Skip to content

4 Common Metal Additive Manufacturing Issues to Avoid

When it comes to manufactured parts, the last thing you want is your product to be riddled with deformations, whether they’re readily visible or not. Not only is this extremely frustrating, but it can set project timelines back to a point of no return. 

Unfortunately, hiccups and mistakes are a natural occurrence in every manufacturing process. And the metal additive manufacturing process is no exception. 

There are many unique advantages of metal additive manufacturing, however, there are many issues to avoid, as the manufacturing process is relatively young.

What is Metal Additive Manufacturing?

The metal additive manufacturing process (also referred to as metal AM) uses metal powders to create strong, complex components for a variety of industries and applications. It’s best described as: “producing components through the deposition of material, layer by layer.”

Different additive manufacturing processes can take on materials other than just metal, such as biochemicals, thermoplastics, and ceramics. 

Some additive manufacturing technology examples include:

  • Binder jetting
  • Material extrusion
  • Material jetting
  • Sheet lamination
  • Directed energy deposition

Metal Additive Manufacturing Issues to Avoid

The metal AM process comes with several advantages, such as the ability to produce complex shapes and be flexible with your design choices. However, there are a few specific issues to avoid:

  • High porosity
  • Residual stress
  • Stair-stepping
  • Lack of quality consistency

High Porosity

The term “porosity” refers to tiny air cavities that form within a component during production. Although generally very minuscule, these pores can reduce the overall density of parts, thus increasing the likelihood it’ll crack or fatigue.

Porosity happens in two primary ways. First, gas pockets sometimes form within the power feedstock during the powder atomization process. Although this issue isn’t as common, it highlights the importance of purchasing materials from a reliable supplier.

The second way that pores form is through the additive process itself. This can occur if the powder particles are bigger than the actual layer thickness of the part, or if the powder being added is loosely packed. 

Your manufacturing partner should make sure your design matches up appropriately with your material specification. They should also own the equipment capabilities to compact your part effectively, brushing aside any concerns about cavities or pores forming.

Residual Stress

Residual stress, which can crack or warp components, might be the metal additive manufacturing process’s most common issue. This stress occurs during the heating-cooling process, which inherently causes components to expand and contract.

Residual stress is the most troublesome at the center of parts, along with the interface between the part and the substrate to which it adheres. Support structures can be added to help reduce residual stress but can deform the part throughout the process if not used properly.

Work with someone who has previous metal AM expertise, as they’ll likely understand how to support the part’s shape without adding deformities.

Stair-Stepping

This is one of the biggest cosmetic challenges that metal additive manufacturers face. “Stair-stepping” is the nickname given to the layering error that causes a part’s finish to look similar to a staircase. In other words, the final layer isn’t smooth and has a slight, unintended incline.

Luckily, many post-processing methods can fix this issue. Sand sintering may be the most effective method, but this process will increase processing time and overall production costs.

Lack of Quality Consistency

This issue exists in nearly every manufacturing process, but it’s something to avoid at all costs in large orders. And while a big step in consistent quality is selecting the right raw material, the manufacturer you choose is ultimately responsible for overall quality control.

If 1,000 of the same component are ordered, each one should be within a very tight variance of one another. Otherwise, there’s a risk of losing functionality in part of the batch. 

This may be an issue common to the industry (especially with AM still in its formative years), but can be minimized simply by selecting an expert team of metal additive manufacturers.

Choose Metal AM Experts

Metal additive manufacturing can be quite challenging, though APG is experienced and ready to meet all your needs. We have an expert team with years of experience who can help bring any design to life.