Manufacturing > Expert Machinist > Using Expert Machinist > No Stock Machining
No Stock Machining
You can machine a reference model without creating a corresponding stock part. This method is convenient when you are dealing with a complex reference part, for example, a casting, where you need to machine a few simple features. Instead of defining an equally complex stock part and assembling it to the reference casting, it may be more efficient to create an NC model with no stock, and then perform some extra steps in defining the machining features.
To create an NC model for No Stock machining:
1. On the Machining tab, click Create Model.
2. Type the NC Model name, or press RETURN to accept the default name.
The system opens a new Creo Creo Parametric window, the NC MODEL menu with the Add Ref Model option already selected, and the browser window listing all parts and assemblies in the current directory.
3. Select the reference model in the browser window.
The system retrieves the selected model and displays it in the window.
4. Instead of defining stock, click Done on the NC MODEL menu.
The system issues a warning that the model is being created with no stock, and asks you whether you wish to continue.
5. Click Yes.
The system closes the window used for defining the model and displays the NC Model in the original window.
Normally, when you create machining features, the system uses the stock definition to determine the thickness of material to be removed. If an NC model has no stock, you have to supply this value yourself. Therefore, whenever you create a machining feature for a No Stock NC model, the feature dialog box will contain one or more extra elements, depending on the type of the feature being created.
For features with a Hard Floor, such as Pocket or Step, the only extra element is Adjust Feature Top. This element is required, that is, once you define the other required elements, such as feature Floor, the system automatically selects the arrow next to Adjust Feature Top and opens the Define/Adjust Feature Top dialog box. You can define the feature top by supplying a thickness value from the feature Floor, selecting a datum plane, or specifying the Z coordinate of the Program Zero coordinate system.
For Through features, such as Through Pocket or Through Slot, you have to specify both the top and the bottom of the material to be removed:
• By default, the system assumes that the top of the feature coincides with the top edge of the feature walls. To adjust the top of the feature, click the arrow next to Adjust Feature Top element. You can define the feature top by supplying an offset value above the top of the feature Hard Walls, selecting a datum plane, or specifying the Z coordinate of the Program Zero coordinate system.
• By default, the system assumes that the bottom of the feature coincides with the bottom edge of the feature walls. To adjust the bottom of the feature, click the arrow next to Adjust Feature Bottom element. You can define the feature bottom by supplying an offset value below the bottom of the feature Hard Walls, selecting a datum plane, or specifying the Z coordinate of the Program Zero coordinate system.
For Profile features, you also have to define both the top and the bottom of the material to be removed, the same as for the other Through features. However, you also have to specify the axial thickness of material to be removed, by using the Offset Wall element and typing an offset value from feature Hard Walls. The default value is 0.1" (in English units) or 3 mm (in metric units). You can type any value.
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When you create a Through Pocket or Through Slot feature for No Stock machining, the system assumes that the whole feature is filled with material. If you have a casting with a cored pocket, use Profile instead of Through Pocket, and specify the appropriate Offset Wall value.