1 Topic by FelixP

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Topic: Revisiting PC/ABS Mixtures

Hi, I'm considering getting a filastruder in a month or so (just bought a kickass delta printer and my wallet is recovering) in particular because I'm interested in making polycarbonate/ABS filament. I've looked over a considerable chunk of the forums and net in general on this topic and I've ended up with a lot of contradictory information. There was another user interested in doing this, but he never reported his findings. I'm going to divide my topic into 3 segments: what I do know, what I don't know, and what I need to know. If I get a filastruder and test for myself I will make sure to return and document my results.

What I know:

1. Polycarbonate by itself cannot be printed successfully with most hobby level printers due to the heat differential. PC needs to be printed in a heated chamber.
2. Any mixture of PC and ABS needs to be at least a 40/60 PC/ABS ratio for the full spectrum of PC attributes to begin to shine through.
3. PC/ABS with a ratio of PC greater than 60% seems to not have as dramatic an impact on performance as the difference between 20% and 40%.
4. Mixing materials (such as colorants) requires an initial mix into filament, a chopping of filament and a second extrusion to ensure mixture.
5. re-extruding materials (such as cutting up failprints and making filament out of them) weakens the material due to the printing and/or filament remaking process putting thermal effects on the plastic that destroy its properties.
6. Pure Polycarbonate cannot be extruded by default with a filastruder.
7. Suppliers of premixed PC/ABS pellets have issues. Some don't list the ratio of PC to ABS they mix, others do not have a high enough PC to ABS content, and still others only sell directly from china in 1 ton shipments.

What I don't know:
1. What ratios of PC/ABS can be succesfully printed without a heated print chamber.
2. What temperature is required to combine PC and ABS without damaging either of them. I have been given numbers such as 250C as when both are damaged, yet I've been told PC needs to be at least 250C to be extruded according to this thread: (nevermind, can't add links, look for "Polycarbonate?" in the DIY filament forum). Whether attempting to combine the two materials with a filastruder will actually allow for successful combination.
4. Whether the extrusion, chop, re-extrude process will end up significantly damaging the component materials, making for flawed filament.

What I need to know:
1. What are the minimum/recommended/maximum temperatures for a filastruder for PC?
2. What are the minimum/recommended/maximum temperatures for a filastruder for ABS? (not as obvious to find as I hoped)
3. What is the maximum temperature the filastruder can normally reach, and if it is not enough, how do I get it higher?
4. if the temperatures between these two materials are different enough such that one of them will have difficulty being extruded normally (such as if the normal extrusion temperature of ABS is 20 degrees below the normal extrusion temperature of PC) is it possible to extrude at a slower speed with a lower temperature?
5. What parts would I need to modify the filastruder to extrude at higher temperatures? According to the previously linked topic, the default filastruder setup maxes out at 230 degrees C, making the extrusion end up rough and too small for the diameter.

2 Reply by elmoret

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Re: Revisiting PC/ABS Mixtures

FelixP wrote:

1. Polycarbonate by itself cannot be printed successfully with most hobby level printers due to the heat differential. PC needs to be printed in a heated chamber.

It can be printed with an all-metal hot end like a E3D.

FelixP1 wrote:

4. Mixing materials (such as colorants) requires an initial mix into filament, a chopping of filament and a second extrusion to ensure mixture.

There are other options, like powered or more finely granulated colorant, or higher concentrations of colorant. Check the colorant thread in this sub forum.

FelixP1 wrote:

5. re-extruding materials (such as cutting up failprints and making filament out of them) weakens the material due to the printing and/or filament remaking process putting thermal effects on the plastic that destroy its properties.

Not really, primarily because the Filastruder does not operate on principles of shear to produce heat.

FelixP1 wrote:

6. Pure Polycarbonate cannot be extruded by default with a filastruder.

It can if your ambients temps are high enough. smile Or if you use a 15v or 18v power supply for the heater.

FelixP1 wrote:

What I don't know:
1. What ratios of PC/ABS can be succesfully printed without a heated print chamber.

None, since you can't print ABS or PC of any considerable size without a HBC, or at least an enclosure.

