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Surfacing

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  • wongsterwish
    Happy New Year folks!!! I had some time this afternoon to do some test cut. Tried surfacing an aluminum block to see if I can get it squared. I took out the
    Message 1 of 17 , Jan 1, 2010
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      Happy New Year folks!!!

      I had some time this afternoon to do some test cut. Tried surfacing an aluminum block to see if I can get it squared. I took out the largest endmill that came with my mill and use the Mach3 wizard. Each pass is set to 0.5mm for a total of 4 passes and step over of 50%.

      The surfacing wasn't even (or should I say flat) as there are some very thin raised line along the toolpath.

      This is the first time I'm using the wizard, so I try to do surfacing manually to see if I've the same problem. The cut was very rough (not smooth to touch). The last time I did this yielded good result. Tried slowing down the spindle (was at almost max speed), reduced feed, and combination of both (spindle speed and feed rate). Same result.

      Any thing else I should try? Should I change the step over to say, 25%?

      regards,
      Wong
    • Hal Campbell
      Is your head trammed in?...Square to the table. This would look like shingles on a roof.   If it is an arc it deals more with the end mill   Hal [Non-text
      Message 2 of 17 , Jan 1, 2010
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        Is your head trammed in?...Square to the table. This would look like shingles on a roof.
         
        If it is an arc it deals more with the end mill
         
        Hal




        [Non-text portions of this message have been removed]
      • a3sigma
        ... Hi Wong, Use a fly cutter: http://tinyurl.com/y9qfy5y or, even better: http://tinyurl.com/ydogvod The ridges are caused by the points of the milling cutter
        Message 3 of 17 , Jan 1, 2010
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          --- In SherlineCNC@yahoogroups.com, "wongsterwish" <wongsterwish@...> wrote:
          >
          >
          >
          > The surfacing wasn't even (or should I say flat) as there are some very thin raised line along the toolpath.
          >
          >

          Hi Wong,

          Use a fly cutter:

          http://tinyurl.com/y9qfy5y

          or, even better:

          http://tinyurl.com/ydogvod

          The ridges are caused by the points of the milling cutter pushing material up from the surface. This is particularly a problem with soft, highly extrudable, aluminum.

          I am not an advocate of "mystery metals" obtained by dumpster diving. Get yourself some known, good, 7075 or MIC 6. Even better, 6020.

          see http://tinyurl.com/yfbdh8p and http://tinyurl.com/yk8r67l

          for much more info.

          Good machining requires a combination of the right tools, the right techniques, and the right materials. Don't try to cut corners on any of them.

          David Clark in Southern Maryland, USA
        • wongsterwish
          Hi DC, The aluminum I was practising on is T6061, bought previously from a shop selling only aluminum product. I was hoping to use the endmill as it doesn t
          Message 4 of 17 , Jan 1, 2010
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            Hi DC,

            The aluminum I was practising on is T6061, bought previously from a shop selling only aluminum product. I was hoping to use the endmill as it doesn't produce the mess that flycutter generate. Further, it worked well previously.

            Maybe I can take this opportunity to ask about using the flycutter here (P/N 3052). I lower the flycutter down to just touch the stock and set z=0. Without lowering z, I run the cutter across the stock and it started cutting. What I'm trying to do is when I say z=-1, 1mm worth of material will be removed from the stock. If the cutter starts cutting at z=0, I'll find out how much is removed at z=0 to compensate for it.

            Using the endmill, at z=0, nothing gets cut. So I'm confident that I'm cutting exactly the amount programmed.

            Am I making it more complicated than it actually is?

