Precision Machining for Die Casting: High Efficiency and Quality

After the die casting has been ejected from the cavity, the next step is post-processing, such as machining. Are you curious about what kind of machining can be applied to die casting parts? If your answer is “yes”, the following article will be very helpful for you.

Necessity of Machining for Die Casting Parts

Die casting metal parts are often near net shapes and sizes. However, some castings need machining of the surfaces to reduce material and meet dimensional tolerances.

Furthermore, if you need your castings to have a higher surface quality or you want to improve the precision in the final assembly, machining can also be done.

Machining Techniques for Die Casting Parts

Machining is a subtractive manufacturing process where material is selectively removed from a workpiece, using precision tools such as drills, lathes, or grinding wheels. 

Unlike additive methods, machining focuses on achieving tight tolerances and refined surface finishes by cutting away excess material, creating features like holes, threads, or complex contours with high accuracy.

So if you want to machine a die casting, a certain amount of machining allowance away from the desired shape is needed. Whether your die casting parts are made of aluminum alloy or zinc alloy, machining is always well-suited for.

Common operations in machining include milling, turning, drilling & tapping, and grinding.

Milling

The die-cast workparts are secured in place during milling, and the metal is cut using cylindrical cutters. Milling can produce complex structures on die-cast parts that cannot be directly produced through die casting, such as deep grooves and holes. The milling process can be done by multiple axes with low or high pressure.

Excess material on die-cast parts, such as flash along parting lines or burrs, can be corrected during milling. Milling is also used for the improvement of dimensional accuracies like flatness and perpendicularity in die-cast parts.

If you plan to die-cast automotive transmission housings or electronic components, milling after die-casting can better meet industry requirements.

Turning

Unlike milling, turning is a machining process in which the workpiece rotates while the tool moves linearly to machine the workpiece. 

The whole turning process is done by a lathe. The workpiece is placed on it. The cutting tool on the lathe is made up of blades, which are used to cut the die casting parts into the desired shape. Turning is primarily used to machine the outer cylindrical surfaces and conical surfaces of die-cast parts, as well as for thread machining. 

If your die-cast parts are aluminum alloy automotive engine components, valve bodies, bearing housings, or similar products, it is highly recommended to incorporate turning in the post-processing stage.

Drilling & Tapping

Almost every metal part needs threading holes to assemble with other components. That is why drilling and tapping are so important for die casting parts.

Drilling and tapping are machining methods that allow die cast parts to be better assembled. Drilling involves using a high-speed drill to drill precise round holes where die-cast parts need to accommodate bolts and screws of specific sizes. 

Tapping adds threads to the walls of the drilled holes by using a precision tapping head. You must choose suitable taps for different screw sizes, diameters, threads per inch, etc.

These two machining techniques can provide a good connection between bolts and screws, and primarily offer more secure fastening options for die cast parts. 

If the die casting is securely fastened to other components, it will be able to function properly for a longer period of time in actual use, which means that the life of the product will be extended.

Grinding

If your die casting has a structure like a crankshaft bearing hole that needs to be rounded to a certain degree, it needs to undergo grinding.

Like any other machining, grinding enhances the surface finish of the casting to meet the casting’s requirements in terms of sealing.

If your casting is made of aluminum alloy, grinding can remove the oxidized skin on the surface of the aluminum alloy casting due to the high temperature.

You can choose a soft, coarse-grained wheel for your aluminum alloy die castings or a wheel that doesn’t heat up easily for your zinc or magnesium alloy die castings.

Conclusion

Machining can provide die-cast parts with better surface quality and higher dimensional accuracy. If you are looking for a manufacturer who can provide one-stop service from die casting to machining, Sunrise can be your ideal choice. Please contact us NOW and start your die casting and machining journey.