ABS or PLA for toddler toys?

[Eric U.]

I've just ordered my first printer [an M2!], and am trying to decide what filament to buy.

My first project is a set of puzzle blocks I've designed for my son.  I was thinking of using PLA because:

1) ABS fumes make me feel sick;

2) I see lots of folks talking about easier prints, less shrinkage, etc.

However, I'm now noticing people talking about it being more brittle than ABS, and toddlers do tend to be pretty rough with their toys.  I don't want him to be able to shatter things or break edges off by whanging them on the floor or each other.  Here's an example of the kind of shape I'm planning to make:

Imagine that with about 2.5-3" diameter.  Would he be able to chip off the corners if I printed with a fairly dense infill in PLA?  Would ABS be a better choice?

Thanks,

     Eric

[Ross Mosshart]

Where you would need to kind of watch are on parts that have heat or sustained mechanical stress. I have thrown bottle openers onto the concrete floor at work, and they come away relatively unscathed.

You would want to be sure to handle the parts occasionally just to make sure they are still sound, because PLA will eventually biodegrade. At higher infills, I suspect they will last for several years, but it is better to be safe.

For cleanup, use a fine wire brush over the surface of the part. PLA can be kind of stringy, and could possibly leave 'hairs' that are not immediately noticeable.

PLA holds spray on enamel paint rather well, even moreso with a coat of John Deere buff primer, though I don't know for sure how child safe enamel paint is! ;)

Good Luck, hope this helped!

[Rick Pollack]

Eric - given the risks, I'd think very carefully about making toddler toys.

[Eric Uhrhane]

On Fri, Aug 24, 2012 at 8:24 AM, Ross Mosshart <ross.m...@gmail.com> wrote:
> Where you would need to kind of watch are on parts that have heat or
> sustained mechanical stress. I have thrown bottle openers onto the concrete
> floor at work, and they come away relatively unscathed.

There shouldn't be any heat, but banging these toys on the floor while
holding them is going to be a lot higher-impact than just throwing a
light-weight bottle opener.

> You would want to be sure to handle the parts occasionally just to make sure
> they are still sound, because PLA will eventually biodegrade. At higher
> infills, I suspect they will last for several years, but it is better to be
> safe.

Good point; I'll have to check up on them now and then.

> For cleanup, use a fine wire brush over the surface of the part. PLA can be
> kind of stringy, and could possibly leave 'hairs' that are not immediately
> noticeable.

Thanks, that's a good tip.

> PLA holds spray on enamel paint rather well, even moreso with a coat of John
> Deere buff primer, though I don't know for sure how child safe enamel paint
> is! ;)

I'll probably skip the painting step, for that reason. I'm pretty
confident that ABS+PLA are non-toxic, but paints that will stick to
them are a different matter.

Eric

[Eric Uhrhane]

On Fri, Aug 24, 2012 at 8:28 AM, Rick Pollack <ri...@makergear.com> wrote:
> Eric - given the risks, I'd think very carefully about making toddler toys.

Well, of course I've been thinking about this a lot, but so far the
risks seem small. I've done a test print at 1/3 scale on a friend's
printer in ABS, and was quite happy with the results. And of course
legos are made of ABS, and they seem tough enough for toddlers [though
too small, of course, presenting a choking hazard--I'm just talking
about the durability]. I just don't have any experience with PLA.

Were you thinking of risks other than cracking/chipping, that I might
not know about?

Thanks,

Eric

[NCBob]

I would suggest 50% honeycomb infill and you shouldn't have any problems with breaking.

I agree about abs over PLA, Lego is abs, and it's less likely to crack and split than abs. Just make sure you run the nozzle hot enough to get good layer adhesion that will be 'toddler proof'

[David Buggs]

I'd be more worried about chewing them and taking a bite out of em,
especially if painted.

David

[James Husum]

Greetings,

For a toddler's toy I'd be concerned about the points and edges on this design.

--
James Husum
The Quixote Project - one guy's quest to make the world a better place - http://www.thequixoteproject.org/
Brainsludge - all the shtuff running around my brain - http://www.brainsludge.com/
Currently reading: Swords of Mars by Edgar Rice Burroughs

[Nolan Poe]

Nobody has mentioned delamination... No matter how toddler-safe you design the model, they can just put it in their mouth and *crunch* delaminate it somewhere in the middle. those edges are sharpand there will be loose plastic and choking-hazard sized pieces. 

[Nolan Poe]

Sorry about the double-post, but you should attempt to crush these parts in a vise in every orientation before you give one to a kid. Heck, I do that before giving them to adults!

[Triffid Hunter]

DiamondAge (with printbl reselling in USA) have IMPLA, an impact-resistant mix that's significantly tougher than the regular stuff. That's the only plastic I'd even consider giving to a toddler!

[Eric U.]

I think a vise would be overdoing it; that would likely crush half the toys he's playing with right now.  I'll certainly smack them onto a tile floor a bit, and chew on them myself, before I let him have them.  If they delaminate that easily, I'll have to try printing hotter for better adhesion.

Regarding the sharp points in the design: they'll print a bit rounder than that, and then I'll file/sand them down further.   So they'll have protrusions, but they shouldn't be sharp.  As long as he's really got to try hard to poke himself with them, I'm OK with it.

From the recommendations so far, I'm thinking that printing in ABS, a bit hot, with 50% honeycomb infill, and 3-layer borders, is the first thing to try.  If that makes them too heavy, I might try 25% infill but a thicker surface; I'm not sure what the tradeoff is like there in terms of strength, cracking, delamination, crushing, etc.

[Eric U.]

Triffid Hunter, have you tried the IMPLA or HIMPLA yourself?  They say the goal is to make the PLA more similar to ABS, but they don't say if they've actually caught up, or if ABS is still tougher.

Anyone else tried it?

Thanks,

     Eric

[Eric U.]

On reflection, I won't be using the IMPLA or HIPLA because I don't know enough about it.  ABS and PLA are non-toxic in their standard forms.  I don't know anything about the additives in the modified PLAs.