How I broke a brand new E3D Lite6

Update 2015.06.23, E3D going above and beyond.

I messed up when trying to extract the nozzle, and the extractor broke off inside the block, making it near impossible to fix.

Driving out a drill bit with a drill bit
turned out to be difficult, as the softer
metal in the block gave away.

The issue with the nozzle breaking was due to me not following the nozzle swap procedure, which has to be done at 245C... As well as the liner compressing thus forming a plug.

I always ment to pay for new parts, but E3D actually gave me store credit to buy a new one(!) which was far beyond what I would have expected.

From E3D/Sanjay email: "The reasoning for me providing a replacement is that I think there could be an issue with the tube/lining coupling, and that there may be an issue on the internal bore which prevented you from inserting your liner fully. I am absolutely certain that the leaking you experienced is a result of the nozzle tightening procedure not quite being performed properly. You should be able to solve any leaking issues with a quick nip up and tighten of the nozzle when hot."

I'll report back with a new modified wades and my experiences with a more carefully assembled lite6.

Original post:

I just finished building a Mendel 90 sturdy for the school I work at, and started printing today together with my students. Everything worked pretty well and we did a few various prints, they really enjoyed this one. 

The extruder is the standard 3mm wades that comes with the Mendel 90 source, printed in ABS. I drilled out the filament path to fit the PTFE liner and just used it stock like that.

I had some issues dialling in the extruder settings though, and had to increase the extrusion multiplier to 1.1-1.2 to get acceptable solid prints, but there was still a lot of stringing. After a while I chose to remove the extruder idler to have a look inside, and I saw this.

The bottom PTFE liner should be flush with the plastic,
but it have moved quite a lot upwards.

The collet looks like to be in the right position.

I removed a good chunk of plastic to avoid moving the collet when inserting the hotend.

Teeth looks fine, and have not clogged.

Since this is the 3mm version, and the filament path hole is not moved, the idler does have to be tightened almost all the way, and the bearing does bend the filament slightly. But since there are no clogs, and it was easy to change out the filament, I reasoned it would be fine.

The nozzle is positioned correctly according to the assembly instructions.

I had to heat the hotend to 120C to unscrew the nozzle.
This is what it looked like.

The filament is pulled out and clearly shows the
PTFE liner was not completely flush with the nozzle.

Slight leaking from the top of the heat block.

After looking at it a bit and reinserting the PTFE liner a few times, I felt there was a tiny edge at the bottom of the heat sink, and you need to use quite some force to push the liner past it. I figured I rather push the liner through the heat sink and the heat block and then screw the nozzle into the heat block moving the liner upwards to make sure there is a tight fit.
Update: This was a terrible idea, the liner got compressed and probably had a lot to do with the nozzle breaking.

I started screwing in the nozzle with the liner like this. 

It was quite hard to screw the nozzle back on, possibly due to the plastic left in the threads, so I heated the hotend to 120C to make it soft and started out. Then...

Snap...

Seems like I need a new nozzle, liner and heat block..

Any ideas to what could have caused this? I followed the instructions very carefully. The collet was properly secured, I could not move the PTFE liner up and down by hand. Thermistor settings were correct. I ran a M303 to ensure the temperature didn't overshoot, before heating to 245C and tightening the nozzle.

My guess is I only got the PTFE liner down to the small lip inside the heat sink opening, and there was a gap allowing the PTFE liner to move.

I'm in contact with E3D support already (they answered very fast), and wrote this post to better show my problem to them and to help others avoid the same mistake.

Thanks for reading!

-Peter

New Prusa snap fit x-ends not fit for PLA?

I just printed the new snap fit Prusa x ends, and ran into a few problems.

The red highlights are where the part cracked under stress. First from inserting the smooth rods, then along the holes for the zip tie, when I pushed in the top lm8uu bearing.

Print settings

This is printed in white PLA from Ultimachine @200 deg C. Nozzle is 0.5mm, layer height is 0.35mm, it has 2 extra shells (thus 3 in total) and infill of 30%. I believe the problem is the flexible part of the push fit design, which doesn't flex at all. I don't know whether it's because of the brittle PLA, or if it can be avoided by using either fewer or more outer shells. Heating the part before inserting the smooth rod will probably help, but

If this is a problem with PLA, I hope there will be an option to switch out the push fit with m3 nut and bolt. Looking forward to having a look at the OpenSCAD files!