            Regards,
            Wong


            --- In SherlineCNC@yahoogroups.com, "a3sigma" <dcclark111@...> wrote:
            >
            >
            >
            > --- In SherlineCNC@yahoogroups.com, "wongsterwish" <wongsterwish@> wrote:
            > >
            > >
            > >
            > > The surfacing wasn't even (or should I say flat) as there are some very thin raised line along the toolpath.
            > >
            > >
            >
            > Hi Wong,
            >
            > Use a fly cutter:
            >
            > http://tinyurl.com/y9qfy5y
            >
            > or, even better:
            >
            > http://tinyurl.com/ydogvod
            >
            > The ridges are caused by the points of the milling cutter pushing material up from the surface. This is particularly a problem with soft, highly extrudable, aluminum.
            >
            > I am not an advocate of "mystery metals" obtained by dumpster diving. Get yourself some known, good, 7075 or MIC 6. Even better, 6020.
            >
            > see http://tinyurl.com/yfbdh8p and http://tinyurl.com/yk8r67l
            >
            > for much more info.
            >
            > Good machining requires a combination of the right tools, the right techniques, and the right materials. Don't try to cut corners on any of them.
            >
            > David Clark in Southern Maryland, USA
            >
          • a3sigma
            ... That s a pretty good way to flycut to a desired depth. There are a few caveats, though. The material removed will be proportionately less with deep cuts
            Message 5 of 17 , Jan 1, 2010
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              --- In SherlineCNC@yahoogroups.com, "wongsterwish" <wongsterwish@...> wrote:
              >
              > Hi DC,
              >
              > Maybe I can take this opportunity to ask about using the flycutter here (P/N 3052).


              That's a pretty good way to flycut to a desired depth. There are a few caveats, though. The material removed will be proportionately less with deep cuts than with skim cuts, as there is appreciable tool spring in a flycutter of that type. Tool spring, as well as spring in the material, holding, and the machine itself is (like backlash) a fact of life in machining that must be understood and considered. If possible, it's always best to measure after the second to last cut, and then make the final cut with the same parameters.

              For flycutting parameters read: http://www.sherline.com/3052inst.pdf

              Note what it says about the thickness of the chips. For light machine tools like Sherlines, I suggest that chip load is the best entering argument for calculating speeds and feeds with any tool. You can measure the thickness of a chip with your calipers or micrometer. As a rule, if you always keep your chips around .001 or .002 inches thick (0.02 - 0.04 mm)you won't go too far wrong.

              DC
            • wongsterwish
              Thanks DC, I ll try to understand what that article is trying to say. One part of it mentioned that the flycutter would usually have a second cut on its back
              Message 6 of 17 , Jan 1, 2010
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                Thanks DC, I'll try to understand what that article is trying to say.

                One part of it mentioned that the flycutter would usually have a second cut on its back side - it didn't do that the last time I tried flycutting.

                I'll cut some plywood to put around the machine so as to contain the flying chips.

                Regards,
                Wong


                --- In SherlineCNC@yahoogroups.com, "a3sigma" <dcclark111@...> wrote:
                >
                >
                >
                > --- In SherlineCNC@yahoogroups.com, "wongsterwish" <wongsterwish@> wrote:
                > >
                > > Hi DC,
                > >
                > > Maybe I can take this opportunity to ask about using the flycutter here (P/N 3052).
                >
                >
                > That's a pretty good way to flycut to a desired depth. There are a few caveats, though. The material removed will be proportionately less with deep cuts than with skim cuts, as there is appreciable tool spring in a flycutter of that type. Tool spring, as well as spring in the material, holding, and the machine itself is (like backlash) a fact of life in machining that must be understood and considered. If possible, it's always best to measure after the second to last cut, and then make the final cut with the same parameters.
                >
                > For flycutting parameters read: http://www.sherline.com/3052inst.pdf
                >
                > Note what it says about the thickness of the chips. For light machine tools like Sherlines, I suggest that chip load is the best entering argument for calculating speeds and feeds with any tool. You can measure the thickness of a chip with your calipers or micrometer. As a rule, if you always keep your chips around .001 or .002 inches thick (0.02 - 0.04 mm)you won't go too far wrong.
                >
                > DC
                >
              • a3sigma
                ... That s an indication that your mill is out of tram , meaning the spindle axis is not perpendicular to the table. Read the section on squaring the mill in
                Message 7 of 17 , Jan 1, 2010
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                  --- In SherlineCNC@yahoogroups.com, "wongsterwish" <wongsterwish@...> wrote:
                  >
                  > Thanks DC, I'll try to understand what that article is trying to say.
                  >
                  > One part of it mentioned that the flycutter would usually have a second cut on its back side - it didn't do that the last time I tried flycutting.
                  >
                  >

                  That's an indication that your mill is "out of tram", meaning the spindle axis is not perpendicular to the table. Read the section on squaring the mill in the Assembly and Instruction Guide http://www.sherline.com/InstVol5.pdf beginning on page 13.

                  Here's how I do it: http://tinyurl.com/yc4s6sb

                  If you have a 5000 series mill, first square the X axis. Loosen the 4 screws that hold the column onto the column base. Adjust to make the indicator read equally on each side of the table. Tighten the screws and check the Y axis. If it's out significantly, you must shim under the front or rear edge of the column base to compensate.

