HIPS soluble support

Hi, just a short introduction as I'm new here. I'm also new to 3D printing, having become interested a few months ago and got myself a Flashforge Creator in April this year. I'm not sure if it is well known, but it is essentially a Chinese clone of the Makerbot Dual with a few improvements (or perhaps just differences). I had originally meant to build a 3d printer myself and was shopping on eBay for thecomponents but then I came across this printer with a very attractive price shipping from within Europe so I took the shortcut.

Right from the beginning I started to see the need for soluble supports as many of the things I wanted to make could not get a decent finish on the supported side - the filaments were not packed and fused properly together and the removed supports always left an untidy surface anyway.

I see PVA being mentioned quite often as support but I have not managed to use it succesfully, the main issue being that I cannot get it to stick to the main material, be it ABS or PLA. Sometimes the adhesion is so poor as to be non existent and the filament comes of even as it is being laid down. I have however seen very little mention of such problems so I wonder if it is a problem with my printer or something I am doing wrong.

In any case I gave up after not too long and then discovered HIPS (High Impact Polystyrene) which happens to be cheaper and has turned out to work rather well. ABS laid down on HIPS sticks very well (just as well as it sticks to itself I would say). The inverse is not quite as good but still more or less acceptable and can usually be worked around. The downside of HIPS is the solvent needed. Rather than water it needs a solvent which I cannot find locally so I have to get by mail which is quite costly (d-limonene or di-pentene). Still cheaper than the PLA/water combination though.

One issue I am encountering, and wondering if anyone has solved it, is that the parts become badly stained after immersion in the dipentene. It is OK when using it the first time, but subsequent dips get worse and worse as the solvent becomes contaminated with the dissolved HIPS. Of course I could always use fresh solvent and then throw it away but that would be too expensive and wasteful.

Anyone here encountered such a problem and perhaps found a solution?



This is what some of the parts looked like before dissolving the HIPS. (The stringers are due to a silly mistake - please disregard them):


This is what it looks like after dissolving the HIPS:


The pistons and the two connecting rods which they are attached to were done in fresh dipentene.
The crankshaft and counterbalance weights were done in the solution left after doing the pistons, a couple of days later.
The conencting rod on the left and the horizontal one touching the build plate were done with a solvent that I had used a lot and has become viscous due to the amount of plastic dissolved in it.

It seems like the solvent is 'ruined' after just one dip, and while it continues to dissolve the HIPS even after being used many times the contamination heavily stains parts even after just one use.

Interesting results. I don't think many people have tried this before.

Odd that the residue leaves a grey stain when the HIPS was orange originally.

I wonder if the limonene can be recovered with distillation.

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[www.hydraraptor.blogspot.com]

My mom taught me to clean paint brushes without wasting turpentine. Perhaps it could work to minimise the plastic load in the solvent when dissolving the supports. Test it out by trying to do a second wash with a bit of fresh solvent.

You take 4 suitable sealed containers (glass jam jars) and almost fill them with turpentine.

When the time comes to clean a brush you pour out the turps without the sediment from jar #1 into a dish and clean the brush and then return the turps to the same jar. Then use jar #2 and #3 and #4 in sequence.

Each subsequent jar has cleaner solvent and the bulk of the paint is in the early jars. Next week most of the pigment will have settled to the bottom and the turps is almost clean and can be used many times. After a long time the paint binders and other chemicals will stop the first jar from settling and cleaning and then you dispose of the gunk, clean it, fill it with fresh turps and label it jar #5 and start cleaning with jar #2. My upgrade was to put mesh in the jars and do the washing in the jar without disturbing the sediment below the mesh which worked once the sediment was semi solid otherwise decanting gets you to the clear solvent better.

Distilling of solvents is quite possible in most cases but not cost effective or safe unless you have reasonable apparatus and understand the safety and fire hazards, take care perhaps get advice from a university science lab (after you convince them you are not a moon shiner) on how best to proceed.

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Kalle
--
Lahti, Finland
The only stable form of government is Open Source Government. - Kalle Pihlajasaari 2013

Cool post. Did it just stain the piece, or does it also affect the dimensions at all?

Have you tried printing ABS with PLA support ? The PLA dissolves in a heated sodium hydroxide solution (drain cleaner): [forums.reprap.org]
It works very well for me : [www.youtube.com]

Wow Petrus, that is a great result! The cylinders your machine was making during the build are for wiping ooze?

