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Thread: Tooling marks Buddy Prs

  1. #11
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    Quote Originally Posted by cowboy1296 View Post
    I have started getting tooling marks while doing 3-d finishing. I cut against the grain but dont think that is a problem and that is generally in the Y direction. I use 8-10% step over and 3 inch per second feed and plunge.

    Cutting against the grain is generally a no-no. Try to always cut in the same direction as the grain. 3" per second is too fast for this, especially if you have not done a proper 3D rouging pass over the entire plaque first. You'd be surprised how much cleaner your work will look when you first rough out, then slow down the cutting speed to something like 2,1.

    It pays to check your speeds in your mind's eye, imagining what is actually happening at set speeds. Depending on your VR settings, it is likely that across an 18" surface with raised letters, that the tool is almost never reaching its set speed of 3" per second. Instead, the software is trimming off the speed for accel/decel and in fact, causing the tool to make sharp, clunky moves. If there is a volume of material that was not removed by roughing, it is pretty touch on the mechanicals and router to plunge right into material at 3 IPS.

    Just for the heck of it try roughing, rastering with the grain and slowing the speed down to 2,1. You may find that it doesn't take much longer than setting it at 3,3 & cuts will be more reliable with less chance of losing steps on a Standard machine. The inherent nature of steppers is that they have more torque at lower speeds than higher speeds and 3 IPS is where the torque on those motors really starts to fall off sharply.

    In my experience, 3D takes as long as it takes when the bottom line is quality. I won't put my name on something that looks like I carved it out with a hatchet. If you want high quality & less hand work...slow things down.

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

  2. #12
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    Gotcha. I use to always cut with the grain and then would spend a large amount of time cleaning fuzzies. Cutting against the grain, i have almost zero fuzzies. for VR settings i am using what i believe is your suggestions. I know that a lot of people dont use a roughing pass but i do. Currently my machine allowance is at .013 and i may even trim that down some more.

    Currently I am cutting the finishing pass on a piece which has been running for over an hour now. From what i can see, there is a major improvement. The machine does feel as if it is clunking but barely so i will slow it down in the future. I have received recommendations in the past that suggest that the feed rate should almost be identical to the plunge rate, but yours is different, but you should know best.

  3. #13
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    For roughing, I always go across the grain. If you go with the grain for roughing, depending some on the type of wood, you will get these long slivers that will peel off and plug up your dust pick up and can also peel off extra material that is below the finish pass. I generally leave 0.04 for allowance, but less should make for less fuzzies, but keep in mind that with an end mill, it will not be 0.04 (or whatever you set it at) in all places due to the geometry of tool and design.

    Again, depending on the wood and grain, running the finish pass with the grain can make for a lot of fuzzies that need to be scraped/cut/sanded off and it's not fun when there's a lot of them. I'll decide more on the kind of grain and type of wood as to whether I run with or across. I'd have to say though that there's more times that I wished I'd ran across the grain when I didn't than the other way around. A new sharp exacto knife and some shaving before the sanding mop is needed then. If your stepover is too high (above 10%) and you go across the grain, you'll get unacceptable scoring lines.

    Just finished this one up for a raffle. Across the grain finish pass, 0.0625" BN @ 8%, 5.5 hours, sanding mop and ready for finish.

    https://drive.google.com/open?id=0B5...HYwbmJDMDhBcW8
    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




  4. #14
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    I finished my carving yesterday. There was a vast improvement however there still are some tooling marks. I never really played close attention before of the springs that are on the z axis and not sure since it is geared driven what their use is. I did notice that one of the brings must be lightly hanging up on something quite often. There is a slight delay on that side and then the spring releases and springs up and down for a moment and then resumes as normal. Could that be causing the problem?

  5. #15
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    Quote Originally Posted by cowboy1296 View Post
    I finished my carving yesterday. There was a vast improvement however there still are some tooling marks. I never really played close attention before of the springs that are on the z axis and not sure since it is geared driven what their use is. I did notice that one of the brings must be lightly hanging up on something quite often. There is a slight delay on that side and then the spring releases and springs up and down for a moment and then resumes as normal. Could that be causing the problem?
    Yes. Turn off the control box and move the Z up and down by hand. Run the full +/- stroke of the Z and feel for tight or loose spots. The springs are meant to coutner-balance the spindle.

    After you've done this, turn the control box on & move the Z to different positions of the stroke and grab and wiggle the Z/spindle up down back and forth. Listen for noise and feel for slop. Repeat this along the entire stroke listening for something worn, sloppy or out of adjustment.

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

  6. #16
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    Yesterday i did turn the box off and raised and lowered the z by hand. Its not really as smooth as you would think and at times required more effort to raise it in spots. Today I am going to make a major effort to clean that area.

  7. #17
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    I found what the spring was catching on. I dont remember doing this but must have. I put too long of bolt that holds the stepper motor on the z axis which protruded by 1/8 of an inch into the channel where the spring is. it would hang up momentarily as the z went up and down. the bolt has now been replaced and no more springy. It just seems too easy of a fix but only the next carving will tell

  8. #18
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    For what it is worth, it appears to be a malfunction of the operator error. I have been away for a while and this is my first carving. A memorial plaque for a Houston cop murdered years ago. And this was done with a finishing bit that needed replacing. The flash on the camera distorted the beauty of the wood. This is the first stage of finishing with more to come.
    Attached Images Attached Images

  9. #19
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    Looks pretty good. Still a couple of spots that look like a slight variation in the Z maybe?

    I see that my lost post from some time back finally showed up, for what it's worth, #13.
    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




  10. #20
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    Agree with Scott, much better than when you posted the problem. The slight variations he points out looks limited to the center board of the glue up to me.

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