UV Resin printers

There are several types and styles of Resin Printer: SLA, MSLA, DLP, etc. The commonality among all "Resin Printers", is their use of an ultraviolet radiation source to solidify an ultraviolet sensitive liquid resin into a useful part. MSLA uses a clear bottom tub with a UV lamp under an LCD to mask each layer for exposure, where as DLP typically uses a UV laser and mirrors on motors to draw the exposure into the resin.

Personal Protective Equipment for Resin Printing

Most UV resins do NOT "dry" even if left out long term; they require UV to cure.  That drop that splashed behind a table will still be wet the next time a ball rolls behind the same table.

This is the stuff that keeps me and everyone else safe.



Gloves

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Towels

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Silicone Dog Food Mats

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Plastic Drop Cloth

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Other Useful Equipment for Resin Printing

These things can ease aspects of the resin printing process and make them more convenient


Syringe

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Filters

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Non-UV lighting

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Solvents for cleaning Resin Prints

Something to rinse away the remaining uncured resin so the printed model can be fully cured without additional blemishes.



Isopropyl Alcohol, Isopropanol, Rubbing Alcohol

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Ethyl Alcohol, Ethanol, Liquid Courage

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Water, Agua, Rain

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Methyl Alcohol, Methanol, Wood Spirits

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Acetone, Fingernail Polish Remover

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Other solvents such as Xylene, Mineral Spirits, Paint Thinner, etc.



Post-processing Resin Prints

Once a part is printed, the cleaning and finishing processes begin...


Washing

Dunk Buckets

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Resin Washing Machines

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Compressed Air

Blowing any resin or solvent from within the tiny crevices of a printed part, is a great way to ensure the highest quality finished product.  This also means wearing an apron or smock to cover the body and a face shield to keep splattered resin off our faces.

Air Brushes <10PSI

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Air Compressor <100PSI

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Heated Drying Chambers

This is not truly necessary and doesn't have to be complicated.  Our goal is to warm the printed, cleaned, and forced air dried part enough to dry any remaining solvent that might be hidden somewhere.  Letting a printed, cleaned, and forced air dried part just sit to dry thoroughly overnight is a perfectly reasonable option, heat just makes it FASTER.

Home Made hot boxes

In the summertime, I have draped a black trash bag over a chair to cover my parts left on the seat.  When the chair was left outside in the sun for a few hours everything underneath came out plenty dry and warm.

The PTC controller/sensor, 100W 12v heating element, and fan are the same parts used in the Resin Chamber Heater:

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Heated washing or curing machines

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Curing

Parts that have been printed, washed, and dried are still not up to their final material properties such as: strength, toughness, elasticity, etc.  Parts must be thoroughly cured by using the same Ultraviolet light that was used to create them, except now we are "soaking" them over a longer duration.

UV Lights

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Curing Machines

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Raspberry Pi Zero W as a Wifi connected SMB available USB Drive

This is NOT my work, I started at: https://makerfun3d.com/pizerow-wifi-thumbdrive-send-photon-files-over-the-network and downloaded the 400meg zip file containing a preconfigured SD Image.  After burning the image file onto the SD card I created an empty file on the "boot" partition named "ssh".  That enabled me, after booting up the pi, to log in over SSH and use "sudo raspi-config" to configure the wireless network; I left everything else as default.

This turns the Raspberry Pi Zero W into a WIFI connected, network shared (SMB) USB thumb drive.  I used an old micro USB charging cable to connect the OTG port on the Pi to the USB port of the 3D printer or other computer.

The 2.4GHz WIFI, SMB sharing, and Raspberry Pi Zero W itself, all contribute to a very SLOW but fully functional experience when transferring files to/from the Pi.  Once the files are available from the Pi's USB OTG port, the performance has been comparable to any cheap USB 2.0 thumb drive: slow but useable.

This process takes less than 5 minutes:

(WORKING) Nicks-Fix "Continuous IPA Filtration" system

The alcohol used to wash UV resin printed parts can get slimy as snot in no time at all; fortunately this issue now has a solution!


Who

Nick Wilson of the Youtube channel https://www.youtube.com/@nicks-fix posted a video about a new Continuous IPA Filtration system he had created.  The breakthrough for me was seeing someone pair up the cheap water filters I had already rejected with an alcohol safe diaphragm pump to handle the pressure needed to use those cheap filters!  (...and WHY didn't I think of that?)

Resin Printer Mods and Continuous IPA Filtration!

https://www.youtube.com/watch?v=DfM1CXBOZns


The Basics
  1. Expose the resin containing alcohol to a UV light source
    • Creates a suspension of really tiny & very hard to remove, plastic particles within the alcohol
  2. Separating out these miniscule lightweight plastic bits is harder than one might expect
    • All of the other separation methods had some significant negative, from added cost or labor to increased exposure to chemicals
    • Nick's design used a diaphragm pump to push this nasty alcohol solution through some easily changeable water filters


Background

I have made many unsatisfactory attempts to reclaim some usable alcohol from the resinous sludge left behind after washing resin prints.  The only reliable solution found to date is exposing the mix to UV light, which fortunately & unfortunately hardens each super tiny dissolved particle of resin, creating a gel like plastic/alcohol suspension that is not fun to separate and less fun to use.


What


Why

Nick's continuous filter system enables me to run resin prints through my wash and cure station without additional alcohol rinses.  

      1. <1min - Parts have already been dripping for at least a few minutes, Tilt parts 45 degrees and drip for another few minutes
      2. <2min - Rinse in gooey slimy alcohol to get most of the excess resin off (Nasty alcohol)
      3. <variable> - Remove supports
      4. <2min - Run through a 30 minute wash cycle (medium cleanliness alcohol)
      5. <5min - Hand spray with New alcohol (unused alcohol)
      6. <5min - Dry with compressed air
      1. <1min - Parts have already been dripping for at least a few minutes, Tilt parts 45 degrees and drip for another few minutes
      2. <variable> - Remove supports
      3. <2min - Run through a 30 minute wash cycle (clean? alcohol)
      4. <5min -Dry with compressed air



How

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