Hello, There is a saying that you can get it good, fast, or cheap. Pick two. I am the designer and a manufacturer of the J-Head hot-end. I have been seeing people state that they bought a cheap hot-end, off of E-Bay, and now it doesn't work. So, they blame the type of hot-end. (Note: I've seen complaints about cheap J-Head clones, cheap E3D clones, and other products.) When you buy a clby reifsnyderb - General
Hello, If you got a genuine J-Head from either , or a re-seller, please let me know and I'll replace a broken J-Head. This is the first I've heard of PEEK breaking since I fixed a weak spot almost 2 years ago. Best Regards, Brianby reifsnyderb - Printing
Quotemrkaras yes, its defiantly a clone j-head, not a genuine one, but I have had similar results with a Teflon one and a home made fiberglass one, what's likely to be wrong with a clone one? perhaps I can test the melting point with a soldering iron or heat gun? this one worked fine for an entire print (not a huge print, the car shown in my last attachment but it took most of an hour) Hello, Iby reifsnyderb - General
With the thermistor and resistor, a "J-Head Lite" weighs 33 grams. It's even heavier than the heaviest of true J-Heads. A Mk III-B weighed 30 grams. The current standard J-Head, a J-Head Mk V-BV weighs in at 20.5 grams. I have a table here: I must admit confusion as this "J-Head Lite" is neither light-weight nor even looks like a J-Head. I guess ohioplastics can name it whatever he wants,by reifsnyderb - General
Early hot-end designs used PTFE and brass. The PTFE was known to fail rather quickly as PTFE makes a poor support material. PEEK alone was tried and didn't work well with PLA. Next, a hybrid design was tried that used a PTFE sleeve and PEEK body. Fast forward some time and the modern J-Head venting system was developed. The PEEK wall, between the root of the vents and the PTFE liner, is onlyby reifsnyderb - General
Hello, Marlin has dual thermistor support, for one hot-end, implemented. The instructions are here: Best Regards, Brian QuoteT0mmm Quotefoshon Why? Don't the majority of today's hot ends only utilize one? Is there a firmware available that utilizes two? Marlin, I believe a second 'redundant' thermistor is being implemented? if not i'm planning on having my own separate temperature tripby reifsnyderb - General
Ok, now I understand. I thought you were having problems with the J-Head. (If the J-Head broke, it can be fixed.) You had a J-Head, it broke, and now you are having printing problems with the Prusa Mk II. Regards, Brian thej Wrote: ------------------------------------------------------- > Its the prusa nozzle mkII > > I dont like it this far...by reifsnyderb - General
Hello, Where did you get the J-Head? Was it from hotends.com or somewhere else? Regards, Brian thej Wrote: ------------------------------------------------------- > i did. Nothing changed.by reifsnyderb - General
Hello, What is broken on the J-Head? If everything appears to be ok, physically, try heating it up and tightening the hollow set-screw at the top end. It should take a 4mm hex key. Regards, Brian thej Wrote: ------------------------------------------------------- > my j-head nozzle broke so i though an upgrade to > the Prusa nozzle MKII would be great. Or not? > I have been tryingby reifsnyderb - General
Hello, I probably should buy some new hot-ends to see if they improved. But, this is what I found in December: Regards, Brianby reifsnyderb - General
pm sent... rhmorrison Wrote: ------------------------------------------------------- > @Brian: I have one that is unused.by reifsnyderb - Wanted
Hello, I am looking for an Arcol v3 hot-end for my hot-end collection. While I prefer that it be unused, I'll entertain any offers. Regards, Brianby reifsnyderb - Wanted
Hello, Some people have reported printing at over 200mm/sec w/a J-Head Mk V series hot-end. I've bought a couple J-Head clones, to examine, and posted the results here: In summary, some of the knock-off J-Heads are not to spec. and have taken some of the worst features of previous versions and put them in one package. The only knock-off, that I have reviewed thus far, that is to spec. is thby reifsnyderb - General
Hello, Here is a description of the PEEK failure issue: If anyone experiences such a problem, and they were made by me, please contact me for a replacement. Regards, Brianby reifsnyderb - Mendel90
Hello, I was looking through the reprap forum to see if anyone had any comments about J-Head nozzle failures and found this posting. While there have been some failures, lately, I have tracked the problem down to a tooling issue with one of the machines. The failure is almost identical to what JC61990 has posted. If anybody is sure their hot-end came from me and 150% sure it wasn't from beingby reifsnyderb - General Mendel Topics
