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Help 3D Printer

Posted by pedropin 
Help 3D Printer
August 26, 2015 10:39PM
Hello greetings to all
I have a machine homemade cnc router, wood working, aluminum, acrylic, pcb, etc.
I want to make a 3D printer. but I have some questions for you who are the experts.
It is possible to reach a resolution of 50 microns with a printer homemade?
I need a resolution to print rings jewelry
what factors affect the resolution? nozzle extruder?

thank you
Pedro Pineda
Re: Help 3D Printer
August 27, 2015 12:55AM
it depends on precision of cnc home built equipment and on backlash. if you have a lot of backlash then it is not likely. cnc can compensate for backlash easily, because it can stop cutting at any point in time. it is different when you are laying down plastic constantly with an extruder.. also speed should be high enough to move at 50 mm or more a second. if the z axis tool head is heavy this might not be possible. this is important because it allows tearing of filament string when finished with a surface, and prevents time that oozing can happen and allows for proper bridging with out sagging of hot filament.

factors that affect resolution.
some of them are :
stiffness of frame and thermal expansion of frame
nozzle diameter and quality of temp control
minimal backlash
hardware that supports high pulse rates so more than likely this requires special hardware that does not use slow optical isolated photodiodes or phototransistors. most cnc is optically isolated and this does not work well outside of mach3. timings of motors and pulse rate changes are dramatic and timing is unique with 3d printing.

resolution of a high quality machine is limited by precision leveling, nozzle size. accuracy placement of filament is approximately 1/2 nozzle diameter. z resolution typically can be 0.1mm,

you could buy a 3d printer machine very basic in operation for under 300$ online that will likely work with little modification. of course paying more gets you into better machines that are less temperamental.

if you are brave and have the time to do so there are several bootstraps on reprap.org that are cnc based printers. to bootstrap to a 3d printer. wolfstrap is one of those. I also remember some one has a design out there to cnc wood parts for a mendel derivative. it probably exists for a prusa variant as well. the understanding is that in the end the best machine is a separate machine for 3d printing.

this is not complete by any means. i'm sure more people will have comments.

i just want to give you an insight into things that you would want to think about
Re: Help 3D Printer
August 27, 2015 03:51AM
I think the limiting factor for FDM is the nozzle size. Current readily available nozzles go down to .2mm. It's not hard to make your own nozzles, so it's feasible to get to 50 micron resolution.

SLA printing has higher resolution than FDM, but I haven't looked at them to see what they can achieve.

I've printed 10 micron layer heights on my delta printer as an experiment, but haven't verified how precise the layer heights were.
Re: Help 3D Printer
August 27, 2015 04:05AM
... with FDM printing you'll get big trouble with nozzle diameters below 0.2mm - the needed pressure to get the molten plastic through the nozzle grows roughly exponentially with smaller diameters ... AFAIK the smallest successfully used nozzles were between 0.18 and 0.15 mm (or 150 micron).

The most limiting factor with high resolutions is the building time per layer - my fastest FDM-printer moves with up to 400mm/s, but usefull printing speeds with high resolution+accuracy is more like 30mm/s ... sometimes even slower ... so count with some minutes per layer for some hundred layers of a really precise part ...

In our tests with DIY DLP-3D-printers and reducing lenses 10 microns (0.01mm) resolution in X+Y and 10 microns layer height was no problem anyhow - and the 'printing times' per layer with layer changing are in the range of some ten seconds ... but could be optimized to single seconds too winking smiley

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Re: Help 3D Printer
August 27, 2015 07:09AM
Nozzle diameter !== resolution.

You can get to 50 um resolution in all axes for a small printer without too much difficulty or expense. What you can't do easily is print 50 um features because the nozzle diameter dictates the smallest feature you can print.

In order to get 50 um resolution, you need a very rigid frame and very high precision bearings. Use of linear guides will get you as close to 50 um resolution as is possible in the X and Y axis. In the Z axis you'll need ground (not rolled) lead or ball screw(s). If you're just going to make jewelry and can live with a small build envelope such a machine could be made inexpensively. There are a few other things you'll need- a very reliable extruder/hot-end combo, and a really flat build plate with a properly designed leveling system.

Hey, it really isn't any different from what everyone needs in a printer!

Look into the DLP based resin tank printers. They can do very high resolution small objects and are mechanically much simpler than FDM machines.

Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Help 3D Printer
August 27, 2015 08:36PM
boys thank you very much for your help
I make the printer from 0
I stay clear
very firm frame, lightweight, 0.2mm nozzle, etc.
start the project soon and I'll be sharing with you asking and

greetings to all
Pedro Pin
Re: Help 3D Printer
August 27, 2015 11:28PM
for the resolution I need 50 microns
ABS 1.75mm
0.2mm nozzle
extruder and hot end which I recommend to my project this is very important.
greetings to all
pedro pin
Re: Help 3D Printer
August 28, 2015 01:34AM
You might have to go with an SLA resin printer for super fine detail. I think there a few open source ones as well.
Re: Help 3D Printer
August 28, 2015 01:07PM
I'd recommend starting with a .35 or .4 nozzle. It will make it easier to get the machine calibrated. Once it's running fine, move to the .2 or smaller nozzle.
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