re going to build the actual mold geometry is a bit deceptive. As you have seen, much of what you do in Mold Wizard is to simply tell Mold Wizard what to build and how to build it. The step relies heavily on the Reuse Library and, in particular, the Mold Wizard Engineering Data Base.
It should be mentioned that the Mold Wizard Engineering Data Base must first be downloaded from the Siemens website or our Swoosh Customer Portal and then unzipped to a new folder within the NX base directory. The zip file for NX 10 is “mwnx10_data.zip”. Also, as an environment variable must be created:
MOLDWIZARD_DIR = <youtube>:\<yourbasedir\moldwizard_data
Then, start NX10 and explore your Reuse Library to find stuff like this:
To get these mold assembly parts modeled and built inside our assembly structure, we first make sure we’re working on our “top” assembly file of our mold structure. Then, we go back to the Main group in the Mold Wizard tab of the Ribbon Bar where we started in this article (rememember way back when?) and choose the Mold Base Library icon.
Once selected, it’s possible this can be a bit confusing, especially if your default dialog position is right on top of your resource bar.
Cue Line says nothing. You just gotta know this. It’s waiting for your to move the Mold Base Library dialog and select from the Reuse Library that it just opened for you. And if you don’t have your Member Select group open, you don’t see much of anything to actually pick.
Aaaaahhh! That’s better! Now you can select the various vendor folders above and peruse the vast list of mold configurations.
Speaking of configuration, do you remember when we first created the mold assembly structure by initializing a project? Well, whatever mold configuration you selected then will have a big impact on what and how Mold Wizard will build for you here.
You should also open up the Preview group of the Reuse Library to see what these molds will look like, at least in the basic (vanilla) definition. Once an actual mold base member is selected, be patient. Mold Wizard is going to not only show you a picture in that Preview window but will also display a popup that has a slide view diagram of the plate design. Admittedly, the preview isn’t much but the diagram is WAY helpful.
And if we look a little closer at the Mold Base Library dialog, you’ll see a few things worth noting.
There’s an option for Rename Components so you can replace the default acronyms like TCP_h and EP_3 to something more meaningful to you or that complies with your standard part names.
There’s an Information Window icon that controls that diagram popup that appeared.
You can edit any of the expressions and attributes listed in the Details group, make it smart, base it on a spreadsheet, etc.
And there are options where you can get into the Register and Data Base attributes that Mold Wizard uses prolifically. That’s a whole other story ther.
So choose OK and watch Mold Wizard go to work! And you have to be patient here because it is referencing hundreds of definitions, expressions, attributes, configuration settings, etc. Once it gets finished, you have quite a masterpiece! I just accepted the defaults of that DME sample and let ‘er rip:
But you’ll see, if I go to a right side view, I was a little hasty. I probably needed to resize the A and B plates along with a few other tweaks.
Looking at the Assembly Navigator, you’ll see some new additions to the structure. There’s a whole new “base” subassembly, for instance.
And if you choose the Mold Base Library icon again, it allows you to edit those things. You’ll also notice that many of the expressions in the list have multiple choice drop-down lists to stay with standard sizes offered by those particular vendors.
So with just a few new selections of values and selecting Apply, I can get a whole new design very quickly. And now my cavity and core inserts actually fit!
Now, to be real, there’s a lot more to it than just picking a mold base from a list and let ‘er rip. And, not being a mold designer, there are certainly more considerations for how a mold should be designed. There are functions for family molds, and multi-cavity inserts, thickness variations of the different plates and how much metal I want to use, whether I’m going to cut out my A and B plates and weld in the inserts or keep the plates thin and just secure the inserts with backing bolts and clamps, etc. And, if you look at the orientation of the part, the cavity and core side positions, and the fact that the ejector box is actually on the core side, things would probably work out much if that was reversed. But that’s the beauty of Mold Wizard; all those things can be accommodated when building it or later if you need to make changes – all based on your standard and traditional practices!
As you saw in this article, which is not intended as “training” by any stretch of the imagination, the process of building this whole mold in NX is fairly painless compare to starting from scratch. There are certainly a lot of mold shops that already have their own templates, tool libraries, mold design philosophies, etc. and maybe don’t need to do a lot of everything that Mold Wizard offers. There’s a tremendous amount of enhancements and improvements in the recent years, and a lot of companies are only aware of the price and not the extremely robust capability it now has. I hope I’ve now enlightened you about of its capabilities!
In addition to the tasks that Mold Wizard can help you accomplish within the mold assembly structure that we have in this 3-part article, there are many other common and not so common steps – including but not limited to:
- Molded Design Validation
- Establishing a Mold CSYS
- Incorporating a shrink factor, uniform or non-uniform
- Defining closure (patch) surfaces
- Establishing mold parting surfaces
- Defining regions for cavity and core side surfaces and side-pulls, inserts, slides, sub-inserts, etc
- Creating tool geometry directly from cavity geometry
- Using Standard Parts from the Mold Wizard Data Base
- Designing gate and runner systems
- Inserting the cooling channels and hardware
- Auto-creating pockets for hardware, standard parts, ejector pins, slides and lifters, etc
- Mold parting and ejection simulation
- Merging cavities
- Creating drawings of mold parts and assemblies
- Defining BOMs
- Adding hole tables and ejector pin tables
- Interrogating mold structure and design such as interference, calculating surface area, WAVE management, etc
- Exporting mold data such as BOMs, reusable parts, attributes, etc
- Customizing Mold Wizard
If you’d like to read more about these Mold Wizard capabilities and perhaps even like to see a round of design changes incorporated into this assembly, including changes to part geometry, send us some feedback and let us know! There’s a lot more to talk about!
Now, get back to work
This concludes Part 3 and Mold Wizardry blog series.
Garrett Koch | PLM Application Engineer, Swoosh Technologies
Well-accomplished in drafting, design, and engineering in many industries since 1973, Garrett has been developing patentable designs and has taken on large-scale engineering projects. In 1994, he embarked on a different career in CAD training, courseware development, and technical support – where he focused on teaching a variety of students (including PhD’s from MIT, project engineers at Los Alamos National Labs, officers at NASA, and users across the continent at major manufacturers of aerospace, automotive, and power generation). Garrett excels at the knowledge transfer of NX mechanical CAD and Teamcenter and is considered an expert in NX installation, configuration, and technical support.
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