Page 1 of 2 12 LastLast
Results 1 to 10 of 16

Thread: v-inlay technique problems

  1. #1
    Join Date
    Jun 2017
    Location
    Glendale, WI
    Posts
    107

    Default v-inlay technique problems

    Hi everyone,

    While I have had decent success with V Carve's built-in inlay toolpaths, I also need to use the v-inlay technique for finer details that require sharp corners. And I'm having a problem. For the most part the male pieces are coming out well and "fit" ok in the female pockets. But as you can see in this close up, something is off. I am not getting sharp corners, and it's almost like the v bit is slightly dogboning the corners. The straight portions machined quite well and are a good fit for the male parts.

    IMG_3045.jpg

    I am using a 60 degree v bit for both cuts. Female pocket machined to .15" flat depth using the v-carve toolpath with a 2% stepover to clear out the pocket. Male parts are mirrored, offset outwards .18" and then v-carved at .1 start depth and .1 flat depth to create inverse parts.

    Any ideas?

    Thanks!
    Brian

  2. #2
    Join Date
    Sep 2006
    Location
    Garland Tx
    Posts
    2,334

    Default

    Brian…

    In my experience, this generally means that something isn’t as described to the software… either the 60° V-bit isn’t a true 60° or Z-zero is off.

    SG

  3. #3
    Join Date
    Jun 2017
    Location
    Glendale, WI
    Posts
    107

    Default

    Quote Originally Posted by steve_g View Post
    Brian…

    In my experience, this generally means that something isn’t as described to the software… either the 60° V-bit isn’t a true 60° or Z-zero is off.

    SG
    Thanks Steve! I fear it is both... A slightly off z zero makes sense to me, as that could cause the bit to plunge (or retract I guess) in the corner too early or too late, which could explain the little bite out of the corners, right?

    I don't fully understand how a discrepancy in the v bit angle could cause this issue, but I got a similar response in the Vectric forum.

  4. #4
    Join Date
    Sep 2006
    Location
    Garland Tx
    Posts
    2,334

    Default

    Brian…

    Just for grins, draw several 1” square vectors, V-carve the first one with a 60° bit defined as a 60° bit, define a new bit as 61° and cut the second with the same 60° bit but with the 61° definition then 59° etc. See if you get sharper corners with another of the definitions. It’s not unusual to find that the bit is off…

    SG

  5. #5
    Join Date
    Jan 2011
    Location
    gleason, wi 54435
    Posts
    449

    Default

    It looks to me like your machine is bouncing a little when it changes direction. check that everything is tight in all 3 axes.

  6. #6
    Join Date
    Aug 2011
    Location
    Wilkesboro, NC
    Posts
    108

    Default

    I agree with Steve that the bit angle looks off slightly.

  7. #7
    Join Date
    Jun 2017
    Location
    Glendale, WI
    Posts
    107

    Default

    Quote Originally Posted by steve_g View Post
    Brian…

    Just for grins, draw several 1” square vectors, V-carve the first one with a 60° bit defined as a 60° bit, define a new bit as 61° and cut the second with the same 60° bit but with the 61° definition then 59° etc. See if you get sharper corners with another of the definitions. It’s not unusual to find that the bit is off…

    SG
    Good experiment. I will give it a try. In the Vectric forum someone suggested that my V bit's tip might have worn down to a slight flat tip rather than a point, and that could also cause this. I still can't wrap my head around how bit geometry discrepancies can lead to this particular result, especially since the male pieces machined correctly. But spacial reasoning isn't my strong suit...

    As for Bob's suggestion that my machine could be bouncing around, I'm not sure how to look into that. It's still less than 6 months old and otherwise cuts as expected.

  8. #8
    Join Date
    Jan 2004
    Location
    iBILD Solutions - Southern NJ
    Posts
    7,986

    Default

    Quote Originally Posted by bking1836 View Post
    As for Bob's suggestion that my machine could be bouncing around, I'm not sure how to look into that. It's still less than 6 months old and otherwise cuts as expected.
    Turn the control box on and wiggle the living daylights out of it in ALL DIRECTIONS. Grab the spindle force it by hand up and down. Front and back. Left and right. Feel or hear slop? Find it. Same with the X/gantry @ EACH side. Same with the YZ car.

    Have a PRS? Check the lower v-roller bearings. Remove the black covers and adjust...not too tight...not too loose.

    -B
    High Definition 3D Laser Scanning Services - Advanced ShopBot CNC Training and Consultation - Vectric Custom Video Training IBILD.com

  9. #9
    Join Date
    Jan 2004
    Location
    , Pittsburgh PA
    Posts
    98

    Default

    Brian,

    I agree with Brady. Way back when I had similar results when VCarving. Turns out that the Z axis pinion was not seated far enough on the stepper shaft and was binding near the top of the travel. When VCarving into corners the bit retracts while still moving in the X and Y. If Y lags due to binding or slippage you get what appears to be overcut. Do as Brady said and I think you will find the solution.

    Bill

  10. #10
    Join Date
    Jun 2017
    Location
    Glendale, WI
    Posts
    107

    Default

    Quote Originally Posted by bill_l View Post
    Brian,

    I agree with Brady. Way back when I had similar results when VCarving. Turns out that the Z axis pinion was not seated far enough on the stepper shaft and was binding near the top of the travel. When VCarving into corners the bit retracts while still moving in the X and Y. If Y lags due to binding or slippage you get what appears to be overcut. Do as Brady said and I think you will find the solution.

    Bill
    Ok thanks Bill and Brady. I will look into this.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •