Has anyone had success printing PLA with Magma?

I've sorted out a few issues with my Prusa i3 and have it printing ABS pretty well. There are a few jams here and there but overall ABS seems to be a known quantity.

Now I've circled back to trying to get PLA to print with my 0.40 Magma hot end and I'm having a lot of trouble. There are a few problems:

1. The PLA 3mm filament is softer than ABS and tends to get chewed up by the extruder hobbed bolt more easily. Still trying to verify that I have the right temperature setting.
2. Heat seems to travel up despite the use of thin walled stainless steel tubing and a large aluminum block. I've tried mounting aluminum sheet stock on the cooling block but it still jams sometimes, particular when the hobbed bolt has chewed into the filament enough that it goes into the top of the hot end with some additional roughness. THis is more sensitive to expansion even with a small amount of heat.
3. I'm suspicious the slic3r is not generating the right code for my Marlin / RAMPS 1.4 - when it reverses (on layer change and for longer moves) it sometimes moves the extruder gear MUCH more quickly than seems prudent. It's almost as if the feed rate specified for extruder reversal is getting overridden by some other feed rate setting. This jerky reversal (which happens more on smaller scale objects) seems to contribute to extruder jams (on ABS as well but more on PLA).

I'm wondering if ANYONE has had sucess printing PLA with a Magma hot end???

I would also be interested, as I am having the same problem.

I have had pretty darn good, whati would call success printing with ABS on my i3 with Magma. A couple things that I have read and that you have not likely been exposed to:

1. Wrap the copper or brass end with Teflon tape that will make the extrusions more precise.
2. I am sure that you are using the fan to cool the hot end, I have been using it and it seems to be working OK for me. I have not made anything museum quality yet, but I successfully built the test cube, it is a little warped, but it was successful. I have printed a few thin projects interconnected hearts that were featured on thingiverse. I have printed successfully about 60% of a soap dish that had like 50 little feet that held the soap. My problem was the doggone ABS will NOT stick to the surface. I have tried hair spray, I have tried glue sticks, I have tried it all not sticking.

if my prints stuck, I would be very happy with my magma.

Yeah, I feel like people have had good luck with ABS, just not PLA. I just don't happen to want to run ABS right now.

As for sticking, have you tried an ABS slurry. I have not myself, so I don't have any first-hand experience, but have read people having good luck. Hair spray has been working well for PLA on glass for me, you know, until the printer jams

I hadn't heard the one about wrapping the brass end with teflon tape. Presumably that's to act as a thread sealant? The Magma definitely leaks where the brass nozzle screws into the thin-walled stainless steel tube but it doesn't seem to be a huge problem, I get a little burnt blob which looks ugly but plugs the leak.

As far as sticking, the Garnier Fructis Ultra Hold has been working quite well for me, to the point where I cannot remove larger pieces easily without cooling the bed down. The biggest problems I had in adhesion were in the beginning when I had an underspec power supply and it was not getting the top of the bed hot enough. If it takes more than 5 minutes to get the bed to 115C (the temperature I use, the thermistor is on the bottom of the heated bed PCB and registers a significantly higher temperature than the top of the glass) you may have a problem with the power supply current or with the connection to the heated bed.

When I have ABS pulling away from the heated bed it's only on corners of large slablike pieces. But you might want to measure the temperature on the top of your heated bed to see what you have - an IR thermometer is pretty cheap nowadays. I find I get the best readings pointing down from directly above the spot I want to measure.

I have a fan on my Magma hot end and I recently added fan duct assembly [www.thingiverse.com] to replace the piece of cut aluminum flashing I was using, and so far so good. I'm planning to retry PLA now that the cooling should be more directed to the upper part.

I'm still not able to get PLA to print without frequent jamming on the Magma. It seems that despite all the heat isolation attempts, heat travels up the filament itself and causes swelling in the top part of the hot end.

