[dwg123]

Did you check to see if the Spindle has a Ground you can do this with your meter, check the 4th Pin in the spindle connector to the spindle body ( continuity test ) if it is not connected you will have to connect it, a lot of these spindles do not have the Ground connected and the user has to correct this

The grinding noise could be just bad EMI from no Grounding or Correct Shield Grounding and no EMI Power Filter, Incorrect VFD Drive Parameters set also can cause this also , these are just some of what can be wrong if it is not mechanical

Thanks for the excellent suggestions!

I checked and my meter reads 0 Ohms from the spindle ground pin to the spindle motor housing, which is very well grounded. Oh well, it was worth checking. Do you think it's worth setting up an osciliscope on the power leads? I have a cheap USB osciliscope that should work; I guess I'd be looking for spikes between ground and the three power-in phases, right? Anything that's not the X Hz sine wave I should be seeing?

But I'm starting to strongly suspect it's mechanical. When I warmed up the spindle this morning, starting at 6000 RPM, I heard a squealing noise, like a skidding bearing. Not loud but abnormal. Not good. I immediately jumped in and bumped the RPM to 8000 and the sound wend away. After finishing the warmup routine I dialed it back down to 6000 and the sound was gone.

So yeah, I have a bad feeling about this. I emailed the vendor AlphaCNC about this a week ago and no reply so far. I the past they repeated several times, "polish the spindle", but I KNOW I have a good meter connections and clearly spelled it out with pictures, then they fell silent. And now there's this bearing issue with a brand new motor. This is getting old fast.

If they continue to ignore me I'm thinking of dumping an expose of what they've been putting me through as a warning to others here. That being said, I think the machine itself is pretty good so far. It's definitely stiff and although I'm not pushing it too hard yet I'm impressed with it's performance. It's just the many quality issues & poor support are killing me. This issue is actually only the tip of the iceberg. Guess that's what I get by going with the 'inexpensive' solution. I hope they get back to me so I don't have to go there. If they don't support me I have nothing to lose by burning them down...

[mactec54]

Thanks for the excellent suggestions!

I checked and my meter reads 0 Ohms from the spindle ground pin to the spindle motor housing, which is very well grounded. Oh well, it was worth checking. Do you think it's worth setting up an osciliscope on the power leads? I have a cheap USB osciliscope that should work; I guess I'd be looking for spikes between ground and the three power-in phases, right? Anything that's not the X Hz sine wave I should be seeing?

But I'm starting to strongly suspect it's mechanical. When I warmed up the spindle this morning, starting at 6000 RPM, I heard a squealing noise, like a skidding bearing. Not loud but abnormal. Not good. I immediately jumped in and bumped the RPM to 8000 and the sound wend away. After finishing the warmup routine I dialed it back down to 6000 and the sound was gone.

So yeah, I have a bad feeling about this. I emailed the vendor AlphaCNC about this a week ago and no reply so far. I the past they repeated several times, "polish the spindle", but I KNOW I have a good meter connections and clearly spelled it out with pictures, then they fell silent. And now there's this bearing issue with a brand new motor. This is getting old fast.

If they continue to ignore me I'm thinking of dumping an expose of what they've been putting me through as a warning to others here. That being said, I think the machine itself is pretty good so far. It's definitely stiff and although I'm not pushing it too hard yet I'm impressed with it's performance. It's just the many quality issues & poor support are killing me. This issue is actually only the tip of the iceberg. Guess that's what I get by going with the 'inexpensive' solution. I hope they get back to me so I don't have to go there. If they don't support me I have nothing to lose by burning them down...

You need to check the pins with a continuity test, Ground Pin to the spindle Body

The Bearing problem is not uncommon for the Bearings to make noise when starting up if it has been running for a while the grease gets soft and when the spindle stops the grease will run into the bearings causing the bearing to skid when starting up can your spindle run at 3000 RPM at startup some can and this will help until the grease has moved

The noise problem you have is from the VFD Drive and you need a EMI Power Filter on the input power to the VFD Drive and if your system has any Switch mode Power supplies they should have a EMI Power Filter on there input power supply also

Unless you have a low pass filter I would not try that with your phone

[dwg123]

Thanks again for the feedback. Maybe I'm getting over-concerned about the bearing noises? Being a n00b sucks, so much to learn, so many mistakes to make.

And yeah, sorry for the confusing description, I did test Ground Pin to Body and recall getting wither 0 Ohms or possibly a fraction of an Ohm. I think I'm screwed on the spindle problem (bad pun not intended) and am going to look into getting a switch-based tool height calibrator. It's only money...

