❓Should you remove the factory fan from your laser engraver when using an inline fan?

[@TheLouisianaHobbyGuy]

Please remember, The point of the video was to prove that removing the box fan makes the inline fan more efficient. *This was not scientific testing!*

[@armastat]

Great. this is a question I had, thanks for the work finding out. Now my next question is ... 'Can I mount my laser bed to the wall'? this would be a great space saver since it would take up zero floor space this way, and I have tons of wall space available. (Yes seriously) I only plan on doing thin woods and plastic < 5mm in small 12"x12" blanks. and magnetic holders should keep it flat to the bed even if vertical. and each part will be bridged so should not fall out. (can do slightly not vertical if thats a good idea.) but my real concern is the motors, would they be unacceptable effects by having to move the Y axis up and down instead of flat to gravity.

[@refurbandbuild9492]

Rick, Youre almost there. I'm a ventilation engineer from the UK, we measure in M3/s which is an easy conversion to CFM. What you have shown is air speed thru an opening at the point of measurement. To calculate how much air to remove from a laser cutter I would do the following formula. Measure the cubic area of your enclosure (Say 800mm X 800mm X 500mm 0.32cubic meters). Now decide how many times you would like to replace the air in that enclosure in say 1 hour. So if engraving a piece and it will take an hour then it may be a good idea to change that air say every 6 mins or 10 times an hour. (0.32X10=3.2) So far we now know that we need a fan capable of moving 3.2m3/s of air to move thru the enclosure in 1 hour. Now we need to know the size of the duct for the air to travel thru. This can get complicated due to resistance (Pa) bends, flexibility, and other factors but your audience shouldnt worry too much as a standard 4 or 6" duct is sufficent for these amounts of airflow. So the calculation is "Cubic Meters of your enclosure X the number of air changes required will give the duty of the fan required. For most home/hobby lasers an airflow of circa 200/300cfm thru an opening of either 4 or 6 duct will be sufficent to change the air enough times to prevent smoke in the enclosure. Air speed has no bearing on the outcome. Hope this helps.

Thanks for your explanation. "a fan capable of moving 3.2m3/s [3.2 cubic metres/second] of air to move thru the enclosure in 1 hour" [so 3.2m3/s x 60 x 60 = 11 520m3] ?? What am I getting wrong here? Also, for the enclosure, should there be an inlet opening to allow for clean air to enter at the same rate that it is being expelled? I have a 360m3/hr exhaust fan installed on my 0.33m3 enclosure, with a 150mm duct attached, no inlet opening, yet. I raised the lid slightly to allow fresh air to enter.

[@TheLouisianaHobbyGuy]

The point of this video was to prove the obvious point that some argue, that removing the box fan makes the inline fan more efficient.

@@TheLouisianaHobbyGuy Hi Rich. Apologies. I was not trying to be a wiseguy or demean your good work. My query was intended for the Ventilation Engineer from the UK. Please accept my apologies and keep up the excellent videos.

[@TheLouisianaHobbyGuy]

I know that, no apology necessary! 👍

[@refurbandbuild9492]

Thats 320l/s not 3.2m3/s. Hope this helps

[@Sergiodj453]

As an HVAC technician who deals a lot with airflow this is a no-brainer, thanks Rich!

[@TheLouisianaHobbyGuy]

You bet Sergio, thanks for watching!

[@larrystaas1940]

I added a six inch wood riser with bottom under my MK2 30watt, took out the bottom plate of the laser, removed the factory fan and made a 3mm plywood inlet cover for the opening to allow free air in. I added a six inch outlet to the bottom of the wood riser and connected it to a Vevor six inch duct fan. Needless to say I no longer see any smoke and my cleaning program is great. Thanks for the information you put out to the rest of us.

[@TheLouisianaHobbyGuy]

Sounds like an awesome mod Larry!

[@MileyonDisney]

Thank you for the test and comparison. This should solve the fan issue once and for all.

