Timing Belts

[sdb999]

We use timing belts extensively in our designs. Same part number but infinite iterations. I've got a few solutions but none perfect. Is anyone else doing this? How?

 

[Arlin]

I would create a different part file for each instance of the belt, creating it in-context in your assembly to help it follow your pulley configuration.

Name the file as follows:
belt_pn-assy_pn-#

belt_pn = part number of your belt
assy_pn = assembly part number that this particualar belt file is in
# - sequential number (so that you can have more than one of the same belt in your assembly)

Then change the configuration properties of your belt so that the part number is custom. This way, your belt will show up properly in your BOM.

Thus, if you have 2 4193 belts in assembly 9999, the file names would be:
4193-9999-1
&
4193-9999-2

 

[TheTick]

One method I have seen but never used works as follows:

The timing belt model consists only of a single block of dimensions sufficient to encompass the extremes of the belt application. This "block" is inserted into an assembly, and then cut to shape using assembly-level cuts.

All this machinery making modern music can still be open-hearted.

 

[MadMango]

Arlin, why the seperate files for the belt? Why not different configs of this belt, named after the various applications where it will be used?

Just curious.

MadMango
"Probable impossibilities are to be preferred to improbable possibilities."
Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[Regg]

The method TheTick describes is the method we use as a best practice at my place of employment. We found it works the best for us.

Regg

 

[Arlin]

MadMango,
The reason I suggested this method was due to sdb999's statement 'Same part number but infinite iterations.'

This implies LOTS of variations on a single belt. Plus, belt variations are usually not just a change in dimensions. Instead, belt configurations consist of different paths with varying numbers of pulleys, pulley sizes, and pulley locations. Some belts are even twisted along their route (although rare with timing belts).

Thus, each different configuration would probably need a different sweep path, something that is not easy (if even possible?) in SWX. Even if a different path could be accomplished, the number of paths and features and configurations possible just seems like too much for configurations to me.

In short, I just believe the configuration route for flexible components like belts is just too much work to be worth it.

Tick's idea of a solid block that is cut away at the assembly level does not sound like a bad idea to me. But, I still think I prefer my first suggestion.

 

[sdb999]

Our PDM, and most others I would assume, allow for only one SW file per part number. Although you can have as many configurations as you like and it treats them all as the same part for Bill of Materials. Works great for air cylinders, linear slides, etc. Multiple files are out.

SW does not allow more than one external reference per part file, so in-context is out. Which really hurts because this is one of the few instances when it would be worth the trouble.

Yes the number of configurations in theory would be infinite, but in reality our designs would probably not generate more than could be managed.

I've settled on a Thin Feature extrude, Mid-Plane, Two Direction. This produces a "clearance envelope" based on the pitch line. One sketch, one feature per config, and it's a good bit lighter than a sweep. It only lacks teeth which is not important to me. I'm trying now to create feature palettes for the various styles and pitches but it's slow going.

Thanks All.

 

[JNR]

You could do this with some VBA and API work - any some create math/geometry skills.

BTW: SmarTeam (a PDM system) does allow different partnumbers for different configurations. (Also multiple configurations for each part number).

We do it all the time and it works fine. Looks something like this (in our case):

partname -001
partname -002(fixd)
partname -002(free)
partname -002(expl)
partname -003
partname -003(fixd)


3/4 of all the Spam produced goes to Hawaii - shame that's not true of SPAM also.......

 

[sdb999]

Turns out SW will allow multiple in-context references for one part file if you have Tools-Options-External References-"Allow multiple contexts...." checked. This seems to offer the best of both worlds, we'll see. JNR you are correct about ST and part numbers vs. configurations, but what Arlin described was multiple part files (one for each instance) which SmarTeam will not allow. If you are indeed able to link multiple part FILES to a single SmarTeam data base record (Part) please let me know.

 

[JNR]

True, sdb999, but my comment on ST only refered to the first paragraph of your Sept. 17th post. Sorry about the confusion - I will try to be more specific in future. I got reading down the posts and lost track of the original question!

3/4 of all the Spam produced goes to Hawaii - shame that's not true of SPAM also.......

 

[krywarick6]

Only having used K-groove belts in the past, I have found that assemlby layout sketches work great and can be confugured quite easily. I can send some examples, but I don't know how to relay e-mail address or get an e-mail address of some on this site. Any suggestions?