Newbie

[jimsander]

Looking at a Rostock for my first 3D printer, primarily because of the large build volume and non-moving work surface. So I've been lurking here a while. Hi! Couple/few questions...

1) Acrylic... Up until maybe a week ago there was an acrylic version available (for additional money) - no more? Is that temporary? Was there a "bad" reason those parts are not available any more, or just a practicality / marketing decision? Related: It's my understanding that acrylic (apart from looking über-cool) will be stiffer than wood, and less prone to dimensional changes due to environment so it'd be more reliably accurate. Is that correct theory? How about in practice?

2) Noise... I've listened to the YouTube videos, but can't get a feel for how loud the printer really is. Has anyone measured SPL? If not, maybe just a subjective comparison - "have to raise voice slightly to be heard over the whirring" or something louder? How much of the noise is transferred through the base vs. free-air?

3) Dual extruder... Does the dual head unit reduce the effective build volume any? Seems that unless the single head unit is actually capable of moving outside the work surface, both heads couldn't reach all areas - so any support structures would have to be planned accordingly.

4) Variable resolution... due to "leverage" (OK, simplification there) the printer has greater resolution potential at the platform's edges than in the middle. Right? Does that mean (small) pieces can/should be started "off center" to achieve maximal detail, or is the practical difference between edge and center resolution not important?

Thanks all!

[Polygonhell]

I have no idea why they've stopped doing acrylic, but I didn't go for it given the option because the issue is it's ridiculously easy to crack given almost any stress. It the slots are too tight, or an end used over tightens some thing it will crack. Looks cool, but it's a pain to assemble anything structural out of it without damaging it.

On noise, mine is loud as printers go, some of that is the coupling of the steppers to the base, and it acting as a big resonator. I often work in the room with it running, it's not that loud, but my GF hates the noise.

On the variable resolution, someone on one of the google groups did some math, it's accurate to about 0.8 of a step, a conventional printer is closer to 0.5 of a step in pracice that's irrelevant.

[Bill Havins]

Jim,

Acrylic cracks when stressed. Tighten a screw just a tad too much and..."crack!" And the cracks can continue to grow (depending on where they are). I don't know that this is the reason the acrylic versions are not for sale right now, but I would never have one.

Regarding noise. I've been pleasantly surprised that my Rostock MAX does not make what I would consider a lot of noise. I tend to listen to NPR radio as I work and I don't have to turn the volume of the radio up much at all. My printer is in the next room from our bedroom; if I shut the door my wife doesn't notice the printer as she goes to bed. The noise level is nothing like what you get from an industrial CNC machine. I guess the noise level is just slightly above that of a quieter copy machine with a sheet feeder.

Dual extruder - I have the kit but it's not supported yet. When the software for it is available the build volume will be reduced unless a larger build platform and longer carriage arms are installed. But then other problems will likely arise; plan on a smaller build volume if you eventually go dual extruder.

As Polygonhell indicated the issue of resolution at the edge versus in the center is likely a non-issue. Tonight I printed the "socket" depicted below. It measures less than 13mm long X 10mm wide X 8mm high. I have had these sockets printed by a professional prototyping company in the past. The one I printed in the middle of my build area works just fine. I printed it in .1mm layers.

The socket on the left in the above photo was printed by the prototyping company. My print is on the right (the white one).

Good luck!

Bill

[rs50pilot]

I don't think I could sleep in the same room while it's printing but it's really not that loud and I'm a lite sleeper. I don't have the plastic skirt that goes around the base on it but that my help quiet it down.

[jesse]

I found a couple possible ways to make the motors quieter.

http://www.ebay.com/itm/reprap-bfb-make ... 5654b9403c

http://www.ebay.com/itm/Stepper-Motor-N ... 416061f1ee

[madpenguin0515]

I found a couple possible ways to make the motors quieter.

http://www.ebay.com/itm/reprap-bfb-make ... 5654b9403c

http://www.ebay.com/itm/Stepper-Motor-N ... 416061f1ee

Been lurking for a month and finally decided to contribute here.

I've done this sort of "soft mounting" myself with some success even on industrial machines. In the first case we used a silicone gasket sheet material between the motor and it's mount. This worked reasonably well and I've continued using it. The thing to remember is that if you haven't isolated the bolts from either the motor or the motor mount, they will transmit vibration very effectively too in spite of the gasket under the motor.

A couple things you can do for this. Soft washers between the bolt-heads and the motor/mount usually sandwiched by as large a flat washer as will fit. Also worth trying are nylon bolts. They can help as well.

Definitely worth experimenting with even though the delta may or may not be affected by a soft mount.

[jimsander]

Alrighty then - thanks all, this has turned out to be very educational.

After reading some other posts, I'd expected word about acrylic to be that it cracks easily. Was hoping to confirm or deny, but it's not that important.

"Too loud to sleep next to, but not much louder than NPR" is a pretty good subjective range for me.

Can't wait to hear something definitive about the dual head experience. A lot of what I want to do could benefit.

Again, thanks!

[cassetti]

Just to add my $0.02 to the thread.

1) Just like everyone else said - Acrylic cracks if you aren't careful. I never would build this printer in Acrylic - not worth it, let alone the extra $150 they charged for it

2) It's a delta printer, it sounds a lot different than my previous Cartesian printer (Prusa mendel i2). On my prusa, we could run the printer at night, and wouldn't hear it 25 feet away in the basement, except when the Y axis would whirl back and forth (not often that it did the loud 'whirl') but with this printer, it kinda sounds like an alien screeching constantly. Because all 3 arms are moving, the sound level remains pretty much the same no matter what. While the motors aren't too noisy (we can still sleep at night when it's printing in another room), I have had a few issues with my extruder "creaking" - I've had this issue before on a previous printer, but damn, when the extruder is creaking and squeeking, it can be a bit loud - almost to the point where you need to raise your voice to speak over the squeaking.

3) I've had a dual extruder setup on my work's Makerbot Replicator, and a single extruder on my prusa mendel. While Dual extruders would be really nice, I'm holding off right now on installing a second extruder and hotend until it's officially supported. I'm watching and waiting until I feel the time is right to upgrade. For now, a single extruder is plenty to play with.

I have no comment on the resolution, that's a little beyond me. And I'm not too concerned, don't really plan on building something that will fill the entire build volume anytime soon!