And so now AlphaCNC is ignoring my June 18 emailed plea for support. I just sent them an email threatening to basically burn them down online if they don't make things right with this customer. So many crazy / easily avoidable issues, you guys will enjoy the read about a Really bad customer experience™. It's looking like everyone here who warned me away from getting a Chinese CNC machine were right after all. Serves me right I guess. Hopefully they'll get back to me with some basic support and avoid my email flames of wrath & warning to others...

[mactec54]

Thanks again for the feedback. Maybe I'm getting over-concerned about the bearing noises? Being a n00b sucks, so much to learn, so many mistakes to make.

And yeah, sorry for the confusing description, I did test Ground Pin to Body and recall getting wither 0 Ohms or possibly a fraction of an Ohm. I think I'm screwed on the spindle problem (bad pun not intended) and am going to look into getting a switch-based tool height calibrator. It's only money...

And so now AlphaCNC is ignoring my June 18 emailed plea for support. I just sent them an email threatening to basically burn them down online if they don't make things right with this customer. So many crazy / easily avoidable issues, you guys will enjoy the read about a Really bad customer experience™. It's looking like everyone here who warned me away from getting a Chinese CNC machine were right after all. Serves me right I guess. Hopefully they'll get back to me with some basic support and avoid my email flames of wrath & warning to others...

There are some good Chinese suppliers so this does not reflect on all, they soon figure out when someone is new to CNC machines by how you describe things in your request to get answers, what you get for your money is normally quit good, most of these company's don't have English speaking support so when you buy a Chinese built machine, it's up to you to be able to make what you can out of your machine in most cases there is always going to be some problems with a machine and with no support ( which most don't have ) it is completely up to you, USA made machines you would have the same problem at a much higher cost, some of these manufactures support is no better

So you can forget about customer service once you pay the money for your machine this is a given

Would like to know what kind of problems you have had, any threats in emails you send them will go on deaf ears as it would not translate into Chinese that they would understand

[dwg123]

There are some good Chinese suppliers so this does not reflect on all, they soon figure out when someone is new to CNC machines by how you describe things in your request to get answers, what you get for your money is normally quit good, most of these company's don't have English speaking support so when you buy a Chinese built machine, it's up to you to be able to make what you can out of your machine in most cases there is always going to be some problems with a machine and with no support ( which most don't have ) it is completely up to you, USA made machines you would have the same problem at a much higher cost, some of these manufactures support is no better

So you can forget about customer service once you pay the money for your machine this is a given

Would like to know what kind of problems you have had, any threats in emails you send them will go on deaf ears as it would not translate into Chinese that they would understand

Fair & well said. I agree with your assessment, this is why I chose the machine. It could do what I needed at a cost I could afford.

I'm going to do a mini-brain dump here, hope you don't mind. Not sure if it's tldr, I'm going to vent a little. I'm still awaiting reply from AlphaCNC, hopefully they'll respond, I want to give them another week before deciding how to handle it.

