In this new age of 3D printing, we’ve seen more and more applications where the marriage of conventional manufacturing methods with additive manufacturing has led to amazing custom parts. CNC Machining has proved to be another tool 3D printing customers can take advantage of for optimized parts. As a secondary process, CNC machining provides additional dimensional accuracy on additive parts while maintaining all the benefits of 3D printing technologies like FDM (Fused Deposition Modeling).
When you have a complex geometry that is ideal for FDM, but the part requires critical dimensions and fine features that can’t be achieved as printed, CNC machining after 3D printing will deliver the part you need.
FDM works with engineering-grade thermoplastics that are used for production applications with high requirements. FDM is an ideal choice for production parts because of the unparalleled design freedom possible with the technology while achieving durability and excellent strength-to-weight ratios. The addition of CNC machining to an FDM part manifests in even more accurate parts in lightweight and robust materials.
Additionally, the combination of the two processes can be quicker than most traditional manufacturing methods. Even accounting for printer set up, build, finishing and machining, the additive + machining method is faster than designing and producing a tool for injection molding. It also allows for greater flexibility to make design improvements.
At Stratasys Direct we’ve seen the marriage of additive and conventional technologies add significant value to FDM parts in the following ways:
With this CNC process, we can achieve a positional tolerance of ±0.005” or 0.001 “/”, whichever is greater. Hole size accuracy is typically to ±0.001”. Tighter tolerances are achievable with the careful oversight of our CNC machining experts.
Jigs & Fixtures
A popular application for this process are jigs and fixtures. We commonly build manufacturing aids with FDM that are light weight, ergonomically enhanced and even custom to users. Depending on the complexity of the jig or fixture, they may require CNC machining to line bore parts for alignment, mill for smooth surfaces or machine complementary metal parts.
Sometimes for our own internal manufacturing purposes, we create holding fixtures for parts that need machining in order to ensure accuracy. We can design fixtures and nesting tools to hold parts for machining with an assortment of processes and materials.
Another application is when parts require complementary metal parts or plastic parts in a different material. These assemblies can be achieved mid-build with technologies like FDM by pausing prints and embedding machined metal or plastic parts into the incomplete component.
The hybrid method of using CNC machining with FDM requires specific design considerations:
The value of 3D printing is fully realized when its design freedoms and speed is married to the cost effective methods of conventional manufacturing. CNC machining offers to customers the ability to take advantage of FDM’s benefits while maintaining high tolerance requirements.