At Stratasys Direct Manufacturing, our project engineers often receive the question: What affects the costs of 3D printed metal orders? Part size and geometry understandably affect price, but there are other details that can alter the cost of 3D printing services. Sometimes there are misconceptions about metal additive manufacturing (AM) that can discourage designers and engineers from pursuing the technology.
We’ve broken down five misconceptions of what affects the pricing of additive metal parts and what to focus on to ensure cost-effective parts.
1. Designing for the AM Process
Part geometry is frequently the biggest cost factor in a 3D printing project. Design determines size, complexity and the amount of material needed for the part. The engineering practice Design for Additive Manufacturing (DFAM) is utilized by engineers to simplify and optimize products for manufacturing with AM technology. Without the traditional and manufacturing constraints, complex designs are more cost-effective with AM.
Additionally, the geometry of a 3D printed part influences the number of supports needed, and the amount of support material used to manufacture your design impacts the price. Designs with self-supporting angles (usually around 45 degrees or more) use less support material and can help reduce both material expenses as well as build time. The more supports, the higher the price of a part.
Part orientation also plays a crucial role in the number of supports needed. Reorientation can dramatically reduce the amount of material needed for the supports, therefore reducing costs. Determining optimal orientation is a balance between cost and the integrity of a part; for example, building horizontally on the XY plane to save cost could result in the loss of feature definition, trapped supports, and even worse; an unusable part because it has warped out of tolerance.
When designing for AM, remember:
- Design for function with 3D printing instead of worrying about tooling constraints
- Complexity is not the cost driver in the additive process
- Optimize your design with self-supporting angles (usually around 45 degrees or more)
- Utilize a teardrop shape for internal passageways to avoid supports
- Design for performance and part consolidation to lower the number of assembly components required for construction
2. Picking your metal alloy material
Another big cost factor is which AM metal material you choose for your project. From a casting grade aluminum to mechanically advanced metals like Nickel Alloy 718, there is a range of materials to address a variety of application needs. Many metals cost more due to their performance properties, like chemical resistance, biocompatibility and liquid oxygen compatibility.
It may be tempting to choose a superalloy or high strength metal, but if your application is only needed for fit or function tests or the part will only be utilized for a single operation, you should consider more cost-effective materials. Additive metals such as stainless steel 316L and aluminum AlSi10Mg are perfect for lower-cost prototypes and still offer good thermal properties and strength.
3. Balancing volumes with costs
When your project requires lower volumes (typically 1 - 1,000) 3D printing is a good manufacturing option. It becomes an even better fit if each part of the project is customized. A high mix of parts due to serialization or other distinctions is more cost-effective to manufacture without traditional manufacturing constraints. Developing the tooling or patterns for a low volume project with customization would be highly expensive.
For example, Dr. Dana Piasecki and his small company DanaMed™ developed a unique surgical device called the Pathfinder™ ACL Guide. The tool is specifically shaped to match the anatomy of a knee with six separate versions to accommodate the size of a patient’s knee and the differences of right and left knee. DanaMed manufactured the parts with DMLM in Nickel Alloy 718, finding 3D printing to be about 97% cheaper per part when compared to investment casting the desired quantity of tools.
4. Secondary operations and post-processing
Critical to the production of additive metal parts are the post-processes utilized to meet customer specifications. As new applications and materials for additive metals are developed, post-processing capabilities have also expanded to service desired finishes and critical component features. Some customers are concerned that 3D printing metal parts are weak and need a lot of secondary operations for reinforcement. But generally, DMLM parts achieve great results with mechanical properties above casting grade components and performing at wrought properties.
Stratasys Direct offers heat treatments, machining, annealing, as well as basic media blasting or machine finishing from as-built (250-350 μin RA) down to a mirror polish or another specified finish. These operations might be needed if your parts have higher requirements, but some prototypes or non-structural/load-bearing components may not require secondary processes. It’s best to access if post-processing is necessary or if you can utilize an as-built part in order to save overall costs.
5. Inspection and quality assurance operations
Additively manufactured parts can be heavily scrutinized at a company that’s beginning to integrate AM into their product development. To soothe internal concerns, designers and engineers may opt-in for more inspections and qualifications than necessary. 100 percent inspection may be needed, but many times leveraging statistical sampling and critical factors for your inspection can alleviate costs associated with QC functions.
Inspection and qualification can be costly operations, especially since it adds to the lead time of the project. We suggest every customer evaluate what kind of inspection operations you need for your application. While some quality inspections may be required depending on industry and application requirements, not all inspections may be needed for smaller, functional prototypes.
When you’re ready to start your DMLM project, keep these five things in mind and consult with a project engineer to ensure the best balance of part performance and costs.