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Thread: Project 1 from EmptyNester. Category: Custom Shop Tools - CNC Table

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EmptyNester Project 1 from EmptyNester. ... 07-14-2012, 03:44 PM
Rambozo There is a free Visio viewer... 07-15-2012, 12:05 AM
EmptyNester Current Table State 07-27-2012, 12:27 AM
posixPilot Google sketch up is a good... 07-15-2012, 01:53 AM
EmptyNester Testing the Water Table 08-11-2012, 09:38 PM
zoama May as well put a garden hose... 08-11-2012, 10:12 PM
EmptyNester Zoama, You've become my... 08-11-2012, 11:16 PM
Rambozo That is so not what I meant... 08-11-2012, 11:59 PM
EmptyNester Unfortunately, its a little... 08-12-2012, 12:27 AM
ShaneJackson Just get some of that liquid... 08-12-2012, 03:06 AM
EmptyNester I started final assembly of... 09-12-2012, 01:33 AM
Rambozo This is true. You also don't... 08-12-2012, 05:51 AM
EmptyNester Talked to Precision Plasma... 09-14-2012, 01:11 AM
Rambozo That all depends on the... 09-14-2012, 01:48 AM
acourtjester HI Empty you may have the... 09-14-2012, 02:29 AM
SeanMurphy265 This is an easy way to... 09-14-2012, 03:34 AM
sportbike That thing looks pretty... 09-24-2012, 01:01 AM
EmptyNester Mostly done with the build 09-22-2012, 11:56 PM
EmptyNester Rambozo - thanks. I ran that... 10-09-2012, 12:06 AM
Rambozo There are some options in the... 10-09-2012, 12:36 AM
EmptyNester I did start leveling the... 09-22-2012, 12:40 AM
EmptyNester Adjustable Gantry Mounts 08-25-2012, 09:42 PM
SeanMurphy265 I would add some support in... 08-11-2012, 10:18 PM
EmptyNester I probably won't be doing... 08-11-2012, 11:15 PM
EmptyNester Drive Electronics 08-25-2012, 10:02 PM
EmptyNester I now have the table put... 07-15-2012, 04:09 PM
EmptyNester Carriage Kit 07-16-2012, 12:19 AM
acourtjester Great start empty I built a... 07-16-2012, 03:20 PM
EmptyNester Tom, I have seen Sean's,... 07-16-2012, 04:06 PM
acourtjester Just the added weight of the... 07-16-2012, 05:55 PM
EmptyNester Table Design 07-26-2012, 09:52 PM
sportbike Looking good Nest. I... 07-26-2012, 11:57 PM
EmptyNester Thanks. I did get gear... 07-27-2012, 12:11 AM
acourtjester HI Empty I ran my plasma... 09-24-2012, 03:31 PM
EmptyNester I reinstalled Mach and I was... 10-10-2012, 12:08 AM
Rambozo You can have the IJ in... 10-10-2012, 12:45 AM
acourtjester yes that does I have 2 sizes... 10-30-2012, 07:43 PM
EmptyNester I'm embarassed to say - I... 10-30-2012, 07:01 PM
aaxiss Kinda sounds to me like a... 10-07-2012, 07:57 AM
EmptyNester Thanks for the feedback guys.... 10-11-2012, 01:32 AM
EmptyNester Attempt 2 02-06-2013, 01:01 AM
sportbike My wife was discussing... 03-03-2013, 02:16 PM
ShaneJackson You have mastered the force... 03-03-2013, 02:28 PM
travis took my wife to see a plasma... 03-03-2013, 03:08 PM
EmptyNester Excellent work! All I can... 03-10-2013, 11:27 PM
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  1. #1
    Join Date
    May 2012
    Location
    Disneyland
    Posts
    2,662

    Default

    Quote Originally Posted by EmptyNester View Post
    I'm curious if anyone has suggestions on maximum speed and acceleration rate...........
    That all depends on the strength of your motors and the mass and friction of your machine. Ideally you want to be able to go as fast as possible without losing any steps. There are some motor tuning programs that will help you get in the ballpark. Also a lot depends on your step kernel rate in Mach. Run the drivertest to see what your system can support. Be aware that you can also have resonance problem at some speeds, there are tricks to fix that, if needed. One thing about steppers is that they have a wicked torque curve vs speed. So you need to test and tune from zero through your max feedrate, then at your rapidrate. If you have a resonance between max feed and rapid, you can live with that, but not if it happens below max feedrate. And of course you must never lose a step, no matter what. A general rule of thumb is to adjust velocity up until the motor stalls, then back down about 10%-20%. Then adjust acceleration as high as possible where they can still start from stationary. This will give the best position tracking. If you plan on using constant velocity, everything will have to be tuned really close, for exact stop you don't need to be as precise.
    Long arc, short arc, heliarc and in-the-dark!

  2. #2

    Default

    HI Empty
    you may have the same problem I have with the "Z" axis, it look like your "Z" motor is a direct connect to rack via the motor gear.
    What happens when you drop power to the motor the weight of the z axis will cause the motor to free wheel and the z drops to the limit.
    Slam dunk kind-of-a-thing. I need to remember to prop it up before dropping power.

