China CNC 6040 - Setup, Testing & Review

[hexpope]

Your work looks ok, but my projects are much larger than that little board, so it doesn't have time to give your work massive error. If you look at the attached picture I will show you the size of the circuit plus drilling I am also using a .1mm engraving tip for traces and two size drills for the job

I use Diptrace + Vetric Vcarve pro and Mach3. I used to use Eagle with the ULP PCB-Gcode and I am aware of the G-code Wizard, but how would it compare to Vcarve ? A CNC controller that actually works doesn't need home switches (Desktop version) If you don't loose steps then it returns to where you started the job from.

My milling speed is 150 mm/min @ 11000 RPM with the bit only removing the copper. I usually do the run twice if it's a tight circuit, second pass at a higher feedrate.

I replaced the Caps with Nichicon low esr types on each axis. I have also metered out the amps the motors are drawing etc, transformer etc etc all looks normal. I think there's a lot of noise as when the machine is working and I move the mouse of the CNC computer it changes the speed of the motors and the noise of the goes to a higher pitch. It stops when I don't operate the mouse. Same goes when the Driver Test from Mach3

I never use the probe and I have milled out a square flat bed for the PCB's to be attached to (When it worked normal)

I get vibrations on the X and Y axis also especially during tuns and slow movement. What are you mach3 settings ?

My motors stall even @ 1500mm / min settings. I have to tune mine down to 480mm / min on all axis or I heard high pitch whines and rattling.

I have took apart the CNC table to check for loose screws etc and can't find anything wrong with it. I also checked the coupling to see if their nice and tight on the motors and they are. The cable use for the motors isn't the best, but I have metered them out and they pass.

I have a Pokeys55U already, so I am thinking of ordering the Postep25 boards and dump these YOOCNC cards. They are dirt, and I bet those Toshiba chips are fake and those NXP chips are fake, plus this controller is already a copy of a clone of a clone. God knows.

At least the box and and some of the guts are reusable when I rip out this crap and fit the Pokeys devices.

Unless you have something else to contribute, but I am loosing time and money at the moment because of this.

Just on another note, I done a little bit of SMD work, with very small boards and if everything is fine, you can really make nice boards, but as you can see, even with the small board it lost steps. I can't stand holes not being in the centre, but that circuit worked none the less. and it was double sided hence my big via's so it's easier to solder without a mess with no soldermask. SMT 0805

[Virgus]

Hello,
yeah I wouldn't trust Yoocnc with such a PCB without the groundplane.
As you might have seen from my first post the steps lost by simply milling a flat bed are too many.

I read about a guy who took one month to make everything work correctly and it took to me more than two weeks
to have a minimal decent result with no guarantees for bigger circuits (without ground planes in particular...).
Just mentioning this because if you're loosing too much time with this issue I would suggest indeed to change the controller.

Yesterday I bought some Solder Mask Paint on ebay to try to do some SMD design while keeping ground planes
and keeping milling time low (unless soldering the components would be a PITA) but I'm also oriented in changing sooner or later the yoocnc controller.

I attach you my actual motor configs (all the rest is unchanged compared to the pdf I attached in my first post);
the z motor has half the acceleration than the x,y ones.

I'm curious about the Pokeys solution with Mach3 and the Postep25 boards seem good and affordable, so please keep me informed on how it goes if you'll switch to them!

Cheers,
V.

PS About the home switches, yes I agree with you that a perfect cnc machine would work fine even without them but I have the case when I switched the power switch instead of the motor one while I was looking at the PC and moving my axes and the machine's coordinates messed up. This is just an example where home switches can save your work...

[hexpope]

Hi thanks for showing me your configurations. I presume this is @ 35Khz ? in ports and pins.

I tried those settings, and not a hope of mine running at that speed. Tons of rattling, vibrations and stalling on X and Y axis.

Regarding the ground planes. I do in fact use them all the time (4 spoke on connections), it's just I didn't apply the ground plane in those Diptrace photo's and it' hard to see the spokes on that little board for GND plane, but they are there !

Yes I understand what you mean about the home switches now regarding the unit loosing it's main power etc. Good for that I would gather. I am making the order today for them and I will either PM you, or reply here. I don't want to hijack Metalphreak's thread.

Thanks for the settings ! I will do up a video and post it on youtube and give you a link of what mine sounds like with your settings !!

[Virgus]

Yes 35Khz.

I'm wondering if you got the same motors I have. The labels say: YOC CW5741-2012 1,8° 1,8A for 3020T 3040T

If you've different motors than mine, have you tried the other settings that are available on the net?
Step pulse 3 and Dir pulse 1

When I got the machine i used this settings and it was a mess, so maybe you need other settings than mine.
I also verified that I've got 5 Leadscrew Revolutions per cm and 200 Motor Steps per revolution (1.8° step motor)
so according to what I found here: http://www.aquickcnc.com/tutorials/stepper-motor-calculations/
0.5  x 200 = 100 with no micro-stepping; that meaning that my 400 steps per mm implies a micro-stepping of 1/4
(if I didn't made any mistake...);
You should also check your leadscrews as many others CNC6020 need a setting of 320 steps per mm.