This thread has quite a bit of discussion from 3 months ago and it sounds like there are still outstanding issues with Magma and PLA: Google Groups discussion on Trinity Labs magma

I had read a post from Ezra Zygmuntowicz (here in this discussion on e3d) where he claimed the Magma works flawlessly with PLA, but on going back to MakerFarm (where I bought the magma with my Prusa i3) I see that Makerfarm doesn't claim the Magma works with PLA and specifically says it WON'T print PLA. Sounds like a safe assertion to me!

This is an interesting item from Ezra's (long) post:
3. All metal hot ends seem to prefer as little as half the retraction as their teflon lined bretheren. For example with PLA I retract 0.86mmm in slicer. While with the magma I retracted 0.45mm instead to get similar retraction effects.

Another thing is there seems to be a minimum speed printing PLA with all-metal hot ends.

My conclusion was that retraction (which seems to happen way too fast) is where the hobbed bolt chews into the filament.

I'll try playing with the retraction settings again and see if I get any success...

Edited 1 time(s). Last edit at 09/13/2013 08:44PM by papergeek.

I ran a quick experiment with my magma the other day and here is what i got. It is ABS specific but you may find the results usable.

I have small fan ducted to run directly over the upper portion of the magma, where the heat fins are and very little escapes downward towards the actual hot end area. (http://www.thingiverse.com/thing:147033)

When i cut the power to my hot end and fan, the temperature of the unit rose from 224C to 238C in a mater of 6 or 7 seconds. In order for this to happen there must be a heat reservoir, now i assume the heater is this reservoir, however it may also be that the inner surfaces of the hot end are also acting as a heat reservoir. I take this to mean the indicated temperature of my hot end is lower by (pure guess) 7 or 8C. Try lowering your hot end temperature by a few degrees and see if that helps any.

Also i printed the fan unit off of thingiverse for my printer and i have seen wonderful results. My assumption is that due to the metal body of the magma the PLA is both heated too much and the PLA is heated to soon, having your fan run full speed cooling only the proper area (via a duct system) and running the PLA at a lower temperature would seem to have the best effects.

To get good ABS results i had to do the following, i imagine it must be similar for PLA
.2mm and lower layer heights
- lower temperature by 8C
- reduce flow to 70%
- increase extrusion width on top fill (slic3r setting) to make up for lower flow
- run at around 75mm/s (my magma likes to move relatively fast, when i slow it it gets junky and weak bonding)

I hope this helps and that i'm not just stating the obvious...

Edited 1 time(s). Last edit at 09/23/2013 10:18AM by haitmatthew.

Thanks for the feedback on ABS.
I've been using this: [www.thingiverse.com]
That works well but is a pain when I need to switch the extruder for my tool head [www.thingiverse.com]

Maybe the ducting guide you're using will be easier to switch. I'll give that a try. My current one does seem to be doing a very good job of keeping the top part of the Magma cool and keeping airflow away from the heated bed. With no ducting guide in place and the fan blowing, I have trouble getting the nozzle hot enough. I've also checked the temperature inside the nozzle by sticking a thermocouple hooked up to a multimeter all the way down, so I'm confident in the accuracy of my temperature readings.

I've also found that (somewhat counterintuitively) as you say, speeding up printing with Magma works better.

But your mix of specific settings (increasing fill width to make up for reduced flow) is interesting and I'll have to give it a try. I also haven't tried reducing layer width from 0.3 to 0.2 or less.

The thing is that I have actually gotten ABS printing pretty well. I still get some warping on large slablike pieces but I've just moved to a better ventilated location and probably need to reduce airflow around the edges of my heated bed.

Everything that works for ABS does not seem to work well with PLA. I haven't had the patience to find the right combination of settings for PLA with the Magma - I've been having very good results with ABS and need to circle back to PLA and take the time to work through the problem.

The type of specific settings you're suggesting for ABS are exactly what I was hoping to get from someone who's already successfully printing PLA with the Magma. This does give me some ideas for the next time I try to get PLA to print...

