DIY tech shop defective hotends

Hi all,

I just wanted to relate my experience with these hot ends in case others run into the same things.

I got a Prusa I3xl kit from diytechshop back in Nov. 2013. Once it was all built the biggest problem was
the hot end would jam, but it wasn't just jammed it was fully blocked. I didn't really understand what
was happening just that very little plastic got extruded.

After doing lots of tests etc, I took apart the hotend. I found that the PTFE lining had a big bubble
in it. Inside the bubble was expanded plastic. So I figured I put something together wrong and I ordered
more PTFE tubing. I put the new PTFE inside, and the exact same thing happening.

Now mind you , this was a fully tightened brass piece on the hot end. So I measured the brass and plastic
pieced and found there was a considerable void even when the hot end was fully tightened. So I contacted
diytechshop, of course, anyone that's ordered from them know they don't respond and they stayed true to
form. I sent several emailsi (pretty much one a day for a week), then eventually they responded.

They sent me a whole new hot end which they pre-assembled. When I got it installed, low and behold the
exact same bubble appeared in the PTFE. So I took apart the new hot end, and a very similar void existed
in the new hot end. I emailed them back several times, eventually got a response, but they basically
refused to assist me further or acknowledge any sort of manufacturing problem existed.

dwalker, I agree with you, to anyone purchasing a DIY Tech Shop kit, please expect that you will have to buy a quality hot end from someone else. The one with the kit is of very poor quality. The nozzle I received had a very poor fit in the heater block, you can see a pic here;


Also the hotend leaks badly, between the peek and the brass.

I really feel bad for anyone who just buys this hot end from them, a complete waste

I've got a kit on order from diytechshop. At first they were great with emails and answering the phone. Recently though I haven't been able to get in touch with them for a billing issue.

All these negative posts in the last few days have got me worried.

Are there any hotends you guys recommend as a replacement for this one?

Edited 1 time(s). Last edit at 02/21/2014 11:01PM by cfy7.

Judging from the J-Head Groovemount listed in the parts list, I'm thinking that a proper Reifsnyder J-head will be easy to snap-in and use. The only problem might be the situation where the J-Head Groovemount has a gap wider than the standard J-Head, where that means one has to calibrate and print with the defective print head a correct mount first. I've emailed the good folks at DIY Tech Shop so I could get the .stl files, but I have had no response

Fortunately, I ordered a J-Head back when working on another kit that had a terrible hotend. So when my kit arrives I can check some things:

1. Determine if one can simply snap in the standard J-Head onto the supplied J-Head Groovemount part.
2. I could see if the J-Head brass end is compatible with the J-Head from DIY Tech Shop. This could mean that you order only the brass nozzle instead of a complete new hotend. However:
   
   • The threading and/or diameters may be different.
   • The length might be too short, leading to a gap between the PTFE and nozzle where plastic can potentially jam. This might be a fix as simple as getting some new PTFE tubing, but at that point, the cost in time (and the trouble one might have to go through securing the correct tubing), it might be simpler just to buy a better hot end.
   • There could be other problems with the design of the DIY Tech Shop Cold End that could be exacerbated by using the standard brass end.

I can't say I'm surprised to hear about problems with the hot-end. It's kind of a specialized part and I really only trust the original inventors to manufacture it correctly. I'd rather just have DIY Tech Shop not bother shipping one and have them give me a little discount. However, from what I've heard, they're really slow to respond to emails/calls (again, not surprising for a tiny business), and at the moment seem preoccupied with re-skinning their website to something quite garish.

