1. Hey guyz. Welcome to the All New Phlatforum!



    Sign Up and take a look around. There are so many awesome new features.

    The Phlatforum is a place we can all hang out and

    have fun sharing our RC adventures!

  2. Dismiss Notice

Overhead Gantry check not having affect on Neg Gcode out

Discussion in 'SketchUcam Help' started by ElkaderLight, Feb 20, 2013.

  1. ElkaderLight

    ElkaderLight New Member

    Offline
    Messages:
    19
    Trophy Points:
    1
    Anyone having this same problem I am where I am getting Negative (z-0.25) output in the gcode on centerline cuts regardless of whether you check the overhead gantry or not? Right now I have to intercept each file in notepad and do a search and replace on "Z-" to "Z". I have an overhead gantry and am setting zero azis on the table and working up so having a negative Z value drives the bit into the table top. Anyone have any solutions. I would rather not mess with the motor settings on the Z axis control as it will throw everything else off.
     
  2. Jnida63

    Jnida63 Member

    Offline
    Messages:
    749
    Trophy Points:
    18
    You should just have to go into mach setup and click on the reversed setting if i am reading this right
     
  3. TigerPilot

    TigerPilot Well-Known Member

    Offline
    Messages:
    1,578
    Trophy Points:
    48
    ElkaderLight, I guess you are talking about the 'safe area' for the z axis. Did you do anything to the config.rb file. It may be that a setting there has changed. I get z-0.25 when the bit plunges to cut the material. After the cut it goes up to z0.125 for the travel to the next cut where it plunges again to z-0.25.

    Post your problem g-code file and we'll take a look at it.
     
  4. ElkaderLight

    ElkaderLight New Member

    Offline
    Messages:
    19
    Trophy Points:
    1
    Jeff, Thanks, but I am not using Mach. I am afraid if I start messing with the positive and negative controls in my setup then everything will get messed up. I am actually using the Sketchucam with a Torchmate system and controller.

    Yoram,
    Here is an example with safe travel at 0.5in, Material thickness at 0.25
    The safe travel is correct at Z0.500.
    But since I am trying to cut from table as Z0.00 NOT the top of the material as Z0.00, the negative Z- coordinates when it comes down to cut will actually be cutting 0.125 INTO the table top. (these were 50% centerline cuts which is why it is showing z-0.125 on a 0.25 thick material).
    This all works if Z0.00 is the top of the material, but not if it is measured from the table top surface. Changing the Overhead Gantry check box does not seem to change any of the Z values.

    Your comments are really appreciated!!

    %
    (Generated by PhlatscripT {trunk})
    (Bit diameter: 0.13")
    (Feed rate: 100.00")
    (Material Thickness: 0.25")
    (Material length: 22.00" X width: 42.00")
    (Overhead Gantry: true)
    (www.PhlatBoyz.com)
    G90 G20 G49
    M3 S15000
    G0 Z0.5000
    X4.3958 Y7.0049 Z0.5000
    G1 Z-0.1250 F100
    X9.3758 Y7.0049 Z-0.1250
    Y14.3949 Z-0.1250
     
  5. ElkaderLight

    ElkaderLight New Member

    Offline
    Messages:
    19
    Trophy Points:
    1
    Here is the same file exported with Overhead Gantry not checked -- you can see it is not changing the Z negative values:
    %
    (Generated by PhlatscripT {trunk})
    (Bit diameter: 0.13")
    (Feed rate: 100.00")
    (Material Thickness: 0.25")
    (Material length: 22.00" X width: 42.00")
    (Overhead Gantry: false)
    (www.PhlatBoyz.com)
    G90 G20 G49
    M3 S15000
    G0 Z0.5000
    X4.3958 Y7.0049 Z0.5000
    G1 Z-0.1250 F100
    X9.3758 Y7.0049 Z-0.1250
    Y14.3949 Z-0.1250
     
  6. Jnida63

    Jnida63 Member

    Offline
    Messages:
    749
    Trophy Points:
    18
    I am pretty sure checking the overhead gantry setting has no effect on the Z axis at all, it believe it just reverses the direction that it cuts so you get the smooth side of the cut.
    Check the parameters box and make sure the overcut percentage is set at 100% for flatbed machines, if it is more it will cause you to cut into the bed. Attached files [​IMG]
     
  7. kram242

    kram242 Administrator Staff Member

    Offline
    Messages:
    6,311
    Trophy Points:
    13
    Location:
    NJ
    That's correct Jeff
    -LampGuy you will need to change the direction of the Z axis in your control software, or by swapping the two sets of coil wires(A/B) on your motor driver. Either one of these ways will work.
    Here is a link to the Tourchmate systems control. It looks to me like you can swap the direction here?
    http://torchmate.com/technical_support/ ... version_3/
    Hope this helps
    Mark and Trish
     
  8. TigerPilot

    TigerPilot Well-Known Member

    Offline
    Messages:
    1,578
    Trophy Points:
    48
    LampGuy, you hit the nail on the head. The problem is that SketchUCam is set to calculate the z axis from the material top and not the table top. The only way to change that will have to be done in code inside the .rb file. It can be done rather simply, I think, with an option in the parameter box for 'Table Top' or 'Material Top'.

    BTW, LampGuy, why are you using the table top rather than the material top? Is there any advantage to it? :questions:
     
  9. ElkaderLight

    ElkaderLight New Member

    Offline
    Messages:
    19
    Trophy Points:
    1
    Thanks all!
    Mark and Trish, I could swap directions on the motor, but that means it would be swapped everywhere, for example, when I want to jog the machine up or down. All buttons would be reversed which I would find confusing and the staff even more so!

    I have never worked with .RB code before. I wouldn't mind learning as there are some other automations I would love to set up for other things. Maybe this is a good starter project if it is not too hard. Yoram, can you help me with this or point me in the right direction to start learning how to do it? It would be nice to eliminate that step in the process and avoid costly waste of material and table top by inadvertent accidents.

    Reason I was using Z from table is that my material varied in thickness from sheet to sheet. The acrylic was cast and even varied across the sheet. We were making large boxes from them. We would route the edge down 1/2 thickness to overlap with the next side when glued up. This created a stronger joint, made sure that the light didn't leak out too. But you have to be pretty accurate with how much material you are left with. Since the sheets varied in thickness you would never have the same value from surface down. We had to work from table up so that we knew we were always leaving 3/32 for example. It also allows me to put an aluminum block down that is hooked to the controller/software. I have a button I can press to bring the bit down, when it touches the block it closes/opens the circuit and sets the Z value based on the touch point. I have a 1in block so I set it to offset the Z value automatically 1in below the touchpoint. Makes it quick to set z because I just put the block down. Turn the vacuum on the table to tighten everything up, bring the bit down with the auto-sensing trigger and it touches and retracts, setting Z zero.
     

Share This Page