Cheers,
V.

PS Hope Metalphreak won't mind for our exchange here in his thread but I suppose it's better to keep public all these infos as others might find them useful in the future... And this thread on CNC6040 was the one where I finally got my first answers!

[hexpope]

Would you believe it? there isn't any labels on my motors. Notting. I wrote to the to seller and all he replied back to me was this.

Code: [Select]

Engineer said, the stepper motor is 1.8A/2A one. All motors subject to this feature are alternative.
And that's all I know about the motors on the CNC.    But I have the fourth axis motor here and I can see there is actually a sticker on it saying. YOC2012 -TBD-A 1.8° 1.8A. It looks identical to the motors for the XYZ axis

If I use 320 in the steps per min then I loose my scaling. If I measure from point A, then get Mach3 to move the x axis 250mm and then measure it, it actually moves to 250 exactly. So I think I have it right with "400"

Using step pulse etc

3 / 1 is what I usually use. It doesn't matter which setting I use, it's still the same.


eBay auction: #221236714378

[Virgus]

I am on a hurry, so just a fast reply: did you check with another parallel port what happens?

I'm tried at first with an old laptop and after hibernation I had a behaviour like yours (just saw the video),
so I had to restart and shut down everytime. I guess the parallel port was the problem.
Before doing any other test in my opinion you should try another PC if you can...

Talk to you later.
V.

PS BTW same ebay seller, but I suppose different lots of production...

[hexpope]

Thanks Virgus,

I turned it down to 25khz and 1000mm / min on X and Y, 500 mm / min on Z with accelleration on 200 / 200 / 100 Things seeming to be well now, but when completing a 40 min job, I am off on the X axis or sometimes the Y axis by about 0.9mm.

Also, could you test something out for me ? could you reduce your feedrate for X and Y axis and see if your machine vibrates ? I set mine @ 60 feed rate on a job, and wow, the motor stalls and vibrations are through the roof !

[hexpope]

@ Virgus,

I have replaced the BOB and stepper drivers now. I am using the Pokeys 56U with their Postep25 driver boards. All I can say is wow.

I hardly even hear the motors on 1/16 microstepping and I am not loosing steps anywhere. If your problems persist, get a new controller. Mine is USB now. I used the same controller box etc. I didn't even need to drill any new holes.

I just need to set up PWM now for the spindle, as now when the main power is on, regardless of the spindle switch it just goes full power.

Either way, I am really happy with the new stuff from Pokeys.

[Virgus]

Hello hexpope,
I did not have time lately to experiment further with my CNC,
but many thanks for keeping me updated.

Your news sound great and I'm really curious about the details of your new set up
(part numbers to buy, configuration/programming and eventually some photos would be great)
Did you try both higher speed and lower speed with no loss in the motor steps?

The most interesting to me is the fact that everything is working via USB, I'd love to drop parallel port!

Thanks again and talk to you soon,
Virgus

[hexpope]

Hi speeds is no problem and with the new 1/16 microstepping I can move the gantry at very very slow speeds without vibrations etc and loosing steps.

As in regards Part numbers there isn't any other than a few pull up resistors I needed to use for the Pokeys 56U protection.

I am still using the transformer, the spindle board and +24 for the breakout boards.

http://www.poscope.com/pokeys56u

and then the stepper driver boards, I bought three.

http://www.poscope.com/postep25

Be sure to download the manuals to getting a better understanding.

No pictures yet as I am still in the process of finishing off the spindle part with PWM.

regards

[asboyd]

Guys,
Just bought a CNC 3040T off eBay. and still the same no manual no instructions of any kind, however...
For those of you still looking for a parallel interface without a parallel interface, go to www.warp9td.com
They have a USB stepper motion control board for either USB or Ethernet.
I purchased the USB one and it works well with my old XP laptop....

Cheers,

AlexB

[snoopy]

I am planning on buying one of this chines machines from eBay.
What would you recommend to choose between 6040 or 3040?
What seller do you recommend?
Is higher price = better performance?

Does it matter if I buy from eBay international or from Europe eBay?

Thanks a lot for your reply

I just bought a 6040 from a Sydney ebay dealer for $1450 + $30 postage. A week before they were going for $1300 + $800 postage !! I was originally looking at the 3040's for around $1000 but the bigger table on the 6040 meant that I could do 19 inch rack mount stuff. Also the 6040's has a much bigger motor which needs to be water cooled plus the price drop made the decision a lot easier.

regards

[snoopy]

Does anyone know the feed rate and spindle speed necessary to cut aluminium using a 3.175mm tip ?

cheers

[eKretz]

That will depend on your cutter material and feed rate will also depend on what depth and width of cut and number of cutter teeth. If you're using a carbide cutting tool you want to start around 18,000 RPM and if you are taking a fairly heavy cut and have 2 cutter teeth, about 80 or 90mm/minute. Lighter cuts you can increase both feed and speed considerably.

