Differences between good and really good printers

Hi everybody!

Short story, I wanted to buy a cheap printer and was told (several times) that it's just not a good idea. Save up or build your own was the leitmotif.
As I'm in Europe and printers here are kind of more expensive than in the states, I decided to roll my own.
So I have searched and read a lot, thought this and that and made my decisions. It's very similar to the Smartrapcore (X-Y on top, Z alone, offloaded weight with a bowden extruder to reduce weight on the moving parts etc.), just having the motors more on-board.

But one question keeps me thinking I'm still in the dark and that is:

What is the difference between okay 3D printers and really good 3D printers? (barring the 10-material printers on one side and shitty knockoffs on the other).

Except build quality, what is the most important parts or designs your printer need to make great 3D object?

Obviously I'm a noob here so sorry and thank you for any information :-)

... the biggest difference is the experience/competence of the user

A perfect calibrated RepRap-style FDM printer kit for around 1000€ can outperform a comercial printer for 20k€ in quality/resolution and speed, if good enough calibrated and

Attached are some examples:

The big white rook was printed on a comercial machine, the blue one was printed by me while calibrating an old Orca Mendel, I've got from a friend:




But then, last week, on a meeting in a local hackerspace, one of the guys printed the small transparent rooks on a 800€-kit

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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]

There are a few main difference between a good machine and a crappy machine. In one word it comes down to stability. That means stability in time, temperature, and operation. Any uncontrolled movement of the nozzle relative to the print bed will affect the print. Crappy machines use unstable frames that flex and move during printing. A good machine has a rigid frame. If you push on the frame and see it move, it's crap. That one test will rule out 90% of the machines out there. Avoid cantilevering. Next comes flex in the guide rails and slop in the bearings. Good machines minimize flex and slop everywhere. Use lead/ball screws instead of threaded rods wherever screws are used to provide motion. Use fully supported guide rails or linear guides. The bed should be flat, thermally conductive, and adequately heated, supported by a well designed leveling system. Once you have a mechanically stable machine, you have to calibrate it- that means aligning the axes for orthogonality as well as calibrating the extruder and motion of the axes. Electronics are important too- a good machine will have motors that provide adequate torque and the electronics to ensure that the motors can deliver that torque- that means over sizing the electronics a bit- if your motors need 2A, use drivers that can operate at 3A. If you need 10A from a 12V supply, use a 15A rated supply. Use higher voltage power supplies to power motors. The bed heater should be capable of taking the bed to higher temperatures than you will ever need. Thermal stability is almost as important as mechanical stability. Use PID control for all heaters. If you're going to print with ABS, enclose the machine to keep the build chamber warm and prevent warping and delamination.

I built a good machine. Not perfect, but better than most. See the link in my sig, below.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thanks for the long and detailed answers!

So if you have a modest printer you'll need more skill :-) Interesting to know skill is an important part though, my printer won't be hi quality, at least not from starters...

Lots of info there, thanks Mr dentist, It comforts me in my choices too, and gives me a road to upgrades / fixes I'll would make later on.

You need skill for any printer, but skill can't make up for a bad printer. There are no slicer settings that can remove Z wobble from a poorly made machine.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

... but with gaining experience you will be able to update your printer (or build a new one) with printed parts, so it gets even better.

This was one of the core ideas behind RepRap - build a starter, then enhance/update/evolve it until it's capable to print 'serious' parts, then rethink the complete process again

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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]

When you continue to "evolve" you realize that printed parts don't have many uses in a quality printer (you can't print a part that makes a flexible guide rail stiffer or straightens out a bent threaded rod) and you replace as many as possible with metal.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

... all this is covered by 'experience' and 'vitamins' for not (or not yet) printable parts - I've managed to get positioning resolutions and accuracies of sub-microns with printed and/or milled parts, where the accuracy of the printer was in the 0.05mm and of the CNC-mill in the 0.0125mm ... it's all depending on ideas, related experience and proper tools

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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]

Quote
VDX
I've managed to get positioning resolutions and accuracies of sub-microns with printed and/or milled parts, where the accuracy of the printer was in the 0.05mm and of the CNC-mill in the 0.0125mm

I have never dreamed about such an accuracy. May you comment a bit more on this, that is how you designed the printer and how you measured sub-micron accuracy? I wouldn't even know how to measure it with common means, since it is probably out of the visible spectrum.

Hi VDX, I found the/a page about Reprap 'vitamins', is there another one for its 'experience' or is that intended to be just experience :-) ?

Also interested about your modifications, would you care to share some?

... most of this 'submicron' action was not for 3D-printing, but for microassembly and some nanotech projects - you can find several related threads and posts from me when searching with "All Dates" set

here a list of threads around "microtech"

... and here some other with "nanotech"

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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]