topic Re: Inventor 2018 Creating A Cylindrical Cam Path in Inventor Forum

Inventor 2018 Creating A Cylindrical Cam Path

Anonymous — Thu, 08 Feb 2018 19:51:05 GMT

I am having trouble creating a cam path. I am currently using the emboss feature to wrap my 2D sketch around a cylinder, on the sides of the profile, the walls are not perpendicular to the OD surface of the cylinder. I think I am using the wrong feature to do this. Please help!!

I've attached a copy of my part that includes the 2d Sketch and the Emboss. Thanks in advance!!

- Evan

kelly.young has edited your subject line for clarity: Creating a Cam Path

Re: Inventor 2018 Creating A Cylindrical Cam Path

JDMather — Thu, 08 Feb 2018 19:51:29 GMT

Later today I can show you the hard way (I am not at my computer with the documentation at the moment),

but the easy way is with the Cylindrical Cam Generator

Re: Inventor 2018 Creating A Cylindrical Cam Path

Anonymous — Thu, 08 Feb 2018 19:51:46 GMT

That would be great! Thank you. I've attached a photo of our actual piece off the CNC. You can see the gap between the follower and wall. Not sure if this helps, but wanted to share all the information i have. Thanks again!

-Evan

kelly.young has embedded your image for clarity

Re: Inventor 2018 Creating A Cylindrical Cam Path

JDMather — Thu, 08 Feb 2018 19:52:00 GMT

@Anonymous wrote:

.... You can see the gap between the follower and wall.

Now I am confused - in the picture of the actual manufactured part - it does not appear to have been manufactured correctly.

I would expect the cylindrical follower to be touching full face with the cam (otherwise it will wear quickly and just plane isn't correct).

Are you trying to reproduce the existing part as shown in the image - or are you trying to correct this part for full face contact?

In the document that I will post later - it will show how we used to do this before the Cylindrical Cam generator was added to Inventor.

Re: Inventor 2018 Creating A Cylindrical Cam Path

Anonymous — Thu, 08 Feb 2018 19:52:16 GMT

Sorry for the confusion. The .ipt I attached in the first thread matches the actual manufactured part (the picture in my last thread.) Which both are incorrect. I would like to correct my .ipt file for full face contact. Thanks! Looking forward to your response.

-Evan

Re: Inventor 2018 Creating A Cylindrical Cam Path

JDMather — Thu, 08 Feb 2018 19:52:31 GMT

That is what I thought - but wanted to make sure.

Re: Inventor 2018 Creating A Cylindrical Cam Path

johnsonshiue — Thu, 08 Feb 2018 19:52:47 GMT

Hi! I think the true solution has to be created by sweep the cam volume along the path. Anything otherwise is an approximation. Unfortunately, Inventor 2018 do not support such sweep yet. We are working on a robust solution which will allow a solid body to sweep along a path.

There are approximated solutions available by using Ruled Surface or Profile Sweep or Emboss. But, they are all approximations. I can take a look and propose an acceptable alternative workflow.

Many thanks!

Re: Inventor 2018 Creating A Cylindrical Cam Path

Anonymous — Thu, 08 Feb 2018 19:53:13 GMT

Hi Johnson,

I've attached my files below. Please let me know if there is a solution to create a profile for full face contact of our follower. Thanks!

-Evan

Re: Inventor 2018 Creating A Cylindrical Cam Path

johnsonshiue — Thu, 08 Feb 2018 19:53:29 GMT

Hi Evan,

I have taken a look at the part. For this particular case, I am not aware of a better solution within Inventor right now. The true geometry has to be created by sweeping a solid profile.

Many thanks!

Re: Inventor 2018 Creating A Cylindrical Cam Path

JDMather — Thu, 08 Feb 2018 19:53:49 GMT

There is an easy and absolutely correct solution - but I am tired and shutting down for the night.

Keep checking back for the solution.

Re: Inventor 2018 Creating A Cylindrical Cam Path

Anonymous — Thu, 08 Feb 2018 19:54:09 GMT

Sounds good. I will check back tomorrow. Thanks!

Re: Inventor 2018 Creating A Cylindrical Cam Path

JDMather — Thu, 08 Feb 2018 19:54:26 GMT

Bump.

Looks like I will have a snow day tomorrow and be able to get back to this one.

Re: Inventor 2018 Creating A Cylindrical Cam Path

JDMather — Thu, 08 Feb 2018 19:54:42 GMT

@evancGKMPD

Here you go.

I made a couple of changes to dimensions that I wasn't sure about (didn't make sense a inch or mm), but these are easy for you to change.

The key is that the centerline path of the cutter used to make the cam is known, but the tangent point between cutter and part must be determined from the combined rotational and translational motion.

If this mechanism runs at a relatively high speed - I would probably look at the acceleration curve of the cam motion as well.

If it is slow speed, then the acceleration changes should not be an issue.

kelly.young has removed sick link for clarity

Re: Inventor 2018 Creating A Cylindrical Cam Path

Anonymous — Thu, 08 Feb 2018 19:54:59 GMT

Thank you. This will help us alot!!

-Evan

Re: Inventor 2018 Creating A Cylindrical Cam Path

JDMather — Thu, 08 Feb 2018 19:55:19 GMT

@Anonymous

As a demonstration of the subtle difference - I edited my part to more closely duplicate your dimensions.

Take a look at this file (red is your geometry - blue is mine).

Note that the OD is the same, but the ID is different curve.

Offsetting a 2D curve is not the same as offsetting a 3D surface.