qu-bd Universal 3D Printer Extruder on Kickstarter

Topics Related to the ORD Bot Printer

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby Liberty4Ever » Wed Jul 25, 2012 7:32 am

If the thermal fuse is used to prevent an overtemperature condition in an extruder, it'll completely shut off the extruder heater. If the errant controller keeps trying to extrude, it could damage the extruder. Better than a fire, though. A thermostat would cycle the extruder heater off if it became too hot but would let it stay hot enough to extrude plastic without damaging the extruder. It's essentially a backup thermal controller, at a higher (but safe) temperature.

Small bimetallic thermal switches with a fixed temperature should be not much more expensive than a thermal fuse.
Apparently, I didn't build that! :-)
Liberty4Ever
 
Posts: 274
Joined: Wed May 30, 2012 1:49 am
Location: Lexington KY

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby Boxcar » Wed Jul 25, 2012 8:11 am

Liberty4Ever wrote:If the thermal fuse is used to prevent an overtemperature condition in an extruder, it'll completely shut off the extruder heater. If the errant controller keeps trying to extrude, it could damage the extruder. Better than a fire, though. A thermostat would cycle the extruder heater off if it became too hot but would let it stay hot enough to extrude plastic without damaging the extruder. It's essentially a backup thermal controller, at a higher (but safe) temperature.

Small bimetallic thermal switches with a fixed temperature should be not much more expensive than a thermal fuse.


It's late here so you'll have to excuse me. I'm just offering an alternative. I ordered the thermal cutoffs. If they don't work out for me I'll try something else. Like I said it's $4.00 and it's better than nothing.
Boxcar
 
Posts: 13
Joined: Fri Jun 22, 2012 12:00 am

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby Liberty4Ever » Wed Jul 25, 2012 9:05 am

It's late here too! I was thinking, "Don't you hackers ever sleep?!?" :D

WRT the thermal fuse - go for it! That's what building stuff is all about. Everyone has different wants and needs... and even aesthetics. I didn't intend to come across like a jerk. I was just trying to give a fairly complete answer, and maybe mention some aspects you might not have considered.

I'm considering the thermal runaway problem as well. The smaller wattage resistors for extruder heaters are probably inherently safe. 100% duty cycle probably wouldn't cause a fire or do much serious damage. The higher wattage cartridge heaters can get very hot. If the extruder is mostly metal and all nonflammable parts, it might glow red but probably wouldn't ignite. :shock: But I think it'd be prudent to limit the temperature to something a bit above the maximum you'd ever want for extrusion if using those cartridge heaters.

I may look into inexpensive bimetallic thermal switches. If I find anything that looks promising to me, I'll post in this thread. For now, I'm busy trying to finish a CNC project so I can get back to my neglected mostly-built Hadron.
Apparently, I didn't build that! :-)
Liberty4Ever
 
Posts: 274
Joined: Wed May 30, 2012 1:49 am
Location: Lexington KY

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby Boxcar » Thu Jul 26, 2012 5:02 am

Liberty4Ever wrote:It's late here too! I was thinking, "Don't you hackers ever sleep?!?" :D

WRT the thermal fuse - go for it! That's what building stuff is all about. Everyone has different wants and needs... and even aesthetics. I didn't intend to come across like a jerk. I was just trying to give a fairly complete answer, and maybe mention some aspects you might not have considered.

I'm considering the thermal runaway problem as well. The smaller wattage resistors for extruder heaters are probably inherently safe. 100% duty cycle probably wouldn't cause a fire or do much serious damage. The higher wattage cartridge heaters can get very hot. If the extruder is mostly metal and all nonflammable parts, it might glow red but probably wouldn't ignite. :shock: But I think it'd be prudent to limit the temperature to something a bit above the maximum you'd ever want for extrusion if using those cartridge heaters.

I may look into inexpensive bimetallic thermal switches. If I find anything that looks promising to me, I'll post in this thread. For now, I'm busy trying to finish a CNC project so I can get back to my neglected mostly-built Hadron.


Thank you. Please do let me know if you find more alternatives. I'd like to have an extra layer of protection since I'll be printing in my house.