@nophead
The grey staining is indeed odd. I'm guessing it isn't just a matter of the dissolved HIPS being deposited but instead some sort of chemical reaction may be going on between the pigments of the two plastics. Or maybe it is just roughing the surface.
I have just received a natural colour reel of HIPS, I'll try it out in the coming days. If the pigment is the problem then I should be OK with the natural one. I'll keep you posted on the results.

Regarding distillation I think it should be possible. It does however need a very high temperature as limonene boils at about 180 celcius (356 Fahrenheit) which may be somewhat dangerous as it also happens to have a rather low flashpoint of just 50 celcius. I could probably set up some contraption outdoors and keep my distance from it :-)

@KalleP
I tried washing the stained parts in clean limonene after drying but it doesn;t seem to work. The part looks clean right after dipping in clean limonene but as it starts to dry the stain reappear.
Great idea regarding the jars with varying level of contamination. Very simple but effective and may solve the staining problem. It probably depends at what stage the staining occurs. If it is only after drying then this should solve the problem. The only way to find out is by trying, which I will be be doing.

@maddox
As far as I an tell there is normally no effect on the dimensions but I would need to do some more accurate measurements before being able to say so with certainty. One of the parts in the photos did suffer some distortion, and is the first time I noticed such a thing but I think it is not due to the solvent itself but rather that the part had internal cooling stresses which were relieved when a support pin was removed by dissolving.

@Petrus
I have tried ABS/PLA but the other way round, intending to dissolving the ABS supports in Acetone. I never got to the point of dissolving anything though as I had difficulties with the ABS and PLA not sticking well to eachother and was getting a lot of curling on supported overhangs as the PLA detached from the ABS support and even parts detaching completely.
I see that you have used it to great effect and maybe I should look at that combination again. Perhaps the problems I was having with ABS/PVA is due to the type of prints I try to make, having wide flat surfaces very susceptible to curling.

grumpenstein Wrote:
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> Wow Petrus, that is a great result! The cylinders
> your machine was making during the build are for
> wiping ooze?

I printed a tower in front of the model the prime the extruder the closest to the actual print, I also used a rubber wiper on the left to clean the nozzle from burnt ABS but there is still some brown parts on the print. Ooze is not an issue because the unused nozzle is closed by a blade : [www.youtube.com]

I also have this problem of ABS curling in supported areas but I think it can be reduced with a heated chamber, or my low-cost solution, a heated bubble : [forums.reprap.org]

If the 'residue' is always white then it is a result of surface effects, the question is which plastic is causing it, the support residue in the solvent or the surface of the part.

There are many plastic and solvent combinations that will whiten a plastic surface. I have found when trying to clean the plastic with the wrong solvent that I have almost destroyed the cosmetic look of parts, little moving coil meters are a prime example.

What I have found empirically is that if you can wet it and then remove the solvent real fast with a wipe or blast of air it sometimes does not have time to go white, it seems to occur at the moment that the last of the solvent dries. I have a feeling that it may be associated with absorption of condensed moisture that blends with a thin film of dissolved plastic. Alternately it may be due to too slow a drying of a thick film of softened material.

There are also situations where one can move from one solvent to another, before the first one dries, that does not leave the white surface on drying. Perhaps something as simple as pure alcohol (try all the solvents you can source easily) as a final dip would work.

I like the dissolving of supports a lot and the more combinations that we come up with the better. Keep up the good work.

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Kalle
--
Lahti, Finland
The only stable form of government is Open Source Government. - Kalle Pihlajasaari 2013

The whitening with some solvents is pretty well-known in the plastic modeling community. For example, alcohol will cause the same effect with polystyrene, and is often used as a weathering effect. Clear coats hide this effect, and modelers often use a matte finish, like Testor's Dullcote. Since ABS contains polystyrene, I would guess the same approach would work here.

its probably because abs is naturally white, the limonene probably dissolves the dye.

@JohnSL & aduy
the thing is that the staining only seems to be caused by 'used' solvent. When I use the solvent the first time there is only minimal staining, if at all. I'm guessing that the HIPS dissolved in the limonene is what is causing the staining.

