-
Posted September 8, 2008
Change the Z Direction of Parts!
Many of today’s products contain complex parts. There are many ways to manufacture these parts. Processes such as injection molding, fabrication, and machining are just some of the methods used. Often, each of these processes requires that the orientation of the coordinate system used by a component vary from the orientation in which they have been modeled in the CAD software.
Model orientation in Inventor is driven by the designer’s intent and modeling method employed. As the components are manufactured, the machinists involved must adapt the component’s coordinate system to suit the coordinate system of the machine or process being used. This practice introduces more opportunities for error, as well as increasing the cost of the component due to the increase in manufacturing time. For example, it is generally preferred that the axis of a cylindrical part, which will be cut in a lathe, lies along the Z axis. Many times, this orientation differs from that in which the part was originally modeled in Inventor.
Often, machinists prefer a part be oriented to match the coordinate system employed by their machine. For example, it is generally preferred that the axis of a cylindrical part, which will be cut in a lathe, lies along the Z axis. Many times, this orientation differs from that in which the part was originally modeled in the CAD software.
Autodesk® Inventor® makes it easy to deal with downstream orientation requirements. By providing components with the correct coordinate systems, it is possible to reduce the opportunity for error, and in turn, manufacturing costs.
The Setup
Imagine that you are working on the design of a crankshaft for a small engine. It is a basic single throw crankshaft with a flywheel flange and a taper.
The crank is completely designed and documented. It is time to have it machined from its casting. Your machinist has requested that the shaft axis lie on the Z axis, and that the origin (0,0,0) lies central to the flywheel flange. The crank was modeled so that the axis of the rod journal lies on the Y axis and the origin is located at the midpoint of the rod journal.
Using Inventor, it is very easy to re-orient this part to satisfy the machinist’s requirements without changing or affecting the original model or design.
Let’s look at how this is accomplished.
1. Begin by creating a new assembly document. Insert your completed part into the new assembly document. The component is inserted and automatically grounded at the assembly origin.
2. The next step is to un-ground the component from the origin. This is accomplished by right-clicking on the component in the browser and deselecting Grounded.
3. The re-orientation begins. The idea is to constrain the component to the origin features of the assembly in such a way that the component is re-oriented as required. In this case, to begin re-orienting create a Flush constraint between the YZ Plane of the crank and the YZ plane of the assembly.
4. Next, create a Mate Constraint between the Flywheel Flange and the XY Plane of the assembly.
5. The final constraint is an Axial Mate applied between the axis of the crank and the Z Axis of the assembly.
6. At this point, the component is completely re-oriented. The Axis of the crank lies on the Z axis, and the origin lies on the Flywheel Flange. Using the Save As command, the assembly can be saved as several different file types. The file type you choose will depend on the downstream use of the data.
The Conclusion
This workflow simplifies the re-orientation of an existing component for downstream use. Parts and assemblies can be moved anywhere in relation to the origin. This makes it extremely simple to supply vendors and end users with multiple orientations that are suitable for their equipment and workflows.
By adding this technique to your toolset you have the ability to share your design with downstream users without compromising your data integrety or original design. You can save time and resources, allowing your team to leverage modern manufacturing methods without the need for costly editing processes.
You must be logged in to post a comment.