                  DC

                  DC
                • Scott Meyer
                  You are making a basic assumption that is probably not true with a Sherline mill - that the axis of the spindle is precisely perpendicular to the plane of the
                  Message 8 of 17 , Jan 1, 2010
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                    You are making a basic assumption that is probably not true with a
                    Sherline mill - that the axis of the spindle is precisely perpendicular
                    to the plane of the table. This is called tram.

                    A fly cutter on a mill that is in tram will have a cut on it's back
                    side. Not much, perhaps not even easily measurable, but visually
                    noticeable.

                    Take note of the direction you are cutting with the fly cutter. If you
                    cut left to right and there is no back cut, the spindle is tilted a bit
                    to the right.

                    Assuming you are cutting left to right and there is no back cut, you'll
                    discover that there is a significant back cut when you cut from right to
                    left.

                    wongsterwish wrote:
                    > Thanks DC, I'll try to understand what that article is trying to say.
                    >
                    > One part of it mentioned that the flycutter would usually have a second cut on its back side - it didn't do that the last time I tried flycutting.
                    >
                    > I'll cut some plywood to put around the machine so as to contain the flying chips.
                    >
                    > Regards,
                    > Wong
                    >
                  • wongsterwish
                    Scott / DC, I ll test it out. I m trying to cut the fixed portion of Dave Hyland s fly cutting clamp. Will test it once the kids are in bed. Thank you both.
                    Message 9 of 17 , Jan 1, 2010
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                      Scott / DC,

                      I'll test it out. I'm trying to cut the fixed portion of Dave Hyland's fly cutting clamp.

                      Will test it once the kids are in bed.

                      Thank you both.
                      Wong.

                      --- In SherlineCNC@yahoogroups.com, Scott Meyer <baldysm@...> wrote:
                      >
                      > You are making a basic assumption that is probably not true with a
                      > Sherline mill - that the axis of the spindle is precisely perpendicular
                      > to the plane of the table. This is called tram.
                      >
                      > A fly cutter on a mill that is in tram will have a cut on it's back
                      > side. Not much, perhaps not even easily measurable, but visually
                      > noticeable.
                      >
                      > Take note of the direction you are cutting with the fly cutter. If you
                      > cut left to right and there is no back cut, the spindle is tilted a bit
                      > to the right.
                      >
                      > Assuming you are cutting left to right and there is no back cut, you'll
                      > discover that there is a significant back cut when you cut from right to
                      > left.
                      >
                      > wongsterwish wrote:
                      > > Thanks DC, I'll try to understand what that article is trying to say.
                      > >
                      > > One part of it mentioned that the flycutter would usually have a second cut on its back side - it didn't do that the last time I tried flycutting.
                      > >
                      > > I'll cut some plywood to put around the machine so as to contain the flying chips.
                      > >
                      > > Regards,
                      > > Wong
                      > >
                      >
                    • chieftoolmaker
                      One more thing, Wong; After a test cut with the fly cutter..... Check for a cove/dip across the width of the part.... DI or DTI, or even A DDI.... This will
                      Message 10 of 17 , Jan 1, 2010
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                        One more thing, Wong;
                        After a test cut with the fly cutter.....
                        Check for a cove/dip across the width of the part....
                        DI or DTI, or even A DDI....
                        This will tell you if you are EFFECTIVELY in tram.
                        Later,
                        Jerry G (Glickstein)






                        ----- Original Message -----
                        From: wongsterwish
                        To: SherlineCNC@yahoogroups.com
                        Sent: Friday, January 01, 2010 11:26 AM
                        Subject: [SherlineCNC] Re: Surfacing



                        Scott / DC,

                        I'll test it out. I'm trying to cut the fixed portion of Dave Hyland's fly cutting clamp.

                        Will test it once the kids are in bed.

                        Thank you both.
                        Wong.

