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So, using the 800W VFD Spindle, and a few other modifications, I am starting to get great results cutting aluminum. The main issues I am still having are
Getting homing to work right
Belt slipping on X due to too much force. I added some zip ties that seem to help.
Finding a good coolant lubricant. With this spindle, tapping fluid mostly just makes a lot of smoke.
Chip clearing. I have to stand next to the machine with an air hose to try and keep the cutter tip free of chips.
This was done with a 1/4" two flute aluminum cutting bit (a Destiny Viper), and a 90 degree 1/4" four flute chamfer mill. The feed rates around 400 to 300 mm/sec. Unfortunatly, due to the belt slips, my turners cube has a huge ragged hole in the side. So I need to start over from a new blank.
The VFD spindle is working great. Even plowing through the aluminium like this, it is still only drawing about 1 Amp.
Looking good man! What DOC are you going with on these cuts? How is the surface finish doing? I am finishing up my VFD build today. Just cut the 6061 wire pass through panels out on the OKO and they are in Anodize right now out in the garage. Final wiring will happen this afternoon and then calibration. I am still waiting for the PlanetCNC MK3/4 and Leadshine drivers to show up for the X Carve so going with the TinyG for now. Have you hooked the VFD controller to your mill controller for Gcode spindle control yet? I will post a few pics of my setup this evening once I finish all the wiring. Oh yes. how did you closed loop cooling system work out for you?
I’m using adaptive clearing in fusion 360 to remove most of the hole, bores out the center with a spiral ramp, and then side mills the rest out, so the depth can be as high as about 13mm in this case. I used a cutting feed rate of 400 mm/sec, 24000 RPM, and a optimal load of .5 mm. I found that the spindle was capable of 600 mm/sec, but that put enough force on the piece to make the X belt slip, so I dialed it down (as well as fortifying the belts). When it is working it makes chips that look like steel wool.
You can probably check out the program here. You probably need a modern browser like chrome. Its under setup2, adaptive1.
The closed loop cooling is fine. The latex tubing doesn’t leak, but it tends to collapse depending on the pressure. Also I have the pump a couple of feet under the motor, which might me limiting the coolant flow. The motor is fine after a 20 minute cutting session however. A little bit warm to the touch, but much much cooler than the old 24V spindle.
I’m just using the front panel of the VFD to start, stop, and set speed. I’m still using the stock G-Shield. I think the next step will be to build a new mach3 based controller with an intel NUC and old monitor for the computer, a USB mach3 controller + stepper drivers. It feels like using mach3 is going to have better results than using grbl or tinyg. Especially once I want to set up more advanced things like touch probes, homing that works as expected, and so on. (Plus I happen to have an old mach3 license from a few years ago. :))
For cutting fluid, I will give a small squirt of WD40 every now and then just to keep things relatively cool. This probably isn’t ideal, but hey, its easy to get and it seems to do a good job.
Having an air hose is a must for cutting aluminum; longer tool life, cleaner cuts and a better finish every time. The hose I use is a bit cheap, and the air hose part of it actually broke off from the 1/4" NPT connector. I had to snip the end (which was very frayed) and re-crimp it back on. Not a big deal, took about 2 minutes to fix. The mister part of the system has no flow control at all, so when you put the coolant end into the bottle it sprays WAY too much all over the place. I was looking for something that would very lightly mist the tool, not a flood cooling system. I’m probably gonna make an insert for the coolant hose to reduce how much can go through at a time, but I don’t think I have the drill bit I want to use (I’m thinking a single 3/32" or 3/64" hole).
I’m still on the fence for buying a 800w VFD as well. To be honest, I kind of want to get a “real” z-axis like a THK or NSK linear ballscrew actuator before I go VFD (I’m still using the run-out laden DW660). Definitely would go with a 220v VFD over the 110 since my setup is like 10ft from my breaker box and running 220v would be super easy.
I use a Fog buster cooling system when machining Aluminium. It uses a pressurized tank and injects the coolant just before the nozzle so you have very fine droplets but no mist that fills the shop with a fog. You can see the setup I use in this photo machining new wide tall end plates for my machine.
Look at the Planet CNC controllers and maybe some leadshine DSP drivers. I use these on my big mill and the Shapeoko ( the PlanetCNC setup for the Xcarve is in the mail) and love them. They do everything you spoke of and even more with ease. Though I understand the desire to stay with MACH3/4 if you are used to it. I never liked it much and went the PlanetCNC way instead and love it WAY better over the TinyG I was using before. Looking forward to playing with the digital probe on the X Carve this week also. I will try to post some pics of the setup once I have it all calibrated. Love seeing your results!
Yes all mine are in one room also. I am thinking of doing it this way. But all mine are enclosed also so i would have to hook up a system to connect the fog buster inside each one for it to work for me. It can be done, just still on the list of TO DOs… But I will need one soon as my production runs are getting larger and I need to leave the mills to run and get back in CAD more often to keep up with demands.
How about bulkhead fittings with small quick connects so tank and air supply are out side the enclosure and the head is inside. Then I is just a case of disconnecting from one machine and connecting to another.
Funny you should mention that. I just finished up milling and anodizing the X Carve Pass though bulkhead tonight. Just going to mill the cooling system barb lock rings and anodize them and it will be ready to install and wire up. Even left room to grow a bit and the unused GX16 holes will be plugged with 3D printed covers. The GX20 is for the VFD spindle power pass though. This is the last thing holding back firing up the X Carve. I can add the Fog buster connections later once I have it in hand and see the layout I will want.
Right now after the homing cycle, the machine coordinates are -289,-289,-1. Instead of the 1,1,-1 that I would expect. I can’t figure out where that -290 offset is comming from.
So here is the final product!! I must say that a picture doesn’t really capture how beautiful these aluminium objects are. Also given how light this thing is, most of the mass of the blank was turned into the pile of chips around my machine, no wonder there is such a mess.
So I need to start over from a new blank.
