DIY Resin Printer Build

Part 1. (sorry for any grammar or spelling errors, ill correct this for readability as i go)

OK so following post from "what kind of printer do you use" here are some details on building your own resin printer.

Motion sim'ing has been a casualty for the past several months as ive spent all my spare time on learning the ins and outs of resin printing (partly for hobby stuff but mostly for work purposes) and feel i know enough now to post valid and worthwhile information although some of it is obviously my own personal opinion.​

For those that are not that familiar with resin printing theres 3 main types of consumer tech: Laser, DLP (projector) and LCD. All work in a similar fashion by exposing a vat of UV sensitive resin to a specific wave length of UV light , mostly in 390-410nm region although some are lower eg: crystal clear resins. 365-385.

Lastly there are daylight resin printers that don't use lower wavelength UV but they are general very slow because of this with limited resin choice so not something ive been interested in.

Main points of note for each type:

Laser: Slowest with some distortion/accuracy issues in XY planes but good quality. Works kind of like FDM drawing the outline of each layer hence poor speed. Bigger the build volume the larger the distortion as the fixed point laser moves off centre to draw the outline and laser spot becomes an ellipsoid instead of round (think shining a torch against a wall and moving it left to right). High running costs.

DLP: Fastest as flashes complete layer with one image and highest possible resolution but generally the most expensive. The higher the resolution the smaller the build volume as projected image obviously gets smaller as you reduce the pixel size. Can be prone to barrel distortion across XY build volume (some more expensive models fix this with custom optics).

LCD: Speed varies between almost DLP quick or somewhere between DLP and Laser and again flashes complete layer. Uses "off the shelf" mobile or tablet LCD panel with fixed pixel size across entire build volume no matter how large so Potentially very good XY accuracy and high detail limited by LCD resolution.(ill explain later). Cheapest to build. Cheapest to run.

IMHO Resin is not a replacement for FDM they both have there place.
Generally FDM for larger functional parts
Resin for smaller parts requiring higher detail.

This DIY printer build is an LCD type



Note: the case is obviously not finished yet and the printer is taller than it needs to be (also wider if only using a 5.5" screen but i plan on upgrading to a larger screen/build volume at some point).
Whilst it may not look much, its got it where it counts is super fast by LCD resin printer standards and very accurate with high detail.

Now IMHO this is actually easier to build than an FDM as there is only 1 moving part, the Z axis and 3 main mechanical components which affect the performance of the screen...

1. The LCD (resolution)
2. Quality of the linear rail for Z axis
3. Type of UV engine (single point bulb or UV array)

Don't skimp on 2 and 3 if you want minimal hassle and the best bang for buck!

Screen:

For the screen just choose the cheapest one you can find with the desired resolution, currently 2k is most common eg:

For 8.9" build volume (about 75um XY resolution)
https://www.aliexpress.com/item/256...32805002658.html?spm=a2g0s.8937460.0.0.yjKdIe
(this includes the HDMI driver board also, screen on its own is obviously cheaper)

Or for 5.5" for 47um Resolution
https://www.aliexpress.com/item/5-5...32791465507.html?spm=a2g0s.8937460.0.0.yjKdIe

You will need a version with the HDMI driver board to start then obviously just the screen from then on.
Try to find a supplier that will remove the LCD backlight for you if possible as they are quite tricky to remove and the LCD can be damaged easily. This is needed so that the UV will shine through the screen from below to cure the resin.

The LCD is considered a disposable part as shining low wavelength UV through the screen breaks down the Liquid Crystal after a while. Life span is affected by 1. the intensity of the UV 2. Heat. 50w of LED power is considered about the right compromise of power vs lifespan and you can expect around 1000-1500 hours of use from each screen before replacing (Note this is active UV exposure time, not overall print time).

Z axis.
You can build your own with similar parts to FDM ie rails and bearings or buy something off the shelf. Now if you want the least hassle and best accuracy then id suggest just buying something as this is the main moving part and critical to print quality. After various trials and experiences this is what ive ended up with for this particular build.

http://www.ebay.co.uk/itm/THK-KR20-...165028?hash=item3ad5912f64:g:jM8AAOSwYlRZFa-C

Brand new this is a $1000 rail! and when you print with it you will instantly see why. Has minimum layer height of 10um (will do less) and virtually zero backlash.
This has a stroke of about 130mm so that will be your highest part, but you can buy larger versions ie KR30 if needed.




UV engine



OK this is the real heart of any LCD resin printer and that took the most time to figure out, it is very important to speed and accuracy.

The most popular and cheapest resin printer doing the rounds at the moment is probably the Wanhao D7. This printer actually started out as one before i stripped it.
Why is it so cheap? poor build quality and cheap components with reliability issues and most importantly, uses a single LED in the centre of the build area.
As you can imagine this causes all sorts of issues as you end up with a hot spot in the middle of the build area and the intensity of the light drops off towards the edges of the build area. This causes allot of issue with accuracy as the resin is curing at different rates and causes havoc with getting prints to stick properly to the build plate.