                        --- In SherlineCNC@yahoogroups.com, Scott Meyer <baldysm@...> wrote:
                        >
                        > You are making a basic assumption that is probably not true with a
                        > Sherline mill - that the axis of the spindle is precisely perpendicular
                        > to the plane of the table. This is called tram.
                        >
                        > A fly cutter on a mill that is in tram will have a cut on it's back
                        > side. Not much, perhaps not even easily measurable, but visually
                        > noticeable.
                        >
                        > Take note of the direction you are cutting with the fly cutter. If you
                        > cut left to right and there is no back cut, the spindle is tilted a bit
                        > to the right.
                        >
                        > Assuming you are cutting left to right and there is no back cut, you'll
                        > discover that there is a significant back cut when you cut from right to
                        > left.
                        >
                        > wongsterwish wrote:
                        > > Thanks DC, I'll try to understand what that article is trying to say.
                        > >
                        > > One part of it mentioned that the flycutter would usually have a second cut on its back side - it didn't do that the last time I tried flycutting.
                        > >
                        > > I'll cut some plywood to put around the machine so as to contain the flying chips.
                        > >
                        > > Regards,
                        > > Wong
                        > >
                        >





                        [Non-text portions of this message have been removed]
                      • wongsterwish
                        Some light sanding got rid of the ridges. I ll put the piece on a straight edge tomorrow morning to see if its concave. Can hardly open my eyes now....
                        Message 11 of 17 , Jan 1, 2010
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                          Some light sanding got rid of the ridges. I'll put the piece on a straight edge tomorrow morning to see if its concave. Can hardly open my eyes now....

                          Regards,
                          Wong

                          --- In SherlineCNC@yahoogroups.com, Hal Campbell <hlcmpbll@...> wrote:
                          >
                          > Is your head trammed in?...Square to the table. This would look like shingles on a roof.
                          >  
                          > If it is an arc it deals more with the end mill
                          >  
                          > Hal
                          >
                          >
                          >
                          >
                          > [Non-text portions of this message have been removed]
                          >
                        • wongsterwish
                          Will do that. Dream time for now. Regards, Wong
                          Message 12 of 17 , Jan 1, 2010
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                            Will do that. Dream time for now.

                            Regards,
                            Wong

                            --- In SherlineCNC@yahoogroups.com, "chieftoolmaker" <chieftoolmaker@...> wrote:
                            >
                            > One more thing, Wong;
                            > After a test cut with the fly cutter.....
                            > Check for a cove/dip across the width of the part....
                            > DI or DTI, or even A DDI....
                            > This will tell you if you are EFFECTIVELY in tram.
                            > Later,
                            > Jerry G (Glickstein)
                            >
                            >
                            >
                            >
                            >
                            >
                            > ----- Original Message -----
                            > From: wongsterwish
                            > To: SherlineCNC@yahoogroups.com
                            > Sent: Friday, January 01, 2010 11:26 AM
                            > Subject: [SherlineCNC] Re: Surfacing
                            >
                            >
                            >
                            > Scott / DC,
                            >
                            > I'll test it out. I'm trying to cut the fixed portion of Dave Hyland's fly cutting clamp.
                            >
                            > Will test it once the kids are in bed.
                            >
                            > Thank you both.
                            > Wong.
                            >
                            > --- In SherlineCNC@yahoogroups.com, Scott Meyer <baldysm@> wrote:
                            > >
                            > > You are making a basic assumption that is probably not true with a
                            > > Sherline mill - that the axis of the spindle is precisely perpendicular
                            > > to the plane of the table. This is called tram.
                            > >
                            > > A fly cutter on a mill that is in tram will have a cut on it's back
                            > > side. Not much, perhaps not even easily measurable, but visually
                            > > noticeable.
                            > >
                            > > Take note of the direction you are cutting with the fly cutter. If you
                            > > cut left to right and there is no back cut, the spindle is tilted a bit
                            > > to the right.
                            > >
                            > > Assuming you are cutting left to right and there is no back cut, you'll
                            > > discover that there is a significant back cut when you cut from right to
                            > > left.
                            > >
                            > > wongsterwish wrote:
                            > > > Thanks DC, I'll try to understand what that article is trying to say.
                            > > >
                            > > > One part of it mentioned that the flycutter would usually have a second cut on its back side - it didn't do that the last time I tried flycutting.
                            > > >
                            > > > I'll cut some plywood to put around the machine so as to contain the flying chips.
                            > > >
                            > > > Regards,
                            > > > Wong
                            > > >
                            > >
                            >
                            >
                            >
                            >
                            >
                            > [Non-text portions of this message have been removed]
                            >
                          • Michael Jones
                            You ll want to check for left/right as well as front/back tram. In some cases the z colum will lean forward or backward very slightly and would need to be
                            Message 13 of 17 , Jan 1, 2010
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                              You'll want to check for left/right as well as front/back tram. In
                              some cases the z colum will lean forward or backward very slightly and
                              would need to be shimmed to get things lined up perfectly.