FelixP1 wrote:

2. What temperature is required to combine PC and ABS without damaging either of them. I have been given numbers such as 250C as when both are damaged, yet I've been told PC needs to be at least 250C to be extruded according to this thread: (nevermind, can't add links, look for "Polycarbonate?" in the DIY filament forum). Whether attempting to combine the two materials with a filastruder will actually allow for successful combination.

You don't get ABS/PC by combining ABS and PC pellets. You buy pellets that are already ABS and PC mixed into the same pellet. These are typically extruded at 240-270C (Filastruder temps)

FelixP1 wrote:

4. Whether the extrusion, chop, re-extrude process will end up significantly damaging the component materials, making for flawed filament.

No, it is not a concern in this application.

FelixP1 wrote:

1. What are the minimum/recommended/maximum temperatures for a filastruder for PC?

Depends heavily on the PC. Probably 250-280C.

FelixP1 wrote:

2. What are the minimum/recommended/maximum temperatures for a filastruder for ABS? (not as obvious to find as I hoped)

Its not obvious to find because it depends on what type of ABS we're talking about. Generally 175-200C, with Sabic MG94 doing well at 180-185C

FelixP1 wrote:

3. What is the maximum temperature the filastruder can normally reach, and if it is not enough, how do I get it higher?

Around 230C, depending on ambients and how much insulation you add, if any. The heater can handle 18 volts, but I only supply it with 12 to limit maximum temps to that which are safe for ABS and PLA in the event the controller malfunctions or user makes an error.

FelixP1 wrote:

4. if the temperatures between these two materials are different enough such that one of them will have difficulty being extruded normally (such as if the normal extrusion temperature of ABS is 20 degrees below the normal extrusion temperature of PC) is it possible to extrude at a slower speed with a lower temperature?

Sure, you can slow the motor if you want. Not sure why you'd need to.

FelixP1 wrote:

5. What parts would I need to modify the filastruder to extrude at higher temperatures? According to the previously linked topic, the default filastruder setup maxes out at 230 degrees C, making the extrusion end up rough and too small for the diameter.

An 18 volt power supply. ABS/PC pellets won't end up rough or too small of diameter as long as they are dried properly.

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3 Reply by FelixP (edited by FelixP 2014-09-20 18:37:29)

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Re: Revisiting PC/ABS Mixtures

Apparently, a Heated Build Chamber is just an enclosed area with a heated bed. I was under the assumption that there was more to it than that. My source who sent me on this wild goose chase didn't feel like clarifying.

The reason for the interest in mixing PC and ABS by myself is that the suppliers of PC/ABS mixture either put in too low an amount of PC in their blend, didn't say how much PC they put in their blend, or were in China, and would only sell the blend in 1 ton packages.

So the real questions are:

1. where and what kind of 15v or 18v heater would I need to extrude PC?

2. Do I need any other parts to modify the Filastruder to extrude PC?

4 Reply by elmoret

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Re: Revisiting PC/ABS Mixtures

A heated build chamber does have a second heater. An enclosure may or may not. Not the same thing.

You're not looking hard enough for ABS/PC if that's what you're finding. Mixing ABS/PC by yourself, you're going to run into homogeneity issues. Much better use of time to properly seek out the correct resin up front.

You don't need a new heater. Re-read my post.

No, no other parts.

Filastruder - the robust, inexpensive filament extruder
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5 Reply by FelixP

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Re: Revisiting PC/ABS Mixtures

sorry, powersupply. Where do I find a higher voltage power supply?

6 Reply by elmoret

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Re: Revisiting PC/ABS Mixtures

The internet! I can think of a few dozen vendors off the top of my head.

Honestly if sourcing an appropriate power supply is beyond your area of expertise, playing with high temperatures and experimental polymers might not be suited for you. There's a reason I include a 12 volt power supply in lieu of an 18 volt - it is to keep things safer for folks that are not experienced/knowledgable. Changing to an 18 volt power supply is the type of modification that is aimed at the user that only needs to knwo the heater can handle up to 18 volts. The heater draws 12 volts at 40 watts. For someone experienced, that is enough information to source an appropriate power supply.