One of the problems that seems to occur with PLA is that heat travels up the filament itself and causes expansion. Once PLA has expanded inside the stainless steel tube it's an incredible pain to get out. I've noted that Colin at MakerFarm specifically says the Magma does NOT work with PLA, which is probably a fairly safe assertion. If I can get it to work I suspect it's going to be with a fairly narrow range of settings, unlike ABS. I think the Magma design is just not that suited to PLA.

If the metal body of the hot end seams to be the problem would it be effective to design a hot end which was suspended rigidly from the carriage without a large guide tube. Make it as short as possible. Perhaps even use an aluminum oxide spark plug body hollowed out yo accept the 3mm width of the filament.

I have also been considering casting my own hot end out of aluminum and then throwing it on the lathe to get finer heat fins to try and bring the body temperature down.

Any thoughts would be appreciated.

I did see a video of someone who had built a delta style printer and the extruder was mounted on the supports of the unit and nowhere near the moving hot end. Could this have more benefits than drawbacks. At the moment I can think of only one or two possible coins of the design.

There are quite a few interesting threads on the topic of Magma. I believe the one I have has the fix described in this thread: [groups.google.com]

This posting by Ezra Zygmuntieowicz is inserted in a thread on E3D (for which he got rather well flamed) but has a lot of interesting detail on what MIGHT work for PLA: [forums.reprap.org]

The theory behind Magma is that the thin-walled stainless steel tubing is polished (therefore very smooth inside) and is also a very poor conductor of heat. The large aluminum block above it should help with dispersing any heat that makes it across the SS tubing. Thus the need for a fan blowing on the aluminum block.

When PLA moves too slowly heat travels up the PLA itself (apparently) and gets stuck in the tubing.

I've seen some people claiming they use higher temperatures for PLA but I am assuming their thermistors may not be reading correctly, because PLA will begin burning and leaving burnt-sugar type carbonated deposits if too hot for too long.

I'm also watching for people to report on reproducible success printing PLA with the E3D - I'd dearly love to have a hot end that can print PLA, ABS, nylon and polycarbonate and that doesn't need loads of maintenance. I'm still hoping I might get the right settings for PLA in Slic3r but it's starting to look like Ezra Z's claimed results for printing PLA are just not reproducible, at least not for me...

I've also seen the other extruder design where the filament gets pushed through tubing and the extruder does not move with the X axis. I'm not sure how well that works with all-metal hot ends. I know the E3D can use that as well as the direct type.

my magma hot end is doing fine for smaller ABS prints

I am currently trying to figure out some fix for my layer adhesion issues.

My setup is:
Makerfarm Prusa i3
0.3mm layer height
75mm/s for perimeters
100mm/s for infill
228 C for the extruder
115 C for the hot bed

there was also a 10mm brim around the outer portion of the part
I enclosed the tall walls with a skirt 1mm from the inside wall and the outside wall to protect from both sides.
I used ABS Juice to correct the first layer warp issue.
I mostly enclosed the unit using plastic bags and cardboard. some gaps were left near the z screws

It does not appear to be banded, it mainly seems that in some cases the layer is not bonding to the previous one.

I do plan to enclose the entire unit but i am planning a way to cool the ramps board, when i fully enclose it the PTC fuses overheat and shut down the printer power.

Oh and before it's asked i have calibrated my extruder. 100mm for 100mm request.

Hmm, OK, I had missed a very important point here.

Discussions of PLA being hygroscopic like PETT are limited to problems like blowing bubbles, etc. In my case it seems that as my PLA filament absorbed water during one of the rare humid spells here in So Cal, it increased its tendency to conduct heat and swell further up the tube, thus leading to jamming.

I also needed a much higher temperature (220C) than I remember when I first got it a few months back (185C). And yes, I've checked my nozzle temperature, it's within 2-3C of what the thermistor reads (checked by shoving a calibrated thermocouple lead all the way down to the inside of the nozzle).

I need to try again (with the required settings to reduce reversal) after thoroughly drying the PLA.