Quote
KD0SKH
Judging from the J-Head Groovemount listed in the parts list, I'm thinking that a proper Reifsnyder J-head will be easy to snap-in and use. The only problem might be the situation where the J-Head Groovemount has a gap wider than the standard J-Head, where that means one has to calibrate and print with the defective print head a correct mount first. I've emailed the good folks at DIY Tech Shop so I could get the .stl files, but I have had no response

Fortunately, I ordered a J-Head back when working on another kit that had a terrible hotend. So when my kit arrives I can check some things:

1. Determine if one can simply snap in the standard J-Head onto the supplied J-Head Groovemount part.
2. I could see if the J-Head brass end is compatible with the J-Head from DIY Tech Shop. This could mean that you order only the brass nozzle instead of a complete new hotend. However:
   
   • The threading and/or diameters may be different.
   • The length might be too short, leading to a gap between the PTFE and nozzle where plastic can potentially jam. This might be a fix as simple as getting some new PTFE tubing, but at that point, the cost in time (and the trouble one might have to go through securing the correct tubing), it might be simpler just to buy a better hot end.
   • There could be other problems with the design of the DIY Tech Shop Cold End that could be exacerbated by using the standard brass end.

I can't say I'm surprised to hear about problems with the hot-end. It's kind of a specialized part and I really only trust the original inventors to manufacture it correctly. I'd rather just have DIY Tech Shop not bother shipping one and have them give me a little discount. However, from what I've heard, they're really slow to respond to emails/calls (again, not surprising for a tiny business), and at the moment seem preoccupied with re-skinning their website to something quite garish.

Thanks for the answer and please keep us updated on if it works or not. If the one one on my Omega ends up not working I'll be very interested in this upgrade.

I got an E3D hot end to replace the defective one. I used the original mounting plate for the jhead, but I flipped it over because the groove didn't hold the e3d correctly. I'm planning to print a proper one once the machine is running, but this rigged one works relatively well.

In terms of the overall kit , I would say it's hit and miss. Most of the stuff works just fine, and other stuff works but looks crappy, and some (like the hot end) doesn't work at all. The end stops they provided in my kit are enormous, and although they work, it looks absolutly crappy. They also didn't provide any sort of end stop mounting, so you have to zip tie the endstop to the bearing rods, which is horrible and doesn't work well.

Edited 1 time(s). Last edit at 02/22/2014 09:52PM by dwalker.

The bad hotends you guys had, were they 1.75 or 3mm?

Also, are the cheap ones on ebay, such as this one Ebay any good? Or is this just another case of you get what you pay for?

Edited 1 time(s). Last edit at 02/23/2014 11:08PM by cfy7.

The two I got were 1.75 .. It was two different ones also, the first was a "j-head" , the second one was they little brass hot end similar to n9jcv's picture.

This kinda intresting. I really had a heck of a time getting my i3xl built. But works now. I did notice last night that plastic is leaking though the non metal portion down on to the heater assembly.

Not sure what to do about that yet.. It sounds like miht be the tightening issue discussed earlier in here.

edit: where assembly was concerned my DIY shop jhead was so lose at the top i had to put in a washer to keep it from moving 3mm whe it came under pressure. after that it seemed to work fine had some back pressure issues then lastnight the plastic leaking thing started. I cant seem to find thier jhead picture up anymore to figure out how to comes apart so kinda stuck there.

Edited 1 time(s). Last edit at 02/24/2014 02:00PM by Doug1.

Just wanted to chime in here.
We sell hundreds of kits. Our hot-end is wonderful and they have very low clog rates.
If you send a head back because of defects, leaks, space anything, then we can change our machining process by showing your head to the machine shop and giving us all a way to correct the problem.
But the faulty parts must be sent back.


If your head leaks, let us replace it by sending it back.

N9jvc This applies to you also.

DWalker, your order was placed in November of last year and we would love to see the head in our hands.

My email response is for all to see.
"
Thank you for the post, we work closely with the RepRap community.

Your head is easily replaced please send us what you have for a replacement.
Getting it back into our hands lets us show the machine shop their flaws.

Do you need a label, we will provide one.
Just to let you know we hold strictly to helping our customers.
We did have orders that were affected by new machinists, weather and Chinese New Year, larger location, more employees etc...
But we are also starting programs across the US at major universities, high schools and going into retail locations.

Using the reprap boards is great but we do not use them for customer support.
We looked for a phone number on your account and could not find one.

We have no problem sending you replacement parts, even though your order was placed in November of last year.


Get a hold of us and let us know what you need and no problem we will work with you.

Van

---

Through self sustaining actions comes freedom

DIY Tech Shop

I sent numerous emails to diytechshop on this topic, which is how I got a second hotend. I was never asked to send anything back .. Not only that but getting any sort of response from diytechshop is very difficult ..

