New hybrid resin mix


#81

Sam, good to hear from you. Sorry if I don’t get things right away (maybe it’s my poor english understanding) but for “we’re working to be able to supply you with the resins that you need to get the job done”,  given the context of this thread, do you mean “we are working on a castable resin right now and it might come out in the near future” or “a castable resin surely is one of the items in our to do list but we still have higher priorities by now and it might take a while before it becomes a reality, so don’t hold your breath”? I’d be fine with any of the answers.  I’m very confident my form1 will be  a great machine, be it a machine suitable for the jewelry market or not , but I’d appreciate if I could have a perspective on the issue. Thanks for taking the time and joining the thread.


#82

Good call Paulo! I think that the level of interest in this particular thread speaks volumes, that Form1 user want to see a wax/polymer hybrid material that will enable our print results to function for investment casting. Formlabs themselves mentioned developing a material for lost wax on multiple occasions, let’s hope that it is something that deserves some R&D placed at the head of the queue.


#83

Monger, before you spend a load of cash on the B9 Creator, would you like me to send you some packets of my Microstar HS investment to try?  You’ve nailed the resin mix (50% Form1 Grey, 50% B9 cherry red) as far as print detail goes.  It seems like you’re satisfied with the print quality now.  I think it’s time for you to try an investment that may work better for casting this type of resin.   I promise you that this investment is capable of capturing EVERY detail of any model you invest with it (done properly, of course).  My limited experiments with it (investing/ burnout/ casting) have been successful so far.

What do you think?  Would you like to try it?  If it doesn’t work for you, then move on to the B9 Creator.


#84

Mark, I’ll give it a try. Shoot me an email. Mongerdesigns at live dot com


#85

Paolo, Jesse  – we’re well-aware of the importance that a castable resin would have for many application and we’ve been working on it in our in-house labs. I don’t have any timeline for you on it at the moment, but as we grow, one of our priorities is accelerating our resin development. A castable resin is towards the very top of that list.


#86

Question for all.

Has anyone thought about what might be in Formlabs resin that makes it uncastable?


#87

Whatever it is, it leaves a lot of ash residue.


#88

I think it is something that is not combustible like ceramic. I have been able to take some of the ash and try to over heat it and it just gets white hot but never burns away. I think that even a mixture of resins give you very nice prints it most likely will not be castable with any kind of consistency.


#89

Yes, Bob. That’s exactly what’s happening. Even mixed with the b9 resin, some parts cast well and some don’t.


#90

Will be trying the dental investment that Mark is going to send me, and will post results for that once I have them.


#91

Sorry to cross post this - it seems like this is a better spot for this:

I came across this article the other day on the Ganoksin website. It’s a type of casting plaster that gets really hot and can be used to reduce production times and is used to burn out rapid prototyping materials.

Could this be an option? Maybe this with a a regular burn out cycle could result in a clean mold for casting?

You thoughts?

Here’s the link to the article:

http://www.ganoksin.com/borisat/nenam/revving_the_burnout_process.htm

And the site for the product - scroll to the bottom of the home page for more tech info

http://www.docscasting.blogspot.ca/


#92

So, Monger… On laser power control-- are you thinking you want more output in all cases?  (or are there any situations where one of the settings is ‘too much’ and you’d like to knock it down a bit?)

Lasers are typically current controlled, more current = more output (and more heat/stress on the laser) and the opposite is also true.  From looking at Bunnie’s teardown of the Form1 they have four wires on the module, so presumably two are power/ground and the other two provide either current based control for the laser or possibly some ‘other’ functionality (focal point adjustment?).

What I’m getting at is if you think it’s a matter of just ‘more or less’ laser power at a fixed ratio, we might be able to do that with a hardware hack.  Essentially have a little circuit board in there that plugs in to the control board, intercepts the laser control signals and allows manual control (eg, a knob) that can dial in a new value.  (Think of it as a multiplier-- like from 0.5-1.5 or something-- so you could cut or boost power as a fixed ratio.)  The Form1 and the software wouldn’t “know” about it per se, but you could essentially tell the software to use the “25 grey” setting and then force it to apply ~120% (or whatever) the output power ‘manually’.

