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Air assist

edited June 2015 in Mods / R&D
I was thinking of changing the laser head to accept air assist. I suppose the fan is providing this somewhat. Has anyone tried this or evaluated if it would improve the cutting depth? The way the fan is mounted provides cooling to the laser and blows the smoke out of the printed nozzle. Was a larger fan or squirrel cage blower tried?

Kipp

Comments

  • We did not experiment with air assisted cutting. The fans we use have been tested to provide enough cooling to keep the laser diode happy so whatever you change, please keep this in mind. We are also very consc

    An approach would probably be to introduce the air in through the laser guard.
  • edited May 2015
    I'm thinking of replacing the fan with something MUCH bigger to get a lot of airflow to keep the material cooler and remove crud from the beam.

    How much current can I safely pull from the fan plug?

    Thinking of using http://www.amazon.com/Brushless-Cooling-HT-07530D12-75x75x30mm-Computer/dp/B00B2ARV22

    I probably want to put a high/low switch so I can keep it from blowing stuff like paper around when I don't need the extra air.
  • Look at this Air Assist that was 3D printed in post #925. If someone has a 3D printer, they could get creative and add something like it to there EmBlaser.

    http://hobbycncart.com/forum/63-151-47
  • Gabe,
    I am checking with our engineer on what the current limitations on this fan are.
    I would recommend holding off any experimentation until I have this information as there will be specific limitations with respect to the mainboard and also the FFC capacity.
  • 300mA is a safe level of current to draw through the fan connector on the laser head.

    Any more than that and you would have to supply external power to the fan you plan to use.

    Also, please keep in mind that a great deal of design went into reducing the weight of the laser head and removing as much hinderance to its movement as possible. Adding bulky items to this area could affect the accuracy of the machine due to flexing or inertia.

    Please keep us updated on your experiments / progress.
  • Thanks for the info.

    I'll see what I can source that is as light as possible and run my own power... Maybe run a tube to the head and put a compressor on it.
  • edited May 2015
    Found three ways that might make sense:

    1. 40mm fan from 1U server

    2. 3D print 40mm hose connector and connect it to an external fan/compressor

    3. 3D print 40mm to 80mm adapter and use a big 80mm fan

    All of these require an external power source.

    I'm going to try the 3D print 40mm to 80mm adapter and an extra 80mm fan I have today.
  • So... I can confirm the setup I created does not do anything noticeable. Possibly the adapter I printed was too short and created too much turbulence.

    Don't bother copying this
    image
    image
  • Tried a longer adapter(made from a plastic bottle and tape).

    This one seems to be even worse! I used a little piece of paper to tell how much airflow there was at the laser head end... and turning on the 80mm fan DROPPED the airflow.
    image
    drinkFan.jpg 78.8K
  • Gabe,

    Have you ever been accused of being a mad scientist??

    Before you dismantle everything, have you tried to reverse both fans?

    If you try this you will need to be very careful with the fan on the laser. The 4 screws holding it in place can be easily screwed in too far. Just take your time and you will feel the tension when they have gone far enough.

    If you do get a chance to test this, let us know your findings.

  • bwa ha ha ha!

    Reversing the airflow would pull smoke towards the laser lens... which seems like a bad idea(or do you mean something else)

    I did make sure both fans were pointing the same direction and I also tried removing the original 40mm fan and just using the short yellow adapter, but that seemed to give about the same airflow as the 40mm fan by itself.

    I'm planning on ordering a 40mm server fan and try that
  • We have been discussing a possible design to the laser guard that would allow air to be drawn upwards and not towards the lens. This is just theory at the moment.

    It was just interesting to see how your setup behaved in that reverse mode.
  • Pulling the smoke away would be neat! I'd love to try a design like that.

    The print volume on my printer(Micro 3D) isn't big, but I can print these two max sizes:

    • 91mm x 84mm and 180mm tall

    • 109mm x 113mm and 74mm tall

    Since I live in Manhattan, I can also just send models to Staples for larger/higher-quality stuff. Staples has been putting 3D printers in more and more of their stores.
  • What are the specs of the supplied fan?
  • edited May 2015
    The default fan is
    • SD4010S12M
    • 12V 0.09amp
    • under 10CFM?
    • High Static Pressure
    From the angle of the blades and the power I'm guessing the default fan has a fairly high static pressure and under 10CFM flow.

    I'm going to be trying this beast of a fan out tomorrow:
    • 9CRA0412P5J03
    • 12VDC, 1.4amp
    • 31.8CFM
    • High Static Pressure
    image
  • The specs for the 40mm fan on the laser head are:
    CFM 7.7
    RPM 5000
    Current 0.09A
  • edited May 2015
    Darn! this thing puts out a TON of air!