Ideally what you want is an array like the pictures above which covers the whole build area. That way the resin receives even exposure and cures at the same rate.

This is what you are trying to create:



The above array is for a 5.5" screen but is easily scalable. It consist's of 18 3w 3.6v leds on a surface mount star PCB for total output of 54w. This is wired in serial/parallel with each row in serial and the 3 rows in parallel. Its cooled by 2 60mm noctuas which are basically silent. This also has some redundancy so that if one fan packs up, the whole array dosent go pop! as it will overheat VERY quickly without active cooling.

These are the leds i used or search aliexpress for similar.

https://www.tme.eu/gb/details/pm2l-3lls-sd/uv-leds/prolight-opto/

Now you will notice other 5.5" LCD printers with a much smaller case. The reason for this is they are using led's with the built in collimator to focus the light which is generally about 130 degrees. This means the beam spreads out wider and therefor the array can be closer to the screen.
Some things to note with this approach. 1. It makes it much more challenging to manage heat coming from the array. Apart from UV intensity, heat is the other factor which will determine the life span of the LCD!.
2. And i really need to research this further but as i understand it the straighter or more focused the beam from the led, the sharper the light is and the more focused the important wavelength's are which are hitting the resin (please correct me if I'm wrong here).

For this reason i used extra collimators on the LED's to narrow the beam to 20 degrees. This does mean the array needs to be further from the LCD but this also has the added benefit of making it much easier to control heat. It dosent increase the footprint of the printer buy making it slightly taller so I'm much happier with this approach.

Collimators and holders used:

https://www.tme.eu/gb/details/pg1c-nx17/lens/prolight-opto/

Ive since found a collimator on aliexpress which dosent require a holder so makes it easier to mount, so you may choose to use these or something else, there quite allot of options.

https://www.aliexpress.com/item/10-...32463807940.html?spm=a2g0s.8937460.0.0.wb4kg0

Heat Sink Used (cut down to 120mm):
https://www.ebay.co.uk/itm/Aluminum...-Transistor-/292168449727?hash=item440698bebf

Fans for active heatsink cooling X2:
https://www.ebay.co.uk/itm/Noctua-60x25mm-A-Series-Blades-with-AAO-Frame-SSO2-Bearing-Premium-Fan-Retail/173128136512?_trkparms=aid=555017&algo=PL.CASSINI&ao=1&asc=20160706105120&meid=95b13cb690dc4bf5a52ae8845965fe75&pid=100508&rk=1&rkt=1&&itm=173128136512&_trksid=p2045573.c100508.m3226

Part 2.

MotherBoard and Software

Because this started as a wanhao D7 ive retained the motherboard for this project. The board is not ties to a specific lcd or hdmi driver board but has everything needed to power the stepper for z axis, some fans and a 34v output for UV led (or used a trigger for an array via a relay).

https://www.aliexpress.com/item/Ori...2167-4011-a33e-98ec7179acc7&priceBeautifyAB=0

The printer uses free software called Nanodlp which is fully featured and has pretty much everything you could need, including a browser based interface so that you can run multiple printers on the same network.
https://www.nanodlp.com/

There is a custom version of nanodlp as well as firmware for the board to get things up and running.

Details are all here.

https://3dprinterwiki.info/d7/d7-nanodlp-settings-2/

Two options are available for running the printer. 1. Run directly from a PC using Creation Workshop - This means you need a PC tethered to the print at all times. 2. Use a raspberry Pi3 to make the printer into a stand alone unit. You then just load the prints to nanodlp over web interface and let it do its thing. This is the route i went.

Its also possible to use any ramps board as there is a nanodlp image for ramps also but it didn't look at that.

If your happy to stick with the wanhao board then I can share the image of my SD card which is all set and ready to go. Its a 32gb file though due to the size of SD card i used so i need somewhere practical to upload/host it.

This image is also configured to run a Nextion touch screen which was quite a bit of effort to get running so would save you allot of time. This allows you to get real time status from nanodlp and access basic functions. There is editor software for the Nextion screen so in theory you can add and customise it however you like.

https://nextion.itead.cc/

https://www.aliexpress.com/item/Nex...a3d2-4b1e-b52b-07db442423bd&priceBeautifyAB=0

https://github.com/Tibus/TouchScreen-For-NanoDLP



The second screen at the bottom is for reading voltage and amps at the same time which is really useful when tuning the array (more on that later)

https://www.ebay.co.uk/itm/DROK-Dig...983915&hash=item1a40e27971:g:i-cAAOSw6~VZz5EG

Power, Converter Buck, SSR

Power is from a regulated 12v PSU. 12-15amp should be enough to power the stepper, screen, UV array and RPI3.