    Everlast PM256
    Millermatic 180
    Hypertherm PowerMax 65 with machine torch
    Longevity Force Cut 80I
    DIY CNC table for plasma/routing
    13" metal lathe
    Small Mill
    ect, ect.

  3. #3

    Default

    This is an easy way to calibrate your steps per inch. I did mine with a tape measure because I do not have a dial caliper, but I'm ordering one soon. I'm not good at math, but this is an easy way to get it accurate.

    Lincoln Eagle Engine Drive
    Everlast MTS 250
    Everlast Power Tig 225lx
    HTP Mig 2400
    Everlast Power Plasma 60C --> Just need to finish my CNC Plasma Table!
    Miller Spectrum 375 Extreme Plasma cutter
    Victor cutting torch
    HF 20 Ton Shop Press
    HF 4x6 Band Saw
    HF Air Compressor
    Northern Tool Drill Press


    www.murphywelding.com

  4. #4

    Default

    That thing looks pretty darned nice. I am looking forward to seeing how it works out. I have still been toying with the idea of building a small one for myself.
    Everlast 200DX
    Everlast PT185
    Shoptask 3-in-1 (not currently in my garage, but I own it...)

    Any day on a motorcycle like this that ends just needing parts and labor is a good day.
    4.82, 158.67mph 1/8th mile 7.350, 200.35mph 1/4 mile

  5. #5

    Default Mostly done with the build

    I thought about a couple different ways to support the wire shelf for the energy cable. I ended up getting a U shaped wall bracket for holding shelf supports.

    Click image for larger version. 

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    I didn't install the engery chain because I don't think the torch is long enough to make it. Hopefully, I'll have a longer torch in a couple weeks.

    Click image for larger version. 

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    All I have left to do is:
    • put in the X limit switches
    • complete the wiring on the limit switches
    • use silicone caulking in the problem area that may still have a leak
    • finish leveling the slats

    Before I try a test cut, I need to finish wiring my THC/interface. I don't plan on trying to get the THC working just yet, but it handles the relay for the "torch on".
    Just starting in Aug '10
    ---
    Hobart Handler 187
    Power Plasma 50

  6. #6

    Default

    Rambozo - thanks. I ran that and it went as expected.

    I took one of the odd ones I've generated and stepped through them to identify the commands. I deleted the circles. It seemed to work okay.

    I'll spare the details, but I tried lots of different things and was always getting the conincentric circles in the Mach driver. I run Mach on a PC in the garage and have my drawing program and SheetCam upstairs. To try to save time debugging, I installed mach on the upstairs PC. Everything looks fine. The same file loaded on the table's Mach driver is messed up.

    At this point, I think I have a very hosed installation/configuration on the table's Mach driver.
    Just starting in Aug '10
    ---
    Hobart Handler 187
    Power Plasma 50

  7. #7
    Join Date
    May 2012
    Location
    Disneyland
    Posts
    2,662

    Default

    There are some options in the configuration for arcs. Every control is different, and Mach can be configured to behave in a few different ways. For instance I use an Anilam control that uses absolute coordinates for the centerpoint if the endpoint is absolute, while the standard for Mach and some other controls is that center points are incremental offsets, even when you are in absolute mode. In fact I had to switch my backplot program to get a proper display for your code. Just like some controls can't do a full circle with one arc command, some are limited to 90° and some to 180° so you have to break the circle into multiple arcs.

    Here is a sample with an incremental centerpoint arc.
    N100 G20
    N110 G53 G90 G40
    N120 M06 T1 F20
    N130 G00 Z2.500
    N140 X1. Y1.
    N150 Z0.500
    N160 M03
    N170 G04 P.5
    N180 G01 Z0.100
    N190 Y3.
    N200 G2 X3.Y1.I0.J-2.
    N210 G1 X1.
    N220 M05
    N230 G04 P1.
    N240 G00 Z2.500
    N250 X0.000 Y0.000
    N260 M30

    And here is one with absolute.
    N100 G20
    N110 G53 G90 G40
    N120 M06 T1 F20
    N130 G00 Z2.500
    N140 X1. Y1.
    N150 Z0.500
    N160 M03
    N170 G04 P.5
    N180 G01 Z0.100
    N190 Y3.
    N200 G2 X3.Y1.I1.J1.
    N210 G1 X1.
    N220 M05
    N230 G04 P1.
    N240 G00 Z2.500
    N250 X0.000 Y0.000
    N260 M30

    And finally here is an example where all the X Y moves are in incremental by switching the mode with a G91.

    N100 G20
    N110 G53 G90 G40
    N120 M06 T1 F20
    N130 G00 Z2.500
    N140 X1. Y1.
    N150 Z0.500
    N160 M03
    N170 G04 P.5
    N180 G01 Z0.100
    N190 G91
    N200 Y2.
    N210 G2 X2.Y-2.I0.J-2.
    N220 G1 X-2.
    N230 M05
    N240 G90
    N250 G04 P1.
    N260 G00 Z2.500
    N270 X0.000 Y0.000
    N280 M30
    Last edited by Rambozo; 10-09-2012 at 12:38 AM.
    Long arc, short arc, heliarc and in-the-dark!

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