I’ve had my Glowforge for just under two weeks, and now whenever I try to “print” something, the main cavity fills with smoke and it billows out the lid. If I remove the exhaust hose going to my filter, the smoke clears and the Glowforge will not overheat.
Is this normal?
It totally depends on what you’ve been doing.
The filter lasts until it’s full - which depends on what you’re cutting (draftboard will fill it quickly/acrylic hardly makes a mark).
If you leave it running after you finish printing it’ll lengthen its life - as well as you can adjust the speed via the dial from lowest when it first goes in, all the way up to max. If you’ve already done that and it’s at max, then you’ll probably need a new cartridge (which can be found in the store).
A lot of folks on here have had good luck install pre-filters (which are cheaper) because they’ll catch the big stuff that kills the filter quickly.
*Also, double check that your grate/fan inside the Glowforge hasn’t gotten filled with detritus - it’s no longer on when you’re using the filter, but the stuff still flows by it
Have you checked the filter media to see if it is full? What you describe is what would be expected from a “full” filter.
Edit - if you are engraving a lot of MDF/draftboard type of material, it can only last 20-30hrs by what has been reported here.
~10 hours??? That’s terrible! Of course, when you send out a new Glowforge, you send 5 sheets of Draftboard, so of course, that’s what I used to get up to speed. Now that I’ve just started printing for customer orders, my filter needs to be replaced?
I always leave the filter running after printing, for as long as I print. 1 hour print? Filter is on for an hour after the print.
When I first got my filter, the lowest speed did NOTHING, I had to turn it halfway up for it to actually work. According to the Forum, this is normal.
I’ve ensured that there is nothing in the grate, fan, hose, or anywhere else.
$1000 for a Compact Filter unit that needs a new filter every 2 weeks with regular work hour use?
The Glowforge team did do some early testing to determine how long the filter cartridge will last before needing to be replaced for various materials. Those results are here in the FAQ section on the main Glowforge site:
Estimated Lifespan of the Filter Cartridge
Hopefully, that will help to identify what to avoid with the next one. 
It would be more helpful if it included the Proofgrade Draftboard that is sent out with new units. I am very dissatisfied in this filtration unit.
Per the image you just posted:
The draftboard that is sent with your shipment is for testing the machine, and running the camera calibration - if you have an issue in the future staff will ask you to use it to test it again then.
It’s the same for all filters…Glowforge has never hidden it.
But…I do agree that that can definitely be easy to miss. It’s not something that new users are expected to know if they’ve never used a filter. Unfortunately, there’s no other way for people to find out about it if they don’t read about it on the forum, or do outside research of their own. It’s just physics. The small pores from a filter designed to screen out smells can get clogged, and when they do, they stop working. Some materials are worse than others, and MDF happens to be one of the worst. It’s full of glue holding the paper pulp together. Melt that with a laser and it gets sticky. (There are others, including some hardwoods and softwoods that are just as bad in my mind, but Glowforge will only talk about their proofgrade materials here.)
Things to avoid are anything with a lot of resin in it (padauk, pine, cedar, some oak) because it’s going to throw up sticky smoke, that will narrow the size of the pores, and then particles are going to further clog them. Excellent candidates are stone, paper, metals, dry hardwoods, acrylic and leather. You can try out a prefilter to catch some of the excess particles, but those will need to be changed more frequently.
I’d just dodge the draftboard with the next one and it will last a lot longer for you. Short of that though, there isn’t really a good way to say how long exactly a filter will last…it just depends too much on what is being burned in the machine.
(Sorry, I just don’t know that anyone has those answers.) 
The most economical answer by far is to vent outside if there is any way to swing it. I have mine set up with a quick connect so I can switch to venting outside when cutting draftboard, and save the filter for the stinky stuff like leather and acrylic.
@Jules, I do really appreciate your answers. They are thoughtful and insightful. Yes, I recognize that my post and response are emotionally charged, but I think it’s easy to see why. I’ll likely set up the same venting system that you have, but I’ll re-visit the anger whenever I have to switch them out.
That’s the thing, though. I DID research it. It took me over six months to decide if the filter was worth the investment. The inconclusive data size shows that I was too quick to pull the trigger.
I also understand that they called out their Proofgrade Draftboard @deirdrebeth, mine was a comment on how there was no entry for it in the testing matrix.
I was also hoping for Glowforge to chime in.
They eventually will. 
If you want an idea, take the medium plywood listing and reduce it even further. The medium plywood uses a draftboard core.
For your future reference, Baltic birch plywood is relatively inexpensive and I don’t think it is as hard on filters. Also good old cardboard. These are what I use when prototyping.
Missed this the first time around…may I strongly recommend the Rockler Quick-Connect system that I’m using to switch…it’s a tremendous time saver, and you won’t have time to be even a little bit mad about it.
Give me a second to find the link to it…someone was asking a while back…
Here’s the pictures of how I have it set up…just search the 4" Dust Right Quick Connect system on their site. The hose is about a million times better than the little aluminum ones. It will hold up forever.
It’s not very expensive, either! Thanks for this.
I appreciate the feedback regarding the visibility of the recommendation against using Proofgrade Draftboard with the filter. I’ve shared it with the team.
Regarding the smoke
When your Glowforge and Compact Filter are properly set up, you may have some harmless odor during printing which will rapidly dissipate. You may also smell something when you open the Glowforge lid after a print is complete. This is not harmful.
However, if you notice a strong, unpleasant or irritating odor when printing, or see smoke, shut off your Glowforge unit immediately. Smoke and fumes could be entering the room in excessive concentrations.
It looks like you’ve already narrowed the issue down, but for the sake of completeness, you may want to verify everything in our troubleshooting guide with illustrations. You can see it here: https://glowforge.com/support/topic/troubleshooting/print#excessive-smoke-or-fumes-during-print
If the filter does seem to be the culprit, would you mind sending over a photo of the top of the filter cartridge?
Turn off and unplug your Compact Filter
The power switch is located on the back, next to the cord. Turn it off first, then unplug it from the wall.
Open Compact Filter
There are four latches holding the top of the Compact Filter in place. Lift the bottom of all four latches to release them.
Take a picture
Without removing it, take a picture of the top of the cartridge seated in the Compact Filter and send it in to us. (You can either post it here, or email it to us at support@glowforge.com.)
In perusing their site, I decided I could put together the pieces in the picture so that I NEVER have to move the hose. Just open the Blast Gate as needed.
Thank you for the quick follow up. I’ve looked at your photo and confirmed that the decreased airflow to your Compact Filter is due to the filter cartridge filling up.
We have tested the Compact Filter with our entire line of Proofgrade materials, and found that they are all compatible with the exception of Draftboard (MDF). While many Non-Proofgrade materials are laser compatible, they may impact the lifespan of your cartridge. Unfortunately, we can’t offer specific advice on particular materials provided by other vendors. You can read more about our material recommendations in the Compact Filter manual.
You can purchase a replacement cartridge from our Shop. They are $249, with free shipping. (As already mentioned on this thread, and it sounds like you’re already doing: ) When printing with a new filter cartridge, we recommend running air through your Compact Filter for as long as you print lasted. This will help lengthen the life of your filter.
I’m going to close this thread - if the problem reoccurs, go ahead and post a new topic. Thanks for letting us know about this, and thanks again for the feedback.
