Is There Anybody Out There...

Steve J

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1) EE is an Electrical Engineer. I have a Master's in Electrical Engineering.

2) The CR10 is about as big a printer as you can make using the RepRap design. Look at the reviews on the TRex, which is 500 x 500. Problems scaling up a printer are:
  • Frame stability-You need a different frame design to prevent frame movement. Frame movement will absolutely destroy a decent print.
  • Motion mechanism-The larger you go, the more the notched belt-stepper motor arrangement becomes problematic. Belts stretch, and the more side thrust on the motor bearings, the more problems they will be. Long belts are asking for slippage. You need some sort of linear motor or anti-backlash ball screw arrangement.
  • The longer the rails (for the axis carriages), the more chance of bending. Bigger rails just add mass to the structure. More mass=more energy to move that mass and more strain on the motion components.
  • All of the current RepRap printers are open loop. The only way the software knows where the extruder is is by counting steps. For a bigger printer, you need a closed-loop design where you get position feedback. When you have that, stepper motors only get in the way, and servo motors are they way to go. Then you need a complex controller, like a PID controller.
  • Bigger heated beds-you need a good means of getting a uniform heat across the bed, probably using multiple heaters and multiple thermocouples. The big Chinese printers don't do this (single thermocouple). And you need a thermal camera to check out the heat distribution.
And then there is the problem of multi-material. If you have dual extruders, the second extruder is going to drag on the prints (I found this out the hard way) unless you have a way of either having dual independent extruders (IDEX) or lifting the extruder that isn't being used. The T-REX uses the IDEX method, while some of the high priced models use the lifting method. Both methods have their problems. Why do you want to use multi-material? Disolvable support material, primarily, although some people like prints with different colors. The Prusa MMU sound interesting, using one extruder and switching between filaments. That's why I ordered the Prusa.

And then there is the filament feed mechanism. The direct method is the best, but the heavier the extruder, the more energy it takes to move it. The Bowden system is interesting, but you have a long run of filament to push to get it to extrude properly, and it's a problem with flexible filament. Try pushing a rope sometime.

Yes, bigger printers will use more filament. But only if you print something big. A big printer gives you that option.

I learned most of this working on the design of the big (3' x 3') pen plotters. 3D printers are just plotters with a Z axis.

Anyway that's my take on 3D printers. They're useful coupled with a really good 3D CAD package. Otherwise, they are just a toy (or an interesting hobby).

Anyway, that's probably more than you wanted to know.

Steve
 

stratman

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Steve J

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Thank you. I have put quite a bit of thought into a large 3D printer from an engineering standpoint. I have a small Chinese Prusa-type printer in addition to the Monoprice clone, and that printer is a piece of junk. I have modified the Monoprice clone and it works fairly decently now. I learned a lot from both printers, though, especially the dual extruder problem.
 

The Hat

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Frame stability-You need
Motion mechanism
Anyway, that's probably more than you wanted to know.
Well that’s certainly a great write up.. :thumbsup

I came in at Frame stability and was lost by, Motion mechanism, it was all above my pay grade, because I just go for the simplest things in life, complications are someone else's problem as far as I’m concerned..

I also started off with a Monoprice and learned everything I wanted to know about 3D printers, yes it was small and not very practical, so I went on from there to a CR-10 and others, I am not a perfectionist so the quality I get from my 3D printers satisfy me completely, and the help I was given from many of the members here was unmeasurable..

I only use a single extruder and found it to be more than enough for my type of projects, if I need other colours I just pause the printer and swap one colour for another, and if it weren’t for the Chinese I’d be still be spilling ink and printing in one dimension.

The CR-10 is as big as I need to go and I have learned how to make half parts and glue them together, it’s surprising how big a project can get, when you want too..

Otherwise, they are just a toy (or an interesting hobby).
And that's what I use them for..;)
 

Artur5

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I only use a single extruder and found it to be more than enough for my type of projects, if I need other colours I just pause the printer and swap one colour for another, and if it weren’t for the Chinese I’d be still be spilling ink and printing in one dimension.
One dimension ? . Now I don’t wonder that you don’t like inkjets anymore. Printing only straight lines is boring, You’ll be surprised to know that inkjets print in two dimensions as well. :D . :hide

I’m still out there (answering the original question of this thread ).
Just lurking insidiously, I don’t do 3D. Far beyond my skills and learning steps required.
Cost involved is nothing to disregard either. Filament and electrical energy consumed must come pricey in the long term.
 

The Hat

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One dimension ? . Now I don’t wonder that you don’t like inkjets anymore. Printing only straight lines is boring, You’ll be surprised to know that inkjets print in two dimensions as well. :D .
And you wonder why I got problems..:lol: :hugs
I don’t do 3D. Far beyond my skills and learning steps required.
Cost involved is nothing to disregard either. Filament and electrical energy consumed must come pricey in the long term.
And if I can manage 3D printing then anyone can, sure at the best of times I can’t tell which dimension is which.. :smack

The running costs of 3D printing is probably much same as inkjet printing, but then I’ve never measured the cost of pleasure on either platform, 3D print supplies I reckon have to be much cheaper that inkjet because you’re not been restraint or strangled by Canon/Epson or HP, it’s a free market.. You Choose what you want…

 

Nifty

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Interesting discussion!!!

Anyone have any experience with Octoprint? I don't seem much use for the camera if the printer is in the same room as you. Getting up to look at the printer is good exercise.
I've thought about it, but I also don't have need of a camera and using a combo of direct USB for short prints, and microSD for longer prints has worked just fine, so I don't have a ton of incentive to add more complexity to my setup.

Otherwise, they are just a toy (or an interesting hobby).
I can see how that might be the case for some, but I've found my printer extremely useful for fixing things around the house and either providing me with an instant and cheaper fix than ordering the thing on Amazon or a fix that does't exist (that I could find) and I was able to cobble together in Tinkercad.

I guess like most tools, they can be utilized (or not) for whatever is up to the imagination of the person wielding the tool.

I wish I had really awesome CAD skills (like Fusion360) so I could fix even more things faster and more efficiently!
 
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