written by Genmitsu facebook group member Kirk Yarina
I have an eclectic collection of CNC routers, an old Zenbot Mini (6x8 inch cutting area), a Genmitsu 3018 Pro from 2019, upgraded with the 44mm brushless spindle, a 6.4x24” (160x610mm) rotary axis BobsCNC Revolution with a Makta R&0701C spindle, and a 4x8 foot Maslow CNC that was disassembled for a shop expansion. The new (it’s a mouthful) Genmitsu PROVerXL 4030 V2 has become my favorite. It's my first hands-on experience with a bigger work area and high speed, the Maslow is a lot bigger but much slower.
Overview & Assembly
At 70 pounds (32 kg), it’s hefty. The X and Y ride on stout 40x80 C beam extrusions with eccentric adjustable double V guide wheels, 3 on top and two underneath on both Y and the X carriage. I don’t have the old model but going from pictures and descriptions the big differences are ball screws, interesting closed loop NEMA23 steppers, and a hybrid (18mm MDF strips on an aluminum extrusion with aluminum T slots between the strips) table. The control box has been revised but is still 8-bit. The table won’t flex when I push hard on it. Assembly was straightforward and easy, the most complicated part was connecting all the well-labeled cables, and I got it going in short order. It’s fast, really fast.
It came with conservative max speed settings of 5000 mm/minute (call it 200 ipm). I did my usual speed tests and found the steppers will lock up at 7000 mmpm, and run happily at 6000, so upped the settings to 6000. The default acceleration is 300 mm/sec^2, 1000 shaved a few more seconds off the 90mm circle test. Going up to 2000 worked but didn’t add much run time reduction so they’ll stay at 1000 for now.
Spindle & Wiring
Better tuning there will wait for another day, I was getting eager to start making stuff. It comes with a 300W 52mm spindle (that was bigger than I expected at 21 cm tall), it has wires to two separate brush holders, and looks different than the one they sell separately online. I only peeked through the cooling slots on the controller box, the manual says the opening is a warranty-voiding experience. There is a 115/230 voltage power switch accessible through a hole on the side, mine came set to 230 instead of the US 115, so it’s worth checking when you get yours.
Closed-loop Stepper Motor
The trapezoidal screws on the older model were replaced with 1204 ball screws. The new steppers are very interesting, NEMA 23s with motors that are about 76mm tall, with integrated closed loop controllers on top, rather than a separate box. I can’t find any information on the manufacturer or actual specifications, but they have two flat connectors. One two-pin connector goes to a cable with an X-Motor (Y1, Y2, Z) on the tag that I suspect is power, the other has 4 pins and the cable is labeled X-Signal. I suspect these are ground, enable, step, and dir but that’s a guess, the closed-loop steppers I’ve read about all have their own controllers with the motor. No idea what the encoder resolution is, but firmware on the stepper’s controller will count encoder pulses while keeping track of step position, and juice up the motor power if they start to fall behind. These motors seem to lock up if they can’t recover, and require a power reset. I only managed to do this once, did a rapid into the lower Z limit that was one mm too far. Whoops, user error. I was unable to stall them during cutting or testing, including pushing back against Y2 while it was moving. It’s stronger than I am, I couldn't slow it down let alone stop it.
I made a house number and separate street name signs for friends, both ended up about 330mm long and 130mm tall to match 6” (really 5 1/4 ) rail fence boards. I V-carved them with a ¼” 60 degree two flute whiteside bit, roughed first with a ¼ two-flute down-cut, and only went 10mm deep so the bottom of some characters was flattened. Didn’t really push it, roughed and finished at 2000 mm/min (I actually used ipm, rounded 80ipm to 2 m/min). Including a chamfer around the outside edge, they both took around 25 minutes. The material was reclaimed shelf boards from a shed blown down by Hurricane Ian, well-aged pine that spent a few months outside in the wreckage. Turned out nice, just needed a few minutes with a brass brush to remove a few cross-grain fuzzies.
One of our daughters raised chickens and was the county 4H chicken champion at 15 (20 years ago), another currently has 10. The next project was a 100x120mm 3D carve of a rooster using clip art included with VCarve Desktop. Roughed at 2000 mm/min with the ¼ down-cut at 6mm DOC (hey, it’s a test), took 5 minutes. While the machine and spindle handled that just fine it was a little too fast for the bit and old pine and tore out some chunks in the rooster’s legs. Decided to try finishing anyway, using a 3/32 ball nose at 1000 mmpm. Don’t know if I re-zeroed the bit wrong, or it was an amount to leave after a roughing issue, but it started making 5mm deep cuts. Amazingly no problem, and it worked out with the missing chunks. Using the feed rate sliders in Candle I increased the speed to 1500 mmpm, that got a little fuzzy so I backed off to about 1400. It looked great and it finished in 53 minutes total with the same old pine shelving. The originally 18mm thick pine ended up at 6.5mm, with 3.5mm on the flat areas; sometimes mistakes make good tests :). I used a raster with the grain for finishing, interestingly it produced a long shaving when cutting in one direction, and small chips in the other, a great example of climb vs conventional milling.
After only a few days with the machine, I’m very impressed with the V2, it’s much faster than the 300W 10K spindle and quarter inch two flute bits can handle and more rigid than I expected. It came with a 65mm router mount. I want to spend some time with the stock spindle and larger projects, and then swap it for a Makita trim router and ramp things up. It will be interesting when the expansion kits come out, I think this can be serious competition for similar-sized and higher-priced machines.