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[CNC] CNC from sketch to part the way I do it

Discussion in 'CNC IN THE HOME SHOP' started by jumps4, Dec 17, 2013.

  1. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    I finished up the g-code for the front and back this morning and milled out the rest of the part. except for my pocket measurement error, I think it came out pretty nice for a hobby machinist with Chinese tools.
    notice my edge finder in the photos, a 1/4" gauge pin with marker ink on it.
    thanks for viewing and your comments
    steve

    DSCF1049.JPG DSCF1050.JPG DSCF1053.JPG DSCF1055.JPG DSCF1056.JPG DSCF1057.JPG DSCF1058.JPG DSCF1059.JPG DSCF1061.JPG DSCF1062.JPG DSCF1063.JPG DSCF1064.JPG
     
  2. Tony Wells

    Tony Wells United States Vice President Staff Member Administrator

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    Looks really good. I appreciate all the time and effort put into making all these tutorial videos.


    I cringed a little when you said you were using a gage pin as an edge finder. A standard dowel pin will work just as good and not risk a gage pin. A dowel pin was my first edge finder.
     
  3. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    thanks tony
    I have edge finders I just like the ink method better. my double ended edge finders get stuck in the collets and want to pull apart.
    this pin came in a box of junk, it's not from my set lol
    steve
     
  4. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    any suggestions on what to do next?
    steve
     
  5. angelfj1

    angelfj1 United States Active User Active Member

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    Steve:

    What you have demonstrated in this series of videos is just outstanding. I have downloaded all of this and intend to use it when I get my mill set up this spring.

    As far as what's next, and this might seem elementary to many here, but I would love to see how you actually set up the machine prior to milling parts. In particular, how you hold the blank stock and find your starting point, etc, would be very helpful to me.

    Again, thanks and best regards!

    Frank in PA:))
     
  6. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    Ok, that's a good idea Frank
    Someone else sent me a pm suggesting the same thing yesterday'
    I'll make up a video
    steve
     
  7. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    in this video I show how "I" align certain types of parts and stock and set tool height.
    there are a lot of good ways to do this and maybe others can chime in here too.
    thanks for viewing
    steve

    Note: I pointed out the 4 corners you can zero your stock to but I forgot to mention you can also zero your stock in the center.

    [video=youtube;7F9_dvmX6Qw]
     
    Last edited: Mar 12, 2015
  8. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    In this video I talk about some of what I have learned about working with oval, eclipse, concave and convex shapes and how to draw them.
    I also explain about converting splines to arcs in dxf files so d2nc will recognize them.
    thanks for viewing
    steve

    [video=youtube;B7_xr8Z9Q8k]
     
    Last edited: Mar 12, 2015
  9. Stent

    Stent South Africa Iron Registered Member

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    Good video, thank you!



    Sent from my iPad using Tapatalk
     
  10. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    Thanks stent
    In this video I use some of the features of emachineshop to make a degree wheel
    thanks for viewing
    steve


    [video=youtube;0cVj_zNJndE]
     
    Last edited: Mar 12, 2015
  11. angelfj1

    angelfj1 United States Active User Active Member

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    Steve, here is a simple way to draw an ellipse, either using a compass or with CAD. This is from an old friend who got this from an even older friend. he claimed that this was how the barrel makers of old made their designs. No math is necessary.

    Step 1

    Draw a line that represents the length of the oval and divide it into 3 equal parts defined by points A, B. C and D.

    1.jpg

    Step 2
    using a radius as long as one third of the line, say A to B , draw 2 circles using B and C as centers. These 2 circles will cross each other at 2 points E1 and E2.
    2.jpg

    Step 3
    Create new points on each circle of same radius as above, and by using A and D as centers. Name them as F1, F2, F3 and F4.
    [FONT=&amp] 3.jpg

    [/FONT] Step 4
    Using the distance between F1 and E2 as a radius, and E2 as the center, draw a circular arc from F1 to F2. Repeat this step and draw the arc from F3 to F4 by using E1 as center.

