[Bob_ski]

Hi guys, I'm new here and this is my first post, and hopefully not the last. Please be gentle, lol

I'm in the process of building my first CNC mill. After doing a bit of research, I've decided to go for hybrid servo motors over the traditional steppers as I have heard that steppers are prone to losing steps at high speed. I'm not planning on running the machine fast, but would rather spend the extra money and get the servo's straight up.

I have a bit of a dilemma. I purchased the motors through one of the many Chinese sellers on Ebay. They arrived today in a big white plastic shipping bag with no bubble wrap or any sort of padding around them. The motors were packed in a moulded foam casing and sticky taped together. The foam casing on all of the motors is cracked. They look like they have been dropped or thrown around.

My question is, is there a possibility that there could have been some internal damage caused to encoders or anything else inside the motor? The exterior looks fine, not even a scratch on them. I'm worried if I plug them in and they start smoking, I'll have no chance in returning them for a refund. I have contacted the seller, but have had no reply as yet.

Has anyone been in this situation where they have received the motors with damaged packaging, but they were ok? I have just spent $550 on the 3 motors, so don't want to take any risks. I was looking at the Teknik servo's but unfortunately they were going to be to much to post to AUS. I now wish I had paid the extra money and purchased them.

Any help would be much appreciated.

Regards,
Bob

[Bob_ski]

I've just realise I posted this in the wrong section. Is there any chance it could be moved to milling machines please? Sorry for the stuff around.

[maxspongebob]

Buying from China off Ebay is risky. I have done it way more than I would like. Unfortunately the problem is that there is little way for the buyers to get satisfaction if they are dealing with a less than reputable seller. That is why, on Ebay, you only buy from sellers with a great reputation rating. It sounds like you have have gotten a seller that is less than perfect. My advice is to test the motors as soon as possible to make sure they are working. You may well have gotten lucky and all of them function. If not you may have to suck it up and buy a replacement from another seller.

A stepper motor is pretty robust and the encoders are pretty solid as well. I would suspect that, unless there is visible damage to the motor itself, they are probably ok. It sounds like the foam packaging did it's job and protected the contents.

I always use a credit card for large purchases from Ebay. I have never had to do this, but I think I could cancel payment from the CC company if I got screwed by an Ebay seller.

Finally I can't say enough nice things about the Teknic ClearPath servo's. I use them exclusively on my projects after having bad luck with steppers. It's not that steppers are bad, it's just that ClearPath SD servos are so much better. Yes, they are not cheap, but quality is always more expensive.

[maxspongebob]

duplicate post deleted

[Bob_ski]

Thanks for the reply and also placing the post where it's meant to be maxspongebob. There doesn't seem to be any physical damage to the motors that I can see. The one thing I wasn't sure about is how the internals would cope with being knocked around. I paid via PayPal so I have protection there. In Australia we have a policy where if a product is defective, the seller has a responsibility to replace the item or offer a refund in this situation. They are also responsible for returning the item back to them.

I'm not really keen to plug it in and try it just in case there is an issue with them, and it goes up in smoke, lol. My option to return them would then cease. It's good to know that they are robust though. I'm going to contact Ebay today and see exactly where I stand and what I can do about it. If there's nothing I can do because it's just the packaging that's damaged, then I have to bite the bullet and hope they work. At the end of the day, lesson learnt. I did look at their reviews, they had pretty good stats and sold a lot of these motors recently. I know it still doesn't really mean they are good.

If I can return them, I'm going to go straight to Teknic and buy a set of motors. It's going to be double the price, but you get what you pay for right? Any recommendations on what motor would work really well with the DM45 mill? I thinks its similar to your Grizzly RF45 mill, just has different gear knobs.

This will be my first build so I still have a lot to learn. I understand the mechanical side of the build. The electrical and the operating side is where I'm going to struggle. I can read wiring diagrams so I will work out the electrical eventually.I'm struggling to understand how a drawing on a program like Fusion 360 turns the file into G-Code for the machine to do it's thing. This is one thing I have to try and get my head around, it's pretty daunting.

Thanks again for the reply and advice.

Cheers,
Bob

[Bob_ski]

Thanks for the reply George, I'm going to ring them today and see where I stand.

Cheers,
Bob

[wmgeorge]

File a complaint with eBay and the vender. Since he is in China he will try to stall and delay as long as he can until your Return/Refund time expires.

[blades]

File a complaint with eBay and the vender. Since he is in China he will try to stall and delay as long as he can until your Return/Refund time expires.

Yep, that's their game. But ebay has your back. As long as you file a complaint before the expiration time, they give the seller 2 days to respond. If no response, ebay will refund your $$ and NOT advise you to send the item back. China is great at sending stuff to the US, but woefully incapable of facilitating a return. BTW, per ebay guidelines, the seller is supposed to pay return shipping. I just went through this with a 5 axis controller, and ended up accepting a 50% refund. Had I played it right, I could have gotten a full refund. I made the mistake of filing a complaint with both ebay and Paypal.

[rodw]

Rod, On my Mach4 machine, a 4x4ft router I only use 4 proximity switches total to do the Homing and the Limits. Mach treats the switches as Homing until that routine is done.!

