32 Replies Latest reply on Mar 21, 2017 11:36 AM by Francisco Martínez

    3D formats for a 3D CNC machine ?

    Firas Helou

      hello everyone,
      I need please your help, I would like to know which types will be the ones that I must export my 3D model for a 3D CNC machine ?
      i read at some forums where it says DWG, but I use DWG for a 2D laser printing and not 3D

        • Re: 3D formats for a 3D CNC machine ?
          Timothy Taby

          3D printers usually use STL files.

           

          If you are actually doing 3D machining on a mill or router then you need a CAM software package like Master Cam, Gibbs Cam, or Bobcad to generate the 3D tool paths for you and output the G-code for the machine to use.

            • Re: 3D formats for a 3D CNC machine ?
              Firas Helou

              thank you Timothy, yes i have Surfcam, but I made contact with a shop i asked about the file extension he said send me the solidworks original file, so which means he would do the G code, I am asking for full price now so after if the price would make big difference if i send him the g code i would do it myself

                • Re: 3D formats for a 3D CNC machine ?
                  Timothy Taby

                  It's not likely you can send the G-Code for their machines very easily. Every machine is slightly different, I wouldn't trust your code to run on my machines properly.

                   

                  If they are asking for the solid model then send them the solidworks solid model (or a STEP File of it if your worried about them copying it), most machine shops will have CAM software that has the proper posts for their machines, let them do it.

              • Re: 3D formats for a 3D CNC machine ?
                John Pesaturo

                Firas, I would agree that you would typically only use *.dwg and *.dxf files for what we would consider flat pattern (2D) work on our Water-Jet and Laser machines.

                 

                To add to what Timothy mentioned, we typically use *.step (think the latest we use is *.step 242 format, we don't use any of the MBD based step files yet) files for anything that requires 3D milling or a 3D model for programming a CMM.

                • Re: 3D formats for a 3D CNC machine ?
                  Chris Saller

                  Export in-house, or outside?

                  CAM software can use most type of 3D solids. But, ask them what they want to use.

                  We use MasterCAM. I have used both CAMWorks and MasterCAM within SolidWorks and the code is saved within the models.

                  When there are updates, the code is auto updated.

                  With exported models, the code is not updated as easily.

                  The same goes for 2D. Both DXF and 3D models can be used for flat bed routing, laser, and cutting, etc.

                  All the above can be used for 3D printing.

                  • Re: 3D formats for a 3D CNC machine ?
                    Bjorn Hulman

                    I'd be inclined to use a STEP or an IGES file, that way your curves remain curves. STL files break the geometry into tiny triangles of flat surfaces(tessellate). These can often be seen when printed or CNC'd. If they haven't told you which they accept, send them a selection.

                     

                    Sending your native file is not recommended for IP reasons as well as the fact an exported file is harder to alter.

                    • Re: 3D formats for a 3D CNC machine ?
                      Christian Chu

                      Some cam software now can directly import files from other 3D CAD such as inventor or solidworks

                      • Re: 3D formats for a 3D CNC machine ?
                        Jason Reese

                        DSTV files are common for equipment like beam lines, 8 axis machines and etc.

                        • Re: 3D formats for a 3D CNC machine ?
                          Rick McDonald

                          I would first do what Chris Saller said and "Ask them" what format they want it in.  They might only need a 2d drawing for something simple and then you don't even need to send the model.

                          It will depend on what type of CNC they are using and what software they use (and what version).

                          As has already been said, you also need to be concerned with the IP.  Do you trust the shop? - and even if you do, still don't give them more than they need.

                          I would also lean heavily to sending only in generic parasolid format - not a SWX (or Inventor) file. SWX files can be simply opened and copied with all your critical information.

                          I like Paul Salvador's method.  That is a much safer way - they get what they need to make the part with none of the details they don't need.

                          We use this method even in our own shop - but that is because our CAM software (Gibbs) is an older version than our SWX software and they are not fully compatible for direct import, but the parasolid  .x_t file is version independent and works for both SWX and Inventor (we use both).

                          • Re: 3D formats for a 3D CNC machine ?
                            Paul Risley

                            Firas,

                             

                            One consideration is also the seat of cam software your vendor is using. We have SW 2017 and Gibbs cam 2016. The Gibbs software cannot open native 2017 SW files. So we have to save out Parasolids for machining purposes.

