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Thread: "nicks" in female inlay machining

  1. #1
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    Default "nicks" in female inlay machining

    Hi all,

    Today's inlay production work went a little wonky, and I am curious if anyone has any insight. You can see clearly that it was cut in two passes, which is the minor issue. The bigger issue is the strange "nicks" that were consistently in the same places.

    IMG_4907.jpg

    I used VCarve Pro's female inlay toolpath like I always do. Only difference was I used a new type/brand of 1/8" downcutter. The male inlays using the same bit came out fine. And the large area clearance part of the toolpath went fine too.

    Thanks for your help!
    Brian

  2. #2
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    May 2014
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    Is it possible you lost some steps there? It looks like the tooplath got shifted...

  3. #3
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    iBILD Solutions - Southern NJ
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    Machine model? Cutting speed? RPM?

    If PRS gantry tool - Wiggle the YZ car in ALL directions with the control box on. Feel slop? Tighten lower V-roller bearings. Wiggle Y+/-, slop? Reseat pinion to rack. Wiggle EACH X motor side front & back. Sloppy? Reseat pinion to rack...

    DT/Max/PRT/PRS Standard? Slow down...
    High Definition 3D Laser Scanning Services - Advanced ShopBot CNC Training and Consultation - Vectric Custom Video Training IBILD.com

  4. #4
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    Quote Originally Posted by EricSchimel View Post
    Is it possible you lost some steps there? It looks like the tooplath got shifted...

    Quote Originally Posted by Brady Watson View Post
    Machine model? Cutting speed? RPM?

    If PRS gantry tool - Wiggle the YZ car in ALL directions with the control box on. Feel slop? Tighten lower V-roller bearings. Wiggle Y+/-, slop? Reseat pinion to rack. Wiggle EACH X motor side front & back. Sloppy? Reseat pinion to rack...

    DT/Max/PRT/PRS Standard? Slow down...
    It's a PRS Standard. 13500 rpm, 3ips, 2ips plunge, 1/8" downcutter on hard maple. 1/8" passes.

    This happened consistently across 12 of the same inlays (they are cheese boards with wine glass inlays). And this morning I realized that the wonky parts are all where the bit plunges and retracts, which has to be significant, right?

    I will check that everything is secure this morning.

  5. #5
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    Bit deflection. How long is the tool? Cutting edge length? Sharpness? Ramp your plunges. Try a shorter tool. I really like using the 1/8" shank, 1/2" CEL, 1-1/2 long ones from here.
    Scott

    If guns kill people, I guess pencils misspell words, cars drive drunk and spoons make people fat.

    "Those who hammer their guns into plows, will plow for those who do not" - Thomas Jefferson


  6. #6
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    Quote Originally Posted by srwtlc View Post
    Bit deflection. How long is the tool? Cutting edge length? Sharpness? Ramp your plunges. Try a shorter tool. I really like using the 1/8" shank, 1/2" CEL, 1-1/2 long ones from here.
    The irony is that it's a brand new tool, and shorter than what I normally use (1/2" CEL vs 3/4"). I ramp the plunges always. Get them from these guys in Oregon and have been very pleased with their 3/4" CEL 1/8" bits. https://www.ebay.com/itm/1-8-Solid-C...53.m2749.l2649

  7. #7
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    There's no way that's bit deflection... From the looks of it that is about a 1/16th or more that the path is off. If you put a bit in a vice and tried deflecting it that much with pliers it'd snap long before it got that far off. Assuming the machine is tight, something else is going on here...

    It looks to me like the whole toolpath is shifted up towards the top of the screen (Y direction?) Based on your previous static woes, my guess, and it's just a guess, is that you've lost some steps here. You can see it on the top left of the image too...

  8. #8
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    Here’s a video of the slight slop in the YZ car. Similar amount on the control box side X motor. Other side X motor seems tight. I’m not sure what/how to tighten.

    https://youtu.be/KKYQjmcGk4k

  9. #9
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    Quote Originally Posted by EricSchimel View Post
    It looks to me like the whole toolpath is shifted up towards the top of the screen (Y direction?) Based on your previous static woes, my guess, and it's just a guess, is that you've lost some steps here. You can see it on the top left of the image too...
    But it happened essentially the same on 12 separate pieces all part of the same cut.

    See video in post above for the slop I’m experiencing. And isn’t it relevant that it’s happening where the bit plunges and retracts?

    Here’s a different inlay on the same job. 95689204-AFE8-4377-B5B5-03E4AF9CD7BB.jpg

  10. #10
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    That's way too much slop! Check that pinion for tightness to the shaft and engagement into the rack. How worn are the pinions? As for the toolpath, you can make the profile pass first to keep the tool from being side loaded when it moves out for the profile. I prefer longer smooth ramps to zig zag. A smooth ramp will also relieve the bit as it finishes the cut before lifting.
    Last edited by srwtlc; 11-09-2018 at 12:31 PM.
    Scott

    If guns kill people, I guess pencils misspell words, cars drive drunk and spoons make people fat.

    "Those who hammer their guns into plows, will plow for those who do not" - Thomas Jefferson


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