Stink and smells with resin printers - a possible solution ?!

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Stink and smells with resin printers - a possible solution ?!

Post by Downunder35m »

I am still playing with the idea of getting a resin printer.
Which brings the question of placement and dealing with those fumes.

The one I have in mind uses a hood instead of a door.
I just like the idea better in terms of access.
Should mean all fumes are contained and only while you have it open and handle resin or prints fumes would matter.

Guess we all can imagine how this is sooooo not the case....
Sure, some poeple have a dedicated room with good ventilation, other might use some big cabinet that allows enough acess to all....
But if space is at a premium you start to wonder if there is no other option.

Airflow rates and filtration are the thing that come to mind here.
With the hooded design we can't just add a frame around it the easy way.
Access to the touchscreen, usb port and power switch might come handy one day as well.
And so I started to play around with carboad for a while to figure out what could work to put a box inside a box that isn't a box.
A big fan is one thing, making it suck in what needs to go in when the printer is open while also making sure it is good enough sealed when printing is a different story.
Really struggled for a while here until I remembered those fancy fold and swing away doors.
So why not use a similar approach to fold the front and side parts away to form a nice and high enough U-shape around the open printer to hopefully suck away all the fumes?

Creating or finding a fold away hinge system for the top corners of this enclosure can't be too hard.
And with flexible seeling strips on the inside we can allow for moderate tolerances and magnets to "locks".
A clear front panel to monitor the progress and status messages paired with "hair strips" along the hood when closed and Bo's you uncle ;)
Well, at least with small carboard pieces and in theory...
My problem is that without having the actual printer here I can't really make a suitable enclosure for the bottom part.
Ok, I could go with the pure basics required to cater for the exhaust system and size of the side and front panels to allow for proper removal of the air.
Like a foldable range hood so to say.
But it just seems to be easier and more logical to do this with at least a mock up version of the printer at hand.
Ever tried to find the required measurements for a printer ? LOL
For the entire box, the build volume, certainly.
For the location of ports, switches and such not so much and same for the exact height of the bottom part of these resin printers.
Almost as if no one ever considered to provide more tha washing and curing solutions for models while leaving the to deal with the fumes.

IMHO one of the biggest exposure problems is the handling of the final model.
The foldable rangehood should allow for some good dripping off time without smells but then you need to get it into the washing basket....
I guess there is a reason why on a big scale all is integrated in one big cabin with constand fresh air supply...
For me the most logical conclusion is to have the wash option as close to the printer as possible.
Preferably so that you won't make a dripping mess.
Means either to the left or to the right of the printer.
Area has to be big enough to allow getting the model(s) off the build plate without risking them ending up elsewhere.
My thoughts are going in the direction of a custom made cabinet for the printer.
If I need to take care of these fumes not just when filling and printing but also when handling the finished model it just makes sense.
Here is what I was thinking so far:

A cabinet with the right height to access all and to remove the hood with enough ease - later maybe with some lifting device.
On one side of the printer, like a basin, the washing area as an integrated solution.
Pumps and filters inside the cabinet for an automated cleaning routine with some added UV lights in a filter or settling area.
Maybe someone can help with this question:
If I would use walls coming up and out of the cabinet to seal the printer and created a frame around the washing area: would air inlets on the top of the cabinet provide enough airflow or should I have the inlets in the back of these walls ?
Apart from the problem when spilling some resin that is....
I have a suitable stinless sink that is wide and deep enough for the job and that has a small drinf for just a hose connection.
Perfect for the task at hand after removing the excess steel that once made it an ice container...

Double up or go seperate on the washing options ?
Not all resins are available to be cleaning up with water, especially if you want clear and durable you still need to look at normal resins and alcohol.
For many plastics alcohol can become a problem over time, leaching out the vital softeners and making things brittle.
Fire is a real risk as well and be it water or alcohol, no one wants a leak once resin is added to the mix.
Plumbing wise it means old school with copper, brass and screw connections allows for cleaning with heatand flame if ever required, going plastic means careful selection of what is used.
Either way the main problem will be the pumping and filtration part.
Small washing machine pumps can deal with alcohol for quite a while if you replace the rubber selas with Vitro or similar ones offering a higher chemical resistance.
The rubber goes too brittle quickly with alcohol and makes cleaning the pump hard once the seals get suck on the housing.
Standard polycarbonate filter hosuings are sadly no option for alcohol as they go very brittle and by the time you see surface cracks appearing it is already too late.
While PVC is great for most chemicals including water, it can be a bit problematic with acohol as again there is the risk of the vital softeners leaching out.
Not sure which route to go with the filtration yet but if you have any cheap and chemical resistant ideas then feel free to share ;)

