topic Betreff: Working Model Design Failure in Inventor Forum

Working Model Design Failure

Vagulus — Fri, 15 Mar 2019 05:58:57 GMT

Following advice from a previous thread I have generated what appears to be a working model of a Worm Gear Assembly

This model has dimensions which are within the acceptable range for the purpose so I am happy, but Inventor is not happy. Inventor says this is a failure

I recently read a posting from JD pointing out that gear systems are complicated problems involving a lot of study to achieve competence. He suggested that mere mortals are likely to be much better off outsourcing this sort of work to someone who specializes in it. I agree and hasten out that the fine points of gear train design are far beyond the range of the Engineering Education given me. That is precisely why, given my knowledge and my purposes, I rely on Inventor to do the legwork. I punch in the info and Inventor does the maths.

This project is a toy which I intend to 3D Print in PLA. I am not making the next Mars Rover or a Steel Mill. My project involves minimal forces, no great precision at all, a short life expectancy and I do expect that this model, when printed, will serve its purpose. However, if someone would give in words of two syllables or less a rough and elementary idea of what has failed and its significance ... well, that would be great.

In the meantime, why are there no video (or even PDF) tutorials on the general practice of using the Design Accelerator for this job? Much of a week of hair-tearing frustration bears witness to that. What do the numbers in those text boxes on the Worm Gears Component Generator refer to? How do those numbers interact? Why would unit correction be 0.7? Does that matter? A zillion questions ...

Anyone who posts an elementary tutorial to help beginners make some use of that dialog will surely have Brownie Points laid up for them at the Great Jamboree.

Betreff: Working Model Design Failure

WHolzwarth — Fri, 15 Mar 2019 09:28:52 GMT

Here's a working file set, using your inputs (2018 files).

A very common issue is hidden at the Calculation tab. In many cases the default power settings are too much, and thus the result turns into no design compliance.

After reducing the default power, calculation is ok.

Re: Working Model Design Failure

Frederick_Law — Fri, 15 Mar 2019 13:37:11 GMT

As good as the model looks and works, they're not accurate enough for manufacture.

The gear set will not mesh properly and will wear out or require more power to operate.

Now for 3D printing, its pretty 'good enough'.

Plastic is more forgiving then 4140 case hardened.

Print it and play with it.

You can size it up so its stronger.

Also don't print fine tooth gear. You nozzle is 0.4mm so every corner will have that radius.

I had printed a few gears and they work fine.

Re: Working Model Design Failure

Vagulus — Sat, 16 Mar 2019 00:02:41 GMT

@Frederick_Law wrote:

You nozzle is 0.4mm so every corner will have that radius.

That's a great point. I have traditionally Filleted non-specific edges at radius 0.25 mm. In metalwork I would have called that "Breaking Sharp Edges". As you point out, that is a waste of time.

Thanks.

Betreff: Working Model Design Failure

Vagulus — Sat, 16 Mar 2019 00:16:15 GMT

@WHolzwarth wrote:

A very common issue is hidden at the Calculation tab. In many cases the default power settings are too much, and thus the result turns into no design compliance.

After reducing the default power, calculation is ok.

Great. Thanks, Walter.

Re: Working Model Design Failure

Frederick_Law — Wed, 20 Mar 2019 12:43:54 GMT

Just printed a 40DP 50 teeth gear for a co-worker.