Flat printer

Flat printer

Postby Cozmicray » Mon Aug 25, 2014 6:53 pm

How about more info on the "Flat printer"

https://plus.google.com/u/0/10420990184 ... 5806192943

Parts, Drawings?
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Re: Flat printer

Postby Feign » Tue Aug 26, 2014 3:07 pm

I'll second this, though to be honest, it seems Nick is a bit busy with GUS v2.0, and that single arm SCARA that he keeps mentioning.

We the community might have to be the ones that bring this to fruition.
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Re: Flat printer

Postby Nicholas Seward » Tue Aug 26, 2014 5:46 pm

Here is how my design process goes...

1)Come up the the rough idea.
2)Try to draw up the best implementation
3)Fail at 2
4)Try to draw up an implementation
5)Model
6)Show to people and get feedback
7)Identify problem areas and let it stew in my mind for a long time.
8)Go back to step 4 if anything can be made better/cheaper/etc
9)Build it

I have a few printers in the works. It is hard to say which one will get made next. Once the design is refined digitally and I can get past step 8 then the build can happen in a week.

The FlatPrinter/PackBot/etc has the potential to be my next build. I am actively trying to model an improved version. I made a lot of new design decisions that I just can not get to elegantly work together at this point. I am about to give up on elegant and just remodel it however I can with all the new design features and see if looking at it will help.

New Target Features
  • Linear Z drive to enable simple firmware and manual Z homing. (I will have what looks like a 5th arm positioned below the bed that I can drive as if I had a screw point in the Z direction.)
  • Heated bed (I finally found a power supply that I think I can fit.)
  • Box frames for the top and the bottom to keep everything square.
  • Magnetic attachment for the effector

Who knows when this will mature so I encourage anyone to take the concept and run.

I am also working on a CorEXY. It will be a CoreXY style bot with a static E motor that drives a round belts that will drive a pusher on the effector.

I am also working on a RepRap Tuga style printer that uses a table top for linear motion instead of rails. If I can pull it off, it can be driven like a standard Cartesian bot while having no rails.

etc, etc.

My wife is expecting in December so I have been spending more time designing stuff for the nursery at this point.

I love community driven design because my current lack of productivity doesn't limit others. If anyone else wants to move the ball down the field, I will help however I can.
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Re: Flat printer

Postby Feign » Tue Aug 26, 2014 8:56 pm

Nicholas Seward wrote:The FlatPrinter/PackBot/etc has the potential to be my next build. I am actively trying to model an improved version. I made a lot of new design decisions that I just can not get to elegantly work together at this point. I am about to give up on elegant and just remodel it however I can with all the new design features and see if looking at it will help.

Who knows when this will mature so I encourage anyone to take the concept and run.

Muahaha
Nicholas Seward wrote:I am also working on a CorEXY. It will be a CoreXY style bot with a static E motor that drives a round belts that will drive a pusher on the effector.

I saw that one on your Google+... I was considering a similar system a while ago, but it seems like almost any configuration I came up with would torque the y-axis carriage in the exact way that CoreXY was intended to avoid... It may be worth it to just go with a simpler h-bot setup for the X-Y motion since you have to have the frame rigid anyway for the E-belt.
Nicholas Seward wrote:I am also working on a RepRap Tuga style printer that uses a table top for linear motion instead of rails. If I can pull it off, it can be driven like a standard Cartesian bot while having no rails.

When I looked up the Tuga, I had a different idea for it, flip it on its side so that the single rail is vertical, drive the short arm bearing with a screw drive for the z-axis position (since that would remain linear), and the long arm bearing with a belt for the y-axis position... And then put the whole thing on a turntable to make it a polar bot.

...Okay, so that actually might be a bit too crazy. :lol:

Nicholas Seward wrote:My wife is expecting in December so I have been spending more time designing stuff for the nursery at this point.

Wow, heck with all those other projects, congrats on this one! :D
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Re: Flat printer

Postby Cozmicray » Thu Aug 28, 2014 5:49 pm

Is it a good design to have all the movement by the extruder
with a fixed produces part.

Moving the table with the part onboard seems not to be to good.

Is lifting (Z axis) a heavy X-Y moving platform a good idea
or
does the weight of the lifted X-Y system enhance the system.

I suppose it depends on lift system?

Nick's jack lift system seems to be a very good scheme
or
Would a straight screw lift be simpler / better.

Very interesting design

Wally Chrome (on the retired pile) is envious

:?:
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Re: Flat printer

Postby Feign » Thu Aug 28, 2014 8:26 pm

Cozmicray wrote:Is it a good design to have all the movement by the extruder
with a fixed produces part.

Moving the table with the part onboard seems not to be to good.
If you have a Bowden extruder and a pretty lightweight hotend and such you're probably right. With a driect drive extruder, you'll have many situations where the platform and model are lighter than the extruder and can therefore accelerate faster, unless you have a heated bed, in which case it's more likely to be equal weight.

Momentum affecting the part is negligible, which is a little counter-intuitive, but compared to the force from the viscosity of the melted plastic pulling on the part as the print head passes, the momentum of the cooled plastic is effectively nothing.

