Particule detector  

Re: Particule detector

I cant claim to know to much about it but smoke detectors employ a range of particulate detection depending on the sensor. Ionization types use a small low radioactive material so that probably a no go. Photoelectric may be the direction to take. It will come down to particulate size vs detection delta. Photoelectric sensors in detect larger particles such as cloth or wood burning. Ionization detects smaller particles from vapors and oils.

May even be able to simply harvest a cheep one and use its resistance value to give a usable readout. Hope that helps.

Re: Particule detector

I don't think that sensor will have the resolution. This will do the job but so expensive: http://www.tsi.com/nanoscan_smps_nanoparticle_sizer_3910/

A good read on the subject: http://hackaday.com/2013/11/20/3d-printering-wherein-abs-is-dangerous/

Also check out this thing: http://www.thingiverse.com/thing:125264 and linked info in the comments section.

Another sensor Just as a point of reference:
http://www.dekati.com/products/Fine%20Particle%20Measurement/DGI

Re: Particule detector

Would sometching like this

http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=142040136282&category=43510&pm=1&ds=0&t=1482516433508

Help?

Joan

Re: Particule detector

Would sometching like this

http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=142040136282&category=43510&pm=1&ds=0&t=1482516433508

Help?

Joan

Not sure if it's efficient, but what I'm looking first is a way to make measurement.

Re: Particule detector

How would the system know that you were printing in ABS?

Re: Particule detector

At higher temperatures ABS can decompose into its constituents: butadiene (carcinogenic to humans), acrylonitrile (possibly carcinogenic to humans), and styrene.

To take a measurement, you could put an air pump in the print enclosure and pump the air into a liquid solution of acid or base.

You can buy pH sensors for under $50. I wonder if it would be possible to observer the pH change from the acid or base reacting with the ABS constituents?

Re: Particule detector

David

For ABS to breakdown to it's component parts it requires temperature much higher than what are used for printing, in the neighborhood of 400 ºC.

Re: Particule detector

Just open a window, or if you are truly worried wear a gasmask. < sorry for flippant comment. When I print ABS, (which I have now abandoned for other materials ie NGEN and PLA PLUS) I am not there, And if I do it, I do it in the summer with a window open and the printer room door closed. The particles you want to detect are what specifically ?

Driving a diesel car produces carbon particulates and NO2 to very unhealthy levels in the name of more MPG or KML, killing approx 6000 people a year in the UK. A green policy in the UK promoted by Gordon Brown and the Greens back in the day 🙂

I recommend PLA PLUS and NGEN as materials. ABS is a dead 3D printing material, like diesel cars will be abandoned soon! Petrol Hybrid/Battery vehicles are the in thing as equal MPH and KML to diesel or much better. Go figure.

Re: Particule detector

ABS is not dead. It's useful when:

1. Flex
2. Low density
3. Easy acetone finishing

are desired.

I avoided ABS as long as I could, but finally broke down and started printing ABS last month for some flexible parts.

I agree it smells something awful and is probably not good for you.

The question is how would this system know you were printing in ABS in the first place?

If, at any point in the process, you have manually tell the system it's printing in ABS, then all this automated sensing stuff is useless.

It's a simple "turn the filter on when the print starts" option, and that can be achieved much more easily.

Re: Particule detector

Oh for me ABS is far from being dead, I have many situation where ABS is the preferred choice.

I do no look for an automated system (at least yet) but to find a way to check how efficient may be the filtering solution I want to try. So a simple make wih number on a LCD screen will be fine by me, it can be improved on a later term.

A young indian guy made an interesting modification of one of this dust probe to make cheap pollution measurement box. ( https://indiaairquality.com/ ) I could easily implement the same way but I do not find a lot of information that could confirm that this kind of probe is revelent regarding the ABS particles , especially regarding he size.

Re: Particule detector

Ah, if you really want to measure performance, there's no getting around... measuring it then.