However to be sure I am just now trying a little experiment - I've put three pieces of black ABS in a jar with new clean limonene and will leave it for several hours so everything will be the same except for there being no HIPS involved.

When I remove them I will also treat the three pieces differently. One I will just let stand to dry slowly, one I will try to accelerate drying with compressed air and another will be rinsed with water. The reason I'll be rinsing one is to find out whether water vapour could have anything to do with the problem.

I'm guessing that the first two will both be stain free and the third one will be badly stained, but of course I will only really know once it is done.

@KalleP
If the first two are indeed not stained (as I expect) then I will make another test starting with a limonene sample heavily laden with dissolved HIPS and then see if I can prevent the staining by the quick drying or by quickly rinsing in clean limonene or another solvent as you suggest.

Note that limonene will attack the ABS as well as the HIPS, just not as quickly (HIPS is basically the 'S' and 'B' of ABS). It's really best to use the HIPS as a breakaway support and then try to dissolve any remnants selectively.

I think using PLA as a support material is much better if solubility is desired.

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[haveblue.org]

It doesn't seem to attack the ABS as far as I can tell. When I use clean limonene (straight out of the bottle) I haven't seen any problem. The issue seems to appear only when I reuse the limonene - which I have to because it is costly. The more the limonene is loaded with dissolved HIPS from repeated use the worse is the staining.

A few hours ago I chucked some pieces of black ABS in a jar with clean limonene and also been shaking it from time to time. The ABS still looks perfectly black and shiny and the limonene is still perfectly transparent so it seems like there is no interaction whatsoever between the limonene and the ABS. I've just checked by shining a laser through it and through another jar of unused limonene and the amount of scattered light is indistinguishable between the two,

I had originally intended to leave it only a few hours but I think I'll leave it longer, perhaps until tomorrow evening so that any effects that may be occurring will be more noticeable.

I had tried PLA as support material (and also PLA) but I couldn't get good enough adhesion between it and the ABS.

ok well, the limonene is disolving the hips, then the hips is disolving into the surface of the abs. also the pla is actually cheaper so im not sure what the point of hips is anyways [www.amazon.com]

Edited 1 time(s). Last edit at 08/28/2013 08:46PM by aduy.

@aduy
The problem with PLA is that it does not stick well enough to ABS, or at any rate for me it doesn't, whereas ABS sticks to HIPS almost as well as it does to itself

The solvent for HIPS is also safer even if much more expensive.

If I could solve the ABS-PLA adhesion problem I would switch to that, especially if I don't find a solution to the staining problem.

Just got the results of the staining experiment. This was to find out how limonene itself affects ABS, or if it affects it at all.

The result is that the limonene had no effect whatsoever as far as I can tell, so it seems limonene is very 'friendly' to ABS.

The three black ABS samples were submerged in new clean limonene for over 24 hours, being given an occasional shake and some time in an ultrasonic bath, similar to what I do when actually dissolving HIPS supports except for a longer time to make any effects more visible.

I took out the three samples, leaving one to dry naturally, one dried with compressed air and one rinsed in cold running water. The result is that all three samples appear just as they did before being dunked, except for possibly looking a little cleaner and shinier. Unfortunately I didn;t have the good sense of keeping a fourth untreated control to compare to.

In any case, the parts look at least as good as they did before the experiment. They also don't seem any softer or harder and have not changed dimensionally, at least within the accuracy I can measure.

So it seems that the limonene itself is practically inert and it is the HIPS dissolved in it that is causing the problem, or perhaps the pigment in it.

The next thing I will be doing is finding out how samples that have been in 'dirty' limonene will respond to different post-immersion treatments. I happen to have just made 14 pivot pins and dissolved the HIPS overnight and I will use them for the experiment as their finish is of no consequence.
I will try various things after removal, such as drying with compressed air, rinsing in clean limonene and then drying with compressed air, rinsing in water, rinsing in other solvents as suggested by KalleP and anything else I can think of.


Left:dried with compressed air, middle: rinsed in cold water, right: left to dry naturally

Limonene does have an affect on ABS if you leave it in too long, see [hydraraptor.blogspot.co.uk]

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[www.hydraraptor.blogspot.com]

Was the ABS submerged for several months in the limonene or did it soften several months after having been removed from the limonene?

I'm hoping it's the former as dissolving the HIPS would normally take less than a day and won;t pose a problem, but if the limonene continues to affect the ABS even after removal that will certainly be a problem.