Hello, Lately, there have been some failures, unfortunately. I have been working on the problem and think that I have found it. As the problem has, to the best of my knowledge, only occurred lately I was trying to figure out what was going on. The 5/16-24 thread is quite similar to an m6x1 (it is almost like m8x1) and shouldn't be a problem. Upon measuring the SAE threads, I found out that tby reifsnyderb - General
Hello, For some reason, I've had a couple other reports of the brass nozzle popping out. In one case, it was 100% confirmed that it was not due to temperature. As this has only started in the last month, I have found it quite odd. I think that nophead's theory may be correct about the PTFE tape. If there are too many layers, maybe it is causing it to slide out somehow? I can't think of anyby reifsnyderb - General
Hello, PTFE tubing can be obtained either through McMaster-Carr (http://www.mcmaster.com) and I sell the replacement liners (http://www.hotends.com). At some point, hopefully in the near future, I'll have replacement Mk IV PEEK nozzle holders available as well. Regards, Brian 4t1fy Wrote: ------------------------------------------------------- > I guess I'll just have to watch the tempby reifsnyderb - Printing
Hello, The MakerFarm liners are semi-transparent white in color. (Mine are red.) My guess is that the hot-end died due being slightly overheated and the higher pressure of the Mk IV-B with the nipple on the tip. I have my doubts that there was a jam. However, I would be willing to bet that the temperature was around 248 degrees when the hot-end failed. It doesn't look like a failure where tby reifsnyderb - Printing
Hello, I just saw your post and was wondering if you are printing ABS or PLA and what color was the PTFE liner? The brass nozzle normally doesn't tear out, like that, unless the hot-end is overheated. But, sometimes strange things happen. Did you get this hot-end at hotends.com? Regards, Brian 4t1fy Wrote: ------------------------------------------------------- > > So today I wby reifsnyderb - Printing
Hello, I ordered my solidoodle on May 1st and received it on August 10th. It took a considerable number of complaints, on the #reprap IRC to the solidoodlesupport guy until it was shipped. I think he got tired of me asking him about it. Regards, Brianby reifsnyderb - General
Hello, A Mk IV-B without a setscrew to hold the PEEK in place? The Mk I had the liner held in place by the extruder (No hollow set-screw.) and the major improvement, of the Mk II, was to add the set-screw. Without the set screw, a gap can form in between the liner and brass. This could also cause problems. If the ID, of the liner is too small, you may be able to enlarge it with a drill bit.by reifsnyderb - General
Hello, In all probabiliy, there are one or two problems. 1. The nozzle orifice length could be too long. This will increase the extrusion pressure. 2. The other issue, that happened primarily with the Mk IV-B and earlier designs, is that it is possible for the PTFE tubing to be constricting at the junction with the brass. This can happen if the hollow set-screw is too tight. As I haveby reifsnyderb - General
Hello, PEEK usually softens around 250 degrees. Personally, I wouldn't heat the hot-ends up to more than 240 degrees in order to ensure that there is a margin of error. Regards, Brianby reifsnyderb - Firmware - mainstream and related support
Hello, The J-Head Mk V-B is shorter than the MK IV-B and no longer has a taper on the liner as it goes into the brass nozzle. So, the crimping problem is resolved. In addition the MK V-B has a longer melt zone. Regards, Brianby reifsnyderb - Reprappers
PM Sent. jonasl Wrote: ------------------------------------------------------- > Hi Guys > > After having had only problems with my JHead, I > have decided to get another hotend. > Probably a MakerGear or a Budaschnozzle. What I > just cant get over are the shipping priced from > US. > 43US$ or 60US$ for the cheapest shipping option. I > am in Hong Kong and Denmark &gby reifsnyderb - General
John, Mine is 542. I finally had it delivered on Friday. What happened was that about a month ago I asked about it, on the RepRap IRC, and was told 3 to 4 weeks. So, I waited until Thursday, a week and a half ago, and asked again. I was told another 3 to 4 weeks. I waited a week and asked again. I figured I would start bugging until I got somewhere. So, it was shipped Thursday and I recby reifsnyderb - Australia, Melbourne RUG
Hello, I ordered a Solidoodle on May 1st. It still isn't here and I am told it will be 3 to 4 more weeks. :-( Regards, Brianby reifsnyderb - Australia, Melbourne RUG
Hello, If the walls are too thin, maybe the center should have been drilled out last, after all of the high-stress machining operations are finished? Regards, Brian Ollie Wrote: ------------------------------------------------------- > For anything bigger than the part I'm workin on > Brian, I'd agree with yu, but the walls are too > thin in my opinion for between centers. Althoughby reifsnyderb - General