Brief summary of issues:
1. Ordered machine (100% advance deposit) in early December on assurances machine would ship within 2 weeks. They apparently didn't even start working on it until January. Then delayed due to national holiday. Then COVID (entirely not their fault). They eventually shipped in late March.
2. They wanted me to arrange shipping (brokers, etc). Eventually they pointed me to their people who handled it, still it was difficult & time-consuming.
3. They claimed surprisingly low shipping costs, but eventual cost was > $2000.
4. They offered to under-invoice to reduce Trump import tax. They didnt, additional unexpected cost = $1700
5. Machine arrived in basically good condition but had a few visible issues, namely kinks in fogger lines due to inadequate slack in tubes.
6. Removed z-axis cover to deal with fogger, noticed axis lubrication lines were empty. Several days of investigation lead the the realization that oil drains down into lower part of the system, in order to lube upper parts several actuations of pump lever are required. Results in machine dumping excess oil on shop floor while not (or barely) lubing z-axis screw. AlphaCNC was no help in this. I ended up installing a check-valve in one portion of the system which successfully keeps oil up in the lines but I'm still having problems with oil draining from the z-screw thru distribution manifold into z-sliders. Spring check valve installed here blocked all flow, am going to try a diaphragm check-valve soon. Initial check showed that z-axis screw (the highest wear part) was never lubed, it was totally dry. Still, no z backlash from wear I can see, so *shrug*.
7. Fogger distribution manifold had an open port. It would have spewed cutting fluid all over the inside of the machine if left unblocked. Luckily I was practicing on wood then. Blocked open port, resolved kink issue (no help from AlphaCNC) and fogger is working well.
8. Looking closer at X *& Z axises, there was a lot of buildup of grime where sliders meet rail. It looks like my machine may have been used extensively before they sold it to me 'new'. Additionally, there's evidence of a part being improperly secured to the table & vibrating around leaving scratches. Also there were metal chips everywhere inside, especially around the x-axis. Don't think these are from the machine (!), likely assembled incredibly 'dirty'.
9. The MPG controller I ordered wasn't shipped with the machine. They initially questioned this, then shipped me a model that wasn't what I ordered and didn't work correctly. They eventually shipped the correct MPG and it more or less works well - sometimes jogs in the wrong direction (!) but that's rare.
10. The setup files they shipped had several bad settings in the mach-3 machine configuration XML file, leading to a lot of wasted time debugging the problem. By then I had given up even trying to get help from AlphaCNC on more complex issues, I decided to focus on hardware.
11. Possibly related to #9, I've seen the machine get confused. For example when I pause then resume, it continues moving but the wrong axis. Looks like I may have to have to replace the controller.
12. The E-Stop button on the machine doesn't work. They can't figure it out. It appears to be a configuration issue, at the electrical level everything looks fine. e-stop on the MPG & mach-3 work so I'm using that.
13. As mentioned above (the reason for this thread) there are the spindle tool height calibrator issues and (potentially) spindle bearing noise issues.
14. It looks like the x-axis as configured from the factory is off by 1-2%. Still investigating but it appears to be a steps / inch setting.
15. I ordered the machine with a 4th axis rotary accessory. It didn't quite fit on the table so they chopped away the fence/tub walls roughly with apparently what looks like was a hacksaw. If they had asked I would have said to leave it, let me deal with it.
16. Spindle drive electronics occasionally start with E001 on cold start.
17. They said it came with a license for Mach-3 but it was a demo. I bought a licensed copy, They did supply a pirated version of Aspire, but I will never install it. I don't need Aspire and if I did I'd buy a legitimate copy.

... I could go on, but that's the general idea from the top of my head. I'm pretty sure there's more I'm forgetting.

On the other hand, in some ways I think the machine is pretty good:
1. It (being fixed-gantry) is very stiff and runs tools thru 6061-T6 at Fusion360's recommended feeds & speeds at 100% feed rate with no chatter. I did order the machine with Delta servos & a 3.2KW spindle (+$3000 in options), so I'd hope so. I haven't run high-speed high-efficiency tool paths with larger tools yet, so the verdict is still out but it's looking good so far.
2. Although the machine is pretty rough in some ways, apparently cut with a cutting torch and not cleaned up, with obvious spray-paint runs & drips (where's your pride in workmanship, man!), dirty-casting voids on the surface of the XY table, where it counts it's spot-on. The load-bearing portion of the frame is cast-iron, and where it counts, like where rails are mounted & gantry attached it was ground & properly assembled.
3. Aside from the issues listed above, the machine is working pretty well.
4. AlphaCNC initially did make some half-hearted attempts to support getting the machine set up & running correctly. I think when I asked about spindle noises they decided that potential replacement was going to be too expensive, labeled me a 'troublesome customer' and decided to ignore my emails going forward.

In summary (sorry if that was TMI):
1. I think the machine is a good design, and at it's core is well-built.
2. It looks like they took a machine being used on their production floor and retrofitted it to my specs and sold it to me as new.
3. Quality of final assembly was really, really bad.
4. QC was apparently nonexistent. Open pneumatic ports? Really?
5. Their attempts at support were half-heated & then non-existent.

It's too bad really, I plan on modding this machine for 5-axis - it's a great foundation for that. I expect to eventually have $50K in capability for a $15K investment. If AlhpaCNC were to listen to my suggestions & establish a small distribution & support office here in the USA (or somewhere English speaking) to smooth the shipping & support issues, my guess is they'd develop a following pretty quickly. If they evolved this machine into a budget 5-axis product that can run fairly large parts with good precision at a low cost, I bet they'd have customers lining up to buy it. I would have been first in line for such a machine.

As it is, would I buy the machine again? Although I was probably naive going into the deal, I needed parts quoted at $50K by job-shops and am cutting parts at $10K invested (plus a ton of unexpected lost time) plus cost of bits & material. I don't know, there weren't many alternatives... The rather painful side could have been avoided pretty easily with a little QC & a single good support person. At least the machine is working and I'm getting my parts plus future capability at a price I can afford.