Vibration isolation

[martinf1977]

@Martin:
Have you been at the Form1 userforum? The Form1 uses similar galvos, and Formlabs have had a lot of trubble with them. The printers start out printing really high resolution, but degrade after a while... Some users have had their printers replaced 3 times......

Johan

No I havent.... I have to admit that I would be kinda pissed off, if I payed almost 3000Euro for a printer and they used 100euro galvo's as the key component in them.
but I can see myself building a printer along the principles close to the peachy, but with 100 pound galvos - spending a total of 150 to 200 pounds for a printer. and then maybe living with sometimes needing to replace a galvo. For 3000 I would expect a higher quality overall......

Cheers
Martin

[Pete]

These cheap galvos are an interesting quality. I bought some similar to this and the casings and mounts are great but the electronics and feedback leave a lot to be desired. Unlike the peachy homebuilt galvos which are open loop these are closed loop and rely on a PID controller and reasonable feedback. Unfortunately the feedback in the galvos that I received are optical, there are two light sensors, an LED and a piece of glued cardboard on the spindle, the position is apparently sensed by comparison of the two optical sensors and the cardboard baffle moves and changes the proportion. I can't believe that the accuracy of these is actually any better than the stock peachy galvos (although they will be faster but they do burn significant power).
Also if anyone out there does purchase any of these to play with then I strongly urge you to use your own power supply. The questionable quality of the PSU I've received vs the energy you can get from mains is just not worth the risk.

[martinf1977]

<snip> Unfortunately the feedback in the galvos that I received are optical, there are two light sensors, an LED and a piece of glued cardboard on the spindle, the position is apparently sensed by comparison of the two optical sensors and the cardboard baffle moves and changes the proportion. I can't believe that the accuracy of these is actually any better than the stock peachy galvos (although they will be faster but they do burn significant power).<snip>.

Sounds like it's possible (maybe easy even) to improve the optical feedback to the PID and thereby improving these drastically - Getting closed loop servo's on the printer, should (if the sensor works properly) guarantee repeatability of the printer.
Since you have access to these kind of galvo's,(if you still have them) would it be possible for you to take some pictures of this feedback loop? I'm very curious!

Kind regards
Martin