[snoopy]

That will depend on your cutter material and feed rate will also depend on what depth and width of cut and number of cutter teeth. If you're using a carbide cutting tool you want to start around 18,000 RPM and if you are taking a fairly heavy cut and have 2 cutter teeth, about 80 or 90mm/minute. Lighter cuts you can increase both feed and speed considerably.

Thanks for your reply,

I just checked the end mill bit and it is a 3.175mm bit with 2 cutter teeth. If you were cutting 3.175 mm thick aluminium would you cut the whole piece in one go or would you do it in layers because I have the option of layering the cuts so I could cut 1mm depth at a time etc.

Also what do you suggest setting the Z-axis feed rate to ?

regards

[GeoffS]

Even a 1mm depth of cut on a 6040 is expecting a lot.
I wouldn't go more than .5mm per pass. Spindle speed should be around 11000rpm.
Slow on the feed rate and use something like WD-40 as a coolant.

[abyrvalg]

hexpope, what are your steps from DipTrace PCB project to G-code? I see you've mentinoned Vcarve, but can't find any PCB-related feature description on their site.

[snoopy]

Even a 1mm depth of cut on a 6040 is expecting a lot.
I wouldn't go more than .5mm per pass. Spindle speed should be around 11000rpm.
Slow on the feed rate and use something like WD-40 as a coolant.

Thanks Geoff

I will set the feed rate at 100mm/min but what about the plunge rate ? Is there any rule of thumb ? I thought 30mm/min might be right. What do you think ?

regards

[ecat]

Is there any rule of thumb ?

Probably, but it depends upon:

Cutter/drill type: HSS, carbide etc and the number of flutes.
Cutter/drill size.
Material: Even if you are cutting aluminium you should be aware of the different grades.
Available spindle speeds and if you have sufficient torque available at any given speed.
The alignment limitations of your machine and how well it will hold tolerance over the time it will take for the job.
The capabilities of your CnC machine: Rigidity and speed for each axis given all of the above.

Useful reading... maybe even some some useful software:
http://www.cnccookbook.com/CCCNCMillFeedsSpeeds.htm
http://www.hsmworks.com/docs/cncbook/en/#Ch03_CuttingSpeedsAndFeedsFormulas
http://www.practicalmachinist.com/vb/cnc-machining/online-cnc-speed-feed-calculator-242061/ - this is the thread for ...
http://zero-divide.net/index.php?page=fswizard - this could be very useful, I've not tried it.

Okay, please read, or at least scan through all of those links. It's a lot to take in but I'm not asking that you know it all - I most certainly don't - just that you are aware of what you are trying to achieve and more importantly what you should try to avoid when you start up your machine.

Now, the  important questions:
How much time have you spent playing with your machine?
What did you do to determine the accuracy and repeatability of your machine?
How did you determine the safe maximum speeds of your machine?

I was lucky, my machine started as a simple manual milling machine so I was able to spend hours listening to the noises it made and actually feeling the vibrations as I cut and drilled holes in stuff. No plans, no design just playing around and squaring up reality with the little machining theory I knew. Time well spent.

Get a rough idea of the upper and lower limits you should stay within. Make some test cuts with the tools and materials you are using. To this day I hate CnC drilling, but drill some holes remembering the basic rules of peck drilling (eg, http://www.practicalmachinist.com/vb/cnc-machining/peck-drill-depth-rule-thumb-124486/ maybe start with 1xdiameter to be safe-ish). Never be tempted to use a milling tool in a drill chuck, ever! Listen to your machine, feel the vibrations lol.

[sigxcpu]

I've got myself a 3040, the cheapest version with delrin (teflon?) white nuts (let's not talk about the unobtanium 1204 delrin nuts). I'll replace them with ballscrews once they'll die. Anyway, there are no issues with lost steps even at large speeds (the whole desk that holds the machine shakes like crazy). Initially it had the classic X-axis lost steps that were easily fixed by adding filtering capacitors to the Toshiba drivers inside the controller.

Yesterday I've replaced the whole Mach3 computer with a small Arduino Pro Mini running GRBL and feeding step/dir on all 3 axes. It works perfectly and the real gain is that I feed the job using Universal G-Code sender right from my Mac instead of taking care of a dedicated Windows computer.

If anyone is interested, I can provide more details.

[snoopy]

Is there any rule of thumb ?