I also emailed detailed descriptions of what was happening with my hot end with measurements, and pictures to clist@diytechshop.com .

I asked multiple times "can you please measure your hot ends?" so you could determin how many of your hot ends had similar problems. I ask if I could have a hot end sent to me which was mesured not to have this problem.. Most of this went without response. It was offered that I could talk to your machinist, but there was no follow thru and it never happened.

I gave weeks of advance notice that I would be posting on this forum to the email address above prior to actually doing it.

All I'm saying is that these are my experiences. I would love it if diytechshop corrects this for me , and everyone .

Good News,

I just got off the phone with Van at DIY Tech. I am going to send my hot end back. He will be able to autopsy it both for brass machining/fitting issues and the leaking issue as well. He has some really good ideas on what might be wrong. He is sending me a replacement Little Brass Hot End.

My goal and what I felt is DIY Tech's goal as well, is to improve this product and make it better for customers. I am glad DIY Tech is responsive to this issue. I will report back when I know more.

I guess that's good for you, but they aren't responding to me ;(

You know i got to tell you they are kinda hit and miss. When they actually get time to answer you they are really know thier stuff, willing to do anything to help.

The problem is they hit less then the new york yankees.. ( sorry yankee fans ) . They did offer to replace my hot end but also gave me some advice on how to stop the leak problem ( like cool down your pla )

My hesitiation here is the non-advanced replacement issue. Based on other mistake / replacements if I have to take my hot end send it back and wait to get a new one we are talking a months and i only live across the state. it took 3 weeks to get printer plates sent one direction. So the idea of not having my printer working for 2 months just sucks. So then im left with well just try to fix it. Kinda want to fix it, and kinda dont want to. I would love to send it back after i get a new one which leaves me in the pickel of from where.. Do i really want to spend $50 on a new hot end that very well could be defective or just one elsewhere and send them thiers so they can atleast identify the issue.( now this all hinges on the idea that i am not cause the issue to begin with... which i wount rule out as well )

Hey everyone,

It is for all to see so I thought I would spend a minute to give you our answer.

Just got off the phone with dwalker and sent an express label out to him to send back the hotend/s for a full free replacement on our $20.00 for the express label!
And we will express it back lickety split!

Thank you for making us a better company!

---

Through self sustaining actions comes freedom

DIY Tech Shop

Just wanted to echo I had pretty much the same experience with the little brass hotend and DIY TS.

Not responding to emails, even when sending them in daily trying to get a response. When I had the time during the daytime I called and got the machine, but Van did call me back a few minutes later. When they do get back to you Van at least tries to make it right, although it can be slow going. At least they are trying to get everything straightened out. I only wish the communication was better!

It took calling to get their attention. Then I was told the parts would be shipped out that day, getting a tracking number later that day which seems great, but then a week, sometimes 2 before it was accepted into the USPS system, so it definitely did not go out that day. This happened on at least 4 occasions trying to get the missing parts that were either delayed or not included in the kit. It was nearly 2 months before I had everything between missing parts, getting a package, and still missing parts that were not included again.

I got fed up with this process and instead of asking for a refund I just ordered the parts I was missing from Digikey, ebay and McMasterCarr. I don't mean for this to sound like a rant, its just my frustrating experience with this company. From one small business owner to another I want to see him succeed, but that won't happen if you don't have customer service and communication.

I did eventually get everything, minus a few connector terminals for the RAMPS.

Now on to the hot end. The hot end does have some issues. The machining quality was very poor on mine. It seemed rushed, like all the other parts in the kit. Burrs and very sharp edges on anything that had to be cut, drilled or machined.
1) The holes bored for the heating element and nozzle were not centered or straight through the brass blank.
2) #1 meant the heating element did not fit. At all. I tried heating the brass with a torch to get it swell some to try and get the heating element in, but it still wouldn't go. I had to drill the brass piece out quite a bit to get the heating element to fit, same with the nozzle.
3) The PTFE tubing tends to bubble up as OP mentioned. Mine was very loose around the brass nozzle piece.
4) The PEEK and nozzle were very loose, probably why it leaked.

