Hi all, I have read quite a few posts regarding the 500w DC spindle and the opinions seemed to be mixed…its working great for some people and not others. I have decided to give it a shot…Is this a good one? Should I get a brushless one instead?
Additionally, Can either of these spindles be controlled via Marlin?
This is what the manufacturer tells it like it is:
“greatly reduces the interference of the electric spark to the remote control radio equipment.”
“great support for the operation stability of the equipment.”
“brushless motor is almost a maintenance free motor”
These are all excellent points, and finally:
“By comparing up and down, we can know the advantages of brushless motor over brushless motor.”
They appear to use a poti for speed control. It is possible that poti power pin puts out 10V and the sensor pin reads 0-10VDC. If this is the case, then yes you could control it with marlin using a pwm converter like this:
Note the one linked above says it is good for 0-25kHz PWM. Marlinfw by default puts out 500Hz pwm; make sure what you buy works with that.
The most common solutions for spindle/router for this class of machine across multiple brands is a Makita RT0700 series router or a clone like this one from Carbide 3D. Using this router as a basis and doing some conversion, the Makita is roughly comparable to a 1Kw (1000W) spindle in cutting power.
In the few instances on this forum where I’ve seen someone who has run both a Makita and a 500W spindle, they found the spindle to be underpowered by comparison, which tracks with the wattage estimates. The spindle still got the job done, but they had to use less depth of cut and/or federate in order to avoid chatter and other issues. I’ve not seen a 1000W spindle, but 800W spindles are common, and assuming the wattage rating is accurate, will likely give you a more comparable experience to a Makita router.
As for control, hooking up a relay to control on and off of a router is pretty common on this forum with multiple different solutions (IOT Relay, mechanical relay module, SSR…), so if that is all you want, no problem. If you want to control the speed as well, then that is more of an issue. Just looking at the pictures, most of the lower wattage spindles seemed to be controlled by a physical potentiometer (including the two you linked). Marlin outputs a PWM signal. I’m just a hobbyist with electronics, but if I was to solve this problem, I’d try using a cheap Arduino to take the PWM input and use that input to control a digital potentiometer.
If you go with yet bigger spindles (1.5Kw), then you will be dealing with a VFD. Controlling a VFD from a Marlin control board can (and has) been done, but there is a bit of electronics that needs to be added to convert the (typically) 5V PWM signal from the Marlin control board to a 10V signal at the VFD.
I remember a lot of complaints about the 500 watt spindles using rubber bushings that deliver fantastic runout when measuring, but flex and squish under load when cutting and make a mess of the work piece. It wasn’t all of them, though, just something to look at when you get it so you know whether to return it…
Those BLDC motor drivers use a 5v derived speed signal so will accept a 5v PWM input directly.
I recently acquired a Vevor VFD and that has both 5V and 10V inputs.
When making your decision as to what spindle to go for keep an eye on the max speed of the spindle, a ‘proper’ spindle with ceramic bearings will do 24,000 rpm…that is why they cost twice the price of a DC motor, some of those can only get up to 6500rpm. For some materials that may not be enough.