[ADDED] Dissolvable interface between the print and supports

[James Tyrwhitt-Drake]

Hello to the Simplify community, this is my first post so I'll introduce myself. My name is James and I work on a National Institutes of Health on a project called the NIH 3D Print Exchange. We're working on methods to print ribbons models of proteins, which are essentially all overhangs, possibly the most difficult structures you could try printing.

I've been using a dual extrusion printer (Airwolf HD2X) to print using ABS and HIPS as a dissolvable support material. I'm able to print the models successfully, but removing the support using limonene as a solvent is difficult. The HIPS doesn't dissolve so much as melt into a sticky mass.

My idea is to specify using the secondary nozzle and material only for the interface between the supports and the print. Applying this as a parameter to the 'dense support layers' function would be perfect. That way when the model is placed in a solvent the supports would pop right off, and the small amount of HIPS would be easy to remove. This would also reduce the required volumes (and cost) of solvent and secondary material. I imagine this would be useful for ABS/PLA and PLA/PVA printing as well, but since I haven't experimented with those I can't be sure.

What do you think? Is there anyone else out there who would find this useful? Can you think of another way to implement it?

Thanks for your thoughts.

- James

[BaronWilliams]

+1

This is a really good idea, and probably not difficult to implement.

As far as ABS+HIPS is concerned, I must say that I have not been impressed with using HIPS as soluble support material for ABS. The D-limonene used to dissolve the HIPS doesn't work that well and can damage the ABS, and even dissolve some brands of ABS. Some brands of HIPS also don't dissolve well in D-limonene. I've found this process to be less than ideal. D-limonene is a very strong solvent, and quite expensive. It can dissolve a lot of things, so you need to handle it carefully.

I recommend giving other alternatives a try.


If you need truly soluble support, probably the best one is PVA rather than HIPS. PLA+PVA works well. If you look at reviews for PVA on Amazon you'll see a lot of people are happy with it as soluble support. PVA dissolves quickly and completely in water after only a few hours, even for large prints. For large prints, HIPS can sometimes take days to completely dissolve in D-limonene. At that point the ABS is damaged also. With PVA you can't use ABS though, you must use PLA. PVA is more difficult to print that HIPS, but it's much easier to remove from your prints than HIPS is. Water is super cheap compared to D-limonene, so despite PVA costing more than HIPS, you save money by using water instead of D-limonene. The main problem with PVA is that it can clog your printer if you print it at temperatures above 200 C. Also, when using PVA, you should always remove it from your print head after use (run some other filament at 195 C to get it out of your printer's head).

If we could specify a different material for the dense support layer only, then you could print PLA with PLA support, but use PVA as the dense support in between the object and it's support. This would be great. PLA is practically warp free, and can create very accurate support material. PVA is expensive and doesn't print as well as PLA does. If PVA is used just for the dense support layer, then it wouldn't matter all that much that it doesn't print as accurately, and this would also greatly reduce costs.


If you just need support that's easy to remove, and don't need soluble support then another combination I like is printing PETG on PLA support. PETG has properties similar to ABS. It's got good temperature resistance and is slightly flexible like ABS. PETG and PLA are practically warp free, unlike ABS and HIPS, and neither require a heated build plate. So your prints come out with much greater accuracy. PETG prints very well on PLA and visa versa. After the print is done, the PLA and PETG easily snap apart from each other. I have used this combination many times and am very happy with it. While you can do this also with ABS+HIPS, the result is not as good because ABS and HIPS both warp considerably, and seem to be more difficult to separate from each other.

[jasu]

+1

This would be a very useful feature. We are interested in the same thing - protein ribbon structures.

And we had similar problems to what's been pointed out above. PVA dissolves much better than HIPS. It's very hygroscopic though. Storage in a plastic bag with the air sucked out is best. HIPS is more affordable but dissolving it is very slow and has damaged our PLA printed parts.

[jasu]

If you just need support that's easy to remove, and don't need soluble support then another combination I like is printing PETG on PLA support.

Very interesting! So, in your experience at the same settings like distance, support infill,.. PETG and PLA bond less than say PLA on PLA presumably because of the different chemistry? At my favorite filament supplied PETG at 40€/kg is slightly more expensive than PLA at 20-30€/kg. It would still be worth it, if removing the support is easier.

[BaronWilliams]

Very interesting! So, in your experience at the same settings like distance, support infill,.. PETG and PLA bond less than say PLA on PLA presumably because of the different chemistry? At my favorite filament supplied PETG at 40€/kg is slightly more expensive than PLA at 20-30€/kg. It would still be worth it, if removing the support is easier.

It's really easy to separate PETG from PLA. You can print PETG directly on top of 100% solid PLA support (and vise versa) with no layer separation between them. There's a slight snap when you pull them apart, similar to when you might pull a small PLA part off of the build platform. I have been using PETG as support for PLA and PLA as support for PETG. It works very well. I will have my dense support set at 100% with no separation. I do this all the time. A very large complex print might be a little tough sometimes to remove the support, but it's much easier than removing PLA support from PLA (even with 1 layer separation between PLA and PLA).

[furicks]

This is a good idea

[McSquid]

+1
This idea would make dissolvable support so much easier to use! and It would be easy to implement! Just a separate extruder select for dense support layers. This could also be used to reduce the number of tool changes required when using PETG and PLA, or Ive even heard of people doing ABS and PLA.

[studiodyne]

PVA takes not a few hour , but A FEW DAY
Limonene-D it's the same time


It's a very good option , because , make the dual layer manually in solidworks is pure madness , this must be a batch process in the s3d slicer

Easy to unglue the support in a FEW MINUTES

[KC_703]

Informative thread... I like the idea of using PETG/PLA. Not dissolvable, but good to know they don't bond to each other well.

On that thought for the soluble material. Maybe a work around is to use a dense 100% layer for interface support layers, and a really sparse 10-20% for the rest of the support. This way the sparse supports can be removed or dissolved quicker. Leaving the dense layer near the actual object... not sure how large the spaces are between molecules, but a dremel or soldering iron comes to mind.


The idea to use a soluble material as the final dense layers would be a nice feature.

[studiodyne]

The support engine , is not intelligent , if you reduce the amount of density , it will become ' stupid' , and will make some support that haven't theright angle for bridgind the dense layer , some extrusion were in a void , and too much risk to restart a new print

I have written about it , a support engine ' intelligent ' for usual use , with these options , minimum percent of density , intelligent drawing for the dense layer , or the solid layer supported

This software is NOT FINISHED

Support engine , dual extrusion have to be released