Would that be useful?


#93

Clay,

Do we know if the laser is not already running at the maximum it’s capable of? How would you even measure that? I’m sure opening up the form1 would most likely void the warranty, not counting adding circuit boards etc.

I think the key is not more power, but more curing time per layer. That can only be controlled through the software. When printing at 100 microns for example, you can see the laser spending a lot more time dancing around and curing layer versus when printing on 25 microns. If it was power related, then they would both use the same curing times.

Maybe if enough people asked for it, Form Labs would finally release control over the curing times in software, some sort of advanced options, so that we can use 3rd party resins. Of course that completely falls outside of their business model and I think they want to be the only ones to sell resin for the form1.


#94

Stephen,

It seems like no matter what temperature you burn the form1 resin at, you are always left with a small bunch of ash residue. If you are casting a solid sphere for example, it’s shouldn’t be a problem. You should be able to cast it just fine. But for jewelry with fine detail, it doesn’t work.


#95

Before sending the Microstar HS investment to Monger this morning for him to try, I did more testing of burning out the Form1 resin in my burnout oven to check for ash residue.   As many others have posted here earlier, the Form1 resin does NOT burn out completely. There is a definite ash residue remaining.

I think my early success with casting and pressing using  the Form1 resin was luck, based on having a large pattern with no intricate lobes (like prongs and settings on a ring) and oriented in such a way that the residue ash fell out of the investment through the sprue prior to casting.

An ash-free resin is what’s needed.   A different investment will not help this situation.


#96

A little reverse engineering would likely expose whatever they’re up to.  Watching current in to the laser would tell if they’re actually controlling power going to it in with anything other than “on/off” or not.  Limiting current in to the laser would be relatively easy, so a control that results in “less than 100%” output to the laser is relatively simple.

There’s a few unknowns (but again, with their architecture they can’t really *hide* anything since it ultimately goes to the laser and galvos) as to how it actually operates-- I would suspect that it would all come down to “energy per unit area”.  In theory you could:

* have a fixed laser output power and a fixed drawing speed and draw the same pattern multiple times for longer curing

* have a variable laser output and fixed drawing speed and draw the pattern the same number of times but with different power settings for different thicknesses

* have a fixed laser power and draw the same pattern, but do it with a variable drawing speed/slew rate (faster or slower beam movement) resulting in more or less energy going in

* any other combination or permutation of the above

A hour with an oscilloscope would answer those questions.  I’m probably about out of warranty before too many more weeks here. :wink:

I suppose another approach would be to stick a USB analyzer on the bus and download the smallest possible job at each of the different material/thickness settings and see what differs and if there’s some sort of ‘cure profile’ data that goes by in the clear.


#97

Hey guys. Just came up with a cool idea. Not sure if it’s going to work, but we will know in a couple of hours.

I duplicated the stl file inside PreForm and overlapped it on top of each other. Hopefully this will double the curing time for the print. Unless the printer cancels out the duplicate overlap areas this should result in double the curing time. You can see that the laser paths have doubled using the slice view slider, so in theory it should work.

I am printing using the B9 cherry resin alone. The first time it didn’t even cure properly and the model failed half-way, resulting in a jelly-like flexible print. So if it’s anything better than that this time, we know this method works.


#98

Fantastic idea, Monger! Was it difficult to precisely align the two stl files?


#99

Well if it is successful, keep the software in case Form1 fixes the “bug” in the future lol!

By the way how to make sure they overlap each other when an object is oriented?


#100

The experiment was a success, but the print was not. Overlapping the models does double the laser curing time. Before the cherry resin alone would not print at all and would fail half way, resulting in a very soft jelly like print. Now the model printed all the way and looked like what the b9 red print looked like. Still bumpy and grainy surfaces.

I imagine overlapping the model 3 or 4 times may yield better results, but I may try that later.

I am now trying the same technique on a 50/50 mix of cherry red and regular red. People are having the best success printing using this formula on the b9 forums, so might as well.

I have not tried the overlapping technique on my 50/50 (form1 grey and b9 cherry) mix. But I imagine it may result in crispy sharp prints :wink: