Announcement

Collapse
No announcement yet.

Machining Cast Aluminum

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Machining Cast Aluminum

    I went to buy a piece of 3/8 6061T6 today. My usual supplier did not have any but did have some very nice looking Alcoa Cast Aluminum, exactly .375 thick. The sales person assured me it would cut just like 6061T6.

    Bought it, should not have! Using the same speed and rate as I do for 6061T6 it gums up the bit, and makes a terrible mess! Broke two carbide bits before giving up on the project.

    Can someone tell me the speed and feed that I should be using vs. 6061T6?

    Only trying to cut .015 depth per pass, 10,000 RPM, and 30 IPS. Works great in 6061T6, disaster in Cast Aluminum.

    George
    My Web Site
    www.mrrace.com
    Builder & Test Pilot N73EX

  • #2
    at that rpm i would think you would melt any aluminum that hit the tool . . . just sayin'

    Comment


    • #3
      WOW! 10,000 RPM?
      My little lathe maxes out at 1500 RPM, and it cuts 6061 like a breeze.
      You might want to lower your RPM, and use WD-40 as cutting fluid.
      Works great for me.

      Comment


      • #4
        George,

        It is difficcult, no impossible to figure out a proper rpm when you don't give the cutter diameter.

        Also, 30 ips? That is 1800 ipm. No wonder you are breaking end mills. (bits?)

        Brian
        OPEN EYES, OPEN EARS, OPEN MIND

        THINK HARDER

        BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

        MY NAME IS BRIAN AND I AM A TOOLOHOLIC

        Comment


        • #5
          I suspected "George" was trolling untill I checked his profile. Either he's
          using almost microscopic cutters or "arithmetically challenged" ??? :-)
          ...lew...

          Comment


          • #6
            Cast Alum.

            I'm thinking he meant 30 IPM. The main problem is that cast alum. is soft and gummy compared to 6061. It needs a lot slower spindle speed than 10,000 RPM and either flood coolant or a good alum. cutting fluid.

            Comment


            • #7
              Seems like your biggest problem is the lack of coolant. 95% of what I do at work is aluminum, both 6061 and cast aluminum.

              30 IPM is nothing for what I do. I'll go 6000 RPM, .5" depth of cut, and 60 IPM with a flood coolant designed primarily for aluminum, with a 3/4" roughing end mill for aluminum (not a corn cob).

              Aluminum in general is gummy, cast aluminum is even more so. I don't cut 6061 and cast aluminum any different, but if I loose coolant for some reason, I'll be in trouble in a hurry with aluminum sticking in the flutes of the cutter.

              Comment


              • #8
                Lew, trolling, "arithmetically challenged", I don't get the connection with my question. Maybe I am "reading challenged" too!

                Brian, I did mess up, it should have been IPM, not IPS.
                Bit diameter is .0938 and is a 2 flute carbide end mill.

                Unfortunately, my setup is such that I just cannot use cutting fluid. It would really be messy, so I do everything dry.

                I did end up being able to mill it, using 5000 RPM, .005 cut depth per pass, 5 IPM. Chips were very find, almost powder like in size, no coolant.

                6061T6 is really nice to work with, not gummy. You can see pictures of my setup milling 6061T6 in my post about building Lew's magnetic clock.

                Thanks for all the replies and suggestions. The cast aluminum is going to the scrap bin.
                My Web Site
                www.mrrace.com
                Builder & Test Pilot N73EX

                Comment


                • #9
                  I've seen some cast aluminum auto parts that machine very nicely without coolant at the same speed/feed I use with 6061-T6. It just made a buzzing sound as the tiny chips flew off, and the finish was pretty good.

                  Cast aluminum tooling plate is one of my favorite materials.
                  Any products mentioned in my posts have been endorsed by their manufacturer.

                  Comment


                  • #10
                    At home, I use lard when I'm cutting aluminum. Works fantastic. It's like a gel and stays a gel until it warms up a bit and becomes a thick liquid. WD40 is supposed to work pretty well, but I've never used it.

                    Either would really help solve the loading the cutter problem your having.

                    Comment


                    • #11
                      "Bits" belong in a horses mouth. End mills in milling machines. Has no one here questioned what a piece of "cast" aluminum 3/8 thick would be doing there? The only cast flat aluminum goods that I ever heard of are cast tooling plate which is 6061. It usually is ground and pretty soft. Also usually thicker than 3/8". I don't think he got a real cast aluminum at all. It would be pointless to cast a flat bar or sheet. It's properties are not suitable for flat goods . Cast alloys are for finished shapes.

                      Comment


                      • #12
                        Originally posted by baldysm
                        At home, I use lard when I'm cutting aluminum. Works fantastic. It's like a gel and stays a gel until it warms up a bit and becomes a thick liquid.
                        Can't help myself...have to ask...do you do any projects for Muslims?

                        David
                        David Kaiser
                        “You can have peace. Or you can have freedom. Don't ever count on having both at once.”
                        ― Robert A. Heinlein

                        Comment


                        • #13
                          tdmidget, the stuff was marked ALCA PLUS Cast, Cast Aluminum Tool & Jig Plate and is called a "drop" by the Alro Steel surplus outlet where I got it. The piece I got was 12 X 12 Inches X .375 has a ground looking surface.

                          Thanks guys,a neophyte like me really does appreciate the comments and suggestions.
                          My Web Site
                          www.mrrace.com
                          Builder & Test Pilot N73EX

                          Comment


                          • #14
                            Coolant is not a mess. You are just applying it wrong. You don't need flood. Even a squeeze bottle will do. You need to keep the aluminum from welding to the bit. Misters and micro drop systems work great and have very little clean up.

                            Tooling plate is great stuff. You just need to know how to machine it.

                            Comment


                            • #15
                              "Cast" tooling plate is not the same as cast aluminum. As I previously noted it is 6061 and soft. In tooling applications it is usually anodized for wear resistance. It is cast and stress relieved so that flatness can be maintained. It is not at all like an extruded and heat treated T-6. Now you have seen why the term "billet" is despised by real machinists. Merely pouring into a mold does not produce the same properties as extrusion or rolling.

                              Comment

                              Working...
                              X