On the Wanhao motherboard there is a 34v out which i used as a trigger only for the array. Power is taken direct from the 12v PSU to avoid stressing the wanhao board to much as its not designed to handle the current required by the Array. 34V signal goes to a solid state relay which switches 12v to a step up buck which has pots for voltage and current. This then makes it easy to dial in the power requirements of the array without using resistors. Because it is all triggered from the 34v out of wanhao board (the standard UV output) theres no need to modify nanodlp in anyway.

step up buck used:
https://www.ebay.co.uk/itm/600W-DC-...007480?hash=item3abe2213b8:g:n5cAAOSwQYZWzShZ

DC to DC SSR Used:
https://www.ebay.co.uk/itm/RUIKE-ly...2-100V-L1C6-/282655550589?hash=item41cf956c7d

(Wiring Diagram of all this to follow)

More to follow...

Resins

Vats and Fep

Build Platform

Post Processing

Z Axis Stepper Used:
https://www.ebay.co.uk/itm/42BYGHM8...epper-Motor-/272526413547?hash=item3f73d70eeb​

Very interested in building my own DLP.. More.. more.. more.. Any results yet?!


Just a question to get my bearings right.
The Array of UV leds is under the LCD (which has the backlight removed) an this array is the 'New' Backlight ?! Is that what the idea is ?

That is how I read it Michel

Sorry for slow reply and lack of updates... work got really busy again :/

yes that's correct, the array is the back light that cures the resin through the LCD. Other than having an accurate linear rail, this is where most of the magic happens which affects quality of prints.

Regarding results the printer works great. better than the Phrozen make i have. The DIY is way faster and works with a wider range of resins (phrozen chose a led that's 400-420nm, you need to stick to 405nm for the best compatibility)

Most of my prints are dental parts (i own a dental laboratory) so not particularly interesting for others but i did this at 50um just to see how far i could push small details. The head here is the size of my thumb nail so as you can imagine, the teeth etc are super tiny.



Still a slight bit of undercure as some of the teeth are not fully formed, needed an extra 0.1 seconds per layer i would think.
This is not maximum quality could do 10um per layer but would take forever.

love to see more..

Hello, you could share your g-code, and all part of programming?

hello,
what collimator lenses angles did you use?
could not figure out from the article,
thanks

This runs off nanodlp and Raspberry PI

https://www.nanodlp.com/

20 degrees.

You might wanna d0 yourself a favour and just buy one of these instead, works much better than my DIY version and betime you have gone through the learning curve theres not much if anything in the cost difference.

https://www.phrozen3dp.com/products/paraledmake

Hi Paul,

I'm new here. Just wanted to thank you for your EXCELLENT presentation of information and sources for parts for building a great LCD printer. I've been searching the net for days trying to find something like this. As I'm an inventor by heart, I'm eager to start out on the adventure of building my own unit, but your last statement does slow me down a bit. Should I just make a little money and BUY one instead of going to all the trouble of MAKING one? Could you possibly share why you think a Phrozen off-the-shelf printer is better than the one you've designed?

Hi Paul,

do you think this LED model can be usable on this project ? less heat, more easier to install...

https://fr.aliexpress.com/item/3272...chweb0_0,searchweb201602_4,searchweb201603_52

thanks,

the array is led's.

save yourself the bother of building your own array and buy one of these. Its hard work to make an array with really good even light distribution as ive since found out.

https://www.phrozen3dp.com/products/paraled20

Hi I have all the materials to build my lcd printer. I don't want to buy a printer it's to expensive. I m only using audrino and ramps 1.4 with creation workshop. I desperately need the gcode for the led array as this is the only thing that's stopping me.if you can please copy and paste it. How would I install the gcode?

Hi I re purposed the main board from a wanhao d7 printer and there is already a nanodlp branch for it so i did not have to figure out the gcode for the led on mine. I just build the array and it was plug in and go. sorry i cant help.

@paulg100 Hi there, thanks for the great write up on the resin printers, you've clearly put a lot of effort into this!

Thanks yeah it all worked well. Since building this the price of resin printers has come down so much that im note sure you will really save any money going the DIY ruote but its a good learning experience.

Yeah they really have come down a lot in price, i think my friend paid around $350 AUS for his. Now here's hoping the metal printers become cheaper too. Imagine the possibilities!

Hello, I'm interested in making your printer 3 d. I want to know how much electronic board you are using 1.wanhao 2.rasp pi3 3.NANODLP. Do you have the next article?

Hi Paul, great guide. Building a 3D printer from scratch offers a great learning experience. However, as you already said, in the last years the price of modern resin printers dramatically dropped. In many cases, the time required for building a printer along with the cost of the various components may not worth it.

I strongly agree with your suggestion of buying a Phrozen 3D printer. The last generation of printers allows printing high-resolution parts at a fast speed. They come with an open-material system which makes them compatible with a broad selection of generic resins. This results in wider design flexibility and fields of application.

How much do you estimate the cost of a DIY 3D printer?