Blame the user
The crack along the lm8uu holders is most probably my own fault, it was a tight fit, and I did manhandle the bearing quite a bit. There are some small lips to hold the bearing in place (in the z direction) and the bridge did sag a tad so the bearings didn't fit very well under the top ones. You can sort of see it in the second picture. Using 100% infill might solve this, as moving the holes up would just move the weak spot.

Edit 2011.07.11 :
I just printed the x-end idler, and the bearing holder snapped when I pushed in the bearing (had to use a wood clamp, it was that tight). This trouble might be my printer drawing outside of the lines, instead of on the inside. I'll be back with more info.

Difference in PLA?
This is the first object I have printed in this white PLA, and it might need a little skeinforge tweaking to get perfect. It seems to flow more, and thus pushes out more plastic than with the other Ultimachine PLA I have. (Silver, transulent blue, natural and black).

For this print I tried to drop the speed from 60 to 55mm/s, and on the x ends, it didn't loose enough y-steps to ruin the results. I have a theory it might be the weight of the plastic spool keeping the maching from rattling, anyone else experienced this? I still can't print gregs lm8uu x-carriage properly though.

New hot end review on the way


While I'm blogging, I might as well drop in a picture of a nice little puzzle I got in the mail:

It's an Arcol 0.35mm hot end, which I'm looking forward to try out. One thing I'm a sceptical about is the hot end relying on threaded PEEK to hold the pressure. People have a lot of good of things to say about this design, but to me a push-fit version just seems a the "safe" way to go. Also, it's a bit large to fit on gregs lm8uu x-carriage, so I have to figure out which printer to put it on, as it won't fit on Adesina now.

Tips & Tricks - Tape & Layer thickness

Introducing RepRap Tips & Tricks, short blogposts where I share some of the small things you learn when you have a RepRap.

• Don't tape your PLA filament together! When you're battling with a noncooperative spool of tangled filament, it might seem like a good idea at the time. When you have to degrease the tape residue off 2kg of PLA filament to avoid clogging the extruder, not so much.

• If you have problems printing at high speed because the layer won't stick to the previous, try lowering the layer thickness under carve in Skeinforge (41). I went from 0.4mm to 0.35mm, and have done near-perfect gears at more than 50% speed increase from before. (Went from 20mm/sec to 33mm/sec).

Mendel-parts.com - v6 hot end first impressions

I've been using the v6 hot end from mendel-parts.com for a couple of days now, and although that is not enough time to do a complete review, I would like to share a few things I've learned.

• It's working beautifully! I always thought the hardware was to blame for my sub-par print quality, but with a proper hot end and skeinforge 41, I was able to spot the hardware problems. A new belt on the x-axis and metal gears on x and y axis did the trick.
• I (and I'm not alone) needed to glue the PTFE tube/liner to the brass part to avoid it forming a blob which clogged up the whole thing. I did it by roughing up the surface of the PTFE and the inside of the heater barrel, and put on a very small amount of thermal glue. Take care not to clog the barrel! It seems to be working out nicely. Here's a picture after the first failed attempt at attaching it to a wades. The mounting bracket failed, and both the PTFE and PEEK pushed out of the barrel, resulting in all sorts of funky cleanups.

• I don't like to glue the thermistor in place. Both because it would be impossible to remove, and because the thermistor I have from ultimachine is too big to fit. I could of course use the thermistor supplied with the hot end, but then I would have to change the temperature table which is not readly available. Anyway, I went with my decision of attaching the thermistor to a ring terminal and replace the copper ring with it. It worked out fine, but the temperature was WAY off. Because I use to weak springs on Adrians extruder, I had to increase the temperature to 205 degrees to get proper extrusion. After a while it clogged up and I found this inside the barrel. (Be warned, it's not pretty).
•  I now extrude at 180-185 and it works beautifully, I think I could go lower still.
• EDIT: I have a theory the gunk was bits of PLA the extruder grinded off the filament, and not necessarily the temperature.

• I didn't damage anything apart from breaking off the filament guide off "driven-holder.stl". Here I'm printing a new "idler-holder.stl" to have a spare.

• To sum it up:
• The mendel-parts v6 hot end works great!
• Glue the PTFE tube to the barrel (carefully).
• Use strong springs on Adrians extruder.
• Test your temperatures with natural PLA to check for discolouring.
• Skeinforge 41 with volumetric 5d is incredible! (Don't waste your time slicing with the old repsnapper windows build that's available).
• When you turn off the machine, leave the plastic inside. I had no problems extruding straight away when heating it up again. If you pull it out it will most likely form a plug.

