Happy CAMing with ZW3D: Machine an Engine Block for an Automobile

In the automotive industry, CNC machining is widely used to manufacture almost anything, from headlight covers to engines. As one of the most important parts of a car, the engine block houses the cylinders, coolant passages, oil galleries, etc. and powers the vehicle. In this article, I’ll show you how to machine a four-cylinder engine block in ZW3D.

Figure 1. A Four-Cylinder Engine Block

The common method of machining an engine block involves Deck Surfacing, Cylinder Boring (to save a block or to increase displacements), and Drilling. To generate the respective toolpaths, you’ll need the Topface Cut, Spiral and Hole Tactic strategies in ZW3D. Let’s go through them one by one.

Deck Surfacing

To get a properly functioning engine, you need to first deck the block, a.k.a. remove some portion of the block to level the cylinder heads. This is important for ensuring a good gasket seal and a right deck height. You can use a large step distance, fly-cutter, and finer processing accuracy to achieve a smooth surface. CNC machines will surface the block according to the specified deck height. Therefore, you can specify a proper surface depth to get a perfectly flat and square deck for the cylinder bore. Let’s see how to generate toolpaths for surfacing the deck with Topface Cut.

Step 1: Select the Topface Cut operation in the “2D Face” panel under the “2x Mill” tab, then select the profile as a feature and specify the tool to be D25R3.

Figure 2.  Creating Machining Features and Tools for Deck Surfacing

Step 2: Specify the key parameters as shown in the following figure.

1. Set Tool Location to “Past Boundary” and Bottom to “0” in Limiting.
2. Set Path Tolerance to “0.01”, Stepover to “% Tool Dia” and “120”, and Stepdown Type to “Base Only” in Tolerance and Steps.

Figure 3.  Setting Key Parameters

When the calculations are done, the toolpaths will be generated as the figure below shows.

Figure 4. Topface Cut in ZW3D (Left) and Deck Surfacing with CNC Machines (Right)

Cylinder Boring

Next, you need to create toolpaths for cylinder boring, which enable the carbide cutting tool to cut away the extra metal so that the cylinder bores become larger. Precision also matters in this procedure because we don’t want cylinder bore misalignment. To accurately and evenly bore these four cylinders, Spiral is a good help. Follow the steps below to get prepared for cylinder boring.

Step 1: Click “Spiral” in the “2D Pocket” panel under the “2x Mill” tab.

Step 2: Select the four holes as the profile under Features and use the same tool of the last process.

Figure 5.  Creating Machining Features and Tools for Cylinder Boring

Step 3: Specify the key parameters as shown in Figure 6 and 7.

1. Set Bottom to “-120” in Limiting.
2. Set Stepover to “% Tool Dia” and “60”, and Stepdown to “3” in Tolerance and Steps.
3. Set Plunge Type to “Helical”, Plunge Angle to “3”, and the Engage and Retract links.

Figure 6.  Setting the Values of Boundaries, Stepover, Stepdown

Figure 7.  Setting Plunge Type, Plunge Angle, and Links

Now, the toolpaths should be as the figure below shows.

Figure 8. Spiral Operation in ZW3D (Left) and Cylinder Boring with CNC Machines (Right)

Drilling

Finally, it’s time to drill the engine block for coolant passages, gas vents, etc. With the Hole Tactic strategy of ZW3D, you can do it in a very short time. Keep reading to see how it works.

Step 1: Right-click on “Tactics” in the CAM Manager and select “Insert Hole Tactic” to generate a Hole Tactic strategy, as shown in the figure below.

Figure 9. Creating a Hole Tactic Strategy

Step 2: Select the part as the machining feature and start calculating.

Figure 10. Selecting Machining Features and Generating Hole Tactic Toolpaths

Then, the ZW3D Hole Tactic will automatically identify the hole types on the engine block and generate the drilling toolpaths for different kinds of holes. Hence, your programming efficiency can be remarkably improved.

Figure 11. Automatic Drill, Peck Drill, Counter Bore, and Tap

Generating NC Codes

After all the toolpaths mentioned above are ready, you can output them into NC codes for further machining.

Step 1: Define the machine by selecting “FanucBasic” as the Post Configuration (output machine type) and selecting the “machine_all” file as the Definition File.

Figure 12. Defining the Machine

Step 2: Select all operations to output and get NC data.

Figure 13. Outputting NC data

With the procedures broken down, we can see that it is easy to machine an engine block with ZW3D. Why not follow the tutorial and master the process? Click here to download the latest ZW3D for a free 30-day trial!