    This new fan literally blows the default fan away... I had the original fan under the laser head the first time I turned the new fan on and it literally blew the old fan off to the side...

    Now need to buy a fan speed controller :-)
  • Which model fan are you testing with?

    We have just obtained the following for testing from Digikey:

    259-1547-ND (40mmx40mmx10mm 9CFM)
    P14674-ND (40mmx40mmx20mm 11cfm)
    603-1514-ND (45mmx45mmx15mm 14cfm)

    Pushing too much air through could cause buffeting and affect the accuracy of the laser. Ideally you need good airflow over the heatsink, and a very concentrated flow right at the point of cutting. Difficult to achieve with one fan.
  • edited May 2015
    I'm using 9CRA0412P5J03 (12VDC, 1.4amp, 31.8CFM).

    It's actually 2 fans in a sleeve and both fans are individually controllable via PWM. Just turning on one fan still buffets 3mm balsa around.

    The RPM is adjustable from 2250RPM to 15800RPM with PWM. I'll whip up an Arduino setup to control this with... but I just ended a large project at my real job today and I'm going to bed now.
  • What about using one of these fans? It falls in the amp spec. Darkly Labs specified that can be powered through the fan connector.

    CFM 15.79
    RPM 9500
    Current 240ma

    http://www.amazon.com/gp/product/B005IH0WUI/ref=od_aui_detailpages00?ie=UTF8&psc=1

    Here is the data sheet for it.

    http://download.siliconexpert.com/pdfs/2011/5/29/3/7/15/875/del_/manual/ffb40x40x28mm.pdf

    I have one here and it's not too heavy. The data sheet says 160ma, but the one I have with the same FFB0412VHN part number says .24a on it.

    I may go ahead and try it out on my EmBLaser to blow more of the smoke away.
  • I have control of the 9CRA0412P5J03.

    At ~3% duty it seems to be comparable to the default fan... I'll probably never want to turn it all the way up, but nice to have extra power when cutting thicker wood. The specs say to drive it with a 25Khz signal, but using 31.250Khz from an Arduino works well. I just tied both fans to the same PWM signal.

    Hopefully actually get to try cutting with it tomorrow...
  • Nothing huge to report,

    The extra airflow does seem to help cutting... slightly. e.g. I can reliably cut through balsa at 250mm/sec with the new fan that would take 300mm/sec with the original.

    I'm guessing it will help with image engraving by keeping the laser temp more level(and thus it's light output more consistent).

    Anything anyone wants me to try?
    image
    newFan.jpg 33.2K
  • edited June 2015
    My results have gotten much more consistent since I added the big ass fan; I don't know if all that extra airflow or me getting to know the machine better.

    Regardless, keeping the diode cool and removing debris works well with 9CRA0412P5J03...

    I'm planning on wiring it permanently with four speeds on a knob
    1. PWM line connected to ground - lowest speed, comparable to stock fan
    2. PWM line at 30% - still fairly quiet, and considerably more air than stock fan
    3. PWM line at 60% - a TON of airflow and not too loud. This is where I've been running it.
    4. PWM line connected to 5V - 100% speed, LOUD and too much airflow for many situations!
    I'm planning on using a REALLY bare-bones Arduino to generate the PWM signals.
  • Great info Gabe.

    I think we can officially refer to this upgrade as the 'BAF', Big-Ass-Fan.

    We are still planning to test a number of different fan options and will post those results once completed. It's not at the same scale as the BAF, maybe more like STABAF (smaller than a big ass fan).

    If there is better heat stabilisation within the laser diode temperature then this will definitely offer slightly better performance.
  • Further to the post above:
    @DarklyLabs Have you done any further testing and do you have results to publish?

    John
  • We are testing this at the moment.

    There are definite benefits to using air-assist with the Emblaser. Primarily the increase in cutting ability with the limited laser power we have.

    It would be possible for someone with reasonable machining and electronic skills to implement an air-assist system to their machine, but we are looking at a solution that will be plug-and-play for existing customers.

    Apart from the air-assist system itself, there are a few issues that we need to work through to make it easily attachable to the Emblaser. For one, this involves the connection of the nozzle to the existing laser unit and how this affects cooling, accuracy and focusing.

    There is also the sourcing of a suitably small, quiet and affordable compressor / pump for the system.

    We will start a new discussion topic shortly with how our development has been going.

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