The dreaded waste problem....
I know that a lot of people still dispose of their wash water and used alcohol in the drains.
Some even rinse their water washable models directly under the running sink.
Considering the ingredients and effect on filtration systems and bio cultures in waste water treatment plants a big no go for me.
Curing the liquid wast is must have feature for me.
We will always have things in our resin that dissolve rather than being able to be filtered out, like dyes for example.
And once this contamination that is not particle related becomes to bad we need to replace the entire solution.
No big deal for water - put it in a big plastic container where it gets some sun and no rain and just let it evaporate.
If the container ever turns too full with plastic residue that you can't scrape out get a new one for two bucks ;)
Alcohol on the other hand is not just costly but also a real cost factor when you print a lot.
Often exceeding the resin costs.
Makes sense to keep it usable as long as possible.
A chemical widely used in commercial fryers and for making bio diesel is Magnesium Silicate, most widely knows under the brand name Magnesol.
The stuff is literally inert but similar to activated carbon binds to a lof of nasty things we don't want in our food.
Articifially created it does not have the lung dangers of natural silicates and the surface area is maximised to bind even the smallest of particles.
Used as a disposable filtration media it is a consumable - once it no longer binds more nasties you replace it.
Still won't keep you alcohol clean indefinately and certainly won't be able to filter out all dyes but it will give you a around 50% longer usage time for your alcohol.
Considering the stuff is available quite cheap in big buckets....
The ultimate alcohol recovery from your waste though is to go the distilling way.
A small and relatively cheap (in the long run) reflux or Boka style system will recover your alcohol at about 93-94% and leaves most remaining impurities behind.
Needless to say that adding water to get the acohol down to 30 - 40% is not just vital but laso removes a lot of stuff from the remaining resin that can bind with water better than with alcohol ;)
Over time some of the still remaining nasties will make the alcohol smell a bit off but it won't matter for the cleaning of your model.
For 5 liters of otherwise wasted alcohol you can recover at least 4 liters this way - a significant cost factor especially if you can build you own simple reflux still for this.

Airblade technology ! ??
For decades a well trusted thing in the industry to literally cut soft things like cookies or other food products in a clean and hygenic way.
In some rest rooms a feature to dry your hands and most car wash places used it to drive out water even in areas a normal fan would never reach.
How does it work and why might it be an option to drastically cut down on our alcohol costs?
Airblades use a laminar flow through a rather wide and thin nozzle area.
Unlike a normal stream of air this "blade" stays thin for quite some distance and provides very high velocities.
Like a pressure washer if you like you the nozzle of a good air cleaning gun.
A fully automated system that moves and spins you model with the build plate through one or two of these airblades would remove about 90% of the resin adhering to the model.
Of course not that suited for really thin or fragile parts but most models won't have a problem if the airflow is adjustable.
Especially for those rather thick and sticky resins it could also be a considerable cost saving if you print a lot.
A hollowed out big print might only need 200ml of resin for all, including supports but it might trap 15-20ml on the surface that you would wash off.
Multiply this by a lot of models and after 50 to 70 you saved a whole liter already...
Apart from reducing the overall waste by a good margin.

A lot of ideas, a lot of technologies and options to choose from.
The way I know me it means I will start with something nice and realise right after it needs improvements and changes to make it better.
A solution to allow for airblade, washing and curing almost justifies havin a dedicated room you modify accordingly for just printing needs.
Sadly this is neither an option in my rental, nor in my garage.
Considering the huge popularity of resin printers for hobby use use I wonder if it would be worth to consider going commercial with this idea.
Right now all we find is cleaning and curing stations but nothing really to deal with the fumes or to provide some meaningful integration.
Exploring the works of the old inventors, mixng them up with a modern touch.
To tinker and create means to be alive.
Bringing the long lost back means history comes alive again.
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