Re: Particule detector

I Just ordered two PPD42ns, one will be in the enclosure, the other one in the room where the printer is. My main concern for now is that the heating of a resistance is used to make the air through the probe, and I'm not sure it will be very efficient in hot air, so modifying the probe with a small fan will be probably needed.

it's time to experiment now 🙂

Re: Particule detector

Well, first mock off are promising, I can get temperature, humidity and dust level.

Still got some optimisation to do by modifying the PPD42 sensor with a fan, find the best way to calibrate the data and to make a proper enclosure. I also need to find the better way to graph these.

But this get interesting 🙂

Re: Particule detector

This is an absolutely fantastic idea. There are several solutions proposed by makers and tinkerers within the community, but unfortunately no hard evidence to test the efficacy of the filtration systems. Unfortunately, many rely on the "smell test" to determine the efficacy of their system, but a more objective and analytic approach will certainly yield more effective results.

Have you looked at the equipment being used in some of the studies that have analyzed the ultra fine particles and VOCs from 3d printing?

Re: Particule detector

Hi Andrew.

Yes that the idea, I cannot see how you can qualify the effect of improvement without having tangible measurement. This is a first approach, with some limit, as this sensor can only sense particle from one micrometer, where the particule we are dealing here are going down to 20 nanometer. Well in fact it's a distribution on various size, so the bigger can be detected. But it's a affordable sensor that have already been used by some people and with some feedback on it, so I consider it as a good start,

There are some other sensor, based on laser beam, that can sense smaller size, but the price is higher and I put them aside (for now) as it's still experiment phase. The challenge should be to calibrate it, but for the objective here, having a standard baseline of data without printing is sufficient to judge filtering efficiency, by comparing to data while printing, I do not need absolute values that are comparable with other sensors.

I still have some stuff to figure out the best way to collect and graph data, but I'm beginning to think about next phase, building an experimental electrostatic precipitator (will discuss about that in the "Filtering ABS fumes options for enclosure " thread 🙂

Re: Particule detector

Well, after some try and miss I decided to change probe to a PMS 5003. The PPD42 is not easy to deal with, you have to sample a digital pin and make a ratio between the high and low level then use a polynomial calculation to determine PM2.5, the arduino cannot make a lot of other task and the amount of noise of the measurement is huge. In addition, being based on LED technology, it's limited to 1 µm for particulate size.

PMS 5003 is another story, it's laser based, so can detect particulate down to 0.3 µm, is completely autonomous, make his measurement on his own and provide the data through serial/i2c , and very first result show very consistent measurement !

So with a nice little nodeMCU, it's quite comfortable to send the data to thingspeak on the cloud and to have nice shinny curves, I'm very happy of the result, I will be able to make real test and measurement 🙂

The only con I have is PMS5003 is a bit pricy (~30 € from china) but that's ok if you really want to deal with these kind of data.

Here his my new little POC:

Re: Particule detector

More subject matter for you consideration:

Since acrylonitrile is emitted when printing ABS, perhaps you could try to measure that.

https://www.osha.gov/dts/sltc/methods/organic/org037/org037.html

http://nerdytoad.blogspot.com/2015/01/diy-gas-chromatograph.html

Re: Particule detector

Well, that's interesting, but probably out of my reach 🙂

I'm convinced that regarding VOC anyway, I'll have to rely on activated carbon, but want to have proper particulate filtering before that.

Re: Particule detector

I also started working on an enclosure this past week. My goal is to keep the build chamber relatively sealed minus a vent out.

My build cabinet hopefully will cut the noise down and then trap any VOCs and lower the amount of nanoparticles if possible. The cabinet right now consists of 3 Ikea lac tables put together with 3 sides of it sealed with acrylic sheet and acrylic adhesive. The front will have a door with a rubber seal (still waiting on it to show up). The intake air for the build chamber will be any air that gets past the door not forming an airtight seal with the exhaust fan pushing the exhaust fumes through the top of the printer enclosure and through particle filter and then through a carbon charcoal filter.

The easiest method while not optimal would be to build the setup with a car HVAC hepa filter with charcoal impregnated. While not ideal this would help to some degree for sure.