    4.jpg

    good luck

    1.jpg 2.jpg 3.jpg 4.jpg
     
  12. John Hasler

    John Hasler United States Active User H-M Supporter-Premium

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    This is a clever way to draw an oval but it is not an ellipse. An ellipse is a conic section. Here is how to draw one: http://en.wikipedia.org/wiki/Ellipse#Drawing_ellipses
     
  13. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    that's pretty interesting, I wish I would have known that years ago making oval picture frames. I was pulling my hair out trying to get it right.
    but I don't think the math for that method would make one that fits 6 x 9 or 4 x 7 , I agree it makes an oval shape but not to dimension.
    I could be using the wrong math jargin I may be calling an eclipse an oval.
    I wonder if a true oval is proportional, if the height = "A" then the width has to = "B" ?
    I was in the smoking area at school during math :nuts:
    but thanks i'll remember that
    steve
     
    Last edited: Jan 12, 2014
  14. angelfj1

    angelfj1 United States Active User Active Member

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    Steve, Mr. Hasler is correct. What I offered is not a classical conic section. However, it does result in a pleasant shape. I'm not sure the 6x9 or 4x7 sizes are true ellipses either. Also the term, "oval" is not specific, that is, it does not define a specific mathematical shape, but actual is a general term used to define a "squashed" circle. But an ellipse is very special.In fact a Circle is an Ellipse, where both foci are at the same point (the center).
    In other words, a circle is a "special case" of an ellipse.

    here's a little example for an ellipse that is 9 inches wide and 6 inches high.



    ellipse3.jpg

    ellipse3.jpg
     
  15. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    The pic showing the string trick for drawing an oval works pretty slick, I got 2 thumb tacks and tried it.
    In this video I show a little of what I have learned working with text in Emachineshop. At the end I get tongue tied and have a problem figuring out what was going wrong. I figured it out when i watched the video and the alignment problem I started having was caused by the characters moving to the left instead of staying centered when I re-sized them. so it is better to determine the correct size and then place them instead of trying to edit each one after. I was too close to the problem to see it but I leave my mistakes in the videos if they still make sense.
    thanks for viewing
    Steve


    [video=youtube;LOBejshnoAY]
     
    Last edited: Mar 12, 2015
  16. thebaconbits

    thebaconbits United States Active Member Active Member

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    This is a part that steves videos have helped me out and I hope others have benefited from the time and effort to produce them. A huge thanks!! and this is what watching them has helped me make. Quadcopter arms with support brackets
    Quad.jpg

    Quad.jpg
     
  17. JPigg55

    JPigg55 United States Active User H-M Supporter-Premium

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    Hey Steve,
    Ready for another request or do you need a break ???
    I've been trying to draw something on eMachineshop with limited success.
    Basically, it's a ring (donut shaped kind of) with holes going from the outside edge into the middle through hole.
    I can get the holes every 90 degrees, but was wanting to place them every 30 degrees.
    Dimensions don't really matter at this point I can drw it myself if I can only figure out how to get the holes spaced.
     
  18. Bernie_nor

    Bernie_nor Norway Iron Registered Member

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    Hi!

    This is one way of solving this problem:

    1. Draw the circle where you want the center of the smaler circles to be placed.
    2. Draw a line from the center and out in any direction
    3. Change the angle of the line by selecting it and change the angle (The box for specifing the angle is on the top left corner of the screen). Change the angle to 0, 30, 60 90... degrees.
    4. Repeat from 2 untill you have all the lines you want.
    5. Draw one circle and change the dimention to what you want it to be.
    6. Copy this circle as many times you need and place the copies with their center in the crossing between the helplines and the original circle.
    7. Trim as needed.


    Thanks Steve for helping me find eMachineShop. It's fast and simple to use. I'm still many hours behind on all the videos here. They are of great help for a novice in the CNC world!


    Cheers
    Bernie
     
  19. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    jpigg
    I can't picture what your wanting to draw, can you do a hand drawing, scan it and post the pic.
    I haven't become bored I have just run out of ideas for videos.
    if your wanting to divide a circle into lines at 30 degrees, highlight the circle then go to line divide and enter 12. that will give you an intersect point on the circle every 30 degrees from it's center.
    steve

    spiral.png
     
  20. freeidaho

    freeidaho United States Active User Active Member

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    Sir Steve,

    I have watched all your instructional videos in this thread from the start, some of them more than once. I am very much impressed by your miniature steam engine and crushing mill. That work is absolutely beautiful. Bravo.


    I must say, you are so very kind to help those less schooled in CNC milling. Sharing your experience had helped many people. It has helped people that already have equipment, and those contemplating making the plunge into CNC. Your willingness to share your mistakes as well as successes, helps those of us that would otherwise be stuck when we made a mistake. You are absolutely right, tutorials for software or machines always show everything going perfectly. Which is nice for marketing, but leaves a lot unanswered for the user.