[@TheLouisianaHobbyGuy]

I'll bet money it won't! 🤪 Folks today will argue until they're blue in the face to prove their point, even if it's wrong...

[@MarioBX1405]

I have a 208cfm in line fan and my laser on a grow tent (only option right now}, but open the other fan hole in the tent. That creates negative pressure in the box and you see zero smoke when cutting, lens stays super clean and helps with venting outside where the pressure is higher than indoors. Awesome video Rich, as always!

[@TheLouisianaHobbyGuy]

Great tip Mario!

[@Sevcav1]

That's about as good as it gets! Also, I find its so much easier cleaning an inline fan, since you can open the shroud to get to it, whereas the factory lasers sometimes are buried behind safety screens. Thanks Rich for the demo!

[@TheLouisianaHobbyGuy]

Great point! Thank you! 👍

[@Andy.H.H.]

Thanks for this video Rich. I had thought the airflow would be greater with the factory fan removed but, now I know for sure. I've also added a vent filter to the inside of the enclosure (at the exhaust port) in the hopes of keeping my inline fan a bit cleaner.

[@TheLouisianaHobbyGuy]

Good idea Andy! I take off the hose and rinse it with the garden hose every 6 mos. The housing on my inline fan comes off easy, so a quick cleaning with a paint brush does the trick.

[@Warped1369]

If the in-line fan was in the hose (and not running) when you did the "factory fan only" reading, it would be a restriction against the flow of the factory fan. If you tested the "factory fan only" with the in-line fan removed, and with a shorter overall hose length, that would show that it was even less effective than what you got. The testing should be done with the same length of hose for all tests to give the most accurate results. At any rate, I think the end result is pretty clear. Thanks for putting in the time and effort. The next step would be to show the different amounts of smoke clearing within the enclosure, doing the same tests, while cutting some wood that generates a lot of smoke. Although, I'm pretty sure it would work out showing a similar efficiency benefit in favor of removing the factory fan, and replacing it with the in-line fan.

[@TheLouisianaHobbyGuy]

🤪 I said it wasn't scientific. The point of the video was to prove that removing the box fan makes the inline fan more efficient.

[@norm5785]

Thank you for sharing your test results with us. I have an open frame falcon2 22w. I simply use a floor fan mounted in a window about 2 feet to the right.

[@TheLouisianaHobbyGuy]

Awesome! 👍 Thanks for watching!

[@pyracantha6028]

I've just got the omtech polar 350 and it had a built in fan but it also comes with a big external fan. The inside fan is load so I know a lot of owners have removed the build on fan and just use the external, note to reduce noise though I believe

[@TheLouisianaHobbyGuy]

I have the Gweike Cloud 50 from the manufacturer of the Polar, and removing the fan made a huge difference for me.

[@merrillalbury8214]

Bend of exhause hose and irregular shape of exhaust hose also effects the exhaust capability.

[@TheLouisianaHobbyGuy]

Yes it does, so does the accordion hose vs straight pipe!

[@gerGoPrint3D]

I am considering keeping the internal fan installed, just because sometimes I forget to turn on the inline fan at the start of a cutting job. Using your numbers, having a 2.9 as opposed to 0 has potentially more benefit for these cases compared to gaining from 3.5 to 4.6. If Lightburn let us automatically call a webhook at the beginning and end of jobs, hence giving us the ablity to trigger a smartswitch connected to the inline fan would have me remove the internal fan immediatelly.

[@TheLouisianaHobbyGuy]

I would remove it. If your laser control board has M7 terminals, you could hook up a power relay to turn on any 110 or 220V accessory in Lightburn at the start of a job using the M7 command using the start and end Gcode. See this video, I linked it to the time stamp: kzbin.info/www/bejne/naG0eqGggM6XeZosi=CnGRbARSZReJMHPv&t=650

[@gerGoPrint3D]

@@TheLouisianaHobbyGuy Thanks Rich. This is a Ruida printer (Monport Onyx R - I've just reviewed it on my YT channel).

