[ihavenofish]

So, I have finally got time, space, money, to deal with my little CNC "router".
For those who haven't seen it before, it is an "evolution" of the xzero mini raptor, redesigned specifically for high precision aluminium cutting.
This was a prototype, still using the uprights and end frames of the Xzero, The final design already has a number of changes, which I may implement at some point, Because at one point years ago I thought of selling them (no intent for that anymore) I made some curious low cost choices in the spec and now we get to see if any of them were worth the effort.

Specs:

- The frame of this machine is made from solid 6061 aluminium. No extrusions. It is far more beefy than the already beefy original mini.
- The ball screws are NSK compact FA C5 ground, 15mm diam, 10mm pitch. I may swap the Z for a 5mm pitch screw to gain more precision.
- The linear guides are Bosch Rexroth (Star) Precision grade medium preload, 15mm. The arrangement is the same as the old mini, 4 blocks per axis (the bigger raptors had 2 blocks on the Y and Z).
- The ball screw supports are preloaded matched pair NSK angular contact bearings. The old xzero machines used a double row AC bearing, with "tight clearance" of about 0.0002", so this is a big upgrade for stiffness, though not really precision.
- The table is 1" plate, with a 50mm hole pattern, 1/4-20 threads and 5/16" pin bores. Why imperial with metric spacing? Because 1/4-20 has a much stronger thread for repeated use than M6 an most common accessories from clamps to gopro mounts are 1/4-20.
- The cables are all PUR continuous flex.
- I am using a Noga mini cool mister with Koolmist 78.
- I also have a Vacuumtisch 200mm vacuum fixture plate with venturi pump.

So that's the expensive parts...

The interesting low priced this are:

- The control is a DDCSV3.1 stand alone control. These run $200ish and are kinda an unknown to me. There's a bunch of random videos showing it working, and an active firmware dev group. So lets give it a try.
- The servos are JMC IHSV57 180w integrated models. These are very popular in germany. I have the old version with no auto tuning unfortunately, and only a 24V 10A PSU (chip shortages means i cant even buy another right now) But as it turns out, on this machine 10A is proving adequate.
- The spindle I'm putting under low cost, even though it is high end. After seeing all of the Jianken ATC videos I contacted them. I may buy the 80mm 1.5kw ISO20 spindle later on, but I ended up buying their 40000rpm 750w ER11 62mm diametre spindle.
- I got a Delta MS300 drive (from digikey yay). There is a trade with this drive, as it only goes up to 600HZ. As a result my spindle only runs at 36000rpm. This is fine (for now anyway).

So, that's the spec, here is a tease of it cutting! (and yes I need to set up an air blast)







7500mm/m feed (where the control keeps up). 4mm cutter, 0.3 or 0.4mm step over, 6mm depth, 36000rpm.
I am using sandvik coromant's online tool to derive my strategies and feeds. The app tells you not only what rpm, feed, and engagement, but also automatically finds the balance between tool life and machine time. it usually pops up something that seems absolutely insane, like 7500mm/m! But it actually works (if I have a tool similar to theirs). It is kinda throwing my old ideas of feeds out the window.


First machined part is a knock off of the Saunders modular vise, made to fit the spacing on my table. If id have seen his first I would have made the spacing match that and bought his.

Results so far are:

- It is square within a thou over the table.
- The parts come out on size within a thou if machined with proper finish passes.
- Holes are on size and ROUND! This is thanks to both the ground screws and the servos. The pins in the vise (made on the machine) both fit and line up perfectly with the holes in the table (made by someone else years ago) with only 0.0005" or so wiggle room.
- Thread milling is fun.

The Control has 1 main issue. It does not support CV / G64 / constant velocity mode. As a result, it does not keep up with The programed speed in short moves like adaptive clearing and can be a little rough. For this reason I will move to linuxcnc once mesa has cards back in stock in summer.

The servos are hard to tune. These are the old V552 version. Right now, the X and Y track within 0.0003" but have 0.002" transition "bumps" if I set the acceleration up higher thank 0.1G. Under linuxcnc I will be able to put it up to 0.3G as CV mode will remove the spikes. The Z is more of a problem. It will lag begin 0.001" in upward motion, In addition to the transition spike. As a result there are tool marks If the tool goes up then down without an arc transition. I am still looking for help with tuning these a little better.

I have also decided to give the low cost (extremely in some cases) carbide tooling on aliexpress a try.

- I got some of the "blue nano" (AlTiSn) cutters. This coating is useless for aluminium. Like with TiAlN it wears off instantly because aluminium is abrasive. Other than that though the cutters themselves seem great especially for $2.50 each for 4mm.
- I also ordered some micro kyocera cutters of a popular ebay seller. They will arrive in a week or 2.
- I ordered some single flute DLC coated cutters ($5 each for 4mm)
- I also ordered some 3 flute DLC coted cutters ($3 each for 4mm)
- I got my thread mills from mcmaster carr, made by SCT (not cheap of course)
- Lastly I have some KBC house brand cutters ($15 for 4mm). If I am not misled, these are the same as the basic 3/4 flute Maritool cutters (not the fancy ones). Right now at least, ordering maritool isn't cost effective, the shopping it 2x the price of the cutters making them more money than the local KBC.
- On the way

[ihavenofish]

Oh, here's picture of the machine.

[peteeng]

Hi IHNF - Wall mounting is good for chip clearance and coolant clearing ! Peter

[LongRat]

Very nice. I've been to the Datron factory and was impressed by the machines, the Youtube videos aren't lying. Yours is a good imitation.

[ihavenofish]

Very nice. I've been to the Datron factory and was impressed by the machines, the Youtube videos aren't lying. Yours is a good imitation.

Thanks

There are a lot of things I would change if I made it again, but I'm pleasantly surprised with how well it performs. The spindle woks very well, although I'm wishing for an ATC haha and the ability to hold larger shanks. Edge finders are 10mm, facing cutters are all 10mm or bigger etc.

Jianken makes a 60000rpm 62mm ISO10 spindle, but the 80mm ISO20 30000rpnm is cheaper and more versatile. Both will need 220v.

Things to ponder, ha.


Here's is my enclosure I'm building tonight. - a closet in my office. Waterproofed like a shower (I'm renovating my house hand have left over membrane). At a later date I will move it to my work shop shed.