I say all of this as someone that stands to make money on every sale of a Filastruder: it sounds like you need to find someone with a bit of electromechanical experience before proceeding with your plan. If you're thinking about just buying a different extruder (Filabot, Extrusionbot, et al), that's an even worse idea from a safety point of view as those machines all use heaters that can happily push ABS to 400C+, and run on mains current so there's potential for electrocution as well if wired incorrectly. Much over 300C and ABS starts to offgass things like hydrogen cyanide and carbon monoxide.

Safety is paramount. In stock configuration, the Filastruder is reasonably safe (cannot exceed 230C even with multiple points of failure, 12 volts so there's no electrocution potential). If you're going to modify the configuration, you need to have enough knowledge to take appropriate measures.

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7 Reply by FelixP (edited by FelixP 2014-09-26 18:31:47)

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Re: Revisiting PC/ABS Mixtures

After taking a good look at the pictures of the filastruder I realize how dumb my question was. Yes, I can find the power supply no problem. For some reason I thought it was placed inside the filastruder's box of electronics and was confused why the question was considered the way it was.

I've assembled a Mendel I3 from a kit, and I'm going to be assembling a Kossel MiniMax (with its very dangerous-if-you-don't-know-what-you're-doing wiring) sometime this week, so I'm not completely clueless (or at least I don't think so). I also have Joe Mosfet to lean on for expertise (he's the inventor of the Melzi printer mobo, the sanguinololu mobo, stepsticks, and the MiniMax).

My one question I still have is about mixing powdered material with a filastruder. Filabot sells packets of CF powder, and I'm interested in testing it out with various materials. The filabot can mix it, and I'd like to know if the filastruder can mix powders into filament. I thought I read something about the filastruder mixing nylon powder successfully somewhere, but I don't remember what topic.

Oh! also, if the filastruder can mix powders in with pellets, what would you recommend as the best way to do so? (so that the powder isn't wasted and I'm not breathing it in, will be wearing a mask if I use it)

8 Reply by elmoret

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Re: Revisiting PC/ABS Mixtures

Sure, the Filastruder handles powders fine. Just mix with the other material, shake well, pour in the hopper.

Prints made from carbon fiber filament aren't any stronger than prints made from regular filament, though.

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9 Reply by FelixP

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Re: Revisiting PC/ABS Mixtures

Really? I'm planning to test for myself because all the information I've been given is hearsay. People say it doesn't work, Zheng3 says it does, but I haven't seen any side-by-side comparisons or tests. If you have tested it for yourself or have a source, I'd greatly appreciate the information.

10 Reply by elmoret

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Re: Revisiting PC/ABS Mixtures

Doesn't need a test to confirm it doesn't work.

3D printed parts fail on the inter-layer connections. The carbon strands don't end up going across the layers, so it doesn't end up any stronger.

If you don't want to believe me, here's some data: (found from a 10 second google search)

http://www.proto-pasta.com/product#CFdata

Flexural and impact strength are actually reduced relative to regular PLA.

That Zheng guy is on Filabot's payroll. Dig deeper before believing things, my man.

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11 Reply by FelixP

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Re: Revisiting PC/ABS Mixtures

thanks for the sheet on protopasta. Wasn't saying that I believed Zheng outright, its just all of the objections were based on "what should happen", not on testing. While Zheng3 is undeniably on the payroll he at least had something to show. I was working on speculation vs. biased demonstration, neither of which a conclusion should make.

12 Reply by elmoret

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Re: Revisiting PC/ABS Mixtures

Just read his post:

http://www.filabot.com/blogs/news/15428 … -fiber-abs

He never tests ABS or PLA against the carbon fiber (or maybe he did and Filabot left those results out). He does say this:

I've been wiggling squirrel arms trying to get them to break but they're giving me far more resistance than I've come to expect from ABS.

Stiffness and strength are two different things. A piece of glass is much stiffer than for example, a metal chain - but which one would you grab onto if you were falling out of a tree?

Filastruder - the robust, inexpensive filament extruder
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