Hello everyone!
I have started a new MPCNC with some modifications. Now I draw in SketchUp and prints plastic parts on my 3D printer. I have some questions about stepper motors. I want to use geared stepper motors with 5: 1 gear ratio. Is it a good idea? Thanks.
Have you built a stock MPCNC and are having rigidity issues?
I’ll use Makita RT0700C, that is heavy and want the build area approx 0,8mx1,5m. I was going to do a little more stable long side with two tubes. What about my question? Thanks.
5:1 sure you sacrifice speed for power, but why? You can use larger NEMA 17’s up to 96oz/in I believe, or even strap on some NEMA 23’s Geared steppers tend to be very expensive.
Have you built one?
Were the steppers not strong enough?
Was it not rigid enough to support your cutting tool, it is not really significantly larger or heavier than the Dewalt that is being commonly used?
I ask these questions so I can use the input for version 2. There really hasn’t been any complaining from anyone that has built one is why I ask. Sure we all want more rigid but for every decision there are compromises.
I use that Makita in a 2’x3’ configuration with Camar0’s and the Middle_Z_Rigid mods http://www.thingiverse.com/make:169149. I don’t know about the 1.5m/5’ length rigidity though. I agree with Vicious1 that if you have not, you should try the stock MPCNC with these mods.
Also, I don’t see any good reason to go with a geared stepper at all. My NEMA 17 steppers (datasheet enclosed) are very slightly beefier than the standard ones and they have no problem moving the 3.1lb Makita and the extra bearings in Camar0’s mod. They also get barely warmer than room temperature. I think it is a good idea to use the beefier DRV8825 drivers though. I have a small 30mm or so fan blowing across the drivers and they seem to run cool.
I recall that Vicious1’s “parallel processing” printer configuration has extra X or Y sliders and It seems to run fine at high speed. Remember that you will be milling at a fairly low feed rate so moving around the extra mass of the Makita will not translate to that much force on the steppers. Does this make sense? What do you think?
Steve C
BTW, I did have some chatter before I added those mods but I think it may have been mostly due to having the belts on one axis much too loose.
Vicious1 and SteveC many thanks for info!
I also tried to draw the similar build as Camar 0’s and the Middle_Z_Rigid mods but finally became a variant with three tubes in the middle. Plastic parts are almost finished and I start to order other stuff. I plan to use T2.5 belt open ended polyester w / steel wire reinforced and SFU1204 Ball Srew.
I have build a modified version of Eustathios 3D Printer with E3D Volcano and plastic parts are very robust.
I order the 96 oz NEMA 17 then.
Ivans, how do you find the parts printed with the Volcano and the larger nozzles? I already have a good 3d printer for detailed items (using an E3D v6 with a .25mm nozzle). My plan was to use a E3D Volcano and a 1mm nozzle with my MPCNC.
I’d love to hear your thoughts on printing larger parts using the larger nozzle.
I have Prusa i3 with E3D V6 0.4 nozzle and sometimes use 0.4 nozzle Volcano on my Eustathios. I can say that the quality as good and detailer is more rigid. I printed the same detail and having the same PLA with E3D V6 0.4mm on Prusa i3 and with E3D Volcano 0.4 nozzle on my Eustathios. I was easily broken by hand detail that was printed on Prusa i3 and it was is much more difficult break detail that was printed on my Eustathios.
My favorite Volcano nozzle is 0.8 mm. It goes good quality and printing speed. I experimented with 1mm and 1.2mm nozzles too but quality was bad and it was more ooze. You can use 1 mm and 1.2 mm nozzles if it is not required quality and required speed for drafts.
I use a V5 E3D with the stock (0.4 I think). I am really liking PETG for strength. It has much better layer adhesion than PLA and ABS in my crude testing.
PETG cost double that PLA. Hmm … Details ab PETG printed with Volcano becomes like steel then … kidding 
The PETG spools that I have were $18.99/Kg locally at a Cambridge Ma Microcenter. That is cheaper than any ABS or PLA that I have. That said, I did have a clogging problem with a spool of their yellow PETG because of uneven filament thickness.
Play around with your retraction settings to control ooze. I had problems even with the standard .4mm tip. But experimenting with settings solved the problem completely.
Thanks for the feed back on the volcano and the larger nozzles, I look forward to experimenting with them myself.
Cheers.
