mendells

Success! I am able to print XT-CF20 reliably now with some modifications. 1. Olsson Block with 0.4mm Hardened Steel ed3 nozzle. 2. Upgraded gear feeder with 5:1 planetary reduction (Gear Feeder, Geared Stepper) 3. Thin layer of PVA (Elmers) glue. Diluted 3:1 with water and spread with a paper towel over heated bed. Machine Settings: E-Steps per 1mm filament: 443.46 Cura Settings: Layer Height: 0.1mm Print Speed: 50mm/s Initial Layer Thickness: 0.2mm Bottom Layer Speed: 250 Outer shell Speed: 30 Travel Speed: 250mm/s Material Settings: Print Temp: 245C Bed Temp: 70C Flow Rate: 100% Fans: 50% Had one bad spot, not sure what happened there. The cube is measuring a little on the high side, 20.1, but otherwise looks very good. Sorry the video is so dark. Its our old Ultimaker and the LEDs are all but dead.

Update time! I found some gear stock to make the feed gears out of. I have two sets, one tighter set for Ninjaflex and one for PLA/XT filament. I'm using a stepper with a 5:1 gear ratio and initial tests seem very promising. It has tons of grip and doesn't deform the filament very much. An additional plus is the teeth marks stay consistent because they line up with the teeth even after retraction. I am expecting an ED3-V6 in the next week or so so I will update you on how the gearbox performs on our MakerBot conversion.

Thanks for the feedback and the video. I do plan on printing PLA but my main concern is higher temp filaments like ColorFabb XT and XT-CF20, Nylon, PET and TPE. We have multiple machines so we may just keep one or two as a dedicated PLA machine and switch one over to the all metal hot end. I plan on making a number of different nozzles and heater blocks out of different materials, brass, stainless and titanium for testing. I did update the design a little to make it easier to manufacture the nozzles and provide better heat dissipation in the heat sink.

While I love our Ultimakers (2 and Extended) I still have some issues with the hot end. The brass nozzle doesn't hold up well against carbon filled filaments and the PTFE thermal barrier is a source of much headache. My idea is to machine an grade 5 titanium nozzle and heater block as well as a new aluminum heat sink. The nozzle will be a single titanium tube and will be to change over using the front facing set screws. My hope is that the all titanium tube will dissipate heat fast enough to prevent jamming inside the tube while being hard enough to use with carbon filled filaments. Let me know what you think!

This might be a stupid question but haw do you change the extruder steps/mm (drive gear diameter)? I am trying to test my new extruder but can't seem to find a way to change the software to accept the new drive diameter. Any help would be greatly appreciated! Edit: I'm using Cura 15.02 and have tried changing the E-Steps per 1mm filament but when I run the program it doesn't seem to have accepted the new value at the machine.

I was having the exact same stringing problem with one of our Ultimaker 2s. It turned out to be a bad temperature sensor. After replacing it (which is a bit of a pain) the stringing went away.

You shouldn't need to print it at 260º, I had success printing at 245º. Also try using a white PVA (Elmer's) glue/water solution instead of the glue stick. Use something like 3:1 water to glue ratio in a bottle. I usually heat the bed to 70º, put some of the glue/water solution on a paper towel and spread it over the bed. It creates a thinner, more even coating than the glue sticks. Be warned the brass nozzle will degrade significantly over even a half a roll. You will likely need to re-level the bed before every print. https://ultimaker.com/en/community/view/11141-nickel-plating-nozzles-for-carbon-filled-filaments-updated?page=1&sort=

I had a hard time getting XT-CF20 to stick to the bed. Try slowing your Bottom layer speed down (10-20mm/s) and changing the "Initial layer line width" to something like 120%. The XT filament is "sticky" and tends to want to stick to the nozzle itself so make sure its clean before you print.

That seems to have been the problem! I replaced the thermal sensor and started a new print. So far no stringing and better looking walls.

I've got an extra thermal sensor, I'll have to give that a try.

Avoid 5th gen MakerBots like the plague! The 5th Gen replicators have nothing but problems. They are so bad there is a class action lawsuit against MakerBot (Stratasys) for knowingly selling a product that doesn't work. We have a UM Extended as well as 2x UM2s and are very happy with all three. We also have a Replicator 2X which is a generation older than the 5th Gens. Its OK but the Ultimakers are far better.

There will be a belleville spring washer to give it some play but no coil spring.

Here is the second version of my gear feeder design. This one allows for adjustable tension on the filament. I am converting our old MakerBot Replicator 2X to use 2.85mm filament so this should get a good test here soon. Let me know what you think?

We also have 2x UM2s and one of ours started having the exact same problem with stringing a few weeks ago. So far I've replaced the PTFE tube, nozzle, thermal sensor and heater with no change in results. I'll look at the set screw but I have my doubts that that is it. It feels tight from the outside. With "Move Material" on the motor "brake" is on and I can't feel any play in the drive mechanism. Both printers are running the exact same material, the exact same settings and the exact same program with different results.

