Modelling > Tips, Tools & Techniques

3D Printing Tips and Techniques

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robunos:
Otherwise known as the 'pick Frank3K's brains' thread, as it says in the title, this is a thread for asking questions about, and exchanging information on the techniques of using 3D printers, especially for newbies like me . . .   :-[
I'll be posting some questions in due course, but for now, here's a link to a post about 3D resin printing made by Frank previously :-


https://beyondthesprues.com/Forum/index.php?topic=8451.0


Would it be too much to make this thread sticky ?


cheers,
Robin.

Frank3k:
Overview

The most popular 3D resin printers are made by Elegoo, Anycubic and EPAX. These printers (and several others) use a common controller made by Chitu Systems. They work by shining a 405nm UV light through an LCD screen into a vat of UV sensitive resin.

The vat has a film of FEP, tautly stretched  across the bottom. The FEP is in direct contact with the LCD screen, so images displayed on the LCD are transferred to the resin without distortion.
When an object is printed, very thin slices (10-100 microns thick, typically 50 microns) are displayed in sequence on the LCD.

* At the start of the printing process, a metal plate (the build plate) comes to within a layer thickness of the FEP
* The LCD displays a slice and the UV light is turned on for a few seconds.
* Under ideal conditions, the cured resin sticks to the build plate (and not the FEP.) The UV is turned off and the build plate moves up another layer height
* A new slice is displayed, the UV light is turned on for a few seconds, which should cause the resin to cure to the previously printed layer... and so on, until the object is printed., 



Before an object can be printed, it has to be oriented on the build plate to minimize overhangs and excessive force on the FEP (which is thin and relatively delicate). The object will also need to be supported and finally the object and its supports have to be sliced into layers.

Slicing and Verification
There's software to slice your 3D file. Chitubox is the standard slicer program. There are others, like Lychee and PrusaSlicer.

The slicer program will slice your 3D object into cross-sections spaced by the layer thickness you've selected (10-100 microns) and will produce a file for the printer chosen. In a perfect world, you put this file on a USB stick, take it to the printer, and the object prints. Unfortunately, without doing a file verification check chances are good that parts of the model will not print properly and the cured bits will float in the uncured resin. This is a bad thing; cured resin can puncture the FEP which in turn can cause the resin to leak out of the vat, making a mess out of the printer or worse, leaking under or into the printer.

There are several ways of verifying a file: via manually inspection, prayer (never works) or by using a program like UVTools

I've settled on PrusaSlicer and Chitubox as my slicing programs and UVTools as the verification program. UVTools has printer settings to import into PrusaSlicer to allow it to produce slice files for non-Prusa printers.

Design Software
Unless you're downloading and printing other people's 3D files from Thingiverse or similar repositories, you'll want to create the 3D objects on your own. This is a whole different universe with a learning curve, often steep.

Blender This is a free program and can be used for 3D animations as well as static, 3D objects. It use to have a very confusing interface and steep learning curve, but it's greatly improved in the last few years. The Blender organization has tutorials, but they're not great; find a beginner's series on Youtube and follow it.

Fusion 360 Free for personal/hobbyist use.

Rhino 3D Not free, but they have a 30 day demo. This is what I've used over the years.

Meshmixer This is more of a 3D mesh editing tool.

Netfabb standard. This program was bought by Autodesk and is free. It will check and fix your 3D object for printability. Then you slice it.

3DBuilder - comes with Microsoft Windows 10. It will also let you check and fix 3D models and works as well as Netfabb

There's also Sketchup... but it doesn't do a great job at creating printable 3D objects.

Resins
There's a wide variety of resins; soft and squishy, ABS-like, clear or translucent, resin that can be tapped and machined (without shattering) and even dental resins. Most resins are brittle (as brittle or more so than the common resin used in resin kits)
Many "Clear" resins usually aren't - they can yellow over time when exposed to UV, even after they're fully cured.
Elegoo and AnyCubic sell a a wide variety, including plant based and water washable resins. Siraya Tech makes some of the best resin around and they're my favorite resin manufacturers .

Resin exposure and test
All resin manufacturers will list recommended exposures for their resins and for different printers, but it's a good idea to dial in the best exposure. There's the Resin exposure finder, which I find difficult to interpret at times.
The Amerlabs town will test the limits of the printer.

Other sources for help or instruction

Both reddit groups are very helpful:
https://www.reddit.com/r/AnycubicPhoton/
https://www.reddit.com/r/ElegooMars/

These two Youtube channels are also very helpful:
https://www.youtube.com/c/3DPrintFarm
3D Printing Pro

I avoid "Uncle Jessy"'s channel - I haven't found his ideas to be helpful or useful.

Buzzbomb:
Excellent Frank, great overview.

Personally I still use the original type 3D FDM printer (Up 3D Plus) with the spools of ABS or PLA plastic. For actual models, these are now terribly passe as the build texture is awfully hard to get rid of. But they still have a place.
Typically I am using the printer more and  more for producing gadgets, where detail texture is not important.
As described by Frank, using available software and fairly simple shapes enable you to produce your own stuff.

Having a drawer section full of collets from various tools rattling around, led me to design the Collet Holder in 3D Builder provided free as part of Windows 10
Simple cube shape sized to fit the drawer section, then other shapes were used to remove parts of the shape, to leave the finished item



Using this software, it is also possible to edit other models from elsewhere, such as thingiverse to suit your own needs.
This Airbrush holder was modified to change the angle of the holders to suit my workshop, buy cutting all off and keeping one. Get the position right then simply copy/paste and move into position. Again using 3D Builder in Windows 10


Really the possibilities are endless, but the key is have a go at designing your own stuff, that is where the satisfaction lies

Frank3k:
FDM printers still have a place in modelling, especially if it's capable of printing in ABS. You can use Acetone vapors (or just Acetone on a rag) to smooth out the surface. It will obliterate most details, but for things like wings, frames and hulls (ships or planes) etc., they're very handy.

Plus as Brian said, they're really handy for making non-model "things". I'm working on n LED strip and battery holder for my Donegal visor.

robunos:

Thanks, Frank, for the useful post, a lot of good information there.
@Buzzbomb, I made a few simple tools myself, designed them with Tinkercad, then had them printed by Shapeways.
A set of small squares, AFAIK you can't buy them this small . . .





a centre finder for marking the axle holes in replacement cast resin wheels,





and finally a 'Square Checker', for making sure eg. ARV hull parts are square to each other, also tailplanes and fins.





cheers,
Robin.

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