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PLA and ABS 3D Printing while Protecting Your Lungs with an Enclosure

There's not much to a 3D printer enclosure.  Although ours look fancy, functionally they're not much different than putting a cardboard box over the printers since both designs are passively heated by the beds.  How complicated can they be?  This article will explain a little about how they work, and how to manage the temperatures to get quality prints while protecting your lungs.

We generally get two types of customers:

  1. Those interested mostly in air quality.
  2. Those interested mostly in print quality.

Think Airflow, Not Fishtank

The problem is those two goals use two different techniques in terms of airflow.  For the best air quality, we use the same design as industrial equipment, which uses airflow to manage air quality.  Because of physics, the amount of air moving into the enclosure has to be equal to the air moving out of the enclosure. When the air moves out of the enclosure carrying volatile organic compounds it can then be vented to the outside or run through an air filter.  

People often ask us if the enclosures are airtight and have a bottom.  If your main concern is air quality then being airtight doesn't buy you anything since the particles will just float out when you open the door.  It's only by maintaining a negative air pressure that the particles are reliably kept away from human operators, which means having openings for air to both enter and exit the enclosure.  This is the same technique used at hospitals to prevent the spread of airborne infectious diseases, and industrial lasers to maintain indoor air quality.

If the maximum internal temperature is the goal, then being airtight also doesn't help since the main cause of heat loss is through conduction through the sides and top of the enclosure, not through tiny amounts of air loss. A bottom doesn't help either since while heat doesn't rise, hot air does, and thus almost all of the heat of an enclosure is at the top.  A bottom is helpful, however, if your table is too small for the enclosure.

Since airflow is key, all of our enclosures come with fans chosen for CFM ratings to match the cubic size of the enclosures.  This ensures that for cool-loving filament types like PLA there's enough airflow to keep the temperatures in the safe zone.  

Room Temperature

Passively heated enclosures are completely dependent on the room temperature as a starting point.  If you're trying to print ABS in an unheated garage in the winter the temperature inside the enclosure is never going to get hot enough.  The reason is the bed heater has only enough energy to increase temps from the baseline.  If that baseline is 72F, then you've got a good chance of getting into the sweet spot.  If the baseline is 50F, then you'll be lucky to break 72F in the enclosure itself. 

ABS and Nylon

You want the internal temperatures higher for filaments like ABS, which happens naturally because the recommended bed temperatures are much higher.  With the fans turned on we shoot for internal temps between 35C and 40C for 3D printers that use E3D hot ends because E3D recommends that temp range to avoid clogging.  Keeping the temperatures in that range it puts the least stress on the equipment and follows the manufacturer's guidelines.

This works great for people either interested mostly in air quality or those who are risk-averse and don't want to take a chance of clogging their hot ends or decreasing the useful life of their printers.

More experienced 3D printer owners though, those for whom a clogged nozzle is a known risk, might want to run the temperatures higher for less chance warping of ABS parts or to print nylon.  In those cases, you can turn off the fans or even print one of the vent covers and just not vent at all.  For our internal print farm, we do the later on a couple of machines where the temperature when printing ABS gets as high as 46C.  They've been running like that for years with no filament clogging.  Even with no venting of the power supplies, we've never had a power supply fail either. Obviously, your mileage may vary, as it depends on a lot of variables such as filament quality and the quality of the power supply in that particular printer.

If you're looking for the highest temperature's possible, try turning the bed heater on for an hour before you print.   

Perfect Enclosure Printing with PLA

Since PLA is perfectly happy at room temperature, the only reason to enclose it is for improved indoor air quality.  PLA typically prints with a bed temperature of 60C, so it's going to heat the enclosure less than ABS right off the bat. Always make sure to print with an enclosure fan and monitor the internal temperature, which ideally should be in the 30-35C range or lower if you can get it. 

If you'd like to lower the temperature further you can always buy a more powerful fan, but the easiest thing to do is just crack the front door a little to increase airflow.  But won't that let out all of the volatile organic compounds coming off the hot end?  The key is the negative pressure combined with the fact that the particles are extremely small and light. 

As you can see in the video, the fan keeps the air flowing in and the harmful particles flowing into the vent or filter. 

 

3D Printer Design Matters

The other part of the equation is the printer design. Those printers where the hot end is at the top of the enclosure make it easier to achieve higher temperatures because the hot air rises to the top, and the vertical hot end position is fixed.  Those printers with the hot ends at the bottom are always going to have more problems managing temperature simply because the temperature is more likely to vary as the hot end goes from the bottom to the top of the enclosure.

Let Us Help

If you're looking to achieve a particular temperature with your enclosure, let us know and we'll give some advice on how to manage, but it's really not that hard:  

Lower Temperature = More Cold Air
Higher Temperature = Less Cold Air

Pro Tip:  measure your current temperatures before attempting to make any changes.  We get support calls saying "my enclosure is too hot" or "too cold" but they didn't actually measure the temperature.  Without measurements, it's impossible to say if a printing problem is temperature related or not.