Adding a stepper driven lathe to print in 4D

I think it would expand the range of complex shapes that could be extruded if the reprap machine had the option of a stepper driven lathe to rotate a partially completed part and add more sections to it without the 60 degree angle limitation on overhangs. This is intended more to allow the piece to be rotated occasionally while extruding more plastic than to spin rapidly and make surface of revolution pieces. Thus it is more likely to make rectangular cross section pieces.

objects.reprap.org

If the stepper motor and gear reduction are at the edge of the reprap's working volume, you could build a square truss beam (cross bars and 'X's on all four sides) by starting with the bottom layer and end pieces, which is easy to extrude. Then, lift the piece off the bed and place between the lathe head and the tail stock, then start printing again. Now, you can build the two sides, then rotate 90 degrees and do the same process to build the top. Then, assuming a fiberglass extruder has been made, you can wind fiberglass strands not only along the four corner beams, but wrap around all four sides at each cross bar, and then spiral around to reinforce each angle in the 'X's. This would also make strong, stiff torque tubes, to which threads can be added to make plastic threaded rod to use to drive one or more reprap machine axes.

I recommend using a gear reduction between the stepper and the lathe head so that more torque can be applied. This will allow mild milling and lathe work if the extruder is replaced with a mototool with milling bit. Without a several horsepower motor, the lathe will never be strong enough to do normal lathe type cutting with a rapidly spinning piece and cutting tool, but at slow speed with a milling head, it should be possible to mill aluminium.

Mike

Mike,

[spoolhead.blogspot.com]
[reprap.org]
[forums.reprap.org]

Would you like me to move this thread into the "SpoolHead" forum?

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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!

... or add to/from RepCNCLathe ...

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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]

Victor, do you want RepCNCLathe to rain normal lathe cutting techniques? Because I was looking more for a "fourth hand" to reposition pieces for extruding then something powerful enough to do true lathe work. But if you don't mind mixing and matching, I will put my notes and drawings there as I put my ideas together.

Mike

Hi Mike,

... i don't have any problem with mixing tools and methods - my device is usable as CNC-lathe or normal turning lathe, it's the additive tooling and software, what's making the difference.

I built it as experiment with 2-/4-side-milling and for lathe my optical heads, but essentially it's 'only' a 4th axis on my CNC-mill ...

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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]

Remember, you're all RepRap user-developers, and the wiki, RepRap.org, [reprap.org] is for everyone and everything! So log in and create a new page or click "edit" on an old page, and don't forget to upload parts files! grinning smiley

Are you talking about belt driven lazy susan print bed? 4th axis rotary table?

Johnny,
I was thinking more a vertical lazy susan than a normal one. If you are only using a vertical extruder or even a vertical milling bit, there is no advantage to rotating the table (rotating around the vertical axis). But if you put the lazy susan on its side, rotate around a horizontal axis, then you can bring parts that were underneath to the top, or make parts that had vertical overhangs rotate until they are easy to extrude. Plus, if we add a milling head that can cut aluminium, we now have the way to make high temperature parts for our repraps.

Mike

A 4th axis doesn't need to be any more than this




A longer shaft on the motor would let you print in layers from the inside out. The only real improvement you'd need is some higher gearing, to get better angular resolution for larger diameters. Something like a supersized Wade's extruder is what I'm planning, using 608 bearings, with a tailstock to support the far end of a long shaft when used. A lazy susan is overkill I think, as you could have a large (100mm on mendel?) faceplate with a lightweight chuck supported by a pair of 608s.

How many lathe designs do we have?
And what do I need to make a cheap turntable that also may need to be heated? I cannot find any existing budget parts and I don't have a machine shop. Turning an aluminum plate with an extended hub to keep the motor cool and a lip to catch hot air may be a good idea. Than heat this plate with a heat gun heating element.


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