Threads not exported with STL file

[MainJet]

When a hole with a thread in the drawing is exported to a STL file for 3D printing, the thread is not exported.
Do I really have to a helix for each hole ?
Is there a script for this ?
It would also be good if the thread could shown in the model, maybe turned on/off if is gets too slow for bigger models
Using latest 2019 Expert

/k

 

[bigseb]

Do I really have to a helix for each hole ?

Yes.

 

[MainJet]

^%#@*()*)&$

 

[bigseb]

Showing all threads as physical features isn't always practical. File size and all that.

 

[idslk]

^%#@*()*)&$

+1

Is there a script for this ?

Helix isn't supported. As Andy Ajayre would say: Write a feature request...

File size and all that.

...in times where everybody shot's handy photos with more gigabytes than a complex model...
Sebastian, as far as i know, you are a experienced 3D-Printing fan, wouldn't' it be nice for you being able to print also threads?
Regards
Stefan

 

[MKR]

Showing all threads as physical features isn't always practical. File size and all that.

Agree, in big assemblies with many 'real' threads it will slow down Alibre a lot....
When I started using Alibre in 2010 I made 'real' threads on bolts, nuts and threaded rods for my assemblies and Alibre really took a performance hit.

 

[DavidJ]

There is a request with Development to look at a 'real threads' capability (with 3d printing in mind) - no promises as to if or when this might happen. It isn't necessarily as straightforward as it might sound - it throws up the question of 'what are correct dimensions for a thread?' - there is enough variation/debate about that, even before we get to any issues specific to 3D printing.

 

[idslk]

'real threads' capability

a first step "AddHelixBoss/-Cut" in AlibreScript would be helpful...
Regards
Stefan

 

[DBC]

Showing all threads as physical features isn't always practical. File size and all that.

Gosh, even SolidWorks saw the value of adding a thread tool a couple or so versions back. In this day and age realistic/genuine threads is a real need, if only 3D printing as has been mentioned. SW does add a caveat to cover some limitations.

 

[bigseb]

Guys I'm not saying it shouldn't be done, just that not every thread in every design needs to be physically modelled. Often (mostly) it just needs to 'visible' as a thread or be annotated as such for information purposes. I can count on one hand the number of times I needed to model a thread for printing. Usually I just print a hole and fit a threaded insert. Easy peasy japanesey. More durable too.

 

[MikeHenry]

For threaded holes in 3D-printed parts, I just design the holes sized for a 75% thread and tap them after the part is printed. Most of my tapped holes are fairly small. though, say #4 to 1/4" (2.5 to 6 mm).

 

[Lew_Merrick]

For threaded holes in 3D-printed parts, I just design the holes sized for a 75% thread and tap them after the part is printed. Most of my tapped holes are fairly small. though, say #4 to 1/4" (2.5 to 6 mm).

Mike -- You are wrong in that the "tap drill" should create a hole that creates "75^ of full thread interface" according to both inch and metric standards. The attached (xlsx) spreadsheet finds the "standard drill size" that most closely agrees with your desired "percentage of full thread" for a given UN Major Diameter/Threads per Inch thread size.

 

[MikeHenry]

Lew - 3D prints are not terribly accurate, at least compared to what's possible with machined parts. I usually print in ABS as well, which tends to shrink hole diameters by a percent or two. For me, the bottom line is that my approach works well enough for what I do and there is little use in trying to be as accurate as your spreadsheet details. Again, I'm only talking about 3D prints here.

 

[Lew_Merrick]

Lew - 3D prints are not terribly accurate, at least compared to what's possible with machined parts. I usually print in ABS as well, which tends to shrink hole diameters by a percent or two. For me, the bottom line is that my approach works well enough for what I do and there is little use in trying to be as accurate as your spreadsheet details. Again, I'm only talking about 3D prints here.

Mike -- Have you thought of "chasing threads" with a taa? -- Lew

 

[MikeHenry]

Mike -- Have you thought of "chasing threads" with a taa? -- Lew

I assume that "taa" in your reply is a typo for "tap". Sorry if I wasn't clear, but I usually design any parts intended for 3D-printing with holes the size of the corresponding tap drill and then tap them by hand. The chart that I usually use sizes the hole for approximately 75% of the thread diameter, I think. If necessary, I'll drill out the hole using the drill size recommended in the Holo-Krome screw selector chart. I suppose that some could call that chasing threads, but to me I'm cutting new threads in a straight sided hole, not chasing 3D printed threads.

 

[Lew_Merrick]

I assume that "taa" in your reply is a typo for "tap".

Yes, my fingers have reached the age where "sloppy" is a polite description.

Sorry if I wasn't clear, but I usually design any parts intended for 3D-printing with holes the size of the corresponding tap drill and then tap them by hand. The chart that I usually use sizes the hole for approximately 75% of the thread diameter, I think.

If you look at the "calculations" (as I recall) worksheet the actual (to .0001 inch) "pilot hole diameter" is given for a given "Percentage of full thread." -- Lew

 

[JST]

Is the actual hole created the same as the "use tap drill size" or whichever is selected, or is there a particular size that is used?

There should be very little controversy about what the various threadforms are. Threads of each type and system are really VERY well defined. There are books of the proper dimensions, I have several of them.

 

[Jim C]

Having a "reasonable" thread does have its use at times. A part with a thread will have different physical parameters than one without a thread. How much difference will depend on the percent and type of thread as compared to the overall part. It does have a considerable impact at times.

Jim C

 

[MainJet]

as Lew said, there are standards for this. If your 3D printer has variations, you will need to accommodate that. I usually just run a tap thru after to get better final sizing.
In terms of performance hit, it should be so that all threads could be turned on/off in design explorer and you can turn them on for interference checks, printing etc
my 2 c.....