What the hell is a durometer of 95A?

[Rogue3d]

Client is asking if I can print at a durometer of 95A? Have no idea? Anyone know? I have a rep2 printing PLA. Thanks

[DHeadrick]

Google is your friend.

[Rogue3d]

I know it a measurement of hardens or density but how does that relate to PLA objects and how do I measure that? Different infill and wall thickness would change that yea?

[Jetguy]

Durometer is a measurement ususally associated with rubber products but can apply to many thermoplastics as well.

Simple put, some rubber is very soft and easily deformed, others are much stiffer.

In typical usage for tire rubber, the harder the rubber, the longer the wear lifespan.

 

You also may see it shown as "shore hardness".

 

http://en.wikipedia.org/wiki/Shore_durometer

[Rogue3d]

So it is unrelated to PLA? Nylon maybe? How would I test a print or what should I tell my client? Sounds like he may be barking il up the wrong tree with 3d printing if he wants these sort of tolerances.

[Clinton Hoines]

Depends on what he wants to do with the part after it is printed. But just for your info here is a chart that gives you a idea on what various items would rate on a durometer scale. This is a estimate that I use for molding and casting pieces and explaining to clients what the end piece will be.

[Infinityplusplus]

If by "A" he is talking about the shore A scale then I would ask him some more questions about his expectations before continuing. I work in the rubber industry right now and the Shore A scale is what we use to measure Rubber hardness. If I take a shore A scale meant for rubber and press it against a cube gear printed in orange PLA, it reads anywhere from 96 to 99.3. I am going to say the smaller number is the product of the probe end falling into a crevice in the print. It is basically a pointy tip and it tells you how far the material deflects if the material is pressed all the way up against the base of the probe. A piece of low carbon steel will read the same as PLA on the A scale, I just verified this. I do not think the A scale is appropriate for measuring plastic hardness.

 

On Thursday, August 15, 2013 10:53:18 AM UTC-4, Rogue3d wrote:

[Joseph Chiu]

If the part is mechanical in nature, your customer may have a certain flex/stiffness for a given volume of material in mind.  Since you can print at different densities, it could be that a different design might meet his needs?
I would expect harder durometer pays to be used in "crush" applications.  FDM'd parts may not be appropriate for that.

--
You received this message because you are subscribed to the Google Groups "MakerBot Operators" group.
To unsubscribe from this group and stop receiving emails from it, send an email to makerbot+u...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

[Jay]

And I (as some of you know) work in the plastics industry, and like Infinityplusplus, we use durometer shore A and D for Urethane. In this case the client wants a hardness of 95A....which is softer than most of the stuff we use to print. Not only that but since these are printed, which is like a 'laminate', that can change you durometer. 90-95A is so soft it's hard to machine. 

The only material I think that would check that soft would maybe be the wood based PLA....or the 'bendable PLA....makergeeks.com has them.

NOW...I have heard several have modded their machines to use Eagle Belting urethane round belting....and are printing down to that hardness...but it's anectdotal and I have no video proof.

Eagle Belting Link

I think there is a lot of confusion....the 'high dollar' machines (especially the multi-color Objets) can print in several soft resins.....

Good Luck

Jay

[Rogue3d]

Thanks for all the education friends. I've passed on the knowledge to the client and am waiting to hear back. Thanks

[PrintedSolid]

I'd recommend taking the advice about asking him why he wants a specific durometer.  

Like others have said, durometer is how hard the object is.  Simple explanation:  In the Shore test, you have a little tester that is a rod that tapers to rounded or smaller diameter flat end.  A load is placed on the rod.  The tester measures how far the tip penetrates the material.  

In polymers, this correlates to flexibility, strength, and surface friction.  It is a rule of thumb kind of correlation and not an absolute mathematical relationship.  

Your customer might have different things in mind when making that specific request.  While PLA doesn't meet that durometer (although PLA/PHA might get you a little closer), you could still meet his actual requirement by messing around with infill or shells.  

Hope this is useful and good luck.