From the Hackerspace Mailing list...
i3Detroit got a Weike 150W and we've had to repair it about a million times. It's a viable option if you have lots of people with both skills *and* inclination to continually keep after such a beast, and we never would've been able to afford anything approaching the same power from a better name. But, seriously, downtime posts may be the single biggest topic on our internal mailing list. You truly get what you pay for.
There's a good bit of braindump on our public list, here: https://groups.google.com/d/msg/i3detroit-public/V2wlRDYeVKA/AipAKnirkM4J
The autofocus mechanism has gone back and forth between busted and repaired several times, we finally gave up and justuse manual focus. The red-dot pointer similarly, but I think it's working again now.
The door lift-cylinders failed, and when we replaced them with a slightly-stiffer model, the pot-metal door hinges shredded soon after. Lots of metal drilling and beefier hardware later, the door is solid again.
The laser-inhibit switch on the door failed and has been replaced. The wiring between the laser and the chiller is embarrassingly bad but hasn't actually failed yet so it hasn't gone under the knife.
The power supply has failed at least twice. Once was the inrush current limiters, which despite the PSU saying it's the 120v model, were clearly sized for the lower current associated with 240v operation. The manufacturer suggested bypassing them, but we elected to replace them with the right parts. Second, the fuseholder itself inside the PSU melted and blew the fuse at the same time (still not sure how that works), but that was a fairly easy repair. I feel like there was another failure I'm forgetting...
The emergency-stop and key switches have both failed, again being rated for 10 or 13A max, but in a 120v country the machine draws 15A continuously for long stretches and things tend to melt. As referenced in the above-linked post, the power wiring inside the machine is all commensurately undersized, and should be overhauled as soon as you're able. Proper new switches are expensive, yo.
The first tube failed "within warranty", but we had to pay shipping on the replacement tube, which made it all but moot. See if you can find a way to write shipping into your purchase agreement. A cheap laser power meter would be great to have for diagnostics but everything I see is megabucks. Knowing when the machine sucks because the 150W tube is putting out 20W of light, versus when it sucks because something's misaligned or dirty, would be awesome.
There were lights installed on the underside of the gantry, which illuminate the piece being cut. They started going out in places and then failed completely. The machine's internals are 24v so we ran two 12v light strips and put them in series...
The vent fan that came with the machine would've been barely-adequate if it were positioned directly against the wall with a 3-foot duct to the outdoors, but as our location is ~60 feet from the outside wall, it was woefully undersized. We blew a bunch of money on a Serious Industrial Blower and a bunch of smoothwall spiral duct, and it's much better. Building a remote-switch rig to allow the blower to be located near the outside but controlled from the operating position was really helpful.
The Leetro controller (and LaserCut software) are notoriously rough around the edges, crashing on weird files, too braindead to import SVG so you have to use DXF or something, and sometimes failing to recognize the cutter until you unplug and replug all the USB everythings 4 or 5 times. A high-quality active USB extension cable helped but only a little; the USB on the controller is suspect.
The air-assist pump hasn't actually failed, but we finally realized it's barely adequate to blow the smoke away from the head, and not contributing meaningfully to actually removing material from the cut. We plumbed the machine into (dry, filtered) shop-air and *it was like doubling the power overnight* -- we can do much thicker cuts in fewer passes, and if the conditions are precisely right, we've been cutting thin sheets of steel. Set aside the included pump as a backup, but put some proper air into the thing, it's amazing.
Also, possibly the weirdest thing: We got two identical machines from Weike at the same time, one purchased by the space, one purchased by an individual member. They were supposed to be identical in all but paint color, but inexplicably the pulleys in one are a different size, requiring the machine settings (steps per millimeter or something) to change if you're going back and forth between the two machines, say because one is down for repair. We still haven't figured out the reason for the build difference.