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  • Cutting Threads using CNC Mill?????

    Hey Guys,

    I realize the answer to the questions I'm about to ask is likely quite complicated BUT could you possibly provide me with at least some info to help me get started and learn more?

    I recently purchased a CNC mill. My good friend has the smaller version and we are aware that the CNC mill can cut threads but we know NOTHING about the process. I would assume that first off, one would need a threading cutter.

    To begin:
    1. Is threading on a CNC mill a difficult task to learn?
    2. Aside from software and a cutter, are additional accessories required, e.g., index head, etc?

    Harold
    For those having fought for it, Freedom has a flavor the protected will never know.
    Freedom is only one generation away from extinction.

  • #2
    Look up thread milling, it is helical interpolation.

    Thread mills come in many forms, the most useful for a home shop would be "single point" thread mills, they will cut the largest variety of threads with a single cutter. They are NOT cheap, best to buy them off ebay.

    If you do want new, I like Lake Shore: http://www.lakeshorecarbide.com/sing...readmills.aspx

    Comment


    • #3
      Originally posted by macona View Post
      Look up thread milling, it is helical interpolation.

      Thread mills come in many forms, the most useful for a home shop would be "single point" thread mills, they will cut the largest variety of threads with a single cutter. They are NOT cheap, best to buy them off ebay.

      If you do want new, I like Lake Shore: http://www.lakeshorecarbide.com/sing...readmills.aspx
      Macona: Thanks for replying. Is learning to thread easy or difficult? As always, setup will likely be time consuming and likely the main issue but since I have never seen this done, I don't know if it requires more than if I were to, let's say bore or indexing on a manual machine. Can you shed some light on this matter, based on your experience, while keeping in mind that I am a novice at CNC work?

      Thanks,
      Harold
      For those having fought for it, Freedom has a flavor the protected will never know.
      Freedom is only one generation away from extinction.

      Comment


      • #4
        I do a lot of thread milling. On my mill it's very easy because of conversational programming. You fill in the numbers on one page and go.
        The setup of the cutter is the same as an end mill. You designate an x and y zero (the centerline of the thread) and a z zero for the cutting tool.
        The level of difficulty is all in programming, depending on what type of control you have.
        I use cutter comp where you enter the diameter of the cutter and the machine moves off one radius to compensate.
        For the first thread I like to start a little oversize on external and a little undersize on internal and sneak up on the size. After that just run to the final numbers for the rest of the parts.
        For an economy thread mill you can use a 60 degree double angle cutter as found in Grizzly, Enco, MSC or any tool supplier.
        Kansas City area

        Comment


        • #5
          Originally posted by Toolguy View Post
          I do a lot of thread milling. On my mill it's very easy because of conversational programming. You fill in the numbers on one page and go.
          The setup of the cutter is the same as an end mill. You designate an x and y zero (the centerline of the thread) and a z zero for the cutting tool.
          The level of difficulty is all in programming, depending on what type of control you have.
          I use cutter comp where you enter the diameter of the cutter and the machine moves off one radius to compensate.
          For the first thread I like to start a little oversize on external and a little undersize on internal and sneak up on the size. After that just run to the final numbers for the rest of the parts.
          For an economy thread mill you can use a 60 degree double angle cutter as found in Grizzly, Enco, MSC or any tool supplier.
          I was hoping to hear exactly that regarding conversational programming. To the best of my knowledge, the mill comes with a "no frills" program that is used to tell the controller what to do. It was explained that I will need to write, line by line, what I want done. I've seen my friend's computer display from a distance, while the machine was running, but I have no memory of all that's involved when line by line entry was used. Apparently it's a matter of entering info to all axis and "letting her rip".

          I do have a CAD/CAM program, Alibre Design Expert, which is quite sophisticated and at this time not so user friendly. Perhaps the program would be better described as not intuitive. As I get familiar with my new machine while using conversational programming, I will slowly switch to Alibre Design Expert.

          I plan to load the program this morning and take a look at how it works. Currently I am waiting for a power-line-conditioner (voltage regulator) and a battery backup surge protector before adding power.

          Thanks for your reply. Your reply was also very helpful.

          Harold
          For those having fought for it, Freedom has a flavor the protected will never know.
          Freedom is only one generation away from extinction.

          Comment


          • #6
            You're welcome Harold! Best wishes with your new mill. If you need anything else, I will try to help. Several other people on here are better than me at writing G code. I never had to learn it because I have a really good conversational program.
            Kansas City area

            Comment


            • #7
              Harold, What controller does your new mill have ?
              .

              Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



              Comment


              • #8
                Originally posted by John Stevenson View Post
                Harold, What controller does your new mill have ?
                Good Moring John,

                I haven't the foggiest idea. Where would I look to find the answer? The machine is a CNC SUPRA made by CNC MASTERS. I wonder if their web site would tell?

                Harold
                For those having fought for it, Freedom has a flavor the protected will never know.
                Freedom is only one generation away from extinction.

                Comment


                • #9
                  OK had a look and it's special to them but you can use Visual Mill as a CAM program.
                  This means that VM has a post processor that will write the code that the Master controller can read.
                  If VM can do that then most other CAM packages will be able to do the same.
                  .

                  Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



                  Comment


                  • #10
                    Originally posted by John Stevenson View Post
                    OK had a look and it's special to them but you can use Visual Mill as a CAM program.
                    This means that VM has a post processor that will write the code that the Master controller can read.
                    If VM can do that then most other CAM packages will be able to do the same.
                    John,

                    Would Visual Mill be more friendly than Alibre? Alibre came bundled with CAM.

                    Harold
                    For those having fought for it, Freedom has a flavor the protected will never know.
                    Freedom is only one generation away from extinction.

                    Comment


                    • #11
                      A very cheap way to make a threadmill is to use a tap with all the teeth but one ground off.

                      Thus far, everyone has talked of what could be called 'vertical' thread forming: it is possible to do 'horizontal' thread forming using a fourth axis (A-axis). You do not need a 4-axis controller as your Y-axis never moves: the cutter can be a 60 degree engraving cutter.

                      Comment


                      • #12
                        Originally posted by Toolguy View Post
                        I do a lot of thread milling. On my mill it's very easy because of conversational programming. You fill in the numbers on one page and go.........
                        Toolguy (and anyone wishing to reply):

                        As I have previously stated, I do have a CAD / CAM program (Alibre Design Expert). And as previously stated, it's not intuitive. Powerful and expensive but not intuitive. The program is actually geared for those having "grown up" with computers. Stated differently, the program requires prior graphic knowledge, didactic (structured) training, and in my opinion it would be a prerequisite for one to have matriculated from an institution that formally teaches various aspects of computer science. This does not describe me. At my late stage of life, learning Alibre (on my own) is a painful learning experience and requires time that I do not have. I have one foot on a banana peal and the other in the grave.

                        Since you mentioned "Conversational Programming", please elaborate on the differences between Conversational Programing, G-Code, and programs similar to Alibre ..... if you wouldn't mind. My desire (which may be beyond reality) is to have a program that is simple, "fill-in-the-blanks", then set up the machine (as I would with a manual mill) and press GO. For example, I would like to instruct the machine to thread mill a hole for 16 TPI to a depth of X. So I would go to the computer monitor, simply choose external or internal thread, left or right thread, enter hole size in the little window, enter TPI in the window, and enter depth or distance. I may even need to choose thread type e.g., Acme, buttress, UNF, etc. But when finished entering information, and the machine & part are in proper position, press GO and allow the computer to work its magic. Is that asking too much as a beginner?

                        I have read pertinent excerpts of my machine manual dealing with the type language used to communicate with this machine. Though CNC MASTERS produces a proprietary CAD /CAM program (which is also expensive and likely difficult to run), a program did come with the machine that utilizes what I think is G-Code (or a hybrid of G-Code). Regardless, the language is foreign to me and it is assumed by CNC MASTERS that the reader has prior experience writing G-Code. The manual states,"the Master Software works with FANUC G-Code". Naturally, I have no idea what they are saying. It continues by saying, "If you plan to use your own CAM, separate from what CNC Masters sell, use a FANUC based post processor and re-write it to be compatible with our list of G-Codes".

                        So my plea is to acquire a program that's designed for the uneducated, and that I may use this program as a stepping stone to more sophisticated programs as my basic knowledge and understanding improves.

                        Is there such a idiot proof program that would accommodate me and my machine?

                        Harold
                        For those having fought for it, Freedom has a flavor the protected will never know.
                        Freedom is only one generation away from extinction.

