CAM: The Efficient Strategies You Shouldn’t Miss to Process an Impeller

If you are working in the fields of energy, automotive, aviation, maritime navigation, etc., impeller is surely your old friend, who helps increase the pressure and speed of flow of a fluid to produce centrifugal force. Due to the complexity of manufacturing an impeller, it becomes a typical case in 5-axis machining.

ZW3D CAM module offers comprehensive strategies from 2 to 5-axis machining like Smooth Flow, Swarf, Drive Curve, Drive Surface, Flow Cut, etc., which make impeller machining no longer a difficult job. In this article, I’m going to show you how to generate toolpaths for an impeller easily. Let’s get right to it.

Figure 1. The impeller model in this case

Step 1: Choose SmoothFlow strategy in 3x Quick-Rough to remove the excess stock on top of the workpiece.

Figure 2. SmoothFlow in 3x Quick-Rough ribbon

Figure 3. From left to right: the toolpath generated by SmoothFlow strategy, the simulated effect, and the actual machining effect

Step 2: Use SmoothFlow strategy again to conduct indexing roughing on the areas beneath the blades. In this step, the key is to set the correct sub-coordinate system, by which we can process the hub areas directly in different directions without undercutting.

So how to generate toolpaths by sub-coordinates? First, create a sub coordinate on one of the blades, and set the direction of Z-axis pointing to you. Then select the frame just created in the configuration form of Rough SmoothFlow strategy. After that, toolpaths can be created under the blades. You can continue to generate toolpaths for the areas beneath other blades conveniently by Circular Array.

Figure 4. Set the direction of Z-axis of the sub coordinate

Figure 5. From left to right: the toolpaths of areas under the blades, the simulated effect, and the actual machining effect

After the first two steps, the roughing process of the impeller has been completed. Next, we are going to conduct 5-axis simultaneous machining.

Step 3: Use Enlarge Face command to enlarge the top surface of the blade, then use Guide Surface Iso strategy to create extended toolpaths for the enlarged surface, to ensure the thoroughness of actual machining for the top of the blade.

Figure 6. Use Guide Surface Iso strategy to extend toolpaths for the top of the blade

Step 4: Use Offset 3D strategy to create toolpaths for the top of the hub. This strategy can leave out too much tool lifting, and keep the steps equidistant, increasing machining efficiency and quality.

Figure 7. Use Offset 3D to generate toolpaths for the top of the hub

Step 5: Use Swarf strategy to mill the blades. Set the surface of a blade as the Drive Surface, and the hub as the Part Surface. Then use Swarf strategy to generate the toolpaths for one blade.

Figure 8. Set the 5-axis Drive Surface and Part Surface

Figure 9. Refer to the toolpaths generated just now, and create the toolpaths for all other blades by Transform command

Step 6: Process the hub area between two blades. First create the toolpaths for two drive curves as the edges of the area. Then choose 5-axis Flow Cut strategy to create uniform toolpaths to fill the area between two drive curves.

Figure 10. Generate two drive curves and create uniform toolpaths to fill the area between them

Step 7: Finally, use Side strategy in 5x Mill ribbon to create toolpaths for the rest areas of the workpiece.

Figure 11. The generated toolpaths for the rest areas of the workpiece

So far, the machining toolpaths for the impeller have been created. Let’s see the impeller after machining.

Figure 12. The well-processed impeller

Have you got the tricks of machining an impeller? I would recommend you practice with ZW3D CAM module, which is smart and easy-to-operate. Download the model and have a try!