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DLP vs FDM

Posted by sanman 
DLP vs FDM
July 13, 2014 12:33AM
Sorry if this has already been debated to death, but I'm not that knowledgable and I really want to know, before making a purchasing decision.

Which is better overall - DLP printers or FDM printers?

I've read conflicting information about this on the internet - some say that DLP is much more expensive in terms of materials, and that the selection of material types is also more limited. But others swear by DLP and say it far exceeds FDM in resolution and final part quality.

I realize that there may be fanboy biases in the debate, but can somebody please straighten me out?

What are the pro's and cons of each in relation to the other?

Edited 1 time(s). Last edit at 07/13/2014 11:16AM by sanman.
A2
Re: DLP vs FDM
July 13, 2014 03:41AM
Your personal use of the object dictates the technology, method, and materials to employ. Something is only better based upon ones assumptions, and expectations.

Narrow the scope of your query.

Edited 1 time(s). Last edit at 07/13/2014 08:26AM by A2.
Re: DLP vs FDM
July 13, 2014 11:12AM
DLP can make much higher resolutions parts. They also make small parts, take longer to printer, have less design restriction on the parts, and have fragile prints. FFF can make low resolutions parts faster, stronger, and cheaper. As A2 indicated, they are both better than the other. You obviously need to have one of each just like you have a toothbrush and floss.


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Re: DLP vs FDM
July 13, 2014 11:22AM
Hi,

Well, I'd like to be able to print plastic parts which can be directly used in a final product. Or else, I'd like to at least be able to print molds which can be used to make the parts.

From what I've seen, the visible characteristics of DLP-fabricated parts look like that of hardened glue - as if I'd literally squeezed glue out of a glue bottle and let it harden into some precise shape.

FFF/FDM-created parts on the other hand, see to have the option of being made from materials which are more production quality.

So based on what you've said, I guess FFF/FDM is the better choice for me. I value physical robustness of the final part over intricate detail of the geometry.

I was curious to know if DLP can make parts that have the strength and appearance of polycarbonate. Are there any DLP resins which can do this? What about fiber reinforcement - can DLP make parts containing short fibers for structural reinforcement purposes?

What is the cost of DLP resin in comparison to FFF/FDM filament? Again, I've read conflicting information - some people say DLP resin is cheaper, and others say it's more expensive than filament.
Re: DLP vs FDM
July 13, 2014 11:30AM
Quote
sanman
I was curious to know if DLP can make parts that have the strength and appearance of polycarbonate. Are there any DLP resins which can do this? What about fiber reinforcement - can DLP make parts containing short fibers for structural reinforcement purposes?

What is the cost of DLP resin in comparison to FFF/FDM filament? Again, I've read conflicting information - some people say DLP resin is cheaper, and others say it's more expensive than filament.

I am unschooled in the variety of resins available and there properties. My impression is that the resin is more expensive (price a kg of each and see) and that it may make strong parts but they will be brittle. (For instance, I have a tungsten wedding ring and it shattered when I dropped it.)

Having fibers suspended in the resin sounds like an interesting idea. I don't see why it wouldn't work. It will leave your part hairy.


ConceptFORGE
Wally, GUS Simpson, LISA Simpson, THOR Simpson, Sextupteron, CoreXZ
Re: DLP vs FDM
July 13, 2014 12:18PM
Heh, well maybe you could "shave" the part afterwards, as a post-processing step.

Likewise, I'm wondering whether particle suspension in DLP liquid resin would result in a particle-loaded plastic part (eg. carbon black for increased conductivity)


More recently I'd read that DLP may soon be able to create metal parts too, in a non-DMLS way:

[www.engineering.com]


Does anybody even know how that works? Would any SLA printer be able to do this and make metal parts perhaps just by using the right "resin"? Or would it require an SLA printer designed specifically for this purpose?
Re: DLP vs FDM
July 13, 2014 12:24PM
The metal DLP is probably similar to how we can paste extrude metal clay and then put it in a kiln. Probably most SLA printers will work.