With previous experiences of several weeks to get missing parts, I opted to order some PTFE tubing from McmasterCarr so I could just get the thing printing. In a few days I had the tubing and same thing, it bubbled up inside or continuously jammed and leaked. I tried a several different lengths both shorter and longer. Tried putting a few small and large fans on it. It kept jamming or bubbling up+jamming, and the head was leaking really bad with PLA. I tried taping the threads but it would still eventually leak no matter how much or how little tape I used. I spent more time trying to get the hot end working than it took to assemble+solder the whole printer from a box of parts. I literally couldn't get more than 1 maybe 2 calibration cubes printed before issues, sometimes even on the first attempt. It would start to extrude fine on its own, but as soon as it was running for a couple minutes it would jam.

I ended up emailing Hotends.com about when 1.75mm j-heads would be back in stock (they had been out of stock whenever I've looked). I got an immediate response asking for the nozzle sizes I was interested in and they would be made up within 48 hours. The next day they were shipped out. I had them in hand a couple days later. I've printed 1kg of ABS and about .5 of PLA with not 1 single issue and very nice flow, and fairly nice prints. Now I just need to get rid of some wobble and I think I'll be all set.

Edited 1 time(s). Last edit at 02/25/2014 08:55PM by SparkMasterB.

You emailed me , I didn't speak to you on the phone , but whatever ..

I get the feeling that they don't want to fix the tolerance problem with their hotends , it's more like get people replacements and stop this thread from continuing ..

I dont mind spending the cash on a good quality part.

So im looking for suggestions there.

Also i think there is value in taking apart my current hot end to try and repair it. I purchased this device to learn how it worked. Now i can talk same story everyone else who has used this company can but in the end i did get exactly what i wanted which was to learn about 3d printers. Hell due to problems here im half way done with my marlin gui.

Looking at this can any one tell me if the tip unscrews ? mind you that big plastic part is where the leak is comming from. but figured i would start at the tip clean that work my way back.

Yeah, once you take the heating block off, there's a bullet looking part which screws off the plastic. Inside you'll find a plastic tube (PTFE tubing). The filament runs thru the plastic tubing.

I read someplace in this forum a guy had a similar problem as you. He thought the plastic tube didn't seat right against the brass , so he added teflon tape around the plastic tube where it inserts into the brass part ..

When the plastic heats up it expands a lot, so it will expand thru any cracks or opening..Anyplace that's open it'll expand into it. Because the tolerances on these hotends is bad it means there's lots of gaps for the plastic to expand into.. I would guess that's why your seeing leeks, cause it's expanding all the way out of the hot end.

When you put the brass back together with the plastic you have to make sure you get it tight enough so that the brass mates %100 .. If it's loose there's going to be a small void between the brass and plastic, and that will cause permanent damage to the plastic tubing.

sounds like im more likely to destory it then actually fix it lol.

Maybe I'm making it sounds harder than it is.. Just use pliers to tighten it..

ok ill give that a shot thanks!

Attached is a picture of my hot end from Diytechshop. I haven't used it yet, so it is premature of me to rate it.

The parts fit pretty tightly. There is the slightest gap, but if it was any tighter I don't think I could fit the parts together. I tried pushing a piece of paper in it, but it wouldn't fit. I also tried to see if you could see light through it and you couldn't.

I will report back in a few days once everything is assembled.

@Doug1:

[edit]
The heater cartridge is falling out, not fully inserted, it's too long, or the hole was not bored deep enough to encase the heater cartridge.



Have you printed with natural uncolored, or white filament, does the color remain true?
I'm curious if you're operating at too high of a temperature, and boiling or burning the plastic.

Max heat is derived from the center of the heater cartridge, not from distal or proximal ends.
It's a poor design choice, locating the heater cartridge orthogonal to the axis of flow.
The heater cartridge should be located either tangential, or longitudinal to the axis of flow.

Do you have a link to where this hot end was purchased,
I would like to see a clearer picture of its construction,
a disassembled picture would be best.

Edited 2 time(s). Last edit at 02/28/2014 09:50PM by A2.

