I actually just gone done cleaning mine. The tabs you see are attached to the top glass, and need to be pried towards the inside of the GF to release from the bottom of the case. *What I did was hook a pair of bent-nosed tweezers behind each tab, and then from the outside insert a spudger-like object through the gap between the top glass and the siding of the machine (anything relatively long and thin will do). Repeat for the other two tabs and the top should pop up easily.
*This could potentially permanently bent or dent the outside of your case
It took me a while to figure out what the tabs were and how to pry them. See if you can get a camera in there and take a photo of the holes. You might be able to get a better idea. You definitely need some sort of small angled tool to grab them and pull them.
As an aside, if your warrantee is up anyhow, you can do what I did and just cut the finger guard off the back of the exhaust fan so I can easily clean the fan from the outside and forego ever opening this up again.
See my post in "First modification to my basic to see the tool I used. By inserting the sharpened edge under the tab and pushing down, the tab is deflected inward while the heel of the tool pushes out on the case.
The case wall is thin and is given rigidity by the top. There won’t be any damage to the case if you are careful.
See my thread “First Modification to my Basic”
I used an auto trim removal tool like the one below. Dodn’t need to pull, just wedge it up between the clip attached to the glass and the retainer on the side of the case, where shown in the 2nd pic.
I did just that. Didn’t know this forum was here at the time. Cut the "finger guard " completely out, too. Woodcrafter’s store sells woodshop dust collector fittings that are easily modified into an external fan casing, and I used Scotchlock splices to extend the fan wiring back to the power pins inside.
Has anyone removed the fan completely / replaced it with an empty fan housing? If so, how much does it cut the noise on a pro unit? I’ve had mine hooked up to an external extractor for a long time, and even with the compact filter toggle on in the software, it still is pretty loud (and high pitched).
I have a BOFA extractor, so really the fan is probably obstructing the air flow more than helping. The question is more of how good removing that fan is for cutting the noise.
I removed both the exhaust fan and the fan grill. I have a booster with a 4" inlet and a 10 " impeller within 2 feet of the machine.
The stock exhaust fan runs @ 13,000 RPM and the booster runs at a fraction of that. The noise reduction is quite dramatic, and the airflow smoother without the obstruction of the fan grill.
My advice is do yourself a favor and lose the stock fan.
Removing the fan is really a dramatic reduction in noise. It went from something that was uncomfortable to be in the same room as, to something you could be on the phone while next to and the other person would probably not notice. This is the noise level they advertised when the funding campaign started, and honestly I think they need to add an option where you order a fan-less glowforge and external filter unit.
Has anyone used a relay to control their external fan? I would like to remove the stock fan and use an external 115vac blower, but I wanted to use the GF’s 12vdc to actuate a relay that would than turn on the blower. I don’t have much experience with PWM, so I’m not sure exactly how that works, but does the GF turn on and off the 12vdc power each time a cut starts?(in which case I can use that to pull in my relay) Or is the 12vdc always on, and the PWM determines when the fan runs?(in which case I cannot use it to run the relay…)
Basically I want my external fan to come on when the cut starts (like the stock), and shut off when it ends (or a little after, once I install a delayed relay circuit).
The 12VDC is on all the time. The PWM output determines the fan speed.
You could use the exhaust fan’s PWM to drive a relay. The PWM output is not capable of driving a relay directly, though. You would need to use something similar to this to treat the PWM* as a logic signal to drive the relay.
*Normally, a PWM wouldn’t necessarily be suitable to use as a simple on/off signal, but Glowforge doesn’t modulate the exhaust fan. They just turn it on full speed, which effectively is a digital on/off output.
So I have a couple of these left-over from a RasPi project I did a while back…
I suppose I could power the 12v relay module off the exhaust fan 12v, set the module to Low trigger and use the GF PWM for the signal “IN”; thereby using the relay load side to control mains voltage to my fan? Again, I’ve never done anything with PWM, so this is new for me… Don’t I have to worry about the PWM pulse causing chatter on the relay? Or is the pulse fast enough that the relay won’t notice? I noticed that the GF exhaust does come on at a slow speed when the machine boots up; would I have to worry about chatter at boot?
I considered putting a simple RC circuit on the PWM “IN” line to smooth any chatter. But again, I don’t know PWM well enough to make an educated guess on the config. A desirable side-effect of the RC circuit on the “IN” could potentially hold up the optocoupler, and by extension keep the relay closed for a period of time after the GF cut finishes, helping exhaust any final smoke/fumes…
I’m going to experiment with one of my relay modules on an old Dell computer with PWM fans and see what I see. If you have any further input, I would welcome it!
This is what the “fine print” on my response was referring to.
Glowforge doesn’t do any speed control for the exhaust fan. They set it to full blast. For the PWM output, this means either 0% (off) or 100% (on) pulse width. You shouldn’t get any chatter.
You would want to set the IN to trigger on HIGH, assuming you want to fire the relay when Glowforge commands the exhaust fan to turn on. The output voltage level on the PWM is only 3.3V, IIRC. That should probably be enough to trigger those devices.
NOTE: Be VERY careful about what you hook up to that PWM line. There is ZERO input protection on ANY of the IO pins on their factory control board. If you accidentally put 12V into the PWM output, you WILL fry the microprocessor (I know this from personal experience).
