The recent advancements in Direct Metal Laser Sintering (DMLS) have made it easier to print parts in metal. Parts can be printed in as little as a few days. Regardless of these advancements, DMLS will not replace CNC Machining.
Direct Metal Laser Sintering (DMLS) is a 3D printing/additive manufacturing technology that produces metal prototype and production parts. DMLS prints metal parts by sintering various metal and alloy particles together. Whereas CNC machining is the automation on machine tools that cuts away at a piece of material to produce a part.
DMLS is an additive manufacturing process because it is “adding” material to build a part, while CNC machining is a subtractive manufacturing process because it is “subtracting” material in order to produce a part. But how do you know which process is best for your part?
Here are 4 quick points that will help you decide between CNC machining vs DMLS.
Surface Finish As shown on this initial picture below, the surface finish on CNC parts is typically much smoother compared to DMLS.
The DMLS process involves fusing powered metal together. As a result of this fabrication process, the surface finish on DMLS tends to be porous as shown below.
Part Geometry & Design Innovation
Due to the parameters of CNC machining, all features on exotic or complex geometry parts may not be machined. Features like cavities or undercuts may not be able to be machined in traditional CNC machining. Since the DMLS process sinters powered metal together layer by layer, a lot of complex features can now be produced.
Set-up and Fixture Cost
Some CNC parts may require additional charges for setups and fixtures. DMLS does not require any additional setup or fixture charges. DMLS machines run completely unattended, regardless of how complicated the part is.
Prototype vs Production Parts
For one-off prototypes, or very small volumes, DMLS parts can be more economical than CNC machining. DMLS can be a good bridge between initial prototyping and large volume production. CNC machining better utilizes economies of scale once in higher production.
This image is part of a hip replacement-fabricated through DMLS. This component connects the hip bone and the femur. These are produced as individual parts, and can be custom-made to the patient. Because of this, DMLS is the more applicable process. One process is not superior to the other, but rather both have their benefits pending on the objectives of the part. Both processes can complement each other in order to move the part efficiently through the product development cycle.