No bearings for the prototype, just wanted to test the function. There will be bearings in the final version (you can see them in the CAD model. Once I'm happy with the design I'll share the files. I am still experimenting with the fit of the gears to get the best grip. I might see if I can get some stainless steel gears made but that might take a while.

Ok so here is what I have so far. This started because we want to convert our old Makerbot Replicator 2X to use a 3mm E3D-V6 hotend with stainless steel nozzles for use with carbon filled fillament (see: http://umforum.ultimaker.com/index.php?/topic/10141-nickel-plating-nozzles-for-carbon-filled-filaments-updated/) I started off by making a drive gear type similar to printerbot's (and a few others) version. Everything is currently printed using ColorFabb XT-CF20 filament but the results so far are very promising. I am unable to make the filament "slip" and the motor skips steps before it slips so I'm pretty happy with the pressure on the filament. There is minimal marking to the filament itself. Plastic gears won't work in the long run but it serves as a good test. I am using an 5:1 planetary stepper (http://www.omc-stepperonline.com/gear-ratio-51-planetary-gearbox-high-torque-nema-17-stepper-17hs191684spg5-p-40.html) but I may switch to a 19:1 or something in between.

I work at a machine shop so we just ordered a bar of glass filled PTFE and turned them up on a CNC lathe. Great link, thanks for sharing! Unfortunately after round 20 hours of printing XT-CF20 the nickel plating is already gone off the tip of the nozzle. I will switch nozzles here soon but I am not confident that they will make much of a difference. Next step is to make a new nozzle out of stainless but that may take a while as it will require some custom tooling.

I haven't measured it but you can easily move the filament with two fingers. The wheel offset isn't that great and the bearings provide a nice smooth action. I've been using these for months now and they seem to be doing a great job.

The filament isn't "bent" per-say, its just been tightly wound around the spool. The radius at the outside of a new roll is much larger than the filament at the end/center. The smaller radius can cause binding in the bowden tube and PTFE coupler. I don't have a pic of the filament after running through the straightener but it results in a radius larger than the new roll.

I added a filament straightener to our machines that helps immensely with reducing under extrusion. Before we would get about half way through a roll and the radius of the filament would cause binding issues in the head. With the straightener we've been able to use the entire roll without seeing any change in extrusion. It does make loading filament a little more difficult but its worth it. https://www.youmagine.com/designs/um2-filament-straightener

I've asked around and most "diamond" coatings, like those you would find on cutting tools, can't be applied to brass or other alloy substrates. If you had a steel nozzle I imagine it might be possible? Well I'm not worried about the isolator... I work at a machine shop so we just made a bunch of spares. We seem to be replacing them every 2 months or so anyways. I've checked out the bowden tube and drive mechanism and it all looks fine. Brass is really soft so its not surprising that the carbon filament is wearing it down so fast.

Yes, several times actually. It was getting to be a bit annoying, I could get through 2-3 prints then have to re-level the bed. The inconsistency caused by using the glue stick on the bed didn't help either.

I was starting to get bad prints so I decided to swap out the nozzle early. The ID is measuring 0.05mm oversize but the really supprising thing is how far the nozzle tip has degraded. The overall length of the nozzle shrunk by 0.5mm. The tip diameter is hard to measure but its around 2mm now where it should be 1mm. They really aren't kidding when they say the carbon filament is abrasive.

The nozzle has probably seen 500 hours printing PLA and has gone through about half a roll of XT-CF20. The nozzle ID still looks pretty good but the tip is seeing a lot of wear.

I'm not exactly sure how they do the composite coating. Here is their spec sheet: http://www.twincityplating.com/resources/TCP_fctsht_XT.pdf "Electroless Nickel (EN) composites have been used for many different purposes for a number of years. Given EN’s amorphous structure, polymers and other non-conducting materials can be co-deposited providing capabilities above and beyond traditional EN. Teflon, Carbide, Diamond, Boron-Nitride – can all be used to improve the characteristics of the coating – Hardness, Lubricity, Corrosion Resistance, Abrasion Resistance, etc" The plated nozzles should arrive later today. I've been running the XT-CF20 on one of our UM2s to get a good baseline on what the true wear will be on an uncoated nozzle. You can already see some wear on the tip of the nozzle. The leading edges of the nozzle now have a pretty big radius on them. I have to say I LOVE the XT-CF20 filament. Its super rigid and has almost no warping (even better than PLA). Overhangs and bridges are great as well. Small fixture jaw at .05mm (no supports, raft or brim) Large fixture jaw at .12mm (no supports, raft or brim) Gear test at .12mm (no supports, raft or brim) Once I've run through a full roll I will switch to one of the coated nozzles.