    For me, these videos and the lessons therein have changed my hobby machinist future completely. These videos have demystified the whole CNC premise for me, and calmed my fears that even simple jobs could take weeks. I have learned from the videos, that one can draw and cut a simple part the same afternoon just as with a hand crank mill. These videos have convinced me that I will indeed buy a CNC mill for my garage, instead of a hand crank mill with which I am so familiar. You have made a significant influence on my future projects.


    Thank you Sir!


     
  21. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    Thank you for your kind words FreeIdaho
    I'm glad the videos are helping people
    My latest project is designing a 15' x 6' x 8' tall cnc surfboard shaper/hot wire foam cutting machine for a friend and fellow member. I have just started drawing the parts today and I'm designing as I go. I have a picture in my head, now to get it in a dxf format. this machine is being designed to run at speeds of up to 500ipm rapids and will average 300ipm while cutting.
    I have included the spec sheets for the plastics I'm considering for those who think I'm crazy it wont work. :nuts:
    these plastics are self lubricating with a 7500psi load bearing, non-breaking, coefficient of friction as low as .02-.08 and temps of up to 500 degrees F.
    thank you for viewing
    steve

    [video=youtube;-0zAVJsetWk]
     

    Attached Files:

    Last edited: Mar 12, 2015
  22. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    I haven't done anything here for a while and the shaper is on hold waiting approval so I thought I would post a project I just completed here.
    These are handles/latches for the skylights in a 53' yacht, the original ones were made out of plastic and cracked, probably from sun load.
    So I made a drawing of the contour shape and cut new ones out of aluminum.
    I'll just post all the pics including the drawing of the contoured shape. I hope the order comes out right
    thanks for viewing
    steve

    DSCF1074.JPG DSCF1075.JPG DSCF1076.JPG DSCF1077.JPG DSCF1078.JPG DSCF1079.JPG DSCF1080.JPG DSCF1081.JPG DSCF1082.JPG DSCF1083.JPG DSCF1084.JPG DSCF1085.JPG DSCF1086.JPG DSCF1087.JPG DSCF1088.JPG DSCF1089.JPG DSCF1090.JPG DSCF1091.JPG DSCF1092.JPG DSCF1093.JPG DSCF1094.JPG DSCF1095.JPG DSCF1096.JPG DSCF1097.JPG handle contour.jpg
     

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  23. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    In this video I'm going to start showing what I have learned about gibb adjustment and backlash compensation. i'll have to break it up into a few videos to keep them short, that away I'm already set up to do what I want to show.
    I'm not trying to be a know it all and any corrections are more than welcome.
    hobby cnc machines are different in the fact they have to deal with a lot more friction and adhesion problems not encountered in factory machines with roller linear rails, guide ways and massive ball screws . there are ways to improve these faults but not eliminate them totally in a hobby cnc conversion.
    I chased my own tail for years until I understood what was happening under my mill table.
    In this first video I talk about what I have learned about adhesion, torsion, friction, flex and stored motion
    thanks for viewing
    steve

    [video=youtube;CfsiZ-6D0W4]
     
    Last edited: Mar 12, 2015
  24. Dan_S

    Dan_S Active User Active Member

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    Great video Jumps.

    This is one of the reasons I want to use dual closed loop servos when I eventually get around to cncing a mill. It's a lot more expensive to do, but it takes care of some of these issues for you.
     
  25. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    I did some research about a year ago on direct reading scales in each axis directly reading table movement and their use with mach3 and emc2 and at that time the only controller card I found that would support linear scales with custom written software was kflop by Dynomotion. I spoke to the man that designed the card and wrote the software for it and he said he could write me the software but the best mach3 could do with the information was to stop if a preset error level was triggered. if mach3 thought it was at one reading and the scales showed a different reading it would stop mach3 from running. at this time mach3 would not support error correction by moving the axis to where it should be or stop the travel if it is going to overshoot. I figured I could do that by measuring the part after the software ran and didn't invest in it until better software comes around at a hobby price. maybe mach4 will be able to self correct but it's still in beta. when they finally figure out how to do that the sloppiest machine built will make great parts because it wont allow an error to take place. that's going to require a lot of processor speed and programing to look ahead and determine prior to it taking place there will be a problem.
    steve
     