Since the used d-limonene has HIPS dissolved in it, I would expect it to come out of solution and "stick" to the clean ABS, thus giving the ABS a gray-ish white color. I've been using ABS and HIPS, using d-limonene to disolve out the HIPS for over 2 years now and the ABS parts show no signs of solvent attack. Also, since the work is typically for clients, I use fresh d-limonene each time for speed and to keep the ABS parts looking clean.

There may be a way to clean out the dissolved HIPS but I'll have to try a few things to see what works. If the HIPS particles will "glob" to together, then it might be possible to simply filter the d-limonene.

Edited 1 time(s). Last edit at 03/27/2014 04:07PM by adsinfo.com.

Can anybody confirm that HIPS also dissolves in orange oil concentrate? I can't find a good source for d-limonine in germany.
[reprap.org]

Edited 1 time(s). Last edit at 06/18/2014 06:29PM by Dejay.

Have any of you tried black HIPS with black ABS or white HIPS with white ABS to see if staining occurs? I've been trying PVA support material and am dismally disappointed. I've wasted $50 of PVA filament without one successful support print. It just won't stick to anything. I'm looking for an alternative and HIPS sounds a bit better than dissolving PVA as far as the success rate. From what I see there, HIPS has more stick than PLA so the chances of good prints is better. Sure, sodium hydroxide is cheaper than d-limonene but I'm after the end result, not necessarily the cheapest workflow.

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Prusa i3 8" (Makerfarm) / Dual Hexagon 0.4 extruder

1) People keep saying PLA, when I think they mean PVA. Nothing useful disolves PLA (Or so I thought )

2) What is the smell like? I've refused to play with hips support on the basis it leaves everything smelling of Oranges. I don't want smelly parts, especially printed ones.

Quote
UkIan
1) People keep saying PLA, when I think they mean PVA. Nothing useful disolves PLA (Or so I thought )

No, I think they are using the correct names. PLA (not PVA) dissolves in a heated sodium hydroxide solution.

Edited 1 time(s). Last edit at 12/07/2014 12:19PM by RobH2.

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Prusa i3 8" (Makerfarm) / Dual Hexagon 0.4 extruder

Quote
RobH2

Quote
UkIan
1) People keep saying PLA, when I think they mean PVA. Nothing useful disolves PLA (Or so I thought )

No, I think they are using the correct names. PLA (not PVA) dissolves in a heated sodium hydroxide solution.

Oh really? That's interesting. I put hot caustic soda in the "do not play with" section though :/

Ha, no one said it was safe. They just said it can be done. Seriously though, with precautions, it's not too bad from what I read. Just don't splash it around. It's drain cleaner. We use it all the time and rarely have issues because we know it's nasty stuff. Treat dissolving PLA the same way. We reprappers are manufacturers now. Manufactures have all kinds of user "unfriendly processes". Right?

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Prusa i3 8" (Makerfarm) / Dual Hexagon 0.4 extruder

Isnt there a water soluble thermal plastic out there? Whats cheaper than water? I am very curious. Also you should be able to regain the shine back on the abs parts by simply wiping them with a rag soaked in acetone. I do this for my raw printed parts to clean them up and give them a bit of a high polish luster. Works very well for me.

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My Personal Blog. Build blog.
[engineerd3d.ddns.net]

Modicum V1 sold on e-bay user jaguarking11

Quote
RobH2
Ha, no one said it was safe. They just said it can be done. Seriously though, with precautions, it's not too bad from what I read. Just don't splash it around. It's drain cleaner. We use it all the time and rarely have issues because we know it's nasty stuff. Treat dissolving PLA the same way. We reprappers are manufacturers now. Manufactures have all kinds of user "unfriendly processes". Right?

Does it actually have to be warm though? And how warm?? Maybe I'll give it a go, do you not end up with residual cack on the remaining ABS? I mean the acid test (no pun or pun intended) would be would you put the resultant ABS part in your mouth after it had been separated? I don't put a lot of prints in my mouth, but equally I don't want to have to buy new eyes just because I accidently handled a piece that had drain cleaner leaking out of its crevices :/

WHATS BETTER TO USE FOR SUPPORT MATERIAL ON ABS.
PVA or PLA or HIPS


Thank you
Antonio