1. #1
    Rye's Avatar
    Lives in Sheffield, United Kingdom. Last Activity: 1 Week Ago Has been a member for 2-3 years. Has a total post count of 36. Received thanks 3 times, giving thanks to others 0 times.
    Hey all,

    I'm new to CNC and need some advice on ways to avoid or limit tear-out. I'm using a Chinese CNC6040 with a 1.5k spindle and two end-mill bits that came with the machine: 6mm and a 3mm to carve a couple of name plaques on a few scrap planks of softwood(I don't want to be using any expensive material yet as I'm a complete noob.)

    On my first attempt, using the pocket toolpath in vcarve, I used offset and conventional. This came out reasonable well but left very noticeable tool marks on the base of the pocket and quite a bit of tear-out around the lettering. My second attempt, using raster and climb(upcut), came out much better. It had fewer tool marks and less tear-out - although it did leave a little more fuzz.

    I expect a few problems like this when using softwood, but what advice would you give to help limit the tear-out. And what spindle speeds, feed rate and cut-depth would you recommend (the pocket is only 5mm deep. I used 3 passes with the last being 0.3mm.)

    Cheers,
    Rye

  2. #2
    Hi,

    Quote Originally Posted by Rye View Post
    came out reasonable well but left very noticeable tool marks on the base of the pocket
    marks at the bottom are usually caused by misalignment of the spindle (not exactly perpendicular to the machine base).

    Quote Originally Posted by Rye View Post
    but what advice would you give to help limit the tear-out.
    If wood tears out the tool is usually just not sharp enough. Tools desinged to cut steel for examle are dull by design in comparison to tools made for wood or plastics. There are also large differences between cheap and high quality tools.

    Christian
    2D / 3D CAM Software and CNC controller: http://www.estlcam.com

  3. #3
    Rye's Avatar
    Lives in Sheffield, United Kingdom. Last Activity: 1 Week Ago Has been a member for 2-3 years. Has a total post count of 36. Received thanks 3 times, giving thanks to others 0 times.
    Hi mate,

    Thanks for replying. As I said I'm new to all this and kind of in at the deep end. Trying to soak up as much info as possible. I'm guessing the tool marks may have been because my spoiler board was springing up a little in the middle. I've got that sorted now and they've pretty much cleared up(just very minor abrasions.)

    I've ordered some new bits but, until they arrive, I'm just experimenting and trying to gain some confidence using the machine with bits that came with it. My biggest problem is trying to get my head around speed and feed rates. I was thinking if I can get those roughly right I'd be able to limit some of the problems above. That's why I thought I'd ask you guys if you have any tips or advice.

    Thanks again,
    Rye

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