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Why is My Slot Cam Mechanism Not Working

20 REPLIES 20
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Message 1 of 21
akshaykumark
407 Views, 20 Replies

Why is My Slot Cam Mechanism Not Working

Hello,

 

I have created a slot and pin type cam follower mechanism, depicted in the image 1. There are 3 components in the assembly:

  1. A ground plane
  2. A bolt carrier
  3. A bolt inside the bolt carrier

I have created a slider as-built joint between the bolt-carrier and the ground plane and a cylindrical as-built joint between the bolt-carrier and the bolt. I have enabled contact sets and added the 3 components to the set.

 

On the side of the bolt there is a pin (part of the bolt) and on the same side of the bolt-carrier there is an angled slot.

 

Now according to my expectations, when I move the bolt-carrier forward, after hitting the ground-plane's perpendicular extrusion, the bolt should rotate clockwise because the the pin following the slotted-cam. But that is NOT happening. Moving the bolt-carrier backwards the bolt-carrier and bolt move back as expected but only when I move them forward and hit the upward extruded ground plane, the bolts stop.

 

Why is the bolt not rotating as per the slotted-cam and pin mechanism is my question.

 

File attached.

 

My system (office, light workload laptop):

i3 10th gen

8 GB RAM

No graphics card

256 GB NVMe SSd

1 TB HDD

Fusion 360 for hobbyists.

Screenshot 2023-10-01 222252.png

 

Screenshot 2023-10-01 222348.png

 

 

Labels (2)
20 REPLIES 20
Message 2 of 21
davebYYPCU
in reply to: akshaykumark

Without the file for testing, try

 

Disable contact sets.

Motion Study.

Pin needs a Tangent Relationship

Joints need - Joint Limits.

 

Might help....

 

 

Message 3 of 21

@akshaykumark 

Did you create your cam slot correctly? (Almost always done incorrectly by beginners.)

 

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

 

Edit:  I see it now.

The cam slot is not modeled correctly.

In addition - several of your sketches are not fully defined?

Message 4 of 21
akshaykumark
in reply to: davebYYPCU

Does the cylindrical joint need to stay? Because with that the Tangent Relationship is giving a conflict while setting up. 😕
Message 5 of 21

Sure, here.

Message 6 of 21
akshaykumark
in reply to: davebYYPCU

I have edited the pin to make it smaller now, but still it doesn't work..
Message 7 of 21
davebYYPCU
in reply to: akshaykumark

Depends on the answer to this question, 

 

Did you create your cam slot correctly?

 

and the design intent you are looking for.

 

 

Message 8 of 21

There is a slight change that I have made that I have decreased the size of the pin of the bolt. But still it does not work. You can check.
Message 9 of 21

There are quite a few errors.

Are you willing to start over from scratch?

Message 10 of 21
akshaykumark
in reply to: davebYYPCU

I used the emboss tool to create the slot, initially I kept the width and the diameter of the pin same, 5mm, but now I have made the pin smaller.

Sir what is the Design Intent that I'd be looking for?
Message 11 of 21

No problem.
Message 12 of 21

Wow sir is it really you..? I've watched your videos on YouTube..!
Message 13 of 21

No sir they were not fully defined. I did not think they were important. I see may be they are important now. I learnt how to make a slot on a cylinder from YouTube.
Message 14 of 21

@akshaykumark 

What is the link to the YouTube video that showed you how to make a cam slot in a cylinder?

Message 15 of 21
jhackney1972
in reply to: akshaykumark

Animation of the motion of a pin in a cam slot in Fusion 360 is an interesting feat.  I believe the only animation you will get is to drag the plunger manually.   Attached in my simple mock-up of a mechanism like the one you have .  I created my own dimensions as I could not fully decipher yours.  Please review the method of creating the cam slot in the barrel.  Model is attached.

 

I hope this helps and others may give you a better way to animate your model.

 

Cam Slot.gif

 


"If you find my answer solved your question, please select the Accept Solution icon"

John Hackney
Retired

Beyond the Drafting Board


Message 16 of 21
Message 17 of 21
akshaykumark
in reply to: jhackney1972

Sir may I know what is "barrel"?

And referring to "I believe the only animation you will get is to drag the plunger manually", meaning we cannot make the plunger move by manipulating the slotted cylinder?
Message 18 of 21
jhackney1972
in reply to: akshaykumark

The "Barrel" I refer to is the cylindrical outside component with the helical slot in it.  I point to it in the attached screen capture.  You can move either the inside plunger, with the pin, or the outside barrel, with the slot depending on your Joint configuration.  I do think however, all motion will have to be manually driven.

 

Barrel.jpg


"If you find my answer solved your question, please select the Accept Solution icon"

John Hackney
Retired

Beyond the Drafting Board


Message 19 of 21


@akshaykumark wrote:
https://www.youtube.com/watch?v=2Ixp4fpgEgQ

That is what I thought - that video does not create the correct geometry.

Very few people in any CAD software know how to model the geometry correctly.

 

Follow @jhackney1972 instructions.

 

Here is alternative technique but @jhackney1972 technique is a bit easier...

https://www.youtube.com/watch?v=Wekmai5MqFM&t=27s

 

Message 20 of 21


@akshaykumark wrote:
I used the emboss tool to create the slot, 

The created incorrect geometry for a proper cam slot!

Peter Doering

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