First useful print

Good news! "the machine" has finally produced its first meaningful print:
(The bed material was switched to an ABS sheet after observing some FDM machines in the USF industrial engineering lab (special thanks to those who facilitated that)) Warping still occurred, but it is a step in the right direction.











And finally, the part in it's semi-natural habitat:




As the pics illustrate this rep(s)trap is a fairly standard bits from bytes build.

Before successful extrusion modifications had to be made to the extruder. The majority of which are well documented: i.e. sharpening the extruder drive screw; removing the lower pressure bearing spacer plate, etc...

Within the extruder hot section, each wire was individually protected by silicone tubing (think R/C class nitromethane fuel line). Not having adequate protection for these lines caused the shorting and destroyed the PWM board channel 1 MOSFET.
Finally the entire hot section is shrouded by a polycarbonate tube (44.5mm ID, 50.6mm OD) this protects me from myself, and allows the extruder to reach operational temperatures (~240 C) by reducing airflow around the heater.

EDIT: ImageShack is having some problems so some of the images may not be visible... I'm attempting to upload to another host.

Edited 1 time(s). Last edit at 11/23/2008 10:51PM by x2800m.

Awesome! Looks pretty good! I like the heat shield idea; I'm sporting a decent burn on my hand myself at the momnt.

Wade

About that "heat shield"... I decided to install the heat shield after reading one of nophead's articles (something about a bath salt vial). Previous insulation attempts all involved fiberglass, and diagnosing failures was fairly messy. As for the tube, it was obtained from McMaster-Carr (part# 8585K181). While it does work well, there are a curious number of stress fractures in the shield. I believe this is due to the mounting method (3 miss-matched set screws). A rubber o-ring would most likely have been a better solution.

Sorry to bother you, but I'm almost complete myself, but have ended up with parts 95 and 96 (from the lasercut list) that I can't seem to work out what they're used for.

Funny that you should bring that topic up... I believe part# 96 is supposed to be used as some sort of PCB clamp to mount the electronics on the cross braces(but I'
m not sure), and I'm still not certain as to the purpose of part# 95. I did not use these parts during assembly, but I still have them lying around in a bag somewhere. I think the best thing to do at this stage would be to contact Ian (the designer). Good luck

On an unrelated topic, the "heat shield" idea is probably by far not one of my brightest moments. It turns out that us of such a shield with the acrylic kit causes the three standoffs that support the hot section to melt into the support. As one can surmise, this will eventually cause misalignment of the hot section and eventual failure. My current deposition head uses mica insulation and an external a bench power supply to achieve the requisite temperatures without the need for insulation. Finally, whenever the extruder is hot I have a fan continuously running to cool the acrylic sections in question.

Edited 1 time(s). Last edit at 01/14/2009 11:34AM by x2800m.

X2800m, that Y belt arrangement looks different to me - wouldn't the changing belt angle cause your Y steps/mm measurement to change as your X axis moves from one extreme to the other?

Also, are the drive pulleys laser cut, or are they something else? I'm looking for a new set of pulleys, and I'm trying to figure out what will work best.

Wade

The Y belt arrangement is a result of incorrect assembly. (The machine was completely assembled in a single 11 hour stint. This resulted in me using the foot jigs on the wrong set of rails. and I'm far too lazy to fix it). The Y steps/mm will change near the VERY edges of movement. However, I'm generally fabricating small parts and the change while I traverse my typical operating region is not noticeable. Errors in accuracy due to the filament flow are dominant at this scale. The pulleys are acrylic (they're part of the bits from bytes kit)