Every platform is different and of course Mach4 normally does not have enough inputs to do what I did. You can set Linuxcnc up that way but on my 4x4 plasma cutter, I decided to make it a complete build and not cut corners. Thats how I thought most commercial machines were set up so thats what I did!

Hi Rod, thanks for the info and the pics. What is the likelihood of the machine losing the plot and going past it's limits and crashing by only using a homing switch? I was contemplating doing the same thing you've done, except I was only thinking of using 2 switches. I was wondering how it would do the homing. You've cleared that up by having a third switch. Definitely need to do more research when at this stage.

The main thing to understand is that limit switches should never be triggered becasue they sit outside your soft limits (yes Linuxcnc has them too) and outside the limit switches I have hard limit stops.
The scenario you mention is not likely becasue with a shared home/limit switch it is a limit switch all the time unless you are homing and then its a homing switch during the homing sequence..

[OlfCNC]

Every platform is different and of course Mach4 normally does not have enough inputs to do what I did. You can set Linuxcnc up that way but on my 4x4 plasma cutter, I decided to make it a complete build and not cut corners. Thats how I thought most commercial machines were set up so thats what I did!

The main thing to understand is that limit switches should never be triggered becasue they sit outside your soft limits (yes Linuxcnc has them too) and outside the limit switches I have hard limit stops.
The scenario you mention is not likely becasue with a shared home/limit switch it is a limit switch all the time unless you are homing and then its a homing switch during the homing sequence..

Mach4 can have as many inputs as how many it's motion controller has. For example with this card it has 49 digital and 2 analog inputs: CNCdrive - motion controls

[wmgeorge]

Mach4 can have as many inputs as how many it's motion controller has. For example with this card it has 49 digital and 2 analog inputs: CNCdrive - motion controls

That is correct, I use the CNCRP/Avid controller panel with Warp9 ESS. . Mach4 is a huge leap from 3. My machine works just fine using the Limits as a Homing switch, also it just a lot simpler. My proximity switches can never be damaged as the trigger block is totally out of the path. The rubber stops act as a snubber.

WinCNC is a good program, but I really need a Windows system to run a lot of my programs. Yes I have used Linux in the past so I know about it.

[maxspongebob]

Some questions for you.

What software will you run? Linux? Windows? Mach 4?
What motion controller will you be using?
Are you buying a kit with all the brackets, adapters, couplers, ballscrews?
Were your hybrid drives NEMA 34?
What is the diameter and pitch of the ballscrews?

Recomending a particular drive is risky without all the details. My machine is a smaller X2 type system, Grizzly G0704, so it is much lighter then your 45. That said, when I built it, I planned on someday upgrading to a much larger machine and I tried to buy components that I could use on the bigger machine. All my motors on the mill are NEMA 34, yes it looks a bit silly with those big servos on a little mill. I used ClearPath CPM-SDSK-3421S-RLN.

These could probably do well on your system also. The only thing I would really worry about though would be the Z axis. The weight of your head and spindle motor could require a counter balance to achieve a good acceleration in the up direction.

[Bob_ski]

Hi Max,
Not too sure about software yet, still deciding on whether to go for Linux or UCCNC.
As for motion controller, its a toss up between the UC300ETH-5LPT ethernet or Smooth stepper ESS, but not sure if that will work with Linux. Does it?
I'm making all the brackets myself on the old faithful HM32 /RF32

The motors I purchased were Nema 34 12nm. I was looking on Teknics site earlier today and realised I'll be looking at a ballpark figure of about 2K for Nema 34 motors delivered to me, It's just a bit more than I expected. I'll jump on and have a look at the ones you used.
I bought the ball screws from an Ebay seller in China called e-link-world. I have purchased all of the 20mm linear rails and ball screws from him for my router build,(which will happen one day) and they look as though they are of pretty good quality. They manufacture the parts themselves.
I'm using an RM2505 for the Z axis and RM2005 for X and Y

Looking at how big these steppers are, I can imagine the steppers would be the first thing you would notice on yours, lol.

I was actually thinking of using a planetary gearbox, would that work? The counterbalance idea is much better. Your're not wrong about it being heavy, I think there's about 80-90 kgs just in the head. Luckily I have a little digger that'll do all the lifting for me,lol.

Cheers,
Bob

[maxspongebob]

I am running Mach 4 on Windows. I am using an Ethernet Smooth Stepper on the lathe and Pokeys57CNC on the mill. I like the ESS better, but neither will work with Linux. Although I like Linux a lot and use it on many of my systems, the idea of offloading the motion control processing onto a special purpose board was appealing. It's personal preference really.

A planetary would work, but you would loose a lot of rapid movement and would gain a bit of backlash. The best thing would be to try it to see how well a direct drive would work. If it is not great then use a 3:1 or 5:1 reduction gearbox inline. 20 and 25mm screws. Will they fit without much modification?

