20 Replies Latest reply on Feb 26, 2019 8:06 AM by Newell Voss

    How do i solve for unknown coordinates blueprint?

    Christopher Frantz

      Hello

       

      I am an adult student at a Solidworks / Machining class. I'm about 4 weeks in with zero prior experience. I am having trouble with getting XY coordinates on contour parts. My intent is to insert the coordinates onto a program using notepad, then load into Haas control panel simulator. The instructors are top notch (not being sarcastic) but I'm still having trouble grasping the concept.

       

      Request assistance from the esteemed Solidworks Community.

       

      V/r

      Chris

       

       

      IMG_2122.JPG

        • Re: How do i solve for unknown coordinates blueprint?
          Solid Air

          What co-ordinates are you having trouble obtaining?  I have looked over your screen shot (quickly).  I do not see anything missing from the drawing?

          • Re: How do i solve for unknown coordinates blueprint?
            J. Mather

            Attach your *.sldprt file here - I will show how to get any coordinate from the part for the purpose of manually writing the CNC code.

            • Re: How do i solve for unknown coordinates blueprint?
              Erik Bilello

              This is getting a bit off topic, but it's one of my pet peeves, and perhaps its part of the problem you're having. The improper use of center lines.

              A centerline (the C with an L superimposed on it symbol) implies symmetry about the line.  At first glance I thought that there might at least be some rotational symmetry going on around the intersection of the two centerlines, but closer examination shows no overall symmetry at all. The only thing I can see about this part that has any symmetry is the "base" rectangular block, and the R.30 notches.

              If a part is mostly symmetric, but not quite, I can see putting in a centerline, to reduce the number of dimensions on a busy drawing, and adding a note to point out the (one or two) nonsymmetric features. But when the part is mostly nonsymmetric adding a centerline that only applies to a few features will require a note to explain what it applies to, and will most likely add more clutter than the few dimensions it would eliminate.

              On this drawing I'm guessing that the centerlines are intended to show the locations of the four half-round notch centerpoints. Implying that they are centered on the base (I.E. at 1.625 and 1.125). I would also guess that the reason for doing this was to skate around the rounding error you would have if they were given dim's with just 2 decimals. For whatever reason, bad practice in my book, I think there are better ways those features could be dimensioned.

              I'll also guess that the centerpoints of the four half-round notches are supposed to be .10 in from the edges of the base (in line with the milled edges). In that case there should at least be a "TYP" added to the .10 , 2.15 and 3.15 dim's. Much clearer, of course, would be to independently dimension each point, even if they are in line with the edges.

              Without looking at the model I can only guess, so I may be entirely wrong about all of this.

                • Re: How do i solve for unknown coordinates blueprint?
                  Kevin Chandler

                  Erik Bilello wrote:

                   

                  This is getting a bit off topic, but it's one of my pet peeves, and perhaps its part of the problem you're having. The improper use of center lines.

                   

                  Off topic II:

                  I'm also seeing an increase of incomplete CL dimensioning and I think it stems from the decline in training (or poor training).

                  With my suspicious nature, I default to it being laziness, as usually, the part is not completely defined, but to the untrained eye, I'm sure it looks complete.

                   

                  Kevin

                • Re: How do i solve for unknown coordinates blueprint?
                  Frederick Law

                  X Y co-ordinates are there, start with 0.  End at 2.25 and 3.25.

                  With a few assumptions, you can machine the part.

                  • Re: How do i solve for unknown coordinates blueprint?
                    Kevin Chandler

                    Hello,

                     

                    To get your coordinates, I believe you're going to have to do some trigonometry, especially for the 16° and 18° chamfers.

                    Plus the arc center to do circle interpolation.

                     

                    Kevin

                      • Re: How do i solve for unknown coordinates blueprint?
                        David Nelson

                        Kevin Chandler wrote:

                         

                        Hello,

                         

                        To get your coordinates, I believe you're going to have to do some trigonometry, especially for the 16° and 18° chamfers.

                        Plus the arc center to do circle interpolation.

                         

                        Kevin

                         

                         

                        They give the start point for the chamfer and the angle would that not be all that's needed.  The Arc  centers are 1/2 of the total length.

                          • Re: How do i solve for unknown coordinates blueprint?
                            Tony Tieuli

                            David Nelson wrote:

                             

                            Kevin Chandler wrote:

                             

                            Hello,

                             

                            To get your coordinates, I believe you're going to have to do some trigonometry, especially for the 16° and 18° chamfers.

                            Plus the arc center to do circle interpolation.

                             

                            Kevin

                             

                             

                            They give the start point for the chamfer and the angle would that not be all that's needed. The Arc centers are 1/2 of the total length.

                            That would be all you would need if you were only going to model the part but to input the coordinates directly into a machine you would need the X end points as well. So you would need to trig them out or get the points from the model.

                              • Re: How do i solve for unknown coordinates blueprint?
                                Kevin Chandler

                                Tony Tieuli wrote:

                                 

                                David Nelson wrote:

                                 

                                Kevin Chandler wrote:

                                 

                                Hello,

                                 

                                To get your coordinates, I believe you're going to have to do some trigonometry, especially for the 16° and 18° chamfers.

                                Plus the arc center to do circle interpolation.