                        Comment


                        • #13
                          Originally posted by hwingo View Post
                          Since you mentioned "Conversational Programming", please elaborate on the differences between Conversational Programing, G-Code, and programs similar to Alibre ..... if you wouldn't mind. My desire (which may be beyond reality) is to have a program that is simple, "fill-in-the-blanks", then set up the machine (as I would with a manual mill) and press GO. For example, I would like to instruct the machine to thread mill a hole for 16 TPI to a depth of X. So I would go to the computer monitor, simply choose external or internal thread, left or right thread, enter hole size in the little window, enter TPI in the window, and enter depth or distance. I may even need to choose thread type e.g., Acme, buttress, UNF, etc. But when finished entering information, and the machine & part are in proper position, press GO and allow the computer to work its magic. Is that asking too much as a beginner?
                          G-code is a series of low-level motion instructions for the machine. "Turn spindle on clockwise 500RPM." "Move from current position to X=2." And so on. It doesn't really know whether you're running a 2" face mill in titanium or a 50 wire size drill in blue cheese. You can write G-code by hand and sometimes it is useful to do so but in most cases G-code is generated by another program.

                          Conversational controls are basically what you describe in your wish list. They give you a limited set of options (round pocket, square pocket, bolt circle, etc.) and prompt you to enter the required parameters. You still need to understand how the machine works, but it's less complex than writing G-code or using CAM.

                          Alibre is a CAD (Computer Aided Design) program. It allows you to build 3D models of things you want to make. You can get an integrated CAM (Computer Aided Manufacturing) application which can take a part designed in Alibre and generate g-code (also referred to as "toolpaths") to machine the part. Integrated CAM runs inside the CAD application, but you can also buy standalone CAM applications. This is the most powerful approach, but there is more to learn. For some simple tasks, g-code or conversational programming will be easier. For more complex parts, CAM is the only way to make the part.

                          So my plea is to acquire a program that's designed for the uneducated, and that I may use this program as a stepping stone to more sophisticated programs as my basic knowledge and understanding improves.

                          Is there such a idiot proof program that would accommodate me and my machine?
                          In general, conversational programming capabilities are built into the machine control. Mach 3 has wizards, LinuxCNC has subroutines. Kipware is the one program I'm aware of that is stand-alone and designed to be "easy" rather than "powerful." CamBam might also be worth a try and is quite cheap.

                          Another idea to be aware of is that while G-code is pretty standard (Fanuc-style being the most basic/common version) each machine/controller tends to have some differences that need to be accounted for to make the machine run properly. These are referred to usually as "posts" i.e. post-processors because they modify the code to "customize" it for your machine. Some will also allow you to edit and modify these yourself to tweak it. Typically your CAM vendor will either supply a standard post for your control or provide a customized one. Be sure to ask to clarify this before you buy. Without it you may have to manually edit the generated g code before it will run properly.

                          Comment


                          • #14
                            What you describe in your 2nd paragraph is conversational programming. Conversational means - how you talk. Some machines have canned cycles that are sometimes called "Wizards" for a few operations that are like conversational and then the rest you have to write in G code.

                            When you use a wizard or conversational programming you fill in the blanks and then it writes the G code for you. Then the machine runs on the G code.

                            G code is machine language. Somewhere along the line you have to tell the machine what to do in the format that it understands. Different machine controls have variations from each other in terms of the details of the G code.

                            This is an example of a conversational page to make a 3/8-16 external thread 3/4" deep.





                            These 2 pages are the G code written by the above conversational program.







                            John Stevenson and a few others on this board are qualified to answer your computer control questions, I am not.
                            Last edited by Toolguy; 09-26-2013, 09:32 PM. Reason: duplicate photo
                            Kansas City area

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                            • #15
                              Well, this answers a BUNCH of questions thus I have been brought from Darkness to Light. I've taken a look at three programs: Kipware, CAMBAM, and Mach 3. It would appear that Kipware allows one to "rent" a license for one year. It also appears that it will work with my machine, though I will need to contact either CNC MASTERS or Kipware about this matter. Regardless, such a program would get me "up and running" and allow me to "get my feet wet".

                              At this time, I have no desire to design "something". All I wish to do is become acquainted with the mill and how it functions. Most likely, somewhere down the path I will get "the itch" to make something that's complex either out of fun or necessity. It will be that moment when I'm forced to learn CAD / CAM. I can see how CAD would make things very easy when "imported" (is that the correct word?) into CAM for translation to G-Code.

                              All you guys have been super helpful and have provided me with an "origin" for my journey. From time to time I will need to revisit the "water hole" so I hope you guys are sill around at that time.

                              Thanks Again,
                              Harold
                              For those having fought for it, Freedom has a flavor the protected will never know.
                              Freedom is only one generation away from extinction.

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