LOM RepRap?

Just curious if there are any LOM (Laminated Object Manufacturing) RepRap or other DIY projects out there.

Something like this [www.cubictechnologies.com]

Seem like a much easier method for a DIY project. I already have a vinyl-cutter, if I could get something to batch process the layers from a 3d object I could at least manually place the cut layers (using a jig or something) and build up objects.

Anything like this exist?

... i made some lasercutting and laminating with different materials (steel- and ceramic sheets) - some discussion was here and here ...

Most of the work was under NDA but actually i'm already busy developing some diodelaser-modules for cutting sheets and sintering powder for DIY-LOM and DLSM

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I've been hacking a Mendel variation with a thought to the mcor Matrix, that does LOM with paper. My idea is using high speed dentist drill motors (350K - 500K rpm at about $30-$40 per motor) and burrs to rout the paper rather than cutting it with a blade. I'm also thinking that multiple heads could reduce the need for x travel to 50mm - 100mm and speed up the processing. Support material with easy stripping inbuilt, cyanoacrylate can be dribbled through the burrs' slots to consolidate afterwards, if a model's small, multiple layers can be done concurrently on the one sheet. It could be potentially the fastest method of RP, if sheet speed can be gotten down to 15-20 secs, A4 footprint would give around 3 minutes per mm, around 50 cm³ per minute versus 15cm³ per hour for Mendel with plastic, and the mcor site gives an idea of what sort of surface finish can be obtained. Raw material available everywhere.

Hmmm... I was just thinking: Laser printers use a fusible plastic toner. I wonder if you could:

1) Print the layers of an object on paper with a standard laser printer.
2) Put the stack of pages in a heated press to melt the toner and fuse the pages.
3) Use a water bath to dissolve the paper not coated in toner

I suspect that thin paper and an extra-heavy coating of toner might be necessary for the model to make it through Step 3.

Seem like a much easier method for a DIY project. I already have a vinyl-cutter, if I could get something to batch process the layers from a 3d object I could at least manually place the cut layers (using a jig or something) and build up objects.

Try cutting small interior circles out and using a grid of 2 or more pegs to align the layers.

This stuff will do your slicing:
[objects.reprap.org]
(some assembly required)

cyanoacrylate can be dribbled through the burrs' slots to consolidate afterwards

Madness.

Try a glue swabbing thing or inkjet down cyranoacyrlate.
Aside from that, it may work rather well, although you might wear out your bits faster than you'd think. Would you like to document your mendel variation on a new wiki page?

I think we may see a lot of paper-lom once we've implemented more laser stuff.

Hmmm... I was just thinking: Laser printers use a fusible plastic toner. I wonder if you could:

John, try gluing together two sheets of paper, and then dissolving everything but the glued bits.

I think you'd end up with a soggy paper-soup mess. Novel idea, though.

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

> I already have a vinyl-cutter, if I could get
> something to batch process the layers from a 3d
> object I could at least manually place the cut
> layers (using a jig or something) and build up
> objects.

I've not been able to find working links with pictures explaining the concept, but JP System 5 is (was?) a method for manual prototyping of objects from adhesive sheets cut on a plotter and assembled using pegs-and-holes registration system:

[www.silverscreen.com]
[www.cs.cmu.edu]

Essentially the same process is described by a company named Ennex as "Offset fabbing" - not sure if two are related: [www.ennex.com]

As far as DIY developments, I'm not aware of any, except for Viktor's efforts and my "paper prototyper" project which has been on hold for a while: [www.garagefab.cc]

I was planning to cut paper with a knife and glue it using 3M spray adhesive, repeat for every layer. Ideally I'd like to be able to use wood glue, however, it wrinkles the paper, and with hot roller drying it will probably require glue-then-cut process.

Anyway, I think LOM (whether paper or plastic based) is a very promising process due to higher build speeds, and if anyone has achieved any progress with it, I'd love to collaborate.

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Vitaly
[contraptor.org]

SebastienBailard Wrote:
-------------------------------------------------------
>
> cyanoacrylate can be dribbled through the burrs'
> slots to consolidate afterwards
>
> Madness.
>
> Try a glue swabbing thing or inkjet down
> cyranoacyrlate.
> Aside from that, it may work rather well, although
> you might wear out your bits faster than you'd
> think.
>
One man's madness is another's lateral thought
I've done some experiments with cyano such as depositing it on beds of oven cleaner foam, talc and sodium bicarb, all of which accelerate cure. It's the minimal surface tension that attracts me, but how to instantaneously cure it at a flow boundary without clogging the applicator? Perhaps vapour from an amine accelerator with a clean air drench about the tip.
As to how fast the burrs wear, the little buggers come in HSS, carbide and diamond, and they have pressbutton release collets on those dental motors, for convenience. They're air-drenched to cool, too. Time will tell.

