Small-cell foam? 7

[Theophilus]

I've got a novelty product I need to source, which is to be made of a light-weight (low-density?) but tiny-pored foam that would be good for applying screen-print or pad-printing. I'm thinking of a material similar to some of the step-aerobic blocks I've seen before (or preferably even more light-weight than that stuff, with less structural strength), but am unsure of what material that is.

Any ideas, directions to check out?

Thanks!



Jeff Mowry

http://www.industrialdesignhaus.com

A people governed by fear cannot value freedom.

 

[dgowans]

Theo,

When you mention the screen/pad printing, do you mean that you must be able to print on the material or with the material?

Would any of the lower density grades of REN board work?

 

[MacGyverS2000]

Is it printed on the foam directly? A number of foamies I've seen have an ultra-thin rubber coating on them that holds the printing, not the foam itself.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Theophilus]

I mean applying printing directly onto the foam--with something such as a flexible ink. Since this is a simple novelty item, it needs to remain very inexpensive per unit, and will probably need to be sawed or hot-wire cut (or whatever) into its blocky shape. If inexpensive enough, perhaps a thin latex coating could be applied over the foam before printing. But a Ren-type product would be far too expensive for a mass-produced novelty thing that's to be sold inexpensively.

Thanks for the quick input already. Any other ideas? The foam can be quite "squishy", too, but if we print directly onto it, we'll need quite small pores. Lighter weight is better.

Perhaps the priority order is:
1. Cheap
2. Printable (using whatever means)
3. Soft, not rigid
4. Light-weight



Jeff Mowry

http://www.industrialdesignhaus.com

A people governed by fear cannot value freedom.

 

[Pud]

Jeff,

This may be what you want for a google search:

[blue]closed cell polyethylene foam self skinned[/blue]

Seems a lot in your neck o' the woods...

Cheers

Harry

http://www.tynevalleyplastics.co.uk

 

[btrueblood]

Er...Pud, not to whine...but polyethylene won't be very "printable" will it? Would a low-durometer urethane be a closer match, or possibly a simple latex (natural rubber) foam?

 

[MacGyverS2000]

The first thing that came to mind was those hand-squeeze balls handed out at conferences as promo items. I just realized you don't want to manufacture these things yourself, so search on "Promotional Products" and you'll find a ton of pre-made items (send 'em a logo and they'll print from 100-1mil units, even in full color). For a fee, a number of them will custom make a shape for you.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Pud]

PE is ok to print these days - etching inks/surface treatments etc. If colour not important, laser marking may be an option.

It's also cheap - a criterion stated. PU is more expensive. Some foams are skinned with something else but adds cost.

Cheers

Harry

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

Some EVA in the PE will make it softer and improve ink adhesion.

Many grades of PE actually contain a little vinyl acetate to improve stress crack resistance or toughness.

If you are talking directly to a manufacturer rather than a distributor of the foam, they may be able to guide you as to availability of a relativly high VA content grade.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[btrueblood]

Lovely stuff. Theo, you owe a few stars.

 

[Theophilus]

Thanks for all the posts, guys!

And I've finally remembered where I'd seen what I'm imagining in retail before and found examples of the type of foam I've been imagining. If you Google (images) "pilates blocks" you'll see some beveled foam blocks of the small-pore type. One leads here and even demonstrates direct printing:

http://unibodi.com/catalog/images/Pilates_blocks_3_121406b.JPG

Think this is a form of PU or such?

I appreciate all the input on this. Perhaps in the near future I can better disclose what this is all about. Meanwhile, I'm getting pulled back onto yesterday's project for the day and probably into tomorrow until completion. So don't worry (ahem, btrueblood), I'm taking this quite seriously and am very grateful for all the input I'm receiving here. Not sure who else would be able to help in this way, so I truly value your input.



Jeff Mowry

http://www.industrialdesignhaus.com

A people governed by fear cannot value freedom.

 

[Theophilus]

By the way--is it possible/probable to maintain this nice printable surface while reducing the density of this foam (making it softer, if necessary)? I don't need the firm structure of this type of foam--primarily the texture and printability of it.

Thanks!



Jeff Mowry

http://www.industrialdesignhaus.com

A people governed by fear cannot value freedom.

 

[btrueblood]

Uh, I didn't mean me, Theo! Pat, Pud and mac had some enlightening info., as usual, is what I meant. Never knew about the EVA content in PE, didn't even know they were compatible enough to alloy like that. Makes me start to think about some things in a new light.

FWIW the blocks you showed I don't think are a urethane rubber, more likely are cut from larger pieces of EVA, see link below

http://www.atafa.com/sports/product...lock_EVA_Yoga_Block_Yoga_Exercise-173743.html

Theo, do you _not_ want a skin on the surface? Don't know if that can happen without cutting the part from a larger piece, don't all foams tend to form a skin when molded, due to contact/wetting against the mold wall?

Interesting subject here, and want to hear from the expert guys: if you want a lighter foam, doesn't that usually mean coarser bubbles (larger cells) in order to reduce the amount of material? And is this not related to the material chosen, in that a given material will tend to form a certain cell wall thickness?

 

[btrueblood]

Um, and another thought - PE foams always remind me of the "noodles" that you find in just about every swimming pool in town. Is that the right density and softness for you Theo?

 

[Theophilus]

Certainly no offense taken, btrueblood, just a little ribbing back. And great find, by the way--looks just like the EVA blocks. (I really don't use materials like this very often, so I'm stumbling around this whole landscape of "new" stuff.)

If EVA is simple enough to mold, and the mold would provide a skin around the foam, I think that would be ideal. After paying for tooling, the per-unit cost of a molded form ought to be less expensive than one cut on all sides, right? Further, I'd think a skin around the foam might allow more course bubbles within while providing a good surface to receive print, right?

Thanks, all!



Jeff Mowry

http://www.industrialdesignhaus.com

A people governed by fear cannot value freedom.

 

[Theophilus]

Yeah, those pool noodles ought to be a great density for this application. So you think the EVA/PE mix might work out favorably?

In that case, these things could be extruded and cut to lengths (skin around four sides, not on cut ends if cubic in form) and printed on up to four of the skinned sides. I'd like to have stronger opacity than the pool noodles, but that should be a matter of density control, right?



Jeff Mowry

http://www.industrialdesignhaus.com

A people governed by fear cannot value freedom.

 

[btrueblood]

I think the noodles ARE a PE/EVA mix, if Pat is right, and it's just a question of how much, and how much you might need.

Dunno about opacity, but it will probably be a function of fillers, and cell size/density. Probably matters what color you pick too (any color, as long as it's black .

Sorry, not much usable info from me (thus my comment about not feeling like I earned that star) -- and this is pretty much a filler post while we wait for Pat and the rest of the experts to log in again.

 

[patprimmer]

Btrue

The E in EVA is ethylene. It is not normally called EVA until you exceed about 5% VA.

When the VA content gets to around 50% (I think from memory) it can be melted by rubbing between your hands.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[Theophilus]

Thanks, guys. Plenty to get me started in the right direction. I appreciate it.



Jeff Mowry

http://www.industrialdesignhaus.com

A people governed by fear cannot value freedom.

 

[btrueblood]

Ahh...gotcha. Thanks again, Pat, I'm always learning things in this forum. Someday it may come in handy...