topic Re: How to draw a CAM from a sample? in Inventor Forum

How to draw a CAM from a sample?

drawingsCHR7R — Wed, 15 Jul 2020 07:26:22 GMT

Hi Guys,

I have a physical sample of a CAM and I would like to redraw it in Inventor, I'm struggling to find a way to go about this.

Does anyone have some ideas as to how I could do this accurately?

Thanks.

Re: How to draw a CAM from a sample?

JDMather — Wed, 15 Jul 2020 10:37:49 GMT

Cams can take many forms.
Attach image of actual part and the *.ipt of your initial attempt here.

Re: How to draw a CAM from a sample?

JDMather — Wed, 15 Jul 2020 11:36:11 GMT

@JDMather wrote:

Cams can take many forms.
Attach image of actual part and the *.ipt of your initial attempt here.

@drawingsCHR7R

This is the solution???

Re: How to draw a CAM from a sample?

drawingsCHR7R — Wed, 15 Jul 2020 11:57:37 GMT

Hi JD,

I have no idea why but for some reason whenever I post anything to the forum the first reply is automatically marked as the correct solution. It isn't me that is marking it as such so I have no explanation as to why this is happening.

I am out of the office at the moment when I get back I will send a picture of the CAM.

Re: How to draw a CAM from a sample?

JDMather — Wed, 15 Jul 2020 12:18:11 GMT

I will unmark the "solutions" so that this thread gets proper attention when you post the additional information.

The Cam - Design Accelerator creates 3 types of cams, and of course there are manual techniques when the semi-automatic techniques are not suitable (which is probably the case for this one).

Re: How to draw a CAM from a sample?

Frederick_Law — Wed, 15 Jul 2020 12:37:58 GMT

@drawingsCHR7R wrote:

Does anyone have some ideas as to how I could do this accurately?

CMM the CAM profile.

Do some research on CAM design. Beside locating prats, it also contain speed and acceleration in the profile.

Those could affect how the machine run.

Of course it depend on how "accurately", +/-1, +/-0.0001?

Re: How to draw a CAM from a sample?

drawingsCHR7R — Thu, 16 Jul 2020 05:48:22 GMT

Attached is the the picture of the CAM, also the sketch in the ipt file was done in AutoCAD so that is why it is not constrained. I am not very knowledgeable when it comes to CAMs so do bear with me on this please.

Re: How to draw a CAM from a sample?

drawingsCHR7R — Thu, 16 Jul 2020 05:55:05 GMT

I'll do some research and hopefully that will help me.

Re: How to draw a CAM from a sample?

drawingsCHR7R — Thu, 16 Jul 2020 05:56:01 GMT

Thanks JD.

Ill have a look at all three types and see if I can use it to help me redraw the sample.

Re: How to draw a CAM from a sample?

JDMather — Thu, 16 Jul 2020 12:14:26 GMT

The Cam Generator will not help you on this type of cam.

I assume this is a low speed application (not high RPM) which makes everything less critical.

I would go ahead and add the dimensions and the missing Tangents (there is one really bad connection).

In any cam design - the shape and size of the follower is also important as the contact point between the cam and the follower is continuously variable. Do you have an image of the follower.

Can you comment on normal operation of this cam? Is this a cam lock, or does it perform some displacement function?

What I propose to do is place the cam and follower into Dynamic Simulation and observe the Displacement and the Acceleration curves for the follower.

Re: How to draw a CAM from a sample?

drawingsCHR7R — Thu, 16 Jul 2020 12:34:56 GMT

Hi JD thanks for the reply.

You are correct in saying that this is not a high rpm CAM, from what I understand it is used as a sort of lifting mechanism. Not revolving fast at all.

I think that's a good idea, I will definitely add the dimensions that are there, when you say a 'bad connection' could you please show/tell me where it is so that I can rectify it.

The follower in this case is not your traditional one as the one used in the current situation is literally a block, so the follower is not too important in my opinion as it has a large surface area. Unfortunately I do not have a picture.

I like your suggestion, thanks. I'm not proficient in dynamic simulation, but I'll take it as a learning curve and see what I can do.

Thanks for all the help.

Re: How to draw a CAM from a sample?

JDMather — Thu, 16 Jul 2020 12:52:35 GMT

@drawingsCHR7R wrote:

1. ...when you say a 'bad connection' could you please show/tell me where it is so that I can rectify it.

2. ...the follower is not too important in my opinion as it has a large surface area.

3. ...I'm not proficient in dynamic simulation,

1. See Image.

2. Actually, it is. Can explain the unconstrained degrees of freedom that it is free to move through? (Example, a ball has 6 degrees of freedom - it can move anywhere in space until constrained by other items (like the floor).

3. I did not expect that you would have the experience to get anything meaningful from Dynamic Simulation - I was going to do that for you to demonstrate.

Re: How to draw a CAM from a sample?

drawingsCHR7R — Fri, 17 Jul 2020 10:13:27 GMT

1. Thanks a lot JD, I will definitely go and fix that.

2. Allow me to clarify, this CAM that you see is used in a prop that we produce, the CAM will never make a full rotation as it is used to essentially tension the support block to the ceiling of a a mine. So thus the follower is a block with a radius that has a larger surface area than the width of the CAM. I hope that was able to clarify why I said the follower is not as important?

3. Thanks JD, Unfortunately I doubt I would be able to provide enough info on this product for you to be able to run the simulation as I do not know enough about the product, i am more than willing to try though. We will have to go via private messages as this product is a patent.

Re: How to draw a CAM from a sample?

drawingsCHR7R — Fri, 17 Jul 2020 10:14:20 GMT

I can also privately supply you with a picture of the follower if you so wish, maybe that will give a better indication.