>Would you like to document your mendel
> variation on a new wiki page?

When I have something beyond thought experiments to display, I'll take you up on that, Sebastion.

John Wasser's proposal is basically how the Desktop Factory technology works, toner on an offset roller, fused with heat focussed from a halogen bulb.

but how to instantaneously cure it at a flow boundary without clogging the applicator?

use a UV photopolymerizing polymer?
[forums.reprap.org]

One man's madness is another's lateral thought
I misunderstood and thought you were suggesting using hollow bits that also oozed adhesive.

Aside from the whole 'bursting into flame business' I'd suggest a crafter's woodburning kit with the exacto-knife blade tip. [www.amazon.com]
An extreme fire hazard, and all that.

Viktor's done quite a bit of research into Sodium_Silicate_Concrete
[objects.reprap.org]
[en.wikipedia.org]

I'd suggest using it as a adhesive between layers of paper and then cutting the layers with {laser, dragknife, hotknife}. (I was going to suggest acid, but the sodium silicate is a base and would neutralize that.)

My idea is using high speed dentist drill motors (350K - 500K rpm at about $30-$40 per motor).

What's your source for those? Is that a turn-key bolt in spindle?

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-Sebastien, RepRap.org library gnome.

---

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

SebastienBailard Wrote:
-------------------------------------------------------
>
> My idea is using high speed dentist drill motors
> (350K - 500K rpm at about $30-$40 per motor).
>
> What's your source for those? Is that a turn-key
> bolt in spindle?

They are a turn-key item, Chinese sellers on ebay offer them for about USD 30-50 each, like these, [cgi.ebay.com.au].
They're available in linear configuration, but even the offset handpieces are easily configurable, the actual motor is very compact, and they've got gee-whiz ceramic bearings to handle the revs. Pushbutton release collets make good sense.
I got the idea from 1/8" air driven die grinders, owning one of those that turns 50K rpm, but then I remembered the high-speed gravers like turbocarver that people use to engrave eggshells, gunstocks and other things, and realised that their specs read like dental handsets. Dental motors are much, much cheaper.
In addition to all of that, an Australian inventor recently earned a patent for an air recirculating system. Exhausted air from an air tool is recirculated into the intake manifold of the compressor, which conserves the energy retained and means the compressor needs to work less, or a smaller compressor be used, to supply the air requirement. Perhaps ganged dental motors could even be daisy-chained.
[www.abc.net.au]

... atztek made some tests with fusing laser-printed toner stacked to 3D-objects: - seems working ... look here in the german forum ...

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

albanetc Wrote:
-------------------------------------------------------

>
> As far as DIY developments, I'm not aware of any,
> except for Viktor's efforts and my "paper
> prototyper" project which has been on hold for a
> while: [www.garagefab.cc]
>
> I was planning to cut paper with a knife and glue
> it using 3M spray adhesive, repeat for every
> layer. Ideally I'd like to be able to use wood
> glue, however, it wrinkles the paper, and with hot
> roller drying it will probably require
> glue-then-cut process.
>
> Anyway, I think LOM (whether paper or plastic
> based) is a very promising process due to higher
> build speeds, and if anyone has achieved any
> progress with it, I'd love to collaborate.

Me too!

I've been thinking about ways to meet RepRap's cost goals but produce higher quality prints. LOM could do it.

I was thinking, instead of a spray adhesive, why not try to selectively bond thermoplastic sheet. I can think of three ways to do that:

1) "spot weld" layers using a laser at a power just enough to melt the material, but not enough to vaporize it. You can choose how dense the bonding area should be to make the parts less susceptible to warping, or easier to weed

2) use an inkjet or laser printer to print black areas on transparent (or white) film. Then expose the stacked layer to IR radiation. The black areas should heat up preferentially. With good control, you should be able to get only the black parts to bond.

3) use a photostatic drum from a laser printer to selectively "pick up" cut areas of the layer and deliver them to the build surface (or alternatively remove waste areas). The build volume can then be heated uniformly to bond the layers, and you don't have to do any weeding. (this is kind of like the laser printer reprap idea, but using thermoplastic film instead of expensive toner)

... price is still going to be an issue though.

The cheapest thermoplastic sheet is LDPE. You can get a 1000' roll of 0.002" thick sheet from home depot, which equates to a build volume of about 10"x10"x10", for $60. With LOM, you have to pay for that whether you use the whole build volume or not. Better thermoplastics like HDPE, PVC, Polypropylene, and ABS are even more expensive.

I suppose we could still use waxed paper like the old Helisys printers, but those weren't very popular.

Is there a way to move this topic to the LOM sub-forum?

Edited 1 time(s). Last edit at 02/26/2011 06:43AM by NuclearNerd.

Yup.

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-Sebastien, RepRap.org library gnome.

