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Same tool paths from machine bed cut deeper than those from material suface

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  • Same tool paths from machine bed cut deeper than those from material suface


    I recently started using my FTC (fast tool changer) and setting my material setup from the machine bed rather than the material surface. This is so more efficient with all the bit changes required in making guitars. However, I recently ruined an Ebony fretboard because it cut it too thin. I learned this after a 5+ hour run. Interestingly, if I run my toolpaths from the material surface the thickness is right on. I ran a test carving 3D stars. I carved one from the material surface and another from the machine bed. The one from the material surface was .25" thick while the one ran from the machine bed was .185" thick. It seems as if there is an issue with the z axis. Any thoughts? I have a call into Camasters support for help.

    I should also note that I measured the finished piece in the Aspire software and it measures at the designed thickness of .25", but the actual carved piece thickness is .185". This at least tells me its not an input or material setup problem. I am totally lost.
    Last edited by Taxangler; 04-22-2024, 05:25 PM.
  • #2

    In your material settings at the top of the Toolpath panel, check that your model for the fretboard is not depressed down into the material...this is a common reason for results like you mention when measuring off the machine bed. (Be sure you entered the correct thickness into your initial design specifications, too) You have to insure that the model is raised up so that when it cuts, "what's below the surface" provides the correct finished difference. BTW, if it's taking you 5 hours to run your fretboard (assuming I'm not misinterpreting things) you may want to take a closer look at how you've setup your toolpaths for the operation. One relatively quick roughing pass plus a finish pass with reasonable stepover should take a fraction of that time. I know this from experience. Also make sure your raster is not across the fretboard...it should be either the length or at a reasonable diagonal angle and don't use too small of a tool for the finishing pass. Otherwise, there's too much "stop start" happening as you make the cut which slows things to a crawl and fretboards, whether a consistent radius or a graduated radius are still "nearly flat" so you can use a larger tool.
    Last edited by Jim Becker; 04-22-2024, 07:00 PM.
    ---
    Jim Becker

    SR-44 (2018), 1.7kw spindle, Performance Premium, USB, Keypad, T-Slot table (y-axis configuration), WinCNC, VCarve Pro upgraded to Aspire

    Non CNC stuff...

    SCM/Minimax
    Festool "a good collection"
    Stubby - lathe
    Harvey G700 DC
    more...

    Retired from full time work in the telecom industry 9/2017
    Occasional commission work for others, but mostly for me...furniture/tack trunks/signage/guitars
    Located Bucks County PA

    Comment

    • #3

      Thanks for the response. I may have included trouble shooting time in my 5 hours, but much of the time relates to carving the fret slots and detailed inlays with a .023 EM. I finish the fretboard with 135 degree raster. I don't see where the model is depressed, but the actual designer did have a note stating " The material is 0.5mm below the block of wood. Adjust it if necessary." I am not sure what that means and did not make an adjustment because I didn't know where to make such an adjustment.

      Also, as a test comparison, I made two 3D stars. One was machined from the bed and the other from the material surface. The one cut from the surface was at the desired.25", whereas, the one setup at the machine bed was .185" thick. Does this suggest anything?

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      • #4

        You can recalibrate the ftc to any height. If you want to calibrate it to the top of material, then all bit changes will be set to that zero. Just don't forget to reset it when you are done.
        Fixing machines and making sawdust.
        SW side of Houston kenrychlik (at) gmail

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        • #5

          Thank you for the suggestion, but I also want the benefits of cutting from the machine bed. Besides, I think I may have a machine or WinCNC issue that I need to address. Your suggestion gave me the idea to machined from the bed but used the the touch pad on the spoilboard to set the Z. This resulted in the correct thickness but defeats the benefit of having an FTC. I think this suggests the issue may relate to the interface of the FTC and Z axis. Perhaps Camaster technical support may have a resolution. I am totally befuddled.

          Comment

          • #6

            The place to look for where the model is "in the material" is as I noted, on the materials page that you access by the button at the top of the toolpathing panel, typically on the left side of the application window. Don't assume that the model is where it needs to be because the evidence you presented that it cuts too thin points in that direction.
            ---
            Jim Becker

            SR-44 (2018), 1.7kw spindle, Performance Premium, USB, Keypad, T-Slot table (y-axis configuration), WinCNC, VCarve Pro upgraded to Aspire

            Non CNC stuff...

            SCM/Minimax
            Festool "a good collection"
            Stubby - lathe
            Harvey G700 DC
            more...

            Retired from full time work in the telecom industry 9/2017
            Occasional commission work for others, but mostly for me...furniture/tack trunks/signage/guitars
            Located Bucks County PA

            Comment

            • #7

              Thanks again. There were a couple of issues. Camaster support was extremely helpful in recalibrating my machine. But I think the bigger issue may have been between the keyboard and the seat. I hate to admit it, but apparently, after my last spoilboard resurfacing, I recalibrated the FTC in the engraving mode rather than the G54 router mode. Not sure if this was done before or after the fretboard issue, because I resurfaced the spoilboard after carving the fretboard thinking that may have contributed to the issue. Hopefully, with the tune-up all is well now.

              Comment

              • #8

                While I use the touch plate sometimes I make it a point to ALWAYS check the bit height after switching to the machine bed and using the FTC.
                This has saved me a bunch of times. Also run G92 after using the touch plate and before using the FTC.

                Pete
                ----------
                2021 Stinger I SR-24, 1kW Spindle
                Performance Pkg w/Gantry Lift, FTC
                Phenolic Top, Storm Vac, JTech Laser
                VCarve Pro 11.0
                www.gotoguysmarine.com

                Comment

                • #9

                  Finally figured out my toolpath issues. I was going crazy and constantly on the phone with Camaster support. I ruined many exotic fretboards before we figured it out. I need a machine upgrade. I have a Stinger 1 and use it to cut exotic hardwoods with a bit size the Stinger 1 can't handle. I have been trying to finish an Ebony fretboard using 1 1/2" ballnose which runs at a feed rate of 300 to generate the right chip size and not overheat. The Stinger 1 feed rate maxes out at 250. The bit even when using my air assist with such a hardwood was simply too much for stepper motor. It would lose steps and cause all kinds of toolpath problems. Support diagnosed the cause and advised me to step down to a 3/8" ballnose which runs at feed rate of 200. I did that and all is well. If want to continue to use 1/2" diameter bits with hardwood I will need to upgrade the machine.

                  Comment

                  • #10

                    Glad it's working but wow, were you really using a 1.5" ball nose bit or was that a typo?
                    Seems like a 1/2" ball nose going a little slower but with a little more RPMs or shallower cuts would get the job done. 300 IPM is 25' FPM ... pretty fast.

                    Pete
                    ----------
                    2021 Stinger I SR-24, 1kW Spindle
                    Performance Pkg w/Gantry Lift, FTC
                    Phenolic Top, Storm Vac, JTech Laser
                    VCarve Pro 11.0
                    www.gotoguysmarine.com

                    Comment

                    • #11

                      Typo. I was using a 1/2” bullnose. The max feed rate on the SR 24 is 250 even though the display is saying 300. The toolpath with a 3/8” bullnose was only couple more minutes. Camaster told me the 4X4 Stinger has a more powerful motor and can run 1/2 bits with no issues. It may have worked if I was cutting softwoods, but the Ebony was too much for it. Ebony even puts a strain on my desktop Delta planer. I have to use my commercial 5 hp planer with Ebony. I ruined 3 Ebony fretboards. I just didn’t think about the bit. Special thanks to Camaster support for figuring out the problem.

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