Here are links to my mill and lathe conversions. I just finished the lathe last week and now I am getting to learn lots of new things.

https://www.cnczone.com/forums/bench...are-posts.html
https://www.cnczone.com/forums/verti...-software.html

[OlfCNC]

Hi Max,
Not too sure about software yet, still deciding on whether to go for Linux or UCCNC.
As for motion controller, its a toss up between the UC300ETH-5LPT ethernet or Smooth stepper ESS, but not sure if that will work with Linux. Does it?
I'm making all the brackets myself on the old faithful HM32 /RF32

The motors I purchased were Nema 34 12nm. I was looking on Teknics site earlier today and realised I'll be looking at a ballpark figure of about 2K for Nema 34 motors delivered to me, It's just a bit more than I expected. I'll jump on and have a look at the ones you used.
I bought the ball screws from an Ebay seller in China called e-link-world. I have purchased all of the 20mm linear rails and ball screws from him for my router build,(which will happen one day) and they look as though they are of pretty good quality. They manufacture the parts themselves.
I'm using an RM2505 for the Z axis and RM2005 for X and Y

Looking at how big these steppers are, I can imagine the steppers would be the first thing you would notice on yours, lol.

I was actually thinking of using a planetary gearbox, would that work? The counterbalance idea is much better. Your're not wrong about it being heavy, I think there's about 80-90 kgs just in the head. Luckily I have a little digger that'll do all the lifting for me,lol.

Cheers,
Bob

The UC300ETH-5LPT works with UCCNC, Mach3 and Mach4.
The ESS works with Mach3 and Mach4 only.
Non of them work with Linux.

For stepper drive you can use any drives which has step/dir interface. No need to buy the most expensive ones like Technics.
You can get some cheap Nema34 steppers from China and some D860 or DM860 high current stepper drives and they will do the job just fine.
For the stepper motors one thing to take care of is to get a low inductance one to get the best possible performance.

[rodw]

Without knowing details of your servos, you might be better off with Linuxcnc and close the position feedback from your encoders in Linuxcnc.. Most people will use a Mesa 7i77 for servos as that gives you more than enough analog servo interfaces and encoder inputs. for your motors. This is a daughter board so you'd need a pci or pcie Mesa 5i25/6i25 or alternatively one of their ethernet cards to hook the 7i77 to.

If I was going to use servos on a mill, I'd use a 12 volt motherboard with the 7i77 and wire the motherboard into the control box as if its just another component. Then depending on if my mother board had a PCI or PCIe bus, I'd use a 5i25 or 6i25.

[Bob_ski]

Hi Bob,

Thanks for the reply.

I'm still not sure what software to go for. I have been reading a lot of good reviews about the UCCNC. I'll definitely stay away from Mach 3 as they have stopped any future updates, from what I've been reading anyway. I don't think I'll use the planetary gearbox just in case, and stick with direct drive.
I was going to use the inline version.
I looked at the stepper motors you chose and they look like a great motor. Unfortunately I'd be looking at approx 2k delivered to me. It's just a little out of the budget at the moment. I'll end up like John Wayne Bobbitt if I spend lash out on those, lol. Definitely be upgrading later down the track.
I really like your build, You've done a great job. I was contemplating doing the same thing you did with the chip pan. I did the same thing with my lathe a few years back and it works a treat. I like the way toddbeau made his table, I really like the way it all falls in the centre.
Nice job with the enclosure around the mill. I'll be cutting a lot of Delrin, that stuff makes a big mess, so something like that would work really well.

[Bob_ski]

Hey Bob,

Just wondering how you setup your limit switches? I couldn't open the pics.

[maxspongebob]

Hey Bob,

Just wondering how you setup your limit switches? I couldn't open the pics.

Limit switches. Oh fun. Actually mine are setup very simply. For the X axis I used the existing stops that are on the front of the table to trigger a mechanical switch. It replaced the existing center stop that is mounted to the saddle with a bracket that holds the mechanical switch. Then I put a 3D printed plastic cover over the switch to keep the chips out. The other Y and Z are done the same way except there was no existing stop, I had to fabricate them.

If I had it to do again, I would use capacitive proximity sensors instead of mechanical switches. But the mechanical one's work just fine when you keep the chips out of them.

X Axis limit switch.


X Axis limit switch with the cover off.


Y Axis. Way down under the table.


Z Axis on the side of the column/head.


Here is the detail of the X Axis switch cover.

[Bob_ski]

Hi OLFCNC,

Thanks for the reply.

I've been looking on Alibaba the last couple of days and talking to a few sellers. I've never purchased on the site before. I'm hoping I could get a bit of input as to whether it's a trusted site. I did have someone contact me today trying to sell me something regarding industrial equipment. I received a warning from Alibaba letting me know to be careful. I deleted the contact immediately.

I've found a Nema 34 12nm motor that seems to be well priced. I have the option of going for a driver that could be connected to AC voltage of 80-220 volt. I assume this doesn't need to have a PSU attached. Is this correct? Is this a good option to go with or should I stick to one that requires a PSU.

I'm very new to this and still trying to get my head around it. I'm learning new things everyday. Thanks for the advice about searching for a low inductance motor. I'm sorry for sounding dumb, but i'm not sure what that means. What should I be looking for?

Thanks for the clarifying the controllers. I knew the UC300ETH-5LPT works on UCCNC, but didn't know it also works on Mach 4.