[@TheLouisianaHobbyGuy]

I saw it... good review.

[@IanElliott-gy4gj]

Rich another great informative video. You could improve all readings by having the extraction in the side panel. This would eliminate the 90* bend in your hose, any bends in the pipes/hoses of all extraction system slows the air flow. Also you had the lid open this would allow unrestricted air flow into the laser bed, with the lid down you mainly get air in via the passthrough and the small gaps between the lid and the casing. Saying all that, I use the factory fan on my LaserMatic Mk2 straight out the window (no bends) behind my machine which I find adequate for my usage. Cheers Ian

[@TheLouisianaHobbyGuy]

Yes Ian, and using a metal exhaust pipe with no flex ridges would help as well. Open or closed, the variances are going to be the same. This was not scientific.

[@pblais404]

Just a side point. I can tell you probably don't have a motorcycle or you would not be asking for philips head screws that the heads are always stripping in lieu of the more dependable allen head screws. Keep up the good work RIch.... cheers Pierre

[@TheLouisianaHobbyGuy]

Actually, I've been riding my entire life! Had a motorcycle shop for 8 years. If you have the right size Phillips for the screw you're removing, it works every time. We can agree to disagree! 👍

[@beverlybenham3458]

Thanks for the demo! Would you mind sharing what kind of in-line fan you are using?

[@TheLouisianaHobbyGuy]

amzn.to/4e2NYjD

[@cheekyoscar1353]

The answer would've been obvious .. Obviously the external fan "if it's bigger suction fan " . that's going to suck more air providing is not being restricted at the beginning or throughout .. 👍👍

[@TheLouisianaHobbyGuy]

Yep, that's what I said in the beginning, but some folks argue the fact that you need to remove the box fan.

[@cheekyoscar1353]

yes you certainly did . My comment is not against you my friend ... maybe I should've worded it a bit different . 👍

[@TheLouisianaHobbyGuy]

No, it was fine, I got it! 👍

[@shadowfox929]

Have you ever removed an exhaust fan from an Xtool s1? I have a 4" inline fan already but I would like to remove the stock fan but can't find any information on how to go about it.

[@TheLouisianaHobbyGuy]

No, I have not, sorry.

[@BusterBeagle3D]

Good stuff Rich! I've always been curious about this and if it was hurting or helping to keep the fan in there. I was wondering if keeping the fan was hurting because like you said it starts spinning just from the sucking of the inline fan but wasn't sure. I also wonder if the type of fan makes a difference as well as I have seen some much stronger then others but I guess it might be on a case by case basis but my inline is so powerful I'm guessing it's mostly a hindrance.

[@TheLouisianaHobbyGuy]

The test would be to hook up the inline fan and turn on the laser. Listen to the sound of the box fan and then power on the inline fan. If you hear the box fan pitch (sound) raise and spin past it's normal RPMs, overdriven by the inline fan, I would remove the box fan.

[@VinnysProjects]

One measurement I'd like to have seen was the inline fan with the factory fan but the factory fan disconnected from power so it would spin freely from the air movement of the inline fan.

[@TheLouisianaHobbyGuy]

I think you saw that since the inline fan forced the box fan beyond its ability on power.

[@VinnysProjects]

@@TheLouisianaHobbyGuy I was under the impression the internal fan was still under power.

[@rickgibson7876]

I'd like to see the same test measuring aft the outlet of the hose. With the factory fan the way you tested it part of the anemometer is blocked whichcould give false results.

[@TheLouisianaHobbyGuy]

I know Rick, everyone wants to see it done a different way, but the point of the video was to prove that removing the box fan makes the inline fan more efficient. This was not scientific testing as I said in the intro.

[@rickgibson7876]

@@TheLouisianaHobbyGuy I believe it will work better, was just a thought. Got another 6 months for my warranty to expire then the supplied fan is coming out.