In other words, what he's saying is the heater cartidge isn't effective because the heater block isn't designed right. The cartridge should be rotated 90 degs.

I have the little brass hot end from DIYtechshop. the nozze does not fit in the hole machinned in the block. Other people had the same issue?

Do I have to blow torch the block in order to slide in the nozze?

thanks

Quote
thatsme
I have the little brass hot end from DIYtechshop.
the nozze does not fit in the hole machinned in the block.
Other people had the same issue?
Do I have to blow torch the block in order to slide in the nozze?
thanks

If you have calipers measure the bore and nozzle diameters, post your results, a video would be helpful.
Look for burrs on the inside perimeter of the bore of the heater block, if you see any, use a knife and scrape them off.

If there is not a chamfer on the bore of the heater block, and the clearance is small, that would make it bit challenging to get the nozzle aligned.
Heating it will help with assembly but you might not get it apart.

If the diameters are an interference fit, you can do a couple of things to remove metal.

For the heater block make a lapping dowel, use a wooden dowel with a diameter near to the bore of the heater block.
Slot the end of the wooden dowel for about ~50 mm, and slide in a piece of wet-dry sand paper into the slot.
Wrap the sandpaper around the shaft until it's a snug fit in the bore.
Chuck the lapping dowel in a drill, and sand away.

For the nozzle you can chuck it in a drill, and use wet-dry sand paper to reduce it's diameter.
If the fit is grossly mismatched you can use a flat single cut fine mill bastard file (fine pitch) to carefully remove metal.

Ok guys, reporting back as I said I would.

I had a poor fitting brass hot end and a leaking PEEK fitting. I sent the hot end back so Van at DIY Tech could look into it and hopefully resolve. He actually had the machining guys change the process on the PEEK plastic part. Attached is a pic of the replacement hot end he sent to me in 2 days! Van was great about getting it to me quickly.

It came un-assembled, which is great cause I wanted to see it anyway, here is pic


So I put it together, I actually used a bit of teflon tape on the brass as well, lets just call it insurance

I have printed for about 5 hours now, and I gotta tell you, not a single drop has leaked. I think this may have solved the issue.

I have adjusted setting and moved to Cura as well, but I feel the new hot end has contributed to a better flowrate as well, since there is no leaking.

Thanks to Van and DIY Tech Shop for stepping up to this issue here.

How long does the PTFE tubing need to be for a perfect fit? Did you taper the ends? In your kit did you have the necessary cramps to join the thermistor to the wires going to your ramps?

Mine had none so I had to improvise as it is said that solder will not resist the heat near the hot end.

Quote
A2



If you have calipers measure the bore and nozzle diameters, post your results, a video would be helpful.
Look for burrs on the inside perimeter of the bore of the heater block, if you see any, use a knife and scrape them off.

If there is not a chamfer on the bore of the heater block, and the clearance is small, that would make it bit challenging to get the nozzle aligned.
Heating it will help with assembly but you might not get it apart.

If the diameters are an interference fit, you can do a couple of things to remove metal.

For the heater block make a lapping dowel, use a wooden dowel with a diameter near to the bore of the heater block.
Slot the end of the wooden dowel for about ~50 mm, and slide in a piece of wet-dry sand paper into the slot.
Wrap the sandpaper around the shaft until it's a snug fit in the bore.
Chuck the lapping dowel in a drill, and sand away.

For the nozzle you can chuck it in a drill, and use wet-dry sand paper to reduce it's diameter.
If the fit is grossly mismatched you can use a flat single cut fine mill bastard file (fine pitch) to carefully remove metal.

I mounted the nozzle on my drill chuck and used sand paper to reduce it's size. Both holes in the brass block were the exact same size ie: size of nozzle hole = size of heater.

I put the hot end together and slid it in the extruder groove, it fits loosely??. I fed some abs by manually rotating the gear just to see how things lined up. Well 1/2 of the fillament guide on top of the extruder broke off, poor blue PLA plastic (they said they will ship me the black ABS parts). The bottom hole doesn't line up with the top of hot end. Another issue i'll have to deal with.