                              • Re: 3D formats for a 3D CNC machine ?
                                Firas Helou

                                well i am using SW 2012 on my laptop and 2013 from the new generation on my desktop, I don't think that would do any problem would it ?

                                  • Re: 3D formats for a 3D CNC machine ?
                                    Paul Risley

                                    It shouldn't, and this only pertains to native files. If you save it as a Parasolid there is no issue whatsoever.

                                     

                                    Typically if we send something out to external vendors it is always a Parasolid and never a native file.

                                     

                                    As far as parts we receive to machine directly we ask for Parasolids, not native files. The main reason is our machine practices are if provided a neutral format it is in our contracts that we will machine directly to the file as provided. (No engineering time required, which is billed separately)

                                      • Re: 3D formats for a 3D CNC machine ?
                                        Firas Helou

                                        aha I see, which lead to a question, would it be a problem if the model is perfect by looking at it but it is not when breaking it ? i mean like a surface made in SW which is in contact with other surface and not tangent ?

                                          • Re: 3D formats for a 3D CNC machine ?
                                            Rick McDonald

                                            You have to consider how / if the part can be machined.

                                            If your part would leave gaps, or overlapping features that can not be machined the CNC will produce errors or produce a  part that does not match your design.

                                            You need to understand the basic functions of the CNC (or any type of machining) if you are going to design a part to be produced that way.

                                            Your model should be properly constrained so that you don't create situations that are not machinable.

                                            What can be machined also depends some on materials, sizes, CNC capabilities, tools (bits, saws,...) that the shop has available.

                                              • Re: 3D formats for a 3D CNC machine ?
                                                Firas Helou

                                                i see, but the CNC will read the outside surface only right ? i mean like if i made for example 2 extrude cut but i only needed one, would that be a problem ?

                                                  • Re: 3D formats for a 3D CNC machine ?
                                                    Rick McDonald

                                                    Firas,
                                                    A CNC is a computerized machining mill.

                                                    There are different types but basically it will take a block of material and make any cuts in any shape needed (depending on the bits that are chosen and if the design is properly done).  It can drill the holes, tap them if needed, cut out cavities, what ever is needed and can be done from the outside of the material.

                                                    Think of a sculptor carving out a statue from a block of stone.

                                                    The machinist may have to remove the block and move it to a different face and change the bits it can use but it can make the part you design (if you design it correctly).

                                                    That brings up a main point - you need to know what a CNC can do and how.  You need to know it's abilities and limitations. 

                                                    It is a tool, but you need to know the basic operation before you can properly design any part for it.

                                                     

                                                    It sounds like you have no idea of what a CNC is or what it does or how.
                                                    This needs to be your first focus - you don't need to be an expert, just general understanding.

                                        • Re: 3D formats for a 3D CNC machine ?
                                          Paul Risley

                                          Firas,

                                          We design in Solidworks and Machine using Gibbs cam software here.

                                           

                                          Rule of thumb for exporting models to a cam software is whatever the solid is, is what is going to get cut. Now prints help define intent and what may or may not be critical, but a toolmaker is expecting surfaces to be an accurate representation of what the final part is going to be.

                                           

                                          "i mean like a surface made in SW which is in contact with other surface and not tangent ?"

                                           

                                          Your comment above is what  I am referring to. If your model has bad edges, your part will as well. Is it possible to fix a model in cam software? Most definitely, but most shops will cut to your model using your prints as their basis for final parts. If you have faulty edges it will show up in the part more times than not.

                                          • Re: 3D formats for a 3D CNC machine ?
                                            Francisco Martínez

                                            I design and program all my parts  in house, SW2017 and Alphacam 2017.

                                            Each machine needs a custom post processor to function properly, one of our machines has the origin in the upper left instead of lower left so all of our Y values must be in the negative. This is just a small example of how complex programming for cnc machines is.

                                            I have over 8 years of setup and operation on various cnc machines and that is why I am capable of programming proficiently.

                                             

                                            I would suggest getting experience setting up and operating a CNC machine before attempting to program one. This is where you learn a lot of the proper feeds and speeds, entry types, and various setup techniques.

                                             

                                            The models do affect what the final cnc product is, I suggest working with their cam programmer and adjusting the model per his requests.