Using Trigonometry for manual programming
Close
Login to Your Account
Page 1 of 5 123 ... LastLast
Results 1 to 20 of 87
  1. #1
    Join Date
    Feb 2021
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    2

    Default Using Trigonometry for manual programming

    Hello all,

    Extreme novice machinist in training here. Iím currently enrolled in a CNC course at the local community college. Weíve covered a number of basic skills so far such as setting work coordinates, tool length offsets, dialing in a vise, picking up an edge, picking up holes and bosses, etc. Weíve also got the chance to run a few programs to make some parts out of stock that we squared up on the manual mills during the last course that I took.

    This last week, homework has been about using trigonometric functions and right triangles to find missing dimensions on prints. Itís been very challenging for me as before these classes I havenít really done math since about 2005 in college. haha. And even then I never did take a trig class. So Iíve kind of given myself a YouTube crash course in trigonometry over the last week and learned Pythagorean Theorem and all that so I could maybe understand what weíre currently learning.

    Iíll attach a pic to this post. What theyíre looking for is for us to be able to calculate the two XY points of a blend arc. Iím not asking for anyone to do my homework but I feel if I could at least see the right triangles required to do the math I might have an ah ha moment and be able to figure out other similar problems with missing dimensions. So if anyone would care to draw the required triangles or point me in the direction of a good resource it would be much appreciated. Iím just trying to learn all I can and this stuff has me stumped. I have class again on Thursday and would like to come in with some knowledge.

    Thanks for any help. Hopefully this was the correct forum to post in.

    Drew

  2. #2
    Join Date
    Feb 2021
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    2

    Default

    blend-arc.jpg Here's a pic of the print

  3. #3
    Join Date
    Jun 2012
    Location
    Michigan
    Posts
    5,808
    Post Thanks / Like
    Likes (Given)
    5498
    Likes (Received)
    3704

    Default

    Quote Originally Posted by Dhoverson View Post
    So if anyone would care to draw the required triangles or point me in the direction of a good resource it would be much appreciated.
    Excuse the curvy lines, I'm not right handed and can't draw with a mouse.
    On the Vertical line where the red and green meet are your 90 deg angles for each triangle.
    Attached Thumbnails Attached Thumbnails pt.jpg  

  4. #4
    Join Date
    Sep 2010
    Location
    Victoria Australia
    Posts
    4,082
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1712

    Default

    Quote Originally Posted by Mtndew View Post
    Excuse the curvy lines, I'm not right handed and can't draw with a mouse.
    On the Vertical line where the red and green meet are your 90 deg angles for each triangle.
    Hello Mtndew,
    Maybe I'm not seeing it, but I don't believe there is enough information to be able to use the triangles you propose. The only known side of those two triangles is the hypotenuse of the lower triangle.If you knew the chord from P1 to P2, then Heron's Form could be used with your two triangles.

    There are more elegant solutions to this problem, but for the OP to use Trig, I think he would need to get the angle of the line from Y0.5 and tangent to the arc.

    To do this, the acute angle of the Green Triangle (two sides known), shown in the following picture, will allow the acute angle of the Blue Triangle (two sides known after the Green Triangle is resolved)to be calculated. The combination of these two acute angels will allow P2 to be calculated using the Magenta Triangle.

    Regards,

    Bill

    trig3.jpg
    Last edited by angelw; 02-24-2021 at 04:07 PM.

  5. #5
    Join Date
    Feb 2021
    Country
    UNITED KINGDOM
    Posts
    1
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1

    Default

    pic1.jpgpic2.jpg
    First post, thought I'd better try and input something before I ask Bill about Fanuc servo drives!
    Excuse the grease.
    Your tutor is evil.
    No one will ever give you a drawing like that. They are normally dimensioned to the intersection

  6. Likes barratt liked this post
  7. #6
    Join Date
    Sep 2018
    Country
    UNITED STATES
    State/Province
    California
    Posts
    15
    Post Thanks / Like
    Likes (Given)
    11
    Likes (Received)
    6

    Default

    Welcome to the trade. You'll regret it later. lol
    Here's a fun one for you.
    findradius.jpg

  8. Likes ixohhoxi liked this post
  9. #7
    Join Date
    Sep 2002
    Location
    People's Republic
    Posts
    5,827
    Post Thanks / Like
    Likes (Given)
    701
    Likes (Received)
    3646

    Default

    Quote Originally Posted by Mtndew View Post
    Excuse the curvy lines, I'm not right handed and can't draw with a mouse.
    trackball....................without CAD I think you are short a dimension for a solution, either and angle somewhere or a length or something. Where are the Y locations of those triangles ? In CAD you just draw the circle and make a tangent line and pick the point.
    [edit] just figured out Franks scrawl, damn what a pain, CAD is faster, I suppose they make you use trig tables too....