Update 01.02.2012: I've used the v6 hot end for a long time, and it's decent. Though because the melt chamber is so large it drools a lot, and the filament lingers a long time when changing colours. The Arcol v3 and J-heads (and others?) has no such melt chamber, only a straight path to the nozzle, which I find is a better solution. This is written only for completeness sake, as the v6 is no longer sold. Though the v9 looks similar, I have not seen it in person and don't know how it performs.

Well.. I'm off to figure out why skeinforge 41 sometimes decides to home during a print. It's no problem when it homes towards the endstop, then it just goes back to printing. The problem is when it anti-homes away from the endstop, trying to push the x carriage or the bed off the bars. I could attach endstops there probably, but that's just circumventing the problem.

Edit: Oh, and I made a funny Minecraft Creeper Keychain, check it out.

 -Nudel

Mendel-parts.com - New v6 hot end and positive experience.

I cringed when I read Camiels post at the mendel-parts.com blog the other day. It's easy to see the frustration, and he does have a valid point about the negative feedback getting the most attention. As I received a package from mendel-parts today, I'd like to share my positive experience with you, while I make a first-impression preview on their new v6 hot end design.

My order was in the €100+ range, which included a 5mm alu printbed and a few spares of the older simpler hotends (now discontinued?), because I know I can get that to work (at least for a day or two). I also ordered a bunch of bootlace ferrules, as I only seem to find insulated ones on ebay for some reason.

The most interesting item though, is this.

This is the newest v6 hot end design from mendel-parts.com, and it looks like it has great potensial. It's machined beautifully, and has a good deal of weight to it. The added weight might have an impact on a theoretical maximum speed, but my main goal is stability over speed anyway.

The only part I don't like is the thermistor attachment, as I don't trust kapton tape, and neither would I like to glue the thermistor permanently to the block. We'll see if I manage to build up the courage to tap a new hole and use a ring terminal with the thermistor on instead.

Another thing I'm a bit curious about is the gap inside the heater block, between the nozzle and the inlet. I have always understood the inside of the hot end needed to be a smooth as possible to decrease the pressure needed to push plastic through. This design have some pretty big threads where the plastic will pack up, and most of us have probably fought with hardened PLA. Yes, I understand they get the design to work very well, though I don't know if this gap has any down sides, especially regarding long time reliability and cleaning.

Edit: I have the peek block the wrong way around in these pictures. More info from araspitfire here.

Back to the order and lead time discussion.

I put in the order 3/26, got a manual order confirmation 3/31, and the package was shipped 4/6. According to the excellent UPS tracking system, it took less than 8 hours to ship the package the ~1000km from the Netherlands to Oslo. It then took 4 days to ship it the last ~100km from Oslo to me, let's blame the weekend for that. All in all I must say it was pretty good!

In total it took 16 days to receive my order, of which 5 days was in transit. I ordered on a Saturday, so the first working day was 28/3. Is 9 days of lead time something to make a fuzz about? I really don't see why people complain. I'd also like to add that they sent me a new printed baseplate for the v6 hotend for free, which they really weren't obliged to do. That's great service!

Some people will probably mention it, and I'd like to agree in advance; this wasn't a complete mendel kit, which may have a longer lead time. But for those of us who have a mendel in our possession, it's irrelevant, because we're mainly interested in fast dispatching of spare parts anyway. And in that regard, I approve of mendel-parts.com, and recommend them as a webshop who delivers what they promise: high quality parts, and a decent lead time.

Update 01.09.2012: Mendel-parts has been getting a lot of bad press over a long period of time, and although the grief is mostly about Orcas, I can not recommend shopping with them until they fix their issues. For high quality extruder hot ends, check out J-heads at hotends.com and Arcol versions at arcol.hu.

Now I'm looking forward to trying out the slick v6 hot end! A proper review is coming up when I have some experience with it running, and made up my mind about it.

-Nudel

Small (35mm) fan for extruder cooling.

I've been looking around for a small fan for my extruder, but most of the cost about $10 + shipping which I felt was a bit too high.

But dealextreme came to the rescue with a replacement fan for the Nintendo Wii. It only cost $3.60 including shipping, and I just received mine. It is not the most powerful thing, and I have yet to mount it, but I thought this might be of interest to others.

Dimensions are 35x35x15mm and it runs off 5v. The black lead is negative/ground, and the gray is positive. It comes with a small connector which you remove by lifting (hacking off) the tiny tabs. There are mounting brackets on the side, but they can easily be cut off if needed.