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Custom builder wanted.

Posted by RPearce 
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RPearce
Re: Custom builder wanted.
January 26, 2016 06:32PM
1.75mm .04 nozzle
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dc42
Re: Custom builder wanted.
January 26, 2016 06:55PM
Quote
RPearce
1.75mm .04 nozzle

You can't use a layer height greater than about 80% of the nozzle diameter. 50% or less is more usual. You will need a large nozzle size and large layer height in order to complete large prints within a reasonable time. The largest standard nozzles I am aware of are the 1.2mm E3D Volcano ones.


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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ElmoC
Re: Custom builder wanted.
January 26, 2016 06:56PM
Quote
RPearce
1.75mm .04 nozzle

Did you mean 0.4mm nozzle? Or a 0.04mm layer height?
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Koko76
Re: Custom builder wanted.
January 26, 2016 07:10PM
Quote
RPearce


ill build it, figure out what doesn't actually work and go from there, nothing much else i can do.

I've actually found I get much better results with research, planning, and then executing.
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DRobs86
Re: Custom builder wanted.
January 26, 2016 08:40PM
I guess I missed the part where we switched to a moving gantry. I thought we were still building a prusa style machine.

Im glad for Pearce's sake that the bed will be stationary.

I agree with you koko on brazing the angle to it before milling. You are correct on the order thi gs should happen.
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JamesK
Re: Custom builder wanted.
January 26, 2016 09:00PM
We're way outside my realm of experience, but I would imagine that face milling a piece of that size is a fairly specialist task with a cost way outside the budget. Maybe we could side-step most of the flatness issues by using an idea of Mark's (DigitalDentist) - using a sacrificial foam sheet for the print surface. This would also alleviate the need for a bed heater - another significant cost saving.
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RPearce
Re: Custom builder wanted.
January 27, 2016 08:56AM
I ment, .4 nozzle I print in generally. .2mm layer height. And I can tell by the comments most of you are quite lost on the design, the bed was always stationary other people suggest that it move. As for the Prusa part, the idea was to take the gantry of a prusa and just make it bigger to reach the required spec.
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Srek
Re: Custom builder wanted.
January 27, 2016 09:27AM
An accuracy of 1/2mm to 1mm but a layerheight of 2/10 mm?
That doesn't add up. With an 0.4mm Nozzle and 0.2mm Layerheight i would expect that over all precision in X/Y should be 1/10mm, which is no problem with current RepRap builds.
Maybe you mean something different with accuracy?

btw, with a maximum speed of 40mm/sec and a print volume anywhere near the one you plan for, you can expect several days print time per item.

[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]
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Koko76
Re: Custom builder wanted.
January 27, 2016 10:12AM
Quote
RPearce
I ment, .4 nozzle I print in generally. .2mm layer height. And I can tell by the comments most of you are quite lost on the design, the bed was always stationary other people suggest that it move. As for the Prusa part, the idea was to take the gantry of a prusa and just make it bigger to reach the required spec.
I'm not lost on anything here. I have also designed, machined and assembled a printer that has been working for about a year now. You won't get the bed flat within your layer height, and I'm not aware of any firmware that will compensate for your inevitably bowed and warped bed. So spend your money, tell us we are lost. You obviously know better than the people here who have actually done things. Why bother to even ask for advice?
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cozmicray
Re: Custom builder wanted.
January 27, 2016 11:13AM
See the Shapeoko CNC machine for ideas

[docs.shapeoko.com]

You desire a X axis gantry where the entire gantry moves up/down in Z

Trolleys and drive from this type of machine maybe a inspiration.


Might want to look at Vee rails for trolley tracks

[www.vgrooverail.com]

confused smiley
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RPearce
Re: Custom builder wanted.
January 27, 2016 12:48PM
Quote
cozmicray
See the Shapeoko CNC machine for ideas

[docs.shapeoko.com]

You desire a X axis gantry where the entire gantry moves up/down in Z

Trolleys and drive from this type of machine maybe a inspiration.


Might want to look at Vee rails for trolley tracks

[www.vgrooverail.com]

confused smiley

This guy is knows what up, that's perfect! Now how do I make it work for 3D printing?
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RPearce
Re: Custom builder wanted.
January 27, 2016 01:15PM
You know actually the more I look at it that Vgroove rail I think we work perfectly for my application. As for my bed bowing I'll figure something out, maybe put some angle iron under the bottom or something.
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DRobs86
Re: Custom builder wanted.
January 27, 2016 06:05PM
A piece of glass is going to be your only hope in terms of a bed with a planer surface.
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the_digital_dentist
Re: Custom builder wanted.
January 27, 2016 06:09PM
Where does the idea that a piece of glass is flat and won't flex come from?