  10. #8
    Join Date
    May 2017
    Country
    UNITED STATES
    State/Province
    Minnesota
    Posts
    1,743
    Post Thanks / Like
    Likes (Given)
    2261
    Likes (Received)
    1156

    Default

    In industry, the correct answer is to spend three minutes to draw it up in Solidworks. Too much time and chance of error when you do it longhand. That said, it's good to be able to do that sort of thing longhand; I once had to prove longhand that the output of a rolldie post processor was correct before the customer would have their machine checked. Turns out they needed servo tuning.

  11. #9
    Join Date
    Apr 2018
    Country
    UNITED STATES MINOR OUTLYING ISLANDS
    Posts
    7,361
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    3593

    Default

    Quote Originally Posted by mhajicek View Post
    In industry, the correct answer is to spend three minutes to draw it up in Solidworks. Too much time and chance of error when you do it longhand.
    Absolutely, but the point of a school is to teach you how and why something works. When you know the whys you can take shortcuts, but if you don't even know why, you're lost. As we can see in many posts here asking very elementary questions.

    I also think that particular drawing is evil, but obviously it was intended to be

  12. #10
    Join Date
    Jun 2012
    Location
    Michigan
    Posts
    5,808
    Post Thanks / Like
    Likes (Given)
    5498
    Likes (Received)
    3704

    Default

    Quote Originally Posted by angelw View Post
    Hello Mtndew,
    Maybe I'm not seeing it, but I don't believe there is enough information to be able to use the triangles you propose.
    I know, he was asking how to draw initial triangles to solve problems like this.
    I didn't want to do his homework but I gave him an example of how it's done (if all of the dimensions were there).


    Plus it was early I had just got into work and hadn't had my caffeine yet.

  13. #11
    Join Date
    Jan 2007
    Location
    Flushing/Flint, Michigan
    Posts
    10,173
    Post Thanks / Like
    Likes (Given)
    575
    Likes (Received)
    8318

    Default

    Quote Originally Posted by EmanuelGoldstein View Post
    .....
    I also think that particular drawing is evil, but obviously it was intended to be
    This seems very evil for students just entering the world of trig. Is it meant to teach one that cad is much easier?
    There is a button for line tangent to circle through a point. There are of course two but only one makes sense and the cad figures out which from the picks.

    Wonder what project 53-06 was?
    Bob

  14. Likes yardbird liked this post
  15. #12
    Join Date
    May 2019
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    1,911
    Post Thanks / Like
    Likes (Given)
    1056
    Likes (Received)
    1227

    Default

    Everyone knows math is racist and 2+2=5

  16. #13
    Join Date
    Feb 2021
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    2

    Default

    Quote Originally Posted by thedude31 View Post
    Welcome to the trade. You'll regret it later. lol
    Here's a fun one for you.
    findradius.jpg
    Haha! That one looks like a headache. I really appreciate the responses everyone. Iíll take a look at your examples and see if I can make sense of them. I work in the Aerospace industry in WA. Been in if for 10 years now building commercial airline interiors. Everything from working on moving lines building luggage stowage bins to running larger infrared ovens for a vacuum form process for applying decorative laminate to parts, to now for about the last year Iíve been a 3 axis router table operator. Running the 3 axis routers isnít a terrible gig. They give you your work package for the day and you just keep the machine running.

    However, I really wanted to get a transferable skill under my belt. Something that could be applied to any industry in just about any place my family and I would ever live. I started looking into all things machining a while back and felt really drawn to it. Itís definitely the most technical, and vast subject matter Iíve ever looked into. And I thought going through automotive tech school back in 2005-2007 was technical. Haha!

    We have tooling machinists at work that work on press dies and such. Iím aiming to get into that shop and go from there or get into the apprenticeship program if I can get accepted. Itís very competitive and not opened up very regularly. Iíve been bitten by the machining bug so bad Iíve even considered selling an extra vehicle we have to buy a mill for the home shop. Haha.

    I hope to continue learning and as such hopefully I can contribute to this board some day. Iíll be sure to post some pics of the finished parts from school when Iím done.

    Thanks again for your replies everyone.

    Drew

  17. #14
    Join Date
    Dec 2004
    Location
    San Antonio, Texas
    Posts
    216
    Post Thanks / Like
    Likes (Given)
    36
    Likes (Received)
    242

    Default

    Quote Originally Posted by Dhoverson View Post

    I hope to continue learning and as such hopefully I can contribute to this board some day. I’ll be sure to post some pics of the finished parts from school when I’m done.

