Welcome to the SeeMeCNC Community

Hey all!

I'm looking to overhaul my entire printer over this summer while I have time.
I currently have magnetic carbon fiber arms installed and they were the cause of a huge failure that put my printing on hold for over a month.
(not a whole lot of free time during finals week)

I'm looking to ditch the CF magnetic balls for something more reliable, and would really love some insight and help because right now I see only two options really.
1) Go through seemecnc and buy the injected molded cheapskates w/ ball cup assembly, or find someone on here who upgraded and willing to sell ($78 but need to adjust effector for v6)
2) Go with Trick Laser and their quite expensive arms, cheapskates and effector ($260)

I'm also upgrading to a duet here soon as well and some other smaller upgrades here and there, so trying not to break the bank with everything, but will most likely be buying everything at once so its an all in one tune up and not calibrating all over the place.

Any help is welcome!

-Herrm

The newest TrickLaser arms have red sockets to grab onto the stock "dog bone" pieces of the carriages and effector. You can upgrade the arms without having to buy the other bits from TL. It's excellent stuff, though. I've got something aluminum or carbon that Brian made on every single one of my printers. Wouldn't have it any other way.

He doesn't sell any arms, but if you want an effector you ought to check out Matthew's stuff on 713Maker.com as well. Also excellent workmanship and service behind great accessories.

Interesting, I recently upgraded my delta to Haydn Huntley's magnetic arms and ball studs, and I haven't had any problems yet. What arms were you using, and what problems did you encounter?

Jimustanguitar wrote:The newest TrickLaser arms .....

So thinking through this, maybe go with the TL arms and then the Seeme Injected molded cheapskates and figure out a new effector? I currently have a custom printed effector for my ball-magnet set up which I could do again in the interim while I decide on an effector?

dc42 wrote:Interesting, I recently upgraded my delta to Haydn Huntley's magnetic arms and ball studs, and I haven't had any problems yet. What arms were you using, and what problems did you encounter?

*sigh* So mine were custom but really similar to Haydn's, almost exactly actually. So when printing there are times that the nozzle will brush against the print if it didn't do a full retract and raise, and because its just magnets, if it clips the part hard enough there is the possibility that the effector will come loose from an arm or two. It happens every so often on big or complicated prints which is a hassled but not a big deal. So this last time it clipped a part and got loose of ALL the arms and I wasn't around to notice. So it completed the entire 8hr print just laying on the build plate not moving. It encased the entire hotend in plastic and I ended up replacing just about everything (i.e. layer fans, the wiring, new heater and heater block, new thermisitor, new effector) You can see a post I made to reddit here: http://imgur.com/a/8LZqP I would definitely suggest a spring or some kind of sensor to stop the printer to keep this from happening. However, I did print for almost a year without issue, but I am just ready to move on after this last stumble! Any way I can help, I'd be happy to tho!

See Delta Arm Joint Musings for the whole story.

I respectfully submit that magnetic ball arms - like all mechanical joint solutions - are a tradeoff. I have 1000s of hours of experience with them and all the others in my post above so, much like that insurance commercial, "I know a thing or two because I've seen a thing or two."

There are circumstances where mag balls will pop off. In particular, any "partial bridging" like a large hole in a vertical wall can lead to a bit of layer curl that hardens and can cause a pop off. It happens; you can design your part and/or slice appropriately to mitigate the problem but there is still the odd inexplicable thing that can cause a pop off. And working on the effector area like unloading a stubborn filament can also lead to pop offs. Not the end of the world but an annoyance. In exchange, you do get excellent layer registration. BTW, I have mag balls on 5 of my delta printers from a Mini Kossel, to a K250 and two D300VS and all the arms were made by Haden - he's the "guy" when it comes to high quality mag ball arms.

Your description of "laying on the build plate" is exactly why I never print unattended with any printer with mag ball arms in particular. But I don't print unattended whenever possible with ANY printer and when I do I have 2 proximal smoke detectors, two heat detectors and alarms and a fire extinguisher at the ready. I never leave the house with a printer unattended, never.