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
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RPearce
Re: Custom builder wanted.
January 27, 2016 06:53PM
Glass is not happening. I despise working on glass beds.
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cozmicray
Re: Custom builder wanted.
January 27, 2016 10:51PM
If you look at shapeoko design
there are NO 1/4" plates
Beams -- extrusions that are strong over a long distance
bolted together, adjustable, providing guideways for moving trolleys
Channels to accept tee nuts --- easy assembly --- easy rebuild

Triangle plates to connect beams together and hold them in alignment.

CNC cutters need a lot of force to remove material --- thus beefy structures to move them around
squirting out polymer much different

confused smiley


Quote
RPearce
Quote
cozmicray
See the Shapeoko CNC machine for ideas

[docs.shapeoko.com]

You desire a X axis gantry where the entire gantry moves up/down in Z

Trolleys and drive from this type of machine maybe a inspiration.


Might want to look at Vee rails for trolley tracks

[www.vgrooverail.com]

confused smiley

This guy is knows what up, that's perfect! Now how do I make it work for 3D printing?
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jinx
Re: Custom builder wanted.
January 28, 2016 11:56AM
Once you throw out the idea of scaling a prusa i3 and given the limited specs. I find myself leaning towards Titan
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DRobs86
Re: Custom builder wanted.
January 28, 2016 12:45PM
Quote
the_digital_dentist
Where does the idea that a piece of glass is flat and won't flex come from?

I am open to correction, but its my understanding that glass plate is much much flatter than aluminum plate. I didnt say it was necessarily stiff, but it laying ontop of his wavy aluminum plate is a better print surface.

Pearce feel free to use whatver you like. Its your money you are spending, but its just childish to ignore people who have done successful custom builds saying "that wont work and here is why." This is what irks me about the Reprap forum. There are some real innovators here, but for every innovator there are 30 guys saying they want to build a machine much larger than a conventional printer without an ounce of disciplined engineering effort all the while ignoring those who provide reasonable guidance.
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JamesK
Re: Custom builder wanted.
January 28, 2016 12:56PM
For many years glass was used as a reference surface plate for accurate marking out in machining, so that's probably where the idea came from. My recollections of those pieces of glass is that they were typically 3/4 to an inch thick - a bit different from the typical 3mm often used on printers, and I believe glass used for surface plates was ground, not just used straight from the float process. Apparently granite is the material of choice for surface plates these days.
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the_digital_dentist
Re: Custom builder wanted.
January 28, 2016 01:33PM
Quote
DRobs86
I am open to correction, but its my understanding that glass plate is much much flatter than aluminum plate. I didnt say it was necessarily stiff, but it laying ontop of his wavy aluminum plate is a better print surface.

Flatness is a function of the surface itself and the flexibility of the material. If the glass is laying on a flat surface you can tell what the basic surface flatness of the glass is. If it is sitting on a wavy or bent surface, unless it is very thick, the glass will flex and the surface won't be flat. Glass is a thermal insulator -not really ideal for ensuring even temperature across its surface. People usually put a thin piece of glass on top of a thin aluminum "heat spreader" and hope for the best. If they used a stiffer, flat piece of aluminum instead of the thin flexible one, they wouldn't need the glass and would know that the heat is evenly distributed (as evenly as possible given the typical rectangular shape). 1/4" thick cast tooling plate is flat and rigid enough for 3D printers at least up to 300 mm square.

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
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the_digital_dentist
Re: Custom builder wanted.
January 28, 2016 01:40PM
Quote
JamesK
For many years glass was used as a reference surface plate for accurate marking out in machining, so that's probably where the idea came from. My recollections of those pieces of glass is that they were typically 3/4 to an inch thick - a bit different from the typical 3mm often used on printers, and I believe glass used for surface plates was ground, not just used straight from the float process. Apparently granite is the material of choice for surface plates these days.

Yeah, there's glass and then there's glass. And there's aluminum and there's cast tooling plate. It's weird how people focus on the material and completely ignore qualitative differences. Some will think aluminum sucks because they tried a 1.5mm sheet and found that it wasn't flat at room temp and warped when heated. For some reason it's the aluminum that gets the blame and not the fact that it was 1.5 mm thick.

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
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Koko76
Re: Custom builder wanted.
January 28, 2016 01:41PM
Quote
DRobs86
Quote
the_digital_dentist
Where does the idea that a piece of glass is flat and won't flex come from?

