Create Arc Question

[Jake L]

I feel like there must be a function to do this but I can't find it.

I have 2D wireframe (shown light blue) and I want to create the green arc as shown.

Currently I use "Circle Edge Point" set to "2 Points tangent" and adjust the the arc radius until I get something close. But there must be a way to get the exact arc right?

Not sure it matters but I'm in MC2024 TIA

 

[JParis]

Create Arc - Tangent >> to 2 entities

[Radical1]

Try using "arc tangent/arc one point" select the line, then the point that you wish it to go thru. You can then set the radius/diameter of the arc you need.

Sorry just noticed this doesn't create tangent arc on the angled line

Edited April 25 by Radical1

[Jake L]

4 minutes ago, JParis said:

Create Arc - Tangent >> to 2 entities

Thanks for the speedy reply!

With this method there's no way to have the arc tangent to the angled line at its endpoint. It just makes an arc tangent to both lines and then you must specify a radius.

Just now, Radical1 said:

Try using "arc tangent/arc one point" select the line, then the point that you wish it to go thru. You can then set the radius/diameter of the arc you need.

Thanks for the reply!

I'd like the arc tangent to both lines. This method gets me an arc tangent to the "flat" line that goes thru the endpoint of the angled line, but the arc won't be tangent to the angled line.

BTW had a laugh at your signature

[JParis]

Will making a fillet work?

[Jake L]

2 minutes ago, JParis said:

Will making a fillet work?

I think you end up with the same issue of not having the ability to specify you want the arc tangent thru the endpoint of the angled line. Unless there's something I'm missing?

Maybe I'm asking for too much all at once? 

[Jake L]

Here's a video showing another workaround to get the arc I want. 

Dropbox - Create Arc Workaround Example

[JB7280]

59 minutes ago, Jake L said:

I think you end up with the same issue of not having the ability to specify you want the arc tangent thru the endpoint of the angled line. Unless there's something I'm missing?

Maybe I'm asking for too much all at once? 

What if you extend the upper, angled line beyond the intersection point, so it's tangent, rather than an endpoint?  I'm not on MC at the moment to try it, but it seems like it might like that better.  

[gcode]

I sketched something similar to your screen shot  and tried this.

I couldn't come up with a satisfactory solution.

This problem is 15 seconds work in a parametric modeling software like SolidWorks.

[Jake L]

1 minute ago, JB7280 said:

What if you extend the upper, angled line beyond the intersection point, so it's tangent, rather than an endpoint?  I'm not on MC at the moment to try it, but it seems like it might like that better.  

Thanks for the reply!

I could do that but I still want the arc to be tangent to the angled line at the point where it intersects the small vertical line.

When I originally ran into this challenge I needed the radius of the arc I'm trying to get. It wasn't so much about making something close, I was looking for the  actual number

[gcode]

2 minutes ago, Jake L said:

I was looking for the  actual number

post a file

I'll run it through SolidWorks

[cruzila]

If you do not use a second point or specify radius, there will be no solution. 

 

I just tried two entities and you can adjust the radius size until you get really close to the vertical line. It would only be an approximation but short of getting out the old trig book it will work. Start small and work it up.

[Jake L]

3 minutes ago, gcode said:

I sketched something similar to your screen shot  and tried this.

I couldn't come up with a satisfactory solution.

This problem is 15 seconds work in a parametric modeling software like SolidWorks.

Appreciate the effort!

If we assume there isn't a magic easy button to do this, is there an easier way to do it than what I showed in the video above?

1 minute ago, gcode said:

post a file

I'll run it through SolidWorks

Here you go Dropbox Link to Sample File

3 minutes ago, cruzila said:

If you do not use a second point or specify radius, there will be no solution. 

 

I just tried two entities and you can adjust the radius size until you get really close to the vertical line. It would only be an approximation but short of getting out the old trig book it will work. Start small and work it up.

Thanks for the reply!

This is the closest "easy" solution I came up with as well. I figured I was missing something, seems like there should be a "create arc - tangent to two lines and one tangent point"

[gcode]

4 minutes ago, Jake L said:

I figured I was missing something, seems like there should be a "create arc - tangent to two lines and one tangent point"

 

I got 3 point to work, toggling "Tangent" on and off as I selected the three entities, but I was not confident the result was good.

Certainly not confident enough to use the resulting arc in an program

[Jake L]

2 minutes ago, gcode said:

 

I got 3 point to work, toggling "Tangent" on and off as I selected the three entities, but I was not confident the result was good.

Certainly not confident enough to use the resulting arc in an program

Dang I thought that was gonna work. Looks like for some reason MC decides the tangent point should be a little ways up the angled line. It's a little scary how close to correct it is, but also kind of way off

[gcode]

Here you go

This is a zipped Mastecam file

the radius in 3.0176/2

solved Create_Arc_Sample.zip

[bird2010]

33 minutes ago, Jake L said:

seems like there should be a "create arc - tangent to two lines and one tangent point"

There is such an option....but the results from mastercam are incorrect?!

I don't know why?....but it's wrong

[Jake L]

1 minute ago, gcode said:

Here you go

This is a zipped Mastecam file

the radius in 3.0176/2

solved Create_Arc_Sample.zip 6.28 kB · 0 downloads

Thank you sir. That is what I got using the method in the video I posted above. Good to know that method works.

Just curious, was it simple to do in Solidworks? 4 clicks?

[gcode]

This is ridiculous.

Solidworks gave me Ø3.0176

Doing it Bird's way in MC2024 I've done it 3 times and got 3 different answers

9 minutes ago, Jake L said:

Just curious, was it simple to do in Solidworks? 4 clicks?

In SolidWork

Start a sketch,

sketch a circle in space

constrain it to the horizontal line with a tangent constraint

constrain it to the point with a coincident constraint

constrain it to the angled line with a tangent constraint

 

I'm going to ask our Catia designer to solve this in Catia and see what he gets.

 

[bird2010]

3 minutes ago, gcode said:

This is ridiculous.

Solidworks gave me Ø3.0176

Doing it Bird's way in MC2024 I've done it 3 times and got 3 different answers

Yes... I have the same situation!

In mastercam....Jake L's way is the correct result

[gcode]

We did this in CATIA and got Ø3.0177

In SW I got Ø3.0176

In Mastercam I got 3 different results, none of which agreed with CATIA/SW

I'm going to refer this Mastercam QC

[CNC CHRIS]

i used the fillet option and it works. (level 10)

its identical to yours. if im miss understanding, i apologize.

 

Create_Arc_Sample.mcam

[Jake L]

Just now, gcode said:

We did this in CATIA and got Ø3.0177

In SW I got Ø3.0176

In Mastercam I got 3 different results, none of which agreed with CATIA/SW

I'm going to refer this Mastercam QC

Method above gives Ø3.0176

1 minute ago, CNC CHRIS said:

i used the fillet option and it works. (level 10)

its identical to yours. if im miss understanding, i apologize.

 

Create_Arc_Sample.mcam 284.13 kB · 0 downloads

Did you have to specify a radius?

[StevenM]

36 minutes ago, gcode said:

We did this in CATIA and got Ø3.0177

In SW I got Ø3.0176

 

Doing it in NX I also get Ø3.0176

[gcode]

42 minutes ago, CNC CHRIS said:

i used the fillet option and it works. (level 10)

its identical to yours. if im miss understanding, i apologize.

 

Create_Arc_Sample.mcam 284.13 kB · 2 downloads

 

We can't use "Fillet" because we don't know the radius.