Why STL Format CAD Files Cannot be Programmed by CNC Machine?
By Nice Rapid | Apr 01 , 2023

We always receive the question from customer: “why the STL format file cannot be used in production? Why don’t you tell me before start production?”

We know that there are some common format CAD files, like STEP, IGES and X_T, why only STL format file cannot be programmed by CNC Machine? Today let’s explain to our customer in here. 

General speaking, CAD or computer assist design is a 2D/30 process of creating components, which commonly used in engineer digitization model, there are lots of available CAD zip and format file. But if you want to create CAD files for CNC Machining, which kind of format file should we use?  


At the time of looking for CAM to produce components, we found that there are two kinds of format files are suitable for this job, they are STEP and IGES format. Engineer can use the format files to create 3D cnc files by using CAM program. CNC file adopts the format of “G code” to control the motion of CNC Milling. That’s we said the files can be programmed. 


Why STL format file cannot be programmed?

STL file is a kind of 3D file,the model is consist of Triangular mesh geometry, that’s mean the 3D model is divided into hundreds of little triangular surfaces, these surfaces come together into the final design. 3D STL format can used in 3d printing. But it's worth noting that quality will come down when convert the file into STL format.  For example, the round feature will not a perfect round shape, it is consisting of straight line. Therefore, STL format cannot used in CNC Machining because CAM program cannot restore the geometry of a triangular grid, even if to program the STL format, lots of features will be disappeared or become into other shapes, it is difficult to get the correct of original design shape. However, this problem cannot be solved easily by converting the CAD format. If you received the STL format files, you must ask customer to send other format for production. 

Welcome to contact us via enquiry@nice-rapidtooling.com if you need any help, we are very glad to cooperate with you!


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