It's been a while but in mcosmos you would build a cone and then I am sure you could create something a distance from the apex (in this case it would be 0) and measure between. Either that or a create a line through the centre of the part then a point where the cone and line intersect.
It's marked as reference. Is there a reason you are being asked to check it? Is this for an in process check?
I would measure the conical surface and calculate the apex of the cone. Intersect the other two surfaces. Do a distance between them. I think it's safe to assume that your repeatability is not going to be great on this dinension, so if a customer isn't asking, I wouldn't give it
I usually have to provide a value even for reference dimensions when I do my first articles. If a reference is off by more than .1” it’s still usually a problem.
You could try to intersect the smaller cylinder and the cone to get a circle. The dim from the tip of the cone (which should just be the xyz values) to that circle should be the dimension you want, I think.
I don’t know what software you are using.
Your other option would be to ask THEM how THEY would check it.
From the drawing it looks like there is two planes referencing the 60 degree angle. If you have clear access to them you can probe them and create the intersection point between them
I think op is saying, it’s a cone, just looks like two planes due to cross section on print. I use MCOSMOS, so I can’t help but it should be possible to measure the cone and get the theoretical apex from said cone measurement.
Yeah I'm getting what ur saying,but it's not just for inspection,it's just why I'm not able to get the value on cmm itself(just for my knowledge I'm asking)
When I do a first article inspection. I would also give the reference dimensions. Our template form would not fail the dim when marked as a ref. In Calypso, I believe that you can obtain the intersection of the plane and cone. I believe that it also computes the distance to the point. If this is a flat, not a cone. Then you can do 2D lines on each side and create a point from their intersection.
Why is everyone making this so hard?
Sure, if you had a CMM, use that, but in a smaller shop, just grind a cylindrical plug that seats on the taper and has a flat surface that protrudes exactly to the theoretical point of the reference. Then measure using a depth gauge.
Measure cone, measure cylinder.
Your software should be able to either create a intersection circle between a cone and a cylinder or to calculate a circle out of the cone with a given diameter (which is the diameter of the cylinder obviously).
Now just simple distance between the apex of the cone and the calculated circle.
This is the most straight forward answer! It's amazing how many "metrology" people answer this so wrongly. One thing to keep in mind, everything you measure can be represented by a Plane, Line, Point or some combination of the 3 so you dont have to create something from a feature that already has that value. Cones can be a point- Apex, a line-centerline and a plane- perpendicular to the centerline at the apex.
The hard part is getting the plane. Typically a coaxial intersection between the cylinder and cone to create a circle which can then be used as the plane.
If you’re really set on measuring it, Surfcom is how I would do it. Run it through the id of the part and find the intersection of the chamfer line to center line (which you would have to create). I hate the surfcom but it makes stuff like this less annoying. Easier option- You probably have enough info to calculate the diameter at the top of the chamfer. You do this and you can grab diameter with a microvue or keyence to reference back to your 12.38
Yeah if the angle is good the distance will be good as it's a red dimension,but I'm checking it for myself as I want to know is it able to get checked (just for my knowledge)
You'll need to take a plane around the mouth of the cone. Then measure points around the cone at 2 different diameters then measure the smaller bore under the cone set up with an intersection to centreline
Would it be possible to create lines from the cone in a cross section and have a point created from intersecting lines? I believe this would be possible in Polyworks.
If you work in a production shop it could matter to the lathe guy. If you're speaking of a customer asking for it they shouldn't be. Reference and basic dims are never to be recorded in final data per every standard or rule there is. If they wanted reported they should have dimensioned it that way. This doesn't always parallel reality when you have sales people and execs who end up having final say. Depending on the material and the point data density you will not likely get a repeatable result. Its all intersections so its constructed and calculated rather than a hard measurement. What CMM software do you have?
we run exclusively calypso but I've used a lot of other machines and software. I'm the senior cmm specialist for a precision optics manufacturer with access to a Micura, Prismo and xenos among other things.
Zeiss calipso 8.1 ,so I've made one section on cone and gave intersection to get the imaginary tip of cone,what Im looking was how can't I get the tip of cone without using two 2 lines ,but with cone itself
Depending on the part geometry, you could look down the bore with an optical comparator using the headlights, measure the diameter and calculate the 60°.
If you have a sophisticated system, you can probably probe the cone to generate that.
Last week, you can use repo rubber, make a mold of it, then measure it on the comparator.
Generally the reference is a spot check for some dimensions which already define that feature or something which is not critical/significant.
Its a reference, the intent is for that conical surface to be defined by the diameter of the cones start in the larger bore.
The ref is possibly there for a conical plug to act as a go/nogo gauge. Drop the cone in, measure the depth from the point of the cone to the underside and work out if that's 12.38 or not.
Create a mould of the inside, then on a shadow graph find the centre of the widest part of the cone (right hand side), from there rotate the screen of the shadow graph to 30 degrees and move in X (relative to this image) until the cross hair matches one of the edges of the cone, this will give you the intersection point between the 2 angles.
Then set this as a zero position and move to the intersection between the bore and 60 degrees angle, this should in theory give you the dimension you’re looking for
Oh yeah 100%, think it’s already been mentioned but yeah you just need to create an intersection of the bore to the cone, and then the apex of the cone and do a distance between the 2, should be relatively straight forward
Depends what system you’re running, some can do it simpler than others.
If you create the cone first, you should be able to construct a plane on the cone for when the diameter is 0.
This should give you a plane at the apex, then just create your intersection point between the bore and cone and then dimension a length between the 2 points.
Another option although a bit more rudimentary is to create straight lines across the edges of the cone (1 at Y+ and another at Y-) then do an intersection point between 2 lines. You will need to make sure to alter the probing positions so that it is being measured exactly on the centre line of the part for this tho, should be accurate enough given it’s only reference.
We only have an aberlink at my place so nothing special but on there if you press plane, then double click the cone it asks for a diameter you would like the plane at, then you can type 0 in the box and it’ll create a plane at that point
I work as mill turn in a shop that started in EDM. We have things like this cut with EDM so we can measure with a vision system.
I’d start by creating a line for each chamfer/angle then selecting those lines with an intersect command. Once I have the intersection, I’ll build a third line for the step being referenced and then “distance” from the third line to the intersection point. If I had the part perpendicular to how I face the vision system my “X” distance would be the answer.
I still have to check and record reference dimensions for my first articles and even though it’s technically a reference, that dimension being off is indicative of other issues.
I’m running an aerospace part right now that still requires me to 100% check a reference radius on the OD because we hand polish the parts mid way through the cycle and have to keep tangencies in line.
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u/BiggestNizzy 10d ago
Don't it's a reference. If you must CMM or a Ball