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Snap fit printing

Posted by sungod3k 
Snap fit printing
May 16, 2015 08:25PM
Hi,

I sometimes do these clown /model balloon events and I designed this clip to wear my pump on my belt. I works really well.

However they dont last very long, so leaving out the material component (abs, flex etc) itself how would you design the "arm" that need to stretch by 5-7mm every time I clip the pump on.
I though about multiple thinner structures maybe a cross bracing pattern like building cranes. Is there some blog entry anywhere that experimented with that?

Cheers
Re: Snap fit printing
May 17, 2015 04:50AM
I haven't found enough easy info. But I have made enough different prints and tests with different settings to achieve enough flexibility and durability for some pieces: [www.thingiverse.com] for example. Thick enough ABS perimeters and 10% rectilinear infill? Perhaps it is easier to study "clips" what other people have done in thingverse.com for example ( [www.thingiverse.com] and so on). There is of course data for ABS strength calculations, but.

Edited 1 time(s). Last edit at 05/17/2015 04:51AM by Plasteroid.


Prusa i3, Ramps 1.4. Catnozzle 0.4mm
SketchUp - Enveloping Globoid Worm Gear - Part One - 3D Printed: [youtu.be]
DesignSpark Mechanical & more precise screw thread: [youtu.be]
Nicer Screw Thread In SketchUp ( Bolts,Nuts): [youtu.be]
How To Model A Heart Shape In SketchUp: [youtu.be]
How To Draw 3D Printable Snap Fit Ball Joint In SketchUp: [youtu.be]
Re: Snap fit printing
May 17, 2015 02:59PM
Have a look at taulman bridge nylon.
It would be ideal for your application.
Its very strong but has a bit of give to it and prints at a nozzle temp of 240DegC. Not much hotter than abs.
It prints very similar to abs. But you do need to dry it out in the oven before use.

I did something a bit similar for my daughters moth trap.
[www.thingiverse.com]
I found it very dificult to get the shape right to snap round the lamp mount.
If i had nylon available it would have been much more forgiving.
Allthough the abs version i printed has been in use for over a year.

Gordon


Gordon
Currently have a tweaked mendel prusa i2
About to build a P3Steel.
[scratchpad.thisandthose.org]

Printer for hire.
[www.3dhubs.com]

Member of South London Makerspace:
[southlondonmakerspace.org]
Re: Snap fit printing
May 17, 2015 10:58PM
If I'm visualizing this correctly as a traditional belt clip, I have a few thoughts...

All else being equal, if it works with the rest of the design, it would likely be best to print the width of the clip in Z so the clipping elements consist of continuous extrusions.

I'm going to guess it's breaking at what might be called the base of the U. That region probably needs to be a little thicker and as smoothly radiused as you can get it, as it will naturally be a highly-stressed area.

The longer you can make the part of the clip that flexes, the less stress the material will have to undergo for the tip to deflect a given distance. You can extend any design of clip down as far as you can without restricting your movement or making the clip too loose when installed. You could also make a little more sophisticated clip that has two elements that do the "clipping" function and one element that transmits the weight to the belt, as shown below, to move the intersection of the clipping elements as high as you can tolerate (and also relieve the weight-bearing stress from the intersection of the working elements).

^
|\
| \
|--+-     <---- Weight-bearing element
|  |
| /
| \

Most practically, the weight-bearing element would likely be a plate with a slotted hole for one element of the clip to move through.

Edited 1 time(s). Last edit at 05/17/2015 10:59PM by IMBoring25.
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