Need help to get an assembly to work properly.

[CJPolinski]

Hello,

I'm an electrical engineer and has used Autocad in the 80's and 90's to do 2D drawings. I'm now learning Inventor 2020 and have created an adjustable ramp assembly but cannot get it to behave properly. I have watched many videos and cannot get it to behave. I would like anyone's input to help me get past this roadblock. If you would be willing to help, I will send my project for you to see what I am missing.

I'm including a screenshot of the assembly. The bottom board has all the extrusions. The top board has the support board attached to it. First I tried to make one assembly with all of the parts, but then I made a bottom assembly with the board and 2 hinges, and the top board assembly with all of the rest.

I can get the top board to move independently, but I cannot get the support board to move independent.

[JDMather]

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@CJPolinski wrote:

I cannot get the support board to move independent.

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My guess is that you have a sub-assembly that you did not set to Flexible.

Attach your files here.

[mcgyvr]

If you have subassemblies and you need to have access (allow movement) to any degrees of freedom left adjustable in the upper level assembly that sub is placed into you need to right click on the sub in the upper assembly and select "flexible".

Without that any degrees of freedom are "locked" and unflexible in any upper level assemblies.

[CJPolinski]

I think at one time I tried adaptable and flexible on everything I could, but after trying so many things, so many different ways and still not finding the solution it all starts to blend together.

Thanks for you time and knowledge. Stay healthy.

[JDMather]

Set your Top Board sub assembly to Flexible.

I also set some Contact Sets, but it is recommended that you test and then turn off the Contact Solver as this is computationally expensive.

There might be better ways (angle limits or Dynamic Simulation) depending on what you need.

Some of your sketches are not fully defined - for predictable and robust behavior you should fully define each sketch before proceeding on.

And, be careful how you assemble your components...

[WHolzwarth]

Parallel to JD I've been playing with it. 3 new files, others can be used as they are.

Support board can be moved the long way by driving constraint Drive

Two Posreps for Slot1 and Slot2

Another Posrep for a clean Closed position.

Best way for testing: Copy existing files to a new folder, and place the new files there

[CJPolinski]

First I would like to thank everyone for their help and support.

I have not had time to get back to my project. I had to do some unexpected repairs at my house and spent some time with my 89 year old father. I am lucky he is still living at home during these times.

Hopefully I will get back to my project this week.

Stay safe and healthy.

Best regards.

[lena.talkhina]

Hello @CJPolinski !

Great to see you here on Inventor forum.

I hope your father is well, he is lucky to have you to take care of him.

Let us know if you need more help to go back to the project or accept as a solution if anyone's suggestion helped you.

[CJPolinski]

Well I finally have time to get back to my Inventor project. I would first like to thank everyone for their help on my first assembly project. I have found out how much I still have to learn. If anyone can help on my questions below, thank you. I you have good reference material (book / web) that will help me, please let me know.

JD, thank you for teaching me about Active Contact Solver and Analyze Interference. I knew it could be done but I had no idea of how to do it. They are great tools.

WH, I was not sure how to do the assembly, one big assembly or a bottom board and a top board assembly. I did the top board assemble and it looks like you did one full assembly. I’m guessing that is why all of your relationships are grouped together. Is that correct?

I also see that you filleted the support board and set it tangent to the bottom board extrusions. I’m guessing you did this to make the positions and drive easier. Am I correct?

Here is where I get lost - setting positions, mate, angle and drive. I have looked at the help files but they don’t get into enough details. I’m guessing mate, angle, and drive are all part of setting up drive?

Is angle the resting position? How did you set it?

How did you setup up mate and what did you consider when doing it?

It looks like your drive function positions to the master position. How do I create and drive function for the other 2 positions?

How do you set positions?

[WHolzwarth · Accepted solution]

Good morning Craig, I'll answer between the lines.

WH, I was not sure how to do the assembly, one big assembly or a bottom board and a top board assembly. I did the top board assemble and it looks like you did one full assembly. I’m guessing that is why all of your relationships are grouped together. Is that correct?

WH: Best way for me is always placing parts in a separate sub-assembly, if they are fixed versus one another. But not here. The Butt Hinges would be purchased as unit, therefore setting them as sub-assembly is ok. But they need to be set as flexible, otherwise they wouldn't move in the top-level assembly. The screws for fixing them are missing in your fileset; they could be placed as part of an extended Hinge assembly

I also see that you filleted the support board and set it tangent to the bottom board extrusions. I’m guessing you did this to make the positions and drive easier. Am I correct?

WH: Yes

Here is where I get lost - setting positions, mate, angle and drive. I have looked at the help files but they don’t get into enough details. I’m guessing mate, angle, and drive are all part of setting up drive?

WH: You've made 3 slots in the Bottom Board, two narrow ones and a big slot. In the big slot the Support board can move, you can watch this with driving constraint Drive:1. In the narrow slots no real movement is possible; I've used Posreps Slot1 and Slot2 here, for placing the Support board.

Is angle the resting position? How did you set it?

WH: Yes. It's been set as a 0° angle between Top Board and Bottom Board, and is used for the Posrep Closed

How did you setup up mate and what did you consider when doing it?

WH: Mate is the horizontal distance between the inner face of the big slot and the center of the full round fillet of the Support Board. In Posrep Master it's suppressed, Drive:1 is used as substitute, which can be moved by constraint.

But it's active in Posrep Slot1 and Slot2, Drive:1 is suppressed instead. Difference between Slot1 and Slot2: In Slot2 a distance is shown, but not in Slot1.  In Slot1 it's the same position as the distance in Master. I think, Autodesk should do a clean-up here by showing the distance, too.

It looks like your drive function positions to the master position. How do I create and drive function for the other 2 positions?

WH: You can only drive in the big slot. The narrow slots are only switchable by the Posreps

How do you set positions?

WH: By using distance measurements in Bottom Board

That's all for now. Have fun with testing, Craig

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[CJPolinski]

Thank you for your help and knowledge. You have answered my questions and gave me a better understanding of assemblies.

Best regards,

Craig

[lena.talkhina]

@CJPolinski happy to see you back to the project. It's awesome that you found a solution.