- February 23, 2017 at 3:50 pm #28302
Just received an email from John at automationtechnologiesinc.com, regarding my query about an 800-watt spindle and a 110VAC VFD inverter. My question is this, will the weight of the spindle be too much for the MPCNC? I am planning on using 1″ OD 316 stainless tube with a 0.065″ wall, the workable size of the frame will be 24″ x 36″. I have already sourced the stepper motors from StepperOnline (92 oz.in, cheap enough) I will get the power supply as well as the stepper drivers there as well.
Another question, can I still use the Arduino & Ramps 1.4?
Yes, I know, this may all be a tad over-kill, but more power is better (sometimes 🙂 I also know that with this CNC rig, I won’t be able to hurry things along, that is not my intentions I do believe that Ryan has a great thing going here, and I sure look forward to building a MPCNC rig. Yes I am going to have questions, lots of em :), like has anyone used Mach3, I am pretty fuzzy on the setup to get this all working, so far I have just done a lot of reading, and getting more confused all the time :)Why do I want to go with a spindle you ask? Because I really want to have some kind of control over the noise.February 23, 2017 at 7:45 pm #28313
I asked how much weight the z axis can handle last week and so far have not received any input.
I loaded around 9 lbs onto the tool mount and was able to cycle up and down with no problems. The driver and the stepper stayed pretty cool. I’m planning on ordering the 800 watt air-cooled spindle which I believe is just under 6 lbs. Also instead of the vfd you linked you can get a name brand Teco Westinghouse for less money. It specifically states in the specs that it is 110 input and 220 3 phase output.February 23, 2017 at 7:58 pm #28314
Hey Joe, I was looking at a liquid cooled spindle, maybe it is a bit heavier, sure do like the price of that Teco/Westinghouse inverter 🙂February 23, 2017 at 8:16 pm #28315
I would like to change mine to a spindle as well and water cooled is what I’m after but I am still researching these. Interested in where this goesFebruary 23, 2017 at 9:16 pm #28316
Please look through here and make sure you understand what your changes will do. Putting a V8 on a skateboard doesn’t necessarily make it faster. I Feel we have a well balanced machine, any changes will have repercussions.February 24, 2017 at 10:38 am #28353
I know a 400 watt spindle is the safe choice but I’m really curious how an 800 will handle. Below is some info I’ve gathered in case anyone else is interested.
– Slower acceleration in all directions. More importantly, slower deceleration which in my mind would cause loss of precision and resolution.
– Deflection of the gantry assembly on large machines. Again, lower precision.
– Expense. Looking at around $350 for everything if going air-cooled.
– Reliability. No brushes to replace and standard size bearings. Although I’m not sure what bearings the Dewalt uses.
– Precision. Most of the 800 watt spindles have 2 sets of angular contact bearings and are made specifically for cnc.
– Standardized collet system.
– VFD can be used on other tools. 3 phase lathes, mills, drill presses, etc.
As far as other alternatives to the DW660:
– 300-400 watt dc brushed, quite cut type spindle. I’ve read quality on these varies greatly.
– 400 watt 3 phase ac with ER11 collet. Collet is clamped onto the spindle shaft and they do not have a hall effect sensor for rpm feedback. Only 12k rpm.
– 400 watt 3 phase ac with ER8 collet. Collet chuck is part of the spindle shaft so theoretically the tolerances are better. They have a hall effect sensor for rpm feedback. I’ll assume the drivers are able to maintain a constant rpm and not bog down as much under load. Only 12k rpm and smaller collet.
– 600 watt dc brushed. Clamped on collet chuck, brushed, no hall effect, 12k rpm.
– 800 watt 3 phase ac with ER11. Collet is the spindle shaft, collet size, power, true vfd, 24k rpm, and no extra power supply. Major trade off is weight. Also there is no hall effect but you can get rpm from the drive frequency.
– Kress. Probably the correct choice for the mpcnc but is expensive to get in the US.February 24, 2017 at 2:08 pm #28360
800W will do you no good. DW660 is just too fast IMO, and the runout is terrible.
I have a 500W brushed spindle and I usually have to run it at 3/4 speed (about 8000 RPM). I wish I had went with the 400W brushless + Hall sensor.February 24, 2017 at 6:28 pm #28387
I was just beginning to wonder about the high RPM. Sure is making it hard to figure out what to get, like you suggested David, maybe a 400 is the way to go, seems to be a lot available.February 24, 2017 at 6:51 pm #28390
Single flute is essentially half the speed of a 2 flute.February 27, 2017 at 8:17 am #28573
Number of flutes on a mill only affects the feedrate, with 2 flutes you can feed twice as fast as a single flute and maintain the cutdata you have calculated. The thing that affects rpm is mill diameter and the Vc of the material (from cutdata)
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