                                 

                                Kevin

                                 

                                 

                                They give the start point for the chamfer and the angle would that not be all that's needed. The Arc centers are 1/2 of the total length.

                                That would be all you would need if you were only going to model the part but to input the coordinates directly into a machine you would need the X end points as well. So you would need to trig them out or get the points from the model.

                                That's just it...I'm not quite certain what the assignment entails.

                          • Re: How do i solve for unknown coordinates blueprint?
                            Paul Risley

                            I don't think the centerlines are of any value as others have already pointed out. My biggest problem with this print though has to be the use of ordinate dimensions in the lower left corner. This requires a custom setup in most facilities it also allows the most room for errors to be made.

                            I am going to sound like a crotchety old curmudgeon on this one but upper left or lower right corner on position origins for milled parts main detail views. It falls logically in with how fixed jaw vises are usually setup, as well as how most machinists interpret prints. Fixed jaw in rear, stop on left side of vise. Prints read from left to right. Like I said I am going to sound crotchety and  I will admit I am picky, but if you can do something that is going to reduce the chance of a part being made wrong I will take it every day.

                            I can see this part is a training aid, but what is it training with the centerlines calling for symmetry when there is not. Oh well.

                             

                            As far as your coordinates for absolute positioning you would probably be best served drawing this in Solidworks(there are enough dimensions to do so) except thickness. Then you would be able to derive your coordinates.

                              • Re: How do i solve for unknown coordinates blueprint?
                                John Stoltzfus

                                Paul Risley  wrote:

                                 

                                It falls logically in with how fixed jaw vises are usually setup, as well as how most machinists interpret prints. Fixed jaw in rear, stop on left side of vise. Prints read from left to right.

                                Absolutely.......

                                • Re: How do i solve for unknown coordinates blueprint?
                                  Tony Tieuli

                                  Paul Risley wrote:

                                   

                                  I don't think the centerlines are of any value as others have already pointed out. My biggest problem with this print though has to be the use of ordinate dimensions in the lower left corner. This requires a custom setup in most facilities it also allows the most room for errors to be made.

                                  I am going to sound like a crotchety old curmudgeon on this one but upper left or lower right corner on position origins for milled parts main detail views. It falls logically in with how fixed jaw vises are usually setup, as well as how most machinists interpret prints. Fixed jaw in rear, stop on left side of vise. Prints read from left to right. Like I said I am going to sound crotchety and I will admit I am picky, but if you can do something that is going to reduce the chance of a part being made wrong I will take it every day.

                                  I can see this part is a training aid, but what is it training with the centerlines calling for symmetry when there is not. Oh well.

                                   

                                  As far as your coordinates for absolute positioning you would probably be best served drawing this in Solidworks(there are enough dimensions to do so) except thickness. Then you would be able to derive your coordinates.

                                  Being a crotchety old curmudgeon myself as well as having spent my entire career either working in or supporting a milling department I can say that I am in complete agreement with you!

                                  I have always said that any engineer who is going to be designing parts to be made in a machine shop should be required to work for at least a year in a machine shop as part of their education.

                                • Re: How do i solve for unknown coordinates blueprint?
                                  David Matula

                                  did I see that your still using blue prints?  why?

                                  • Re: How do i solve for unknown coordinates blueprint?
                                    Newell Voss

                                    Tell your instructor to kick rocks, no one is doing manual Gcode these days.

                                    Otherwise create the model and then a reference sketch over the top to give you the missing coordinates.

                                    Also regarding centerlines, they do NOT automatically imply symmetry despite what everyone else seems to think. Otherwise they wouldn't have made a separate GD&T symbol to use.

                                      • Re: How do i solve for unknown coordinates blueprint?
                                        Erik Bilello

                                        I would point out that this drawing does not appear to use GD&T.  In this case, the centerlines (long dash/short dash) without the centerline symbol (C with L, I can't find an alt-code for it) indicate that the two R.30 notch centers have the same vertical dimension and the R.35 and R.40 notch centers have the same horizontal dimension.  Neither of those dimensions are specified.

                                        When a centerline is used to delineate an array of holes (technically the center points of the holes), or the axis of a round part, the symbol is not added.

                                        Adding the symbol implies part symmetry of some sort. So I suppose that I should have said that my peeve is the misuse of the centerline symbol.  A centerline by itself, wandering through a drawing, does not imply symmetry, it could be legitimately locating hole centers, but placing a centerline symbol at one end of it implies there is something (besides the circular hole profiles it may be locating) symmetric about it.

                                        If, as I suspect, the centerline symbols are being used here to indicate the locations of the half-round notches relative to the rectangular "base", a clarifying note should be included with the symbols. Simply putting a dimension on each of the centerlines would have been just as easy, and much more definite.

                                        Not to mention that locating features from whatever the centerlines are the center of, seems at odds with calling out the lower left corner as the origin.

                                          • Re: How do i solve for unknown coordinates blueprint?
                                            Newell Voss

                                            Agree to disagree..

                                            It still does not imply symmetry. Centerlines can be used to locate multiple features in any location, the addition of the CL symbol is purely to tell you that those locations are exactly 1/2 of the overall dimension(s) provided. The centermark is added additionally to fully define those features and indicates they lie on the same edge offset dimension as the rest of the profile. If you need a note to distinguish any misconceptions about this print, you should'nt be machinist.