How do I prepare to buy a resin printer (SLA printer or DLP printer)?

The theoretical delivery date of my Kickstarter supported resin printer (SparkMaker FHD) is approaching.

I know from experience that you need a lot more equipment for a resin printer than with an FDM printer. That’s also the case if you have an SLS printer and probably one of the reasons why these technologies don’t easily establish themselves on the broad market.

The Workplace

You have to be aware that with a resin printer you buy a printer that handles different chemical liquids. Some of the fluids can stain, cause allergic reactions, emit unpleasant odours and produce unhealthy vapours.

It is therefore advisable to place the whole thing in a room where you are not always present and which can be well ventilated. I will also make sure that I cover the work surfaces with polypropylene shells (PP), for example, so that I can clean any splashes well again.

Rework for resin printers

When the FDM printer has finished printing, it can be removed from the printing plate and reworked directly (e.g. removing the support, drilling holes, etc.).

With resin printers, the tedious part starts here. You have to remove the component from the printing plate, normally wash it in a bath of 95-99% isopropanol for about 20 minutes. Currently I only know one material that can be washed with water.

!!! Since resin and isopropanol (IPA) are not very pleasant on the skin and may irritate under certain circumstances, chemically resistant gloves are a must for these steps. !!!

And in order to unfold the full range of material properties, it must then be cured in a UV curing box.

This means that I have to plan a washing station and a curing station. You could buy both ready to use from Formlabs, but that’s too expensive for my private laboratory.

Why resin should be hardened

Maybe you’re wondering why you have to harden the materials. The resins can change their properties drastically when they harden. If you study the data sheets on Formlabs, you will discover that there are two columns for all materials in the data sheets. One gives the data for unhardened (green) material and one for hardened (post-cured) material.

For me, the most blatant example is Formlabs’ high-temperature resin. If the material comes directly from the printer, it has a heat distortion temperature of 42.3 °C when cured of 130 °C. That’s a huge difference and that’s why a curing box makes sense. https://formlabs.com/media/upload/HighTemp-DataSheet.pdf

The washing station

!!! Isopropanol is highly flammable and should be handled with care.  !!!

The washing station should be placed in a room that is well ventilated. In addition one should pay attention that one can close the containers, in which one stores the Isopropanol, really tightly.

For the washing station I will buy polypropylene (PP) tanks, which have a large opening at the top with a reclosable lid and a seal. The best way is to organise a mail order business specialising in chemical accessories.

I will also buy Isopropanol at the pharmacy, because you need it to wash about 99% of the resins. It gives way to my current knowledge, only 1 resin that one can wash out with water.

So that I can get the components in and out of the tank, I will get a spaghetti sieve or something similar for the time being. Maybe I will also print something from PLA.

It is also important that you have a waste bin and household paper right next to it so that you can quickly clean away any dirt.

The curing station

I still have to plan the curing staion in detail. But my idea is to build a rotating platform with a NEMA-17 stepper motor, an Arduino Mega, the RAMPS plug-in board and an A4988 motor driver, because it’s still somewhere around here.

It could probably be easier with a DC motor, an Arduino UNO and a corresponding circuit. I’ll have to see what I’m really doing.

I want to build the whole thing into a small frame made of aluminium profiles and board it with cardboard or dibonds for the time being.

Not to forget the UV-LEDs, which I will place at different places and heights in the case.

!!! UV radiation is unhealthy and you should cover the curing station really well and wear protective glasses when testing the LEDs. !!!

The parts that I have to print in 3D for the curing station will be made of PLA, because PLA is used for most

Shopping list:

You can get most of the shopping list from Chinese exporters at quite low prices.

  • Chemically resistant gloves (e.g. nitrile latex gloves without powder)
  • 2x chemically resistant tanks with large opening, so that the components fit in and can be removed (my choice is polypropylene PP)
  • Chrome steel spaghetti strainer (to place and remove the components in the washing tanks)
  • 10l Isopropanol
  • 4x 10W UV-LED
  • 1x Nema 17 stepper motor
  • 1x RAMPS with Arduino Mega and stepper motor card A4988
  • 1x waste bin
  • 1x household paper

Maybe now you’re wondering, why do you do all this to yourself? Because of the much finer resolution, the details and the much smoother surfaces. It opens up a whole new world of development and design.

 

Translated with www.DeepL.com/Translator

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