[@TheLouisianaHobbyGuy]

You won't void the warranty by removing the fan Rick.

[@rickgibson7876]

@@TheLouisianaHobbyGuy Maybe not but then I would never trust a company on the other side of the world to not use any excuse to avoid replacing it.

[@TheLouisianaHobbyGuy]

Join their Facebook group and you'll learn to trust them. The support from the company is unapparelled. They support their machines no matter what the issue! BTW, the owner is from Canada, and the tech on duty in the FB group is from the USA: facebook.com/groups/rolyofficial

[@jimbalz3017]

I'm looking to buy a laser tool. I have no experience. Where does the other end of the exhaust dust go? Outside, or too some sort of filter box? Thank you.

[@TheLouisianaHobbyGuy]

Either way Jim, you can use a dryer vent or a fume extractor.

[@jimbalz3017]

@@TheLouisianaHobbyGuy I googled fume extractors. The costs are all over place. What do you need for a laser tool? Thanks again!

[@TheLouisianaHobbyGuy]

None of the cheaper ones really work well. For one that actually works indoors with no odors, you're looking in the $2K price range.

[@ricknutz1025]

What I'm trying to determine is will it benifit me to replace the stock with a 4 inch fan i have sitting around that has a cfm of 190.

[@TheLouisianaHobbyGuy]

If it's a LaserMATIC, marginally. Maybe around 20% or so IMO.

[@a6etram462]

I watched your short on 3D printing a custom exhaust port for the Roly. Can you pass on/sell the file? Thanks

[@TheLouisianaHobbyGuy]

I got the free file in the Roly Automation Facebook group: facebook.com/groups/rolyofficial

[@Secretlaserman]

Hows the fan on the Roly XW? I have to run about 20ft. I am leaning to get a new inline. Any suggestions?

[@TheLouisianaHobbyGuy]

20' is a long way. Check my Amazon store in the description Lucas for recommended inline fans.

[@hiramabiff4035]

Does anyone know the cure to get a cheap diode laser to burn the same amount in X axis as Y ? Y always cuts/burns better than Y axis, probably due to Dot shape. thanks !

[@TheLouisianaHobbyGuy]

There is no real cure since the diode is a rectangle. The X will always burn deeper than the Y. Run a material test to get the right setting where they both cut through and use that speed and power to cut.

[@hiramabiff4035]

@@TheLouisianaHobbyGuy Thanks for the reply, I was wondering if there was a setting to under-speed X axis or something. Anyways, I'm a noob and ans having fun watching your vids, and playing with LB. Thanks again ! God bless.

[@ricknutz1025]

Does it say somewhere with the lasermatic fan what the CFM is? I have an inline fan with a CFM of 195 sitting on the shelf and wondering if its worth swapping to the inline with 195 CFM or if I need to get another with a bigger CFM? Thanks Rich

[@TheLouisianaHobbyGuy]

No Rick, box fans are rated in RPM. My inline fan is 220 CFM, so that might give you an idea.

[@burtgraham3689]

Rich I have an A20Pro - Im looking for an enclosure for it. Do you have any recommendations. The only enclosure I dont want is the portable ones. I need something sturdy. Any help you can give me is greatly appreciated Burt

[@TheLouisianaHobbyGuy]

Most folks make the enclosure themselves for the A20 Burt. I don't know of any I can recommend, sorry.

[@merrillalbury8214]

Maybe I missed it, but do you have a link for the in line exhaust fan? Best I can find on Amazon is 230 cfm for 4 inch and 469 cfm for 6 in.

[@TheLouisianaHobbyGuy]

amzn.to/4e2NYjD

[@donspoor8367]

What inline fan do you have? How many CFM's is it rated for?

[@TheLouisianaHobbyGuy]

amzn.to/4e2NYjD 402 CFM.

[@carolyntaylor6020]

Will removing the factory fan void my warranty? I've only had my Omtech Polar for a month.

[@TheLouisianaHobbyGuy]

I don't know Carolyn, that would be a question to ask OMTech.