ConceptFORGE
Wally, GUS Simpson, LISA Simpson, THOR Simpson, Sextupteron, CoreXZ
Re: DLP vs FDM
July 13, 2014 12:29PM
The new resins are getting cheaper and you are getting more and more choice of material hardness. Along with getting more suppliers I think resin is the way of the future with its higher quality surface finish. Some of the resin based printers are getting really fast and can print things faster than an FFF machine too (not necessarily including post processing time though). Titan 1 boasts speed of 1.3-2.7 in/hr @ 0.100mm layers.

Have a look at Makerjuice for example. They have 4 different resins at the moment at reasonable prices.


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Re: DLP vs FDM
July 13, 2014 12:41PM
Just throwing a question out there on DLP speed. Would a Sony 4K projector [you know, the $25K one] make for super fast, super sized prints at the same resolution for others? Or am I missing something? Which is likely with my limited DLP printing knowledge.


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Re: DLP vs FDM
July 13, 2014 12:46PM
I am sure it is a balancing act. More lumens could be faster but you also might start curing things you don't want to. I wonder how strong you can go.


ConceptFORGE
Wally, GUS Simpson, LISA Simpson, THOR Simpson, Sextupteron, CoreXZ
Re: DLP vs FDM
July 13, 2014 02:08PM
Quote
nicholas.seward
The metal DLP is probably similar to how we can paste extrude metal clay and then put it in a kiln. Probably most SLA printers will work.

But does this produce a metal part which is as strong as a forged metal part? Or will it be much weaker?
Re: DLP vs FDM
July 13, 2014 02:15PM
Quote
sanman
Quote
nicholas.seward
The metal DLP is probably similar to how we can paste extrude metal clay and then put it in a kiln. Probably most SLA printers will work.

But does this produce a metal part which is as strong as a forged metal part? Or will it be much weaker?

There isn't enough information yet to speculate. My guess is that it won't be as good as a forged part. However, heat treating and surface hardening can probably get you great results but if you have the expertise to heat treat and surface harden it then you probably have a forge.

There really is no substitute for working actual metal. Additive techniques will never produce (IMHO) an optimal grain structure for a metal part but for most applications this is not required.


ConceptFORGE
Wally, GUS Simpson, LISA Simpson, THOR Simpson, Sextupteron, CoreXZ
Re: DLP vs FDM
July 13, 2014 02:17PM
Quote
sanman
Well, I'd like to be able to print plastic parts which can be directly used in a final product. Or else, I'd like to at least be able to print molds which can be used to make the parts.

So based on what you've said, I guess FFF/FDM is the better choice for me. I value physical robustness of the final part over intricate detail of the geometry.

FFF parts don't break when they fall to the floor. It's the same plastics you use in injection molding machines. You don't get all the strength of molded parts, but some 70% of them.

To make molds, DLP/Stereolithography is better. Strength doesn't matter much, surface quality rules.

Quote
sanman
I was curious to know if DLP can make parts that have the strength and appearance of polycarbonate. Are there any DLP resins which can do this? What about fiber reinforcement

DLP/Stereolithography resins (typically acrylate or epoxy) don't even come close to polycarbonate. And fibre reinforcement is so far nowhere seen in 3D printing, certeinly not in commonly used processes.


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Re: DLP vs FDM
July 15, 2014 09:22AM
Quote
sanman
Hi,

Well, I'd like to be able to print plastic parts which can be directly used in a final product. Or else, I'd like to at least be able to print molds which can be used to make the parts.

Ofcourse, for a wide range of applications, a 3D-printer object printed in plastic on a reprap/makerbot/ultimaker is qualitatively 'ok' as a final product.

But, the plastic FDM (or FFF as RepRap calls it) method should really be considered a prototyping technology. I completely understand that in a lot of applications it can however be a final product. I have made many parts for colleague-students at my art academy to function in a machine, contraption or alike.

As said before, it really depends on what you want to do. It's even a big difference if you build it yourself, or have a machine delivered already completed. From self-building, the learning curve might be a bit more challenging, but you will be printing way quicker, and understanding 'what happens' in no time.


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