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Thread: Dialing In a Buddy

  1. #1
    Join Date
    Jun 2008
    Location
    , Fairfield California
    Posts
    36

    Default Dialing In a Buddy

    Over six months with my 32 I'd noticed that my through-cuts seemed consistently a bit shallow... I almost always had some "skin" at the bottom. So this weekend I did a few quick tests.

    Sure enough, it turned out that on cuts from 1/4 to 3/4 deep I was about 0.5 percent shallow (e.g., a cut that should have been 0.5 deep calipered at 0.496). Same factor seemed to apply, roughly, to X and Y... although I didn't mic my 1/4" mill, so that might be just a tooling variance.

    Has anyone else seen consistent small errors on this order? And if so, is it worth adjusting the Bot's setup factors, or should I just apply a correction factor in the fill-in sheet each time I go to cut?

  2. #2
    Join Date
    Jan 2004
    Posts
    707

    Default

    You are well within spec. I would try playing around with they way you are machining. Also your spoil board even if surfaced will change hour to hour. The less stress you put on the machine and bit when cutting the better off you'll be. I know the buddy can cut pretty fast, but that doesn't mean you'll be happy with the results.

  3. #3
    Join Date
    Nov 2007
    Location
    Vankleek Hill, ON
    Posts
    861

    Default

    Sounds like it could be slightly under-sized pinion gears but I'm not sure how this could be verified.

    You might get more feedback on this question on the general forum board.

  4. #4
    Join Date
    Oct 2000
    Location
    Toms River, New Jersey
    Posts
    2,091

    Default

    Art,
    You didn't mention if you had verified the actual thickness of your Z Zero plate yet. If the cuts are consistently shallow you may have the wrong number plugged into your Z Zeroing program. Mic the plate and see if that's the number your machine is using...

  5. #5
    Join Date
    Jul 2007
    Location
    LM Custom Woodcrafts, Cortlandt Manor New York
    Posts
    321

    Default

    Even though the z,x,and y all seem to be the same amount off, they might not be related. The z could be the z zero plate being a different thickness than what SB thinks it is, while it's not uncommon for 1/4" end mills to be off by .004. Just a thought or two....

  6. #6
    Join Date
    Jun 2008
    Location
    , Fairfield California
    Posts
    36

    Default

    Yes, my Z-zero plate thickness is correct at 0.121", and in any event I made my depth measurements relative to a .01" pocket on top just to make sure I wasn't thrown off by material or spoilboard variations.

    And my cut rates are 1 ips in Z and 3 ips in X and Y, which I don't think are excessive for cutting MDF with a quarter inch mill. (And yes, the tool is sharp!)

    So aside from blaming the operator, anyone have any constructive suggestions as to how best to compensate for a reproducible error?

  7. #7
    Join Date
    Jan 2004
    Posts
    707

    Default

    If you are using the same feeds and speeds as well as the same depth of pass you will find your error will be reproducible. Try ramping your plunges and slowing your z down to .5". Also on the x and y try 1 ips and .125" per pass. Cut some test circles and squares with these more mild setting to rule out machine flex. I hope this is constructive enough for you.

  8. #8
    Join Date
    Jun 2008
    Location
    , Fairfield California
    Posts
    36

    Default

    To recap, my questions were: 1) Has anyone else here seen anything similar? (apparently not), and 2) What's the best strategy for compensating? (nobody seems to have one, except for trying to talk the problem away.)

    I'm assuming that slowing down to half an inch per second in MDF was meant as a fix...

  9. #9
    Join Date
    Jan 2004
    Posts
    707

    Default

    Art if you are frustrated don't take it out on the people that are trying to help you for free and out of kindness. No, slowing down was not meant as a fix it was meant as a means to investigate. You act as if you already know that everyone is wrong when you are the one asking the question. When I first started using my Buddy I was coming from a slower PRT machine and was excited about the new found speed and power. I was getting repeatable errors. I asked questions on the forum politely and took suggestions. I can't say for sure the problem I had is the problem you are having, but it sounds similar. Maybe you are too smart to ever have a operator error, but maybe, just maybe you are just like the rest of us.

  10. #10
    Join Date
    Nov 2007
    Location
    Vankleek Hill, ON
    Posts
    861

    Default

    Thanks Erik

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