Got a 3018 mini "mill"

[Braeden P]

so I just bought this https://www.amazon.com/Upgrade-3018-Engraver-Controller-Extension/dp/B07DXMFY38
the one I got has a full set of er 11 collets same price just to mess around with and upgrade the spindle to get rid of back-lash might try to mill aluminum but mostly wood and plastic this would be my first machine tool if it counts as one it should arrive on sunday anyway as soon as it arrives I will get some pictures and test it.

 

[Flynth]

Hi,

I got (almost)the same machine direct from a Chinese seller few days ago. I say almost the same, because the version on amazon appears to have the Z axis assembly and motor mount from grey plastic while my machine uses black plastic. My(black) version is pretty hollow and flimsy. I wonder if the grey version is better. I'll probably replace it with a 3d printed version. Also, my machine came with a laser head, but I'm focusing on getting the dc spindle working first(no pun intended).

I have a fairly well equipped manual hobby machine shop. This is my first CNC machine and I got it primarily to mill PCBs and other miniature things like solder stencils etc.

Out of the box I was faced with horrible vibration during even the smallest cut. I identified its cause as spindle runout. When measured it was approximately half a millimeter :-o (20 thou!). Eventually I managed to get it down to 0.05mm (a bit under 2 thou). This is still pretty bad, but usable to mill PCBs taking multiple shallow passes (2 thou depth of cut, max rpm - 10k and 1.74 inch/min feed). I found out the cause of the runout is horrible fir between the motor shaft and the ER adapter. Also the motor shaft has a large flat causing dynamic imbalance when running, but that is tiny compared to the runout issue. The shaft is smaller than the hole in the collet adapter. The adapter uses two set screws. By very careful adjustment of those screws while looking at a dial test indicator registered against the inside taper (collet and nut removed). It was possible to lower the runout to above mentioned 0.05mm(2 thou).

I'll probably be making a non-ER adapter between the motor shaft and engraving/drilling bits. I'm wondering what would be the best approach to mount it. On the tool side all my tools are 3.175mm (1/8th of an inch). So I'm thinking about making it a tight slip fit or ideally a slight interference fit allowing installation/removal of the tool and adapter when heated with a butane torch slightly. It'll be quite a bit of work(including laping etc), but potentially worth it. Does anyone have any ideas/tips how to improve the TIR without having to machine this new adapter?

Edit: I forgot to say that for milling pcbs on this machine a Z probe is absolutely necessary and this is the first thing I made for it. To make it one has to find a way to attach cables to pins marked A5 and its GND.

 

[Braeden P]

I am going to upgrade the motor with a better one and probably have a spindle mount made from aluminum and upgrade the whole thing and make it stronger but I still will have an engraver not a mill.

 

[Flynth]

I am going to upgrade the motor with a better one and probably have a spindle mount made from aluminum and upgrade the whole thing and make it stronger but I still will have an engraver not a mill.

The "problem" is that all commonly available upgrades are to make it into a kind of mini-mill not a better engraver. For example 300W or 500W motor (still only 12k RPM), or even 800W (24k RPM). However, there is no small, high RPM motor available that would be really cool for an engraver. For me ideal motor would be at most 100W, 400mm diameter and go to at least 35k RPM. As far as I know there is no such spindle made by anyone at hobby price...

Anyway, I ordered a RC motor that goes up to 50k RPM which I'll experiment with in future. I know it will heat up and is not designed to be run for a long time, but I'll be thinking about putting it into an aluminium mount (as a radiator). In the meantime I'm trying to get as much as possible out of the original motor.

Another topic is that I saw the original motor be advertised as a 35kRPM motor. However, in the machine it maxes out at 10k RPM. I'm thinking that perhaps it is due to the voltage used? The machine uses 12V PSU, while the motor sellers claim it is a 24V motor. Perhaps upping the voltage is all that's needed.

 

[Braeden P]

Got it today it works but I need to learn a lot more it come pre programmed with three things two are Chinese letters it engraves and the others writes I-phone broke 5 bit already

 

[Flynth]

Got it today it works but I need to learn a lot more it come pre programmed with three things two are Chinese letters it engraves and the others writes I-phone broke 5 bit already

Do you have a dial test indicator? If you do and you measure and adjust spindle runout you'll have much easier time learning (if there is a runout issue like it was on my unit). It is a simple, but hard to explain in words procedure. I suggest you look on YouTube for how to do it if needed. You'll also need a drill bit ot an end mill with cylindrical shank 1/8th of an inch where the cylindrical section is at least 20mm (almost an inch).

 

[Braeden P]

Yup I have an indicator and I did not measure run out and I went to remove it and the collet chuck is pressed on the motor shaft.

 

[Flynth]

Yup I have an indicator and I did not measure run out and I went to remove it and the collet chuck is pressed on the motor shaft.

That's good. Better than my unit. Mine is just a slip/loose fit. Good thing is that the seller will send me a replacement. I wonder how long it'll take to arrive from China...

 

[Braeden P]

Pushing on the spindle back and forth pretty hard only 30 thou of flex in it but the computer still can’t run it because it crashes every time so time to get a new computer.

 

[Braeden P]

got it working problem with the g code went through the work and ate the table alive not too good