    Thanks again for your replies everyone.

    Drew
    You'll do fine. I also used community college to break into machining. And then I used it again to break into NC programming. Onwards and upward!

  18. #15
    Join Date
    Feb 2021
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    2

    Default

    Quote Originally Posted by davehud View Post
    You'll do fine. I also used community college to break into machining. And then I used it again to break into NC programming. Onwards and upward!
    Right on. Glad to hear I'm not the only one. The machinists at work tell me to never stop learning. They take a Mastercam class every year to stay current among other things. Feels good to turn the brain back on after a decade of doing repetitive manufacturing.

  19. #16
    Join Date
    Sep 2010
    Location
    Victoria Australia
    Posts
    4,082
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1712

    Default

    Quote Originally Posted by thedude31 View Post
    Welcome to the trade. You'll regret it later. lol
    Here's a fun one for you.
    findradius.jpg
    Hello thedude31,

    You've got to make it a bit harder than that for him.

    The hypotenuse = 8.6023

    Therefore
    A = 7 x 5 x 0.5
    A = 17.5
    Where:
    A = Area

    HP = (7 + 5 + 8.6023) / 2
    HP = 10.30115
    Where:
    HP = Half Perimeter

    R = A/HP = 17.5 / 10.30115
    R = 1.6988



    Regards,

    Bill

  20. Likes jz79, thedude31 liked this post
  21. #17
    Join Date
    Feb 2008
    Location
    MI, USA
    Posts
    957
    Post Thanks / Like
    Likes (Given)
    70
    Likes (Received)
    395

    Default

    Quote Originally Posted by angelw View Post
    Hello thedude31,

    You've got to make it a bit harder than that for him.

    The hypotenuse = 8.6023

    Therefore
    A = 7 x 5 x 0.5
    A = 17.5
    Where:
    A = Area

    HP = (7 + 5 + 8.6023) / 2
    HP = 10.30115
    Where:
    HP = Half Perimeter

    R = A/HP = 17.5 / 10.30115
    R = 1.6988



    Regards,

    Bill
    I've had lots of higher maths and I've never been taught this shit. Wtf

    Semiperimeter - Wikipedia

    Learned something today. A=rs. huh.

  22. Likes Conrad Hoffman, mountie liked this post
  23. #18
    Join Date
    Dec 2004
    Location
    San Antonio, Texas
    Posts
    216
    Post Thanks / Like
    Likes (Given)
    36
    Likes (Received)
    242

    Default

    Quote Originally Posted by Dhoverson View Post
    Right on. Glad to hear I'm not the only one. The machinists at work tell me to never stop learning. They take a Mastercam class every year to stay current among other things. Feels good to turn the brain back on after a decade of doing repetitive manufacturing.
    I had a 40 year career in aerospace. Loved it. From running engine pylons on manual DeVliegs to programming landing gear parts on a 5-axis rotary head gantry.
    Attached Thumbnails Attached Thumbnails scan0003.jpg   m2.jpg  

  24. Likes Johnhudson, Dhoverson, mountie liked this post
  25. #19
    Join Date
    Sep 2018
    Country
    UNITED STATES
    State/Province
    California
    Posts
    15
    Post Thanks / Like
    Likes (Given)
    11
    Likes (Received)
    6

    Default

    Quote Originally Posted by angelw View Post
    Hello thedude31,

    You've got to make it a bit harder than that for him.

    The hypotenuse = 8.6023

    Therefore
    A = 7 x 5 x 0.5
    A = 17.5
    Where:
    A = Area

    HP = (7 + 5 + 8.6023) / 2
    HP = 10.30115
    Where:
    HP = Half Perimeter

    R = A/HP = 17.5 / 10.30115
    R = 1.6988



    Regards,

    Bill
    Dear mother of god... lol

  26. #20
    Join Date
    Nov 2004
    Location
    RC, CA
    Posts
    2,187
    Post Thanks / Like
    Likes (Given)
    224
    Likes (Received)
    472

    Default

    I had something like that to program a wire EDM to make a die. It had a tab hanging off part of it, not fully dimensioned. I struggled and struggled with it, and after many steps had a solution the machine would accept. I figured I just sucked at Trig.

    Some time later a rep for the machine dealer stopped by and saw it. He'd been through some CAM classes, 'that looks pretty tough, how did you program it?'. By hand. 'Umm, how would you like to teach a programming class?' No thanks.

    I've seen a lot more since. And as already noted, I generally draw it up in CAD and pull numbers off of it. Unless I'm feeling like I need a challenge for some stupid reason.


Tags for this Thread

Bookmarks

Posting Permissions

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