I've been thinking about the Dual MK7s and what the best way of mounting them would be. I saw a video of a single MK7 mounted with the motor side to the carriage. Doing it that way left the nozzle off center. My thought was to remove the fans and heat sink in order to mount them either facing each other or gear side in. Maybe a fan or two on the side.I imagine our aluminum carriage would act as a heat sink and it would also help center the weight on the carriage. What do you guys think? What solutions have you come up with?
Boxcar
 
Posts: 13
Joined: Fri Jun 22, 2012 12:00 am

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby Nick Brawne » Thu Jul 26, 2012 6:09 am

QU-BD have been really slow at posting STEP files of the extruder, so today I downloaded the STL's that they provided, converted the meshes to solids, then re-built the parts and created an assembly file of the complete extruder with stepper and fans. The models do not have threads, and I am sure that there are several small components missing, but what is there should be more than enough to help in designing a bracket so that you can mount it on a ORD Bot.

The model is on Thingiverse here: http://www.thingiverse.com/thing:27397
Nick Brawne
 
Posts: 27
Joined: Mon Apr 30, 2012 10:33 pm

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby Liberty4Ever » Thu Jul 26, 2012 6:11 am

I'm planning on mounting three of the QU-BD extruders side by side on my second Hadron. They're very compact. They'll be cantilevered a bit away from the X axis rails though and might exert a bit too much stress on the Delrin V wheels, although they're not too heavy so I hope it won't be a problem.
Apparently, I didn't build that! :-)
Liberty4Ever
 
Posts: 274
Joined: Wed May 30, 2012 1:49 am
Location: Lexington KY

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby Nick Brawne » Thu Jul 26, 2012 6:54 am

Three extruders are going to be pretty heavy, and the minimum width of the setup would be 126mm (thats with the extruders edge to edge and no air gap for cooling the steppers). Your 200mm square build platform would be transformed to approximately 200 x 100. You might be a lot better off using a bowden type set-up and locating the extruders off to the side and then mounting just the hot ends on the carriage. Looks like converting to a bowden tube drive should be pretty easy, either by turning something up on a lathe so that one end is M6 to screw into the block below the drive gear, with the other end having an internal M4 thread to capture a 2mm ID 4mm OD Teflon-PFA tube. The alternative is to print something up that will capture the tube and create a bracket for mounting the extruder mechanism.
Nick Brawne
 
Posts: 27
Joined: Mon Apr 30, 2012 10:33 pm

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby Liberty4Ever » Thu Jul 26, 2012 8:17 am

I thought about using Bowden style extruders to reduce the moving mass on the gantry for faster acceleration and deceleration, and to spare the cantilevered mass stress on the X axis Delrin V wheels, but I'm not convinced that the Bowden style extruders are as precise. I'm pushing for maximum print quality. However, I've seen some very nice print quality from the Ultimaker and it uses a Bowden style extruder.

I even considered a slight space between the outer two QU-BD extruders and offsetting the middle extruder above them so it had a 45 mm stalk to the hotend, but decided that would be too complex and the middle extruder would be different and would thus work differently.

My original idea was a taller Hadron with the electronics plate about 8" higher and a second X axis on the back side, with two X axis motors wired like the dual motor Z axis. That probably wouldn't work very well, because the Z axis barely moves most of the time on a 3D printer, but the X axis gets a workout. I might need to use one of the controllers that would allow a 24V supply for the series X steppers to maintain the speed.

Most people want two extruders to print in two colors, or print a support material. My goal is a 3D printer that can crank out a lot of high quality small parts quickly. In that regard, some lost X axis travel isn't that big of a deal for me if I'm printing three or six identical parts side by side in X, and probably a matrix two to four parts deep in the Y direction. I can buy a longer X axis belt and a longer Misumi extrusion for the base and longer electronics plate to go with a longer piece of X axis Makerslide I already have, and widen the Hadron enough to get back the full X axis build plate capacity if I need it, but I'm not that worried about it. The three extruders will fit on the gantry with some hole drilling, and I only lose about 25 mm in build width so I'd have a 7" X 8" X 8" build volume instead of an 8" cube.
Apparently, I didn't build that! :-)
Liberty4Ever
 
Posts: 274
Joined: Wed May 30, 2012 1:49 am
Location: Lexington KY

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby automationtech » Sat Jul 28, 2012 2:01 am

Hi

Can you share your experience of qu-bd 3D extruder?

is it good and reliable?
automationtech
 
Posts: 46
Joined: Wed Jul 18, 2012 10:20 pm

Re: qu-bd Universal 3D Printer Extruder on Kickstarter

Postby Enraged » Sat Jul 28, 2012 2:49 am

don't know yet, they haven't shipped out the Kickstarter buy yet. They took addresses today, so we'll see soon.
Enraged
 
Posts: 439
Joined: Fri May 06, 2011 3:13 pm

PreviousNext

Return to ORD Bot

Who is online

Users browsing this forum: No registered users and 2 guests

cron