I am open to correction, but its my understanding that glass plate is much much flatter than aluminum plate. I didnt say it was necessarily stiff, but it laying ontop of his wavy aluminum plate is a better print surface.

Pearce feel free to use whatver you like. Its your money you are spending, but its just childish to ignore people who have done successful custom builds saying "that wont work and here is why." This is what irks me about the Reprap forum. There are some real innovators here, but for every innovator there are 30 guys saying they want to build a machine much larger than a conventional printer without an ounce of disciplined engineering effort all the while ignoring those who provide reasonable guidance.
It is pointless to generalize "what is flatter". Material varies, and doesn't always meet spec. An indicator and a known reference flat will tell you the actual answer. As well as the you actual info if it isn't within spec. Glass isn't inherently anything, and can and does bend, especially at the size in question, and especially when it's base isn't flat.
The op won't use glass any way, so it's kind of moot. I'm also interested to know what kind of material will be printed on this machine.
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RPearce
Re: Custom builder wanted.
January 28, 2016 01:50PM
Carbon fiber is planned, that and or Nylon and other exotics, along with the normal stuff.
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cozmicray
Re: Custom builder wanted.
January 28, 2016 07:05PM
Where was glass used as a machining flat?
Glass is a supercooled fluid --- not a good alignment surface

I saw many the machining of parts for spacecraft and other mechanisms with very tight tolerances
and
the alignment base was a block of granite
-- that was measured and if necessary ground to spec flatness much as an optical flat
some specially suspended to damp local vibrations.

not practical for 3D printer bed

FWIW

confused smiley

Quote
JamesK
For many years glass was used as a reference surface plate for accurate marking out in machining, so that's probably where the idea came from. My recollections of those pieces of glass is that they were typically 3/4 to an inch thick - a bit different from the typical 3mm often used on printers, and I believe glass used for surface plates was ground, not just used straight from the float process. Apparently granite is the material of choice for surface plates these days.
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JamesK
Re: Custom builder wanted.
January 28, 2016 08:28PM
It was common in the UK through the war years, and continued in hobby use for many years after. I well remember using a glass surface plate in my grandfathers workshop. The fact that he was not unusual in that regard is supported by wikipedia
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DRobs86
Re: Custom builder wanted.
January 28, 2016 09:19PM
Quote
Koko76
It is pointless to generalize "what is flatter". Material varies, and doesn't always meet spec. An indicator and a known reference flat will tell you the actual answer. As well as the you actual info if it isn't within spec. Glass isn't inherently anything, and can and does bend, especially at the size in question, and especially when it's base isn't flat.
The op won't use glass any way, so it's kind of moot. I'm also interested to know what kind of material will be printed on this machine.

I dont think anyone was generalizing. We were talking standard aluminum plate versus glass plate.

You are right that it is a moot point, however.
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stonedcoldskier
Re: Custom builder wanted.
January 30, 2016 11:15PM
Quote
Frans@France
Maybe try this mostly (3d) printed CNC [www.thingiverse.com] which can also be extended to be used as an 3d printer [youtu.be]

I'm surprised that nobody has picked up on this. Based on the size requirements, budget, and stationary bed, the Mostly Printed CNC Machine could be the best platform for this project. It is easily scalable in all dimensions and the rails can easily be supported for longer spans. Even with $200 per machine going to towards the heated bed, there's no reason why it can't be done reasonably well and under budget. Of course, I'd ditch the printrboard in favor of RAMPS electronics so that I could afford to add the Volcano pack to that E3D hotend.
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RPearce
Re: Custom builder wanted.
January 31, 2016 01:12AM
the Mostly 3D printed CNC is the route we are going, we are going to buy there kit, thank you.
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JamesK
Re: Custom builder wanted.
January 31, 2016 07:54AM
To my mind that design falls uncomfortably between 3d printer and cnc. As a CNC I'd be worried about the use of belt drives allowing too much lateral head movement under heavy side loads. As a printer, it has two motors for each of X & Y - and they all move. That's both unnecessary and adding a lot of moving mass. Core XY designs seem the more natural direction for large format printers, with the bed moving in Z seeming like the simpler approach for the 3rd dimension.
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Dirty Steve
Re: Custom builder wanted.
January 31, 2016 11:36AM
So, I'm curious who in the U.S. did you tell you could build a machine for this cost? What are they paying YOU?

Edited 2 time(s). Last edit at 01/31/2016 01:06PM by Dirty Steve.
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