  26. Dan_S

    Dan_S Active User Active Member

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    Yea, that's what I was referring to, its talked about on these pages.
    http://www.dynomotion.com/Help/Mach3Plugin/Mach3.htm
    https://groups.yahoo.com/neo/groups/DynoMotion/conversations/topics/2297
    http://dynomotion.com/Help/CoordinatedMotion.htm


    as I understand it you take, mach3 out of the equation. the dynamotion mach 3 plugin converts the gcode to coordinate motion commands that get sent to kflop and stored in memory. this offloads the actual control grunt work to the kflop. you feed kflop 2 inputs per axis. A linear encoder provides position feed back and a rotary encoder on the servo or ball screw provides velocity feedback. You feed this into a custom C script that runs on the kflop to adjust the output signal to the amplifier that's feeding power to the servo. If I understand everything correctly you would need a kflop a kanalog and a couple snapamps, so the system would not be cheap.
     
  27. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    I'm a member of the yahoo group and followed it daily until a few months ago
    there is way too much code work required to operate the system and you have to do your own code work
    it has been in beta since I first read about it with no stable release to date
    at the time I stopped reading it daily there were nothing but " how do I code this " questions on the forum
    at my level or lack of knowledge I should say, I didn't want to take on learning the code to run a hobby machine in my back yard making no money lol
    but believe me I'd love to see it really work.
    join their yahoo group and read it daily you will see what I'm talking about
    my primary interest in the kflop was speed and it has that but for my needs I settled with a usb uc100 at 100khz and for $149 It has been just great for everything but threading on a cnc lathe, at this time I cant give real time feedback to mach3 to sync the motion to the spindle correctly. but then again mach3 has a problem doing it itself and that's one of the main reasons for mach4, the way mach3 was originally written could not be fixed to hold the sync and required a complete rewrite . mach3 will thread for short distances but nothing more than a couple inches without loosing track and starting out of location destroying the thread.
    I'm into building the best I can for the least amount of money invested, trying to keep it in an affordable price so others can play too.
    you have my interest back up though I'm going to see if I can find a video of a kflop system up and running.
    steve
     
  28. Dan_S

    Dan_S Active User Active Member

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    I'm about ready to order a mill (pm45-pdf most likely) and then a bigger lathe probably within the next year and then I'm going to cnc my little 8x14 lathe. I actually want to use kflop for the reason you mentioned threading. I probably have a step on most people though, as I'm a programmer by day and was a computer physics major in college. The biggest hurdle for me will be building up my electronics vocabulary and knowledge, because while I took some basic electronics courses in college, that was 10 years ago, and it wasn't anything advanced.
     
    Last edited: Mar 10, 2014
  29. JimDawson

    JimDawson Global Moderator Staff Member Director

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    This is exactly why I wrote my own CNC control software. After about a year of playing around with Mach3 / Kflop, and Mach3 / Galil trying to get a high speed CNC router to run correctly I finally gave up designed a system that works like I wanted it to.

    The up side of my system is that it uses a Galil Motion Control board, the down side of my system is the Galil card is expensive, and may be priced out of the hobby range for that reason. They are available on Ebay sometimes. Some day I may make my software compatible with the Kflop board and some others.

    I offload all of the motion control duties to the Galil board, that's what it does for a living and is very good at it. It will run servo or stepper motors, and supports single and dual loops when using servos, and supports single loop and open ended stepper control.

    I am using both a stepper and servos on my mill, all with a single loop via magnetic scales. All of the velocity feedback that is required comes from the magnetic scales, there is no need for an encoder on the motor unless the servo drive requires it. There is no under or over shoot, it goes where it is told to go and is accurate to within plus/minus 1 pulse. In my case, 1 pulse is 0.000039 inches (1 micron)

    As soon as I get the tach sensors installed, it will also be controlling my spindle drive VFD.
     
  30. jumps4

    jumps4 Global Moderator Staff Member Active Member

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    it's good to see more programmers showing interested in hobby cnc and I hope they can get something to market in an affordable price range, I have no problems with mach3 and the uc100 controller running my mills I have built but I have found nothing I feel comfortable with to run my cnc lathe, it works if you babysit it but there always seems to be a lack of trust on my part. my mill I can just install the stock and hit cycle start over and over the lathe seems to lack my trust it just does weird crap whenever it feels like it.
    I have just done a redo on my lathe setup this week and will start testing to see if I can get better repeatability.
    http://www.hobby-machinist.com/showthread.php?t=8692
    steve
     

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