3D printed soft jaws

[Neil WyattModerator @neilwyatt]

Posted by Michael-w on 28/06/2017 15:38:50:

I find in a lot of 3D printed assemblies that they incorporate a hexagon space for a nut to sit sunken into the body rather than bother with thread printing, that way you've got metal to metal contact which will likely have a much stronger gripping power.

That can work very well, but the pull-out strength of threads, even in plastic, is very high. Obviously inserts are best for things that come apart with any frequency.

[Neil WyattModerator @neilwyatt]

Posted by richardandtracy on 28/06/2017 15:14:55:

Muzzer,

With regard to the threads in SW, thanks for suggesting what you did, but I can't get them anywhere, and also have no dropdown adjacent the hole wizard button on the ribbon. Using the 2014 edn which may explain it. There is no option to use anything other than cosmetic. Maybe we need an upgrade version, though it won't happen for another 3 years given the company's computer upgrade cycles.

Regards,

Richard.

There are lots of free screw downloads on the web. To create a threaded hole just subtract a screw, perhaps allowing a fraction of an mm for over-extrusion.

[Neil LickfoldParticipant @neillickfold44316]

And I was thinking that you had replacement metal jaws 3d printed. That will be the next level in printing, being able to make special shaped jaws for lots of things, not just chucks.

Neil

[jimmy bParticipant @jimmyb]

I quite like the idea of printing jaws with the correct profile, leaving small skim on face and bore/od.

Extra reinforcing webs could added etc.

[opochkaParticipant @opochka]

Posted by Muzzer on 28/06/2017 13:48:16:

About the printed jaws – did you change the settings to increase the density, rather than the default 20% or so fill? Normally the slicer s/w will allow to change the density of the honeycombing. Depending on the size of the part and the machining forces anticipated, it is a tradeoff between the time and cost of printing vs the strength of the jaws.

Murray

.

I suppose it depends on which 3D printer you have, and the slicing program that you use with it.

I have a Zortrax M200, which is an excellent printer for mechanical prints, virtually plug and play.

It comes with it's own slicing program, I just set the lathe jaws prints to solid, although you don't get solid, there are still internal honeycombs, but they are tightly packed together in the solid print option.

In the light option, the honeycomb is quite widely spaced, and in the shell option, there is no honeycomb at all.

.

[opochkaParticipant @opochka]

Posted by Michael-w on 28/06/2017 15:38:50:

I find in a lot of 3D printed assemblies that they incorporate a hexagon space for a nut to sit sunken into the body rather than bother with thread printing, that way you've got metal to metal contact which will likely have a much stronger gripping power.

Michael W

That is usually the best way of doing it, inserting a hexagon cavity half way into the print to put a nut in, using the print pause function, and then continue printing over the nut, but sometimes even that idea is not practical.

.

[opochkaParticipant @opochka]

Posted by Muzzer on 28/06/2017 13:35:29:

SW models the threads by default, assuming you use the standard thread wizard. Fusion 360 (and Onshape? I forget) allow you to save computing power by turning "cosmetic" threads off – in many situations, modelled threads serve no purpose even if they look pretty on the screen. Arguably, as long as they are called out on the drawing they don't need to be fully modelled in the CAD. But if you are planning to print them out / save as STL, clearly you want them to be modelled.

Murray

Sorry – to answer your question, you will find the thread wizard if you click the pull down under the hole wizard in the std ribbon. You need a circular feature to point it at eg an existing hole or a sketch, then it has all the data for std metric, imperial etc threads.

Edited By Muzzer on 28/06/2017 13:40:46

.

The thread wizard and I don't get along too well !

I find it too restrictive, you get what you are given, and it is difficult to tweak it afterwards.

I prefer to make my own threads, easy to change if needed.

I make up threads and put them into the library, just drag them out and drop them into place when I need it.

Also a proper thread looks good on cross sections in coloured presentation drawings.

.

[opochkaParticipant @opochka]

Posted by richardandtracy on 28/06/2017 12:45:09:

Dave,

Silly SolidWorks question – how do you model the thread? Is it a triangle swept on a multi turn helix or is there something in the hole wizard I've missed? Just trying to find the quickest way of doing it.

Regards,

Richard

 

Yes correct !

But a little more involved than that.

I don't use the hole wizard….not user friendly, not easy to tweak.

I have made a rough and scratchy video, but can't seem to upload it on this site … it had to go to Youtube !

You see how, when the triangle is too big, the cut sweep fails.

Make the hole the thread core diameter, then move the triangle pointy end to the o/d of the thread + 0.2mm to compensate for plastic shrinkage.

Screen recorder software makes the mouse cursor stick to the screen for a second or two, a bit annoying.

I suppose most other cad software packages use similar methods.

.

 

Edited By Neil Wyatt on 29/06/2017 09:51:25

[MuzzerParticipant @muzzer]

Some CAD systems such as Onshape (and Alibre/Geomagic?) don't "do" modelled threads, so that method of doing a spiral cut with a triangle is the way you need to do it. Having said that, there now seems to be a script for Onshape to do it for you, whoopee.

"Also a proper thread looks good on cross sections in coloured presentation drawings." Que? The threads in SW show up as modelled, so what's the difference?

Fusion asks if you want cosmetic or modelled BTW.

Murray

[richardandtracyParticipant @richardandtracy]

Dave,

Thanks for the video – exactly as I would have modelled it. The only thing I could comment on is you create axes down the centres of holes, if you were to make 'Temporary Axes' visible, you'll find each cylinder or portion of cylinder has one (SW2006 on, may be before but that was the first version I saw).

Murray,

Your version showing modelled threads is an advance on the 2014 Premium version I use, which does not show modelled threads. The only way I can get my one to do threads is the same as Dave showed. Interesting upgrade if you do lots of 3d printing.

Regards,

Richard.

[Paul H 1Participant @paulh1]

That is a very nice set of jaws. It gives ideas me for holding more irregular shapes. If you want to go the whole hog though why not print a whole lathe. I receive regular news emails from Instructables and in one was this printed lathe by a young man at a US high school.

http://www.instructables.com/id/3D-Printed-Lathe

Various contributers to this forum have discussed where are the next generation of model engineers will come from and the cross over between makers and model engineering. This I think is a good example.

[Nick HulmeParticipant @nickhulme30114]

Posted by opochka on 28/06/2017 11:00:42

Hi Nick,

I use hips filament mainly, ( High impact poly styrene ) I find this material gives the best crisp and strong prints.

It is also possible to print threads directly into the 3D print, depending on your cad software.

I use Solidworks, put threads in the holes, and the printer prints threads !

Just run a new hss tap down the threads to clean it up, eg. M4 makes a surprisingly strong thread in the plastic.

Don't have to mess about fitting steel nuts inside casings, etc.

dave

Dave,

I print threads but I was responding to your use of super glue and brass tube in your starting post,

– Nick

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