[@LahirAli]

Hi Rich, first off thanks for the wealth of knowledge I binge watched your college lightburn course and I learned a bunch as I just got my laser today. I was wondering if you knew the solution to an issue I’m having with my lasermatic mk2 20w, whenever I home the machine it gives me the Alarm 8 error. I followed along while you went through the settings for your heart project video and I went through your forums to see if there was answer there. I saw one post where you mentioned that the Y axis had to be reduced (?) to compensate for the larger laser but I don’t by what value or how. Either way thanks again for the wealth of knowledge!

[@TheLouisianaHobbyGuy]

It's likely the laser is on a limit switch in a corner. Move it by hand away from the corner and then hit home.

[@Jerry-Mesa]

While this is an interesting test, the lid was open. The real results of interest to me would be with the lid closed as the I think the exhaust is dependent on air availability for the fan to draw from which is unrestricted in this method is restricted with lid closed. Maybe similar results but maybe not as big a difference.

[@TheLouisianaHobbyGuy]

The point of the video was to prove that removing the box fan makes the inline fan more efficient. Lid open or closed makes no difference for this test.

[@Jerry-Mesa]

I know the purpose of the test but I believe the delta advantage would be less with the lid closed. My opinion.

[@TheLouisianaHobbyGuy]

Not by much Jerry. The LaserMATIC has two 24" x 1" passthroughs, front an back, so there is adequate air in. The RPMs of the box fan alone doesn't change when you close the cover. Now with just the inline fan, it's the same. No motor sound difference with the cover open or closed.

[@TheLouisianaHobbyGuy]

As a non-scientific test and observation, using just the inline fan keeps the enclosure much more free from smoke and smell. There is plenty of air in on this machine with the two passthroughs.

[@Jerry-Mesa]

@@TheLouisianaHobbyGuy Thank you, I’m still ‘laboring’ with a Mark1 with just the handle opening which was my perspective. Have a great day.

[@Essentialvideophoto]

Thank you Sir. We all know now where is the truth!! Awesome.

[@TheLouisianaHobbyGuy]

Thank you Sir!

[@armastat]

Yes what u did WAS scientific (the engineer's version of science) and perfectly acceptable. Ignore the Negative Nancys. To math it out all you need to do is multiply the meters per second with the cross section of the fan to get the Volume of air moved. 4" fan is just over 1 sq ft.. 1 meter is Approx 3.3 feet so each mps speed comes to abt 4 cu ft of air so CFM (cu ft / min) is abt 240 cfm. the actual value with smoke and particulates will be lower since that air is more dense than 'clean' air. even lower when cold or high moisture. This normally wont have an effect on a exhaust system except in the case of weak under powered fans (sch as the computer style case fans).Back pressure from a slight wind can bring those to a stop, lol.

[@TheLouisianaHobbyGuy]

I appreciate that, *thanks!*

[@Bespokelasers]

4.87 M/s = 334.64cfm

[@TheLouisianaHobbyGuy]

Well my inline fan is 402 CFM, so that sounds right, thanks!

[@jsidva]

The correct answer is simply NO, do not remove the factory fan. Even if it isn't powered on, it still provides additional airflow as a passive fan. If you power it on along with your inline fan, even better. That is why we use both active and passive fans in hvac systems. The most likely culprit to create a challenge is insufficient air inlet into the cabinet. Continue to provide expert advice on lasers, and other areas where you have expertise.

[@TheLouisianaHobbyGuy]

I'll agree to disagree! 👍 The LaserMATIC has enough air in to accommodate the air out with the double 24" x 1" passthroughs. Considering the inline fan spins up the box fan passed it rated RPMs when turned on, I don't know anyone who would consider it anything but a restriction, certainly not a passive fan!

[@VeeSwan]

Thank you for doing this little test Rich!

[@TheLouisianaHobbyGuy]

My pleasure Vee! Thanks for watching!