Cozmicray wrote:Is lifting (Z axis) a heavy X-Y moving platform a good idea
or
does the weight of the lifted X-Y system enhance the system.

I suppose it depends on lift system?
It also depends on what you are printing and how bit you're printing it more than the specific method of vertical movement. If vertical stability is the priority, then move the x-y carriage. If speed is the priority, move the platform, it would be much lighter than the rest x-y carriage unless you're printing solid plastic that takes up a lot of the build volume.

Cozmicray wrote:Nick's jack lift system seems to be a very good scheme
or
Would a straight screw lift be simpler / better.

Well, sure it would be simple... but it wouldn't be flat... :P
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Re: Flat printer

Postby Cozmicray » Thu Aug 28, 2014 11:53 pm

Flat is nice
but
What if I don't need Flat?

What is Best Z for coreXY system
with dual direct extruders?

Lift the table?
Lift the XY system?

Nick type lifts (Z axis) or leadscrews?

:?:
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Re: Flat printer

Postby Feign » Fri Aug 29, 2014 4:46 pm

If you dont' want a flat printer, you might be a little off the topic for the "flat printer" thread... :lol:

But really, with two direct drive extruders you'd have better speed and acceleration with a bed moving in the x-y plane and the heads moving in the z, most printers absolutely won't do that because it locks the machine into having to be at least twice the size of the bed, which just doesn't look good.

On the other hand, being able to move your high-acceleration axes in only one direction each is even better, because then you're only moving the bare minimum weight of the extruder or the print bed, rather than one of the axes having to move the part that needs to move and a set of rails that support it.

Basically, the Mendel is pretty much the optimum configuration for simplicity and speed (The Delta form factor being even more optimal is debatable as long as the print head is very lightweight)... So it makes sense that there are a million variations on that form factor that change all the specifics about how the rails are held and how the overall asthetic of the machine, but the core principle remains the same.

It's only when you want other considerations that you start to even need other form factors. Therefore, people who want to come up with a new form factor have to first come up with a problem to solve. Therefore the goals of having a minimal-rails printer (Morgan and other polar printers) or a no-rails printer (GUS and Wally) or a no-screws printer (CoreXZ, though it's still a Mendel motion system), or even a flat printer, which is at least in its beginnings right here.


All of that said, perhaps if the scissor lifts on this flat printer were just supporting the print head moving on the x-axis, and the table moved on the y-axis. The four lifts seem like they would be rigid at first, but they aren't rigid against torque at all, if the load on them is only moving in one axis, you don't have to worry about it.

However, in order to keep the legs out of the way of a moving bed and rigid in the axis perpendicular to the bed's movement, you either have to make the thing like a Mendel with the x-axis legs sticking out of the sides of the printer... Or. Maybe a polar print bed. (I know, I know, they get messy in the center, there's still a lot of good to be had in a polar printer.)
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Re: Flat printer

Postby Nicholas Seward » Fri Aug 29, 2014 5:18 pm

Good and bad are arbitrary here. I will have to frame my responses in terms of my goals which may not be the goals of others.

Goals:
  • Fit in a backpack.
  • 200x200x150 target work volume
  • No deploy operations. (Plug in and print)
  • Quality is important but not speed.

The target volume that I picked dictates that the effector has to move in the XY plane. Some printers can keep the overall dimension under 150% of the build dimension if the effector moves. If the bed moves, you are stuck at 200%+ unless you let the bed move outside the bounds of the printer.

Cozmicray wrote:Is it a good design to have all the movement by the extruder
with a fixed produces part.

Moving the table with the part onboard seems not to be to good.

Moving the platform isn't really a problem since plastic forces are >> than gravity forces. One problem with my first concept is that the movement of the extruder could cause the whole top to start rocking back and forth. It was suggested that the printer can be turned upside down and the platform can be raised. Alternatively, feet could be deployed (against my goals) and the bed could be dropped.

Cozmicray wrote:Is lifting (Z axis) a heavy X-Y moving platform a good idea
or
does the weight of the lifted X-Y system enhance the system.

More mass will dampen vibrations. You want as much mass on the top as the lift can handle and would make sense. (Clarification: the top needs more mass but the effector needs to have less mass.)

Cozmicray wrote:I suppose it depends on lift system?

Nick's jack lift system seems to be a very good scheme
or
Would a straight screw lift be simpler / better.

A screw lift would have to be deployed and you would usually need linear guides. I am not in love with my idea. I am exploring other options. My lift system is cool in that it is compact and I can drive it linearly. I am not aware of too many ways to accomplish that. Rigid chain/belt lifts are another but not precise enough.
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Re: Flat printer

Postby Nicholas Seward » Fri Aug 29, 2014 6:26 pm

@Feign: I too am concerned about the lack of torsional stability of the top. I am not really concerned about speed so I thought I would just put in some really low acceleration and jerk values and hope for the best. However, I am still thinking. I would prefer something that can get bumped and not get messed up.
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