Printing faster with finer layers

I am printing with Nylon trimmer line, and so I need the layers to be printed on top of eachother as quickly as possible, to reduce cooling between layers. This way I can completely bond the layers without need for a heated chamber. Right now the limiting factor on print speed is the grip on the filament. I am assuming that since smaller layers require less extrusion, you could print them faster? Would decreasing layer height make it so I can print faster and therefore have less cooling between layers, or would it have no effect since the extruder is not adding as much heat to the part?

Another question, if I were to increase my bed temp from 125 to 150, how much of an effect would this have on layer adhesion for upper layers?

If anyone wants to know about extruding trimmer line, search it on the forum, there is a thread about it.

do the parts that come out still have that nice self lubricating properties ?

There is a forumla floating around to calculate instant bonding between layers. The trick isn't to raise the heatbed temp or even printing faster, but actually raising the extrusion temperature of your hotend. An increased temp will partially re-melt previous layers and induce instant bonding. I would recommend doing that in a well ventilated area though, as high temperature nylon releases some nasty chemicals, especially Hydrogen cyanide, which is poisonous by ingestion and also irritant to the skin.

Edited 1 time(s). Last edit at 08/17/2012 04:08AM by Lodorenos.

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Charles S.
Software Engineer
Prusa Mendel I2, RAMPS 1.4, Marlin 1.0 R2, Pronterface, Slic3r

... what's about 'reheating' the area directly under the extruder with a focussed IR-bulb/heater or -laser?

Depending on the absoption and heated area this could be done with a 200mW-laserdiode from a salvaged DVD-burner ...

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Viktor
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VDX Wrote:
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> ... what's about 'reheating' the area directly
> under the extruder with a focussed IR-bulb/heater
> or -laser?
>
> Depending on the absoption and heated area this
> could be done with a 200mW-laserdiode from a
> salvaged DVD-burner ...

That's a new idea I haven't seen around before. Most lasers work perfectly with the power that RAMPS or similar electronics can supply and designing a holder for it to attach to the extruder should be simple.

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Charles S.
Software Engineer
Prusa Mendel I2, RAMPS 1.4, Marlin 1.0 R2, Pronterface, Slic3r

... something like this is used in DLM (for Direct-Laser-Melting, in contrary to SLS / Selective-Laser-Sintering) - a laser-spot heats a small area on the surface of the object and a jet of dust is blown in the spot, so it melts, fuses with the surface and forms a dome.

With ON / OFF or continuous feeding in XYZ you can 3D-print highly complex 3D-shapes normally not possible without support and with a perfect solidity and surface finish, as you don't have not or only partially melted dust surrounding the melted area creating a 'sandy' finish.

With changing the dust and laser parameters during print you can make multi-material objects and/or change the chemistry of the formed alloy - e.g. hardening/crystallizing the outer shell while the inner volume stays elastic/amorphous ...

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

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@VDX
That's a very interesting idea. I wonder if I could somehow source a laser off of ebay. I wonder how much of a difference it would make though, and what kind of surface defects might result.

@Lodo
I know that increasing hotend temperature increases bonding, but I can't get bring my hotend over 250 C due to the PEEK insulator. Therefore I am looking for a solution that will heat the layer below it, so that the average temperature of the two will be above melting temperature.

I do like the laser idea, because it directly affects the layer below it rather than trying to heat the whole part.

... you may think about using dark fishing line (or black/light-absorbing plastic wire with e.g. 0.3mm diameter) directly from a roll with a wire-feeder instead of melting and extruding filament.

With pressing the tip of the wire to the surface and melting it, you'll get a fused blob of material ... with vector-feeding (synchronous feeding in XY and turning your head) you'll get a trace ... when lifting in Z while the laser is on the wire will cut off without stringing, so you can create single blobs ...

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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]