                              On Jan 1, 2010, at 10:23 AM, wongsterwish wrote:

                              > Some light sanding got rid of the ridges. I'll put the piece on a
                              > straight edge tomorrow morning to see if its concave. Can hardly
                              > open my eyes now....
                              >
                              > Regards,
                              > Wong
                              >
                              > --- In SherlineCNC@yahoogroups.com, Hal Campbell <hlcmpbll@...> wrote:
                              > >
                              > > Is your head trammed in?...Square to the table. This would look
                              > like shingles on a roof.
                              > >
                              > > If it is an arc it deals more with the end mill
                              > >
                              > > Hal
                              > >
                              > >
                              > >
                              > >
                              > > [Non-text portions of this message have been removed]
                              > >
                              >
                              >
                              >



                              [Non-text portions of this message have been removed]
                            • wongsterwish
                              I found one of the cause of the mis-aligned mill. The alignment key for the A2Z spacer block didn t quite fit the Sherline s slots. Don t know how I missed
                              Message 14 of 17 , Jan 2, 2010
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                                I found one of the cause of the mis-aligned mill. The alignment key for the A2Z spacer block didn't quite fit the Sherline's slots. Don't know how I missed out the big gap on the top of the spacer block. The caused the spindle to be tilted forward. The only way I can fit the 2 spacer blocks is to move the key up. The key in question is now stick out by half its length (pics posted in photo section under Wongster).

                                Tried fly cutting this afternoon to square up a small block of 6061. When I went from right to left, the cut at the back sort of polish up the cut in front - cool!!! The only 2 problems I faced:

                                1) placement of the round rod on the moveable jaw of the vise. I cut the rod to short so have to use a small plier to insert it into the vise;
                                2) facing the 2 ends after squaring the 4 sides. The longer ends were faced using the endmills that came with the machine. I was trying to cut with the entire length of the endmill. Changing to my 4mm endmill works. I went to and fro at each pass and the return direction (I think its called climb milling) kind of clean up the surface.

                                One more thing I need to work on is to learn how to cut to the required size before starting the project.

                                To me, this is a good progress. Now my mill is trammed (shimmed the front the column by 0.02"), I can get on with more practice.

                                Regards,
                                Wong
                              • PJ
                                Wong, I am not an expert by any means but I notice that when I cut softer materials such as aluminum that the tips of the cutter flukes will sometimes pick up
                                Message 15 of 17 , Jan 2, 2010
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                                  Wong,
                                  I am not an expert by any means but I notice that when I cut softer materials such as aluminum that the tips of the cutter flukes will sometimes pick up a 'film' or 'coating' of the material and then the cutting edges are not cutting cleanly but are pushing material around in clumps.
                                  pj
                                • wongsterwish
                                  Hello PJ, what did you do to solve this? Regards, Wong
                                  Message 16 of 17 , Jan 2, 2010
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                                    Hello PJ,

                                    what did you do to solve this?

                                    Regards,
                                    Wong

                                    --- In SherlineCNC@yahoogroups.com, "PJ" <hickspj467@...> wrote:
                                    >
                                    > Wong,
                                    > I am not an expert by any means but I notice that when I cut softer materials such as aluminum that the tips of the cutter flukes will sometimes pick up a 'film' or 'coating' of the material and then the cutting edges are not cutting cleanly but are pushing material around in clumps.
                                    > pj
                                    >
                                  • PJ
                                    Several things help but materials like soft gummy alloys of aluminum and copper seem very prone to this effect. First I make sure the tool is as sharp as I can
                                    Message 17 of 17 , Jan 3, 2010
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                                      Several things help but materials like soft gummy alloys of aluminum and copper seem very prone to this effect. First I make sure the tool is as sharp as I can get it; then I experiment with cutting SFM. I use copious amounts of cutting lubricant/coolant and I stop much more often to check (and clean or resharpen) the tool.

                                      Hope this helps, PJ

                                      --- In SherlineCNC@yahoogroups.com, "wongsterwish" <wongsterwish@...> wrote:
                                      >
                                      > Hello PJ,
                                      >
                                      > what did you do to solve this?
                                      >
                                      > Regards,
                                      > Wong
                                      >
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