---

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

I've spent a little time looking for cheaper film. The

Quote
http://www.mcmaster.com/#catalog/117/3565/=b7e77q
cheapest is by far LDPE (visqueen)

, usually as window or other "self-adhesive" (statically charged) film, anywhere from 0.002 to 0.010" thick. You can also get LDPE film in a nice sized roll for laminating machines, but it's a little more expensive. PVC (vinyl) rolls exist too, but they're about 50% more than visqueen.

Another material option for LOM is Tyvek, which is basically HDPE felt. It's still a bit more expensive than ldpe, but it's a lot cheaper than solid HDPE - $60 for a 3' x 150' roll. Homewrap is apparently 0.005" (0.12mm) thick, which gives a 6" x 6" x 9" build volume (if you cut the roll into 6" widths) . This material should give about twice the z resolution of a Mendel.

The cost per cubic inch is about the same as extruded ABS (less than $0.2/cu in), but with LOM you have to pay for the whole build volume, so we would need much cheaper feedstock to be competitive. I suppose if we were very clever you could make up a laminator that only spreads tape strips where you will need them, instead of the whole build volume. Alternating layers would have to be applied at 90 degrees. That would be pretty neat, but mechanically challenging.

Speaking of tape, I thought of another way to selectively bond sheets:
4) Use film with a pre-applied adhesive (tape). Use an inkjet head to coat/dissolve the glue in sections where it shouldn't adhere.

For completeness: 40 lb "basis weight" wax papercosts only $60 for a 18" x 1200' roll. It's hard to find an actual thickness, but it's probably between 0.007 and 0.01", or 0.15-0.2mm. That gives a build volume of 12" x 12" x 12", or about 1/5 the cost per cubic inch of plastic sheet.

I'm hesitant to recommend using wax paper because it's probably won't have the surface finish, strength or stability of plastic film, but it might be a good place to start cheaply.

Edited 1 time(s). Last edit at 02/26/2011 04:55PM by NuclearNerd.

One more thought before bed:

With wax paper, the melting point is low enough to a thermal printing head to selectively bond layers before or after cutting.

Actually now I'm trying to think of a way to use thermal transfer printing to lay down wax layers without the need for laminates. You'd need some sort of aborbant scaffold (tissue?) that could draw the wax from the ribbon, made from a material you could later dissolve without dissolving the wax. I'm drawing a blank.

If you made a LOM Reprap could you still call it additive manufacturing? Seems like that's subtractive, with all the associated waste of materials.

... the LOM fabbing process is additive, as you stack layer on layer, until your object is complete ...

But you're cutting (or engravin, or milling, or ...) each respective layer, so per layer it's subtractive ...

With proper object-space-management the wasted areas are only the spaces inside the object footprint, but this is normally no essential point if you use a cheap material as paper or plastic sheets ... or if you can remelt and reuse the material, (e.g. wax-sheets).

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Quote
makeme
If you made a LOM Reprap could you still call it additive manufacturing? Seems like that's subtractive, with all the associated waste of materials.

Yeah, I definitely think LOM is on the border. For instance, Solidica makes (made?) a sweet little aluminum foil LOM machine, but it ends up looking a lot like a machining center.

On the other hand, if you include the "wasted" support structure, FDM does some subtraction too. The distinction is probably moot anyway. As long as we can make an inexpensive machine that prints out usable parts in a home setting, who cares!

Regarding thermal printer ribbons - the economics look even worse than laser printing. The rolls of wax are relatively cheap, but the ink is only 4 microns thick, so it would take quite a few to build any significant height.
[www.tscprinters.com]

I also found another commercial LOM casualty (to neighbor the Helisys and Solido graves). The Japanese company Kira used to sell a LOM printer that joined paper sheets using xerox toner. It sounds like a neat process, but unfortunately no one seems to be buying because almost all trace of the product has been removed from Kira's website.
[www.rapidmockup.com]
[www.kiracorp.co.jp]

So LOM doesn't seem to be succeeding in the commercial market. I wonder if the economics look better as a "home" printer, or if people really don't want that type of model.

LOM-printing had its best time around 1994, then the stereolitho process was capable of bigger objects and the LOMming systems vanished from the market

In 2005 i found the SD printers from solidimension ltd., which were LOMming with thin PVC-sheets and a solvent to fab really rigid parts ... but this company vanished too ...

I'm testing with LOM-fabbing cutting thin sheets with a laser - and not stacking horizontally, but continuous winding the endless sheet on a cylinder, so the laminating process won't consume extra time ... here the software for placing the objects into the cylinder and calculate correct cutting lines is the main hurdle ...

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I used a kira some time ago, it was very flakey, it was rare for it to finish a build, the papar jammed or it was a full moon, not to mention the archaeology involved in removing the waste material, only any use at simple blob shapes, that experience put me of lom, and the fact that a small part uses as much material as a large part.

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Random Precision