The folks at SUMPOD are sending me one of their newer hotends, but this will be the second one they shipped me (the first one never showed up). Hopefully it’ll arrive and I’ll be able to at least get it running, if only to print out some upgrades like a new extruder and hotend brackets.

If you could email me the files (or make them available somewhere) for the bracket I’d appreciate it. If I can’t get to the point that I can print them myself, I’ll let you know. Thanks again!

Some parts did spoil the Sumpod, the extruder just was not up to the job. I’ve printed about 6kg of plastic so far with the updates I’ve made and the printer is still going strong. I plan to change the X and Y carriages for much lighter versions for faster and better quality printing.

I can send the files for the J-head bracket but I guess you will have difficulty printing your own without access to a working printer. The bracket is untested but as long as the bowden cable is long enough not to pull on the fitting it should work fine.

If it will help you out, I can mail you the bracket I’ve printed to get you started.

Mark

Thanks for all the info you put up here, it’s very helpful!

As expected, I ran into issues extruding after trying to convert to 1.75mm using PTFE tubing. Still working on it, but having the dimensions properly machined would (of course) be the best solution. We’ll see if I can make do on my limited budget.

Personally I would not use thermistors that has not been properly identified by the supplier as with the case on my J-Head purchase. I think the recommendations that hotends.com makes is based on the kit that they supply and test.
To make sure you get the temperature reading as expected it is best source your own thermistors that match those in the firmware configuration list. The following link is a type I use and I believe hotends.com has just started recommending the same:
http://www.rapidonline.com/Electronic-Components/GT-THERMISTOR-100K-3-61-0452

#define TEMP_SENSOR_0 1 should be enough to get your hot end heating up as long as you are getting an ambient reading from the thermistor.

I’m not familiar with the board you are using but defining TEMP_SENSOR_0 1 should enable extruder heater 0. One common error to check for is the power input cable; making sure it’s connected to the correct power input socket.

There is not really a lot to do to get the heaters going on the extruder and the heated bed, It’s just a case of good wiring connections and setting thermistors in firmware and of course choosing the correct motherboard configuration.

It will be interesting to see how you do with the MK-IVB.

Good luck with your first printer,

Mark

I bought an MK-IVB a while ago and am now installing it in my first printer. It is machined for a 3mm filament, but I also tried converting it to use 1.75mm with some PTFE tubing… I’ll let you know how reliable I find that to be.

One question regarding the hot end: I thought I fully installed the resistor into the board (RAMBo) properly, but when I try heating it up the hot end just remains at room temperature. With the MK-IV, are we supposed to declare thermal settings differently in Marlin, or keep it like:
#define TEMP_SENSOR_0 1
as the hotends website suggests?

Any help would be much appreciated!

Kevin

Internally, the filament path is identical to that of an already proven design.
The design is simple as the number of custom machined parts is kept to a minimum.
If necessary (and for 3mm hot-ends only), the PTFE liner can be replaced by using an off-the-shelf piece of PTFE tubing.
The PTFE is not stressed nor used to provide support. This reduces a point of failure that is part of other designs.
A resistor is used as a heater. There is no need to wrap nichrome wire or to bake a heater core.
Heat transmission is improved as there is no thermal junction where a separate heater screws onto the nozzle.

Included

Assembled J Head MK V-BV Hot-End.
Power Resistor, 5.6 ohm or 6.8 ohm (depending upon availability)
Thermistor, 100k, 3%
PTFE Insulation for the resistor and thermistor

I had already got the QU-BD MBE extruder before discovering the bad reports being made against it. As far as I know, it just fails on PLA extrusion. I believe the extruder works fine with ABS filament.

The MBE extruder hot end is nicely engineered and I think it would have worked better with PLA filament if the nozzle tube was polished on the inside like the Prusa’s new all metal hot end.

There is also no retention ring at the top to retain the PTFE liner. To be fair to snipermind, he did replace the PEEK tube, and I did keep the hotend – it’s sitting around if everything else breaks.

I ended up stateside, so picked up a 3mm and a 1.75mm version from Brian @ hotends.com. As usual and as expected, the quality is stunning. I just wish I’d picked up two of the 1.75′s – I want to play with dual extrusion!

FYI – Not sure if you’ve tested one, but the QU-BD extruder is not very reliable and I don’t recommend it at all. That said, a couple of folks have identified a couple of the problems, and it looks like you can at least use it as a decent extruder. Nothing short of replacement will fix the cone slope on the orifice, however, so if you ever crash it into your bed it’s done..

I think when selecting a hot end, it might be a good idea to get the opinions from those on the RepRap Forums before buying. I’ve noticed that some of the long experienced experts are still sticking to 3mm filament; I think the hot ends are more reliable for this size.

I’ll be doing a review of the MBE extruder after more tests. The reason I’ve had problems with it is that it does not prevent PLA from swelling in side the tube. The PLA filament jams quickly after being stood for a few seconds.

Mark