When to use additive manufacturing vs machining?

Introduction

As engineers with a manufacturing background, you are likely familiar with the two main processes used in creating parts: additive manufacturing and machining.

Both methods have their own set of advantages and disadvantages, making it important to understand when to use each technique. 

Cost Considerations

One of the primary factors to consider when choosing between additive manufacturing and machining is the cost.

Additive manufacturing, also known as 3D printing, can often be more cost-effective for manufacturing complex geometries and low-volume production.

The cost of additive manufacturing is typically based on the volume of material used, making it a cost-efficient option for intricate designs that would be expensive to machine.

On the other hand, machining can be more cost-effective for producing parts in high volumes.

While the initial setup costs for machining may be higher, the per-unit cost for machining decreases as the volume of parts increases.

Machining is also a more suitable option for parts that require high precision and tight tolerances.

Material Properties

Another important consideration when choosing between additive manufacturing and machining is the material properties required for the final part.

Additive manufacturing offers a wider range of material options, including metals, plastics, and composites.

This allows for greater flexibility in material selection, making it a suitable option for parts with specific material requirements.

On the other hand, machining is more limited in terms of material options.

While machining can be used with a variety of materials, including metals, plastics, and ceramics, the process may be more challenging for certain materials.

Machining is often preferred for parts that require specific material properties, such as high strength or heat resistance.

Lead Time

Lead time is also an important factor to consider when choosing between additive manufacturing and machining.

Additive manufacturing is often faster than machining for producing prototypes and small-batch production runs.

The layer-by-layer building process of additive manufacturing allows for quick turnaround times, making it an ideal option for rapid prototyping.

On the other hand, machining may be more time-consuming, especially for parts with complex geometries.

Machining involves the removal of material from a solid block, which can be a slower process compared to additive manufacturing.

Machining is often preferred for parts that require high precision and tight tolerances, even if it means a longer lead time.

Surface Finish

The surface finish of the final part is another important consideration when choosing between additive manufacturing and machining.

Additive manufacturing can produce parts with a rough surface finish, due to the layer-by-layer building process.

While post-processing techniques can improve the surface finish of additive manufactured parts, machining often produces parts with a smoother surface finish.

For parts that require a high-quality surface finish, machining may be the preferred option.

Machining allows for tight tolerances and smooth finishes, making it a suitable choice for parts that will be visible or require a specific surface finish.

Additive manufacturing may be more suitable for parts where surface finish is less critical.

Complexity of Design

The complexity of the design is an important factor to consider when choosing between additive manufacturing and machining.

Additive manufacturing excels at producing complex geometries that would be difficult or impossible to machine.

The layer-by-layer building process of additive manufacturing allows for intricate designs with internal features and complex shapes.

On the other hand, machining is more limited in terms of the complexity of designs that can be produced.

While machining can produce parts with high precision and tight tolerances, it may struggle with intricate or complex geometries. Machining is often preferred for parts with simple or straightforward designs.

Conclusion

When deciding between additive manufacturing and machining, it is important to consider a variety of factors, including cost, material properties, lead time, surface finish, and complexity of design.

Additive manufacturing may be more cost-effective for producing complex geometries in low volumes, while machining may be more suitable for high-volume production runs with tight tolerances.

By carefully evaluating these factors, you can make informed decisions on when to use additive manufacturing versus machining in your manufacturing processes.

Both methods offer unique benefits and challenges, making it essential to choose the right technique for each particular application.

By understanding the strengths and limitations of both additive manufacturing and machining, you can optimize your manufacturing processes and create high-quality parts efficiently and effectively.