Pre-Purchase Questions

[jasay]

Not an expert in anything, but my experience.

Prior to assembly, is it necessary to check the stepper motor potential? If so, how does one do that? Can adjustments be made after assembly?

I assume you are talking about reading the potential of the stepper motor drivers on the board. This can be done at any point with a multimeter and can be adjusted with a (preferably non-conductive screwdriver (which Colin helpfully includes in the kit)). I think some boards may also be able to adjust this in software, but I am not sure (I run RAMPs).

If one is going to go with the regular heated bed and use a glass plate, what type of glass is recommended? Does the glass have to be borosilicate or can it be a different material such as a piece of granite like a granite tile (very flat) from Home Depot?

I run borosilicate as some people have said that window glass can shatter depending on heating/cooling rates, etc. It's WAY more expensive though (think my 10" x 1/8" plate was ~$35 vs $2-3 for cut glass from the hardware store). I just didn't want my kids to walk into the room barefoot and find glass on the floor.

For the best and most consistent, even heating, is an aluminum bed necessary? If I chose to machine my own metal bed, could I use something with a thickness of 1/4-3/8 inch? Could it be cast iron, stainless steel or aluminum? Would that work? Would that change the power requirements?

I don't have a way to heat map my bed, but it works sufficiently well that I haven't had parts lifting up anywhere across it. I do use PLA though, so it's less likely than ABS. I would anticipate that anything other than aluminum would be too heavy and restrict the maximum speed/acceleration of the machine. Since printing is already a long process I would hesitate to go that route. Metal being a better conductor than glass would probably transfer more heat to the air and require more energy to maintain temperatures. If you do go metal, make sure it is flat as almost all plates I've seen are not.

Does the heated bed relay significantly improve temperature control and reduce risk of damaging electronics? Is it easy to install and set up?

Not sure that it really helps with temp control. Not an electronics expert, but I think it actually limits the current to either on or off, whereas without the relay the boards have PWM and can more closely control the power to the bed. That said, most of the Reprap boards are not built to handle the current (amperage) requirements of big beds and will probably die a short, painful death if you try to run say a 12" bed off of RAMPs directly. The relay is pretty easy to setup and use, but the clicking on/off may be the loudest part of the printer.

Which electronics packages has the best expandability?

RUMBA has more built in inputs/outputs for heaters, nozzles, fans etc.

Can this 3-D printer print metal filaments? How easy is it to change nozzles for different size filaments?

Metal filaments, no. Plastic filaments with metal (e.g. bronzefill) should be okay. The hexagon hotend should be able to print more materials, especially hotter melting point materials than the J-head. Changing just the nozzle at the end of the hotend is a bit of pain since it has to be done hot for the metal hotends, but not that bad. This would allow different extrusion diameters. To change actual input filament diameter, however, the entire hotend and extruder would likely have to be swapped out. It's two bolts, but z-height is so critical that switching could be a major pain in the butt calibration wise. Either way make sure you update your slicer software to match any changes.

With respect to the couplers, there is a recommendation to get metal couplers. Do you recommend this, and what type?

Most people seem to suggest the 5mmx5mm spiral aluminum couplers that are not split along the diameter. Something similar to this: http://smile.amazon.com/gp/product/B...?ie=UTF8&psc=1 I actually ordered those, but had already finished the machine when they arrived. Haven't had a chance to see if they improve anything yet.

Is Kapton tape necessary for anything?

Attaching the thermister to the heated bed. Useful for temporally holding the hotend together while tightening the nozzle (hexagon).

What Windows operating systems will work with this machine?

I've used XP and would imagine 2000 would be fine as well. Not sure about older than that. Anything newer should be fine.

Are the .stl files for all components available for download?

The only printed parts of this kit are the extruder. I think it is just a standard accessible Greg's extruder which can be downloaded from all over the place. The lasercut files are available in weird format that almost no one can open. I believe a few people have translated them to more usable files, but don't have a link handy.

With improved hardware adjustments, what is an anticipated total cost?

With glass, power supply, Raspberry Pi (octoprint setup), webcam, sorbothane feet, couplers, extra hotend (now using itty bitty flex extruder), spare belts, wheels, etc. I think I was around $800-$850 for the 10" machine. Closer to $1k with a bunch of new filament colors.