One final note, with the release of the E3D Titan Aero direct drive extruder, the Bondtech BMG direct drive extruder and the UltiBots Micro Extruder I have come to recognize the big print quality trade-off we've made over the past few years on large delta printers with long Bowden tubes. The Bowden on smaller deltas like the Mini Kossels are not so problematic but is on machines the size of a Rostock and D300VS. Even with high quality 1.8mm ID PTFE tube that I've been using for my Bowdens for several years (this minimizes the "slop" of the filament traveling through the tube and results in more precise retracts at the expense of more friction to push the filament - which is one of the main reasons I use Bondtech QR extruders) a direct driver extruder will give significantly better results. But, the extra mass on the effector puts more burden on the mag balls. Again, usually not an issue but one that must be considered.

Off topic a bit for direct drive extruders. Since a picture is worth a 1000 words here are 4000 words:

This gear is extremely difficult to print without a LOT of stringing between the gear teeth. There are 1000s of short segments followed by short hops. A challenging part to print cleanly. This photo shows a very good part printed on my Rostock MAX V3 with a 1.8mm ID Bowden and Bondtech QR extruder with a E3D V6 hot end. But as good as it is, you can see the little wisps of filament strings between some the teeth (click the photo for high res view). This part was printed on the same printer but with the Titan Aero direct drive. Same g-code and same spool of filament. In other words, a very good 1-1 comparison test. Not a hair on its Chiny-chin-chin (or is it toothy-tooth-tooth?)

Here's an example of the type of geometry that can be problematic for mag ball arms printed in PLA: To mitigate, improve cooling significantly, use .1mm layers, slow down significantly, add support to the hole/opening, etc. It can be printed with mag ball arms but if you are not experienced and don't "think through the print" it will likely fail with popped off arms. Even the small 3mm through holes can cause problems.

This problem typically arises when there is not a continuous bridging action across a highly overhung geometry - like the layer highlighted in yellow. We can argue about this not being an ideal geometry (as it is presented) for FFM printing and I will not refute - it isn't. But there are many bad geometries on the sharing sites that are problematic in this way. In my example, I simply design-in a "T" support for the top arch and solve the problem - "think through the print."

mhackney wrote:See Delta Arm Joint Musings
I respectfully submit that magnetic ball arms - ....

Thank you for the insight and I definitely agree. The magnetic arms have provided me 1,200 hrs of my total ~1,680 hrs of printing on my Rostock and have done so very well! Biggest issue is that I personally made them and they don't have nearly the precision a set of well made arms would have. Theres slop and in combination with a large amount of issues I just need to cut my losses and also have piece of mind!

I did notice that on your delta you're running the Trick Laser arms, but where did you get the metal effector? It looks almost like the stock Seemecnc effector. Also what "cheapskates" do you use on your machines? I am definitely not in love with the original cheapskates (version before injected molded)

Again thanks for the input and I may actually look into the direct drive as well, that print is beautiful.

Herrminator117 wrote:

mhackney wrote:See Delta Arm Joint Musings
I respectfully submit that magnetic ball arms - ....

Thank you for the insight and I definitely agree. The magnetic arms have provided me 1,200 hrs of my total ~1,680 hrs of printing on my Rostock and have done so very well! Biggest issue is that I personally made them and they don't have nearly the precision a set of well made arms would have. Theres slop and in combination with a large amount of issues I just need to cut my losses and also have piece of mind!

I did notice that on your delta you're running the Trick Laser arms, but where did you get the metal effector? It looks almost like the stock Seemecnc effector. Also what "cheapskates" do you use on your machines? I am definitely not in love with the original cheapskates (version before injected molded)

Again thanks for the input and I may actually look into the direct drive as well, that print is beautiful.

That's a 713 Maker Ball joint effector. They are quite lovely, and leave a lot of space open in the middle (I am proud to say I have one of the first to be sold, and have never had an issue with it)

+1 for 713maker effector platform. Have it anodized to your liking. Get cool mount at the same time. I have nothing to do with them, just love the effector.