Probably, but it depends upon:

Cutter/drill type: HSS, carbide etc and the number of flutes.
Cutter/drill size.
Material: Even if you are cutting aluminium you should be aware of the different grades.
Available spindle speeds and if you have sufficient torque available at any given speed.
The alignment limitations of your machine and how well it will hold tolerance over the time it will take for the job.
The capabilities of your CnC machine: Rigidity and speed for each axis given all of the above.

Useful reading... maybe even some some useful software:
http://www.cnccookbook.com/CCCNCMillFeedsSpeeds.htm
http://www.hsmworks.com/docs/cncbook/en/#Ch03_CuttingSpeedsAndFeedsFormulas
http://www.practicalmachinist.com/vb/cnc-machining/online-cnc-speed-feed-calculator-242061/ - this is the thread for ...
http://zero-divide.net/index.php?page=fswizard - this could be very useful, I've not tried it.

Okay, please read, or at least scan through all of those links. It's a lot to take in but I'm not asking that you know it all - I most certainly don't - just that you are aware of what you are trying to achieve and more importantly what you should try to avoid when you start up your machine.

Now, the  important questions:
How much time have you spent playing with your machine?
What did you do to determine the accuracy and repeatability of your machine?
How did you determine the safe maximum speeds of your machine?

I was lucky, my machine started as a simple manual milling machine so I was able to spend hours listening to the noises it made and actually feeling the vibrations as I cut and drilled holes in stuff. No plans, no design just playing around and squaring up reality with the little machining theory I knew. Time well spent.

Get a rough idea of the upper and lower limits you should stay within. Make some test cuts with the tools and materials you are using. To this day I hate CnC drilling, but drill some holes remembering the basic rules of peck drilling (eg, http://www.practicalmachinist.com/vb/cnc-machining/peck-drill-depth-rule-thumb-124486/ maybe start with 1xdiameter to be safe-ish). Never be tempted to use a milling tool in a drill chuck, ever! Listen to your machine, feel the vibrations lol.

Thanks

Excellent resources. I have already started reading

regards

[snoopy]

I've got myself a 3040, the cheapest version with delrin (teflon?) white nuts (let's not talk about the unobtanium 1204 delrin nuts). I'll replace them with ballscrews once they'll die. Anyway, there are no issues with lost steps even at large speeds (the whole desk that holds the machine shakes like crazy). Initially it had the classic X-axis lost steps that were easily fixed by adding filtering capacitors to the Toshiba drivers inside the controller.

Yesterday I've replaced the whole Mach3 computer with a small Arduino Pro Mini running GRBL and feeding step/dir on all 3 axes. It works perfectly and the real gain is that I feed the job using Universal G-Code sender right from my Mac instead of taking care of a dedicated Windows computer.

If anyone is interested, I can provide more details.

I had the power supply go in mine. There was no blown components as I first suspected but the board had lots of dry joints. The unleaded wave soldering was of very poor standard so much so that two heavy duty bus links had arced on their joints and eventually went open circuit. You could literally see the carbon around the joint where it had arced (see pictures below) I had to re-solder every joint on the board with led solder and take out the heavy duty links and literally file the ends down in order to make a proper joint. In fact one link just dropped out when I applied the soldering iron to the other end of it. How these supplies ever worked properly is beyond me but I bet there are a lot of dodgy supplies in these machines The power supply was a Mean Well brand 6A 24V switch mode supply. At first when I thought the power supply had shat itself it maybe because it was under rated. There were a whole heap of higher capacity PS's on ebay which I was contemplating on purchasing before I found the real cause of the fault which was the bad soldering.

Once I fixed the supply I also observed another strange behaviour with the VFD on minimum speed when the Y-axis stepper would start to chatter slightly which meant some cross talk from the spindle motor into the stepper circuit. When I earthed the table the chatter would stop. I also note that the 24V floats with respect to the power supply chassis so I'm wondering if tying the negative side of the 24V to ground will fix this problem rather than have me earth the table. When I get a chance I will experiment with this as I feel this could be causing problems with a lot of other users. I note that some people have gone to the trouble of rewiring the steppers and spindle motor with shielded cable and earthing the steeper motors, but I am wondering if tying one side of the 24V rail to earth will cure all of these problems ?

[GeoffS]

On the 6040, you'll find that the spindle connection has no earth so there's no earth to the main chassis.
You definitely need to fix this as apart from the noise issue,  the spindle runs at 380V.
 Most of the metal parts of the controller are not connected to protective earth. You may have  addressed this one as you already have the power supply open but if not, it should be fixed too.

[sigxcpu]

I am the lucky (?) ones with the black controller box. It has 2 boards in it and a huge toroidal transformer with 2 outputs. The boards are: spindle control (PWM with external knob) running at 36V I think and the stepper drivers board. There is no high voltage anywhere.

[David_AVD]

The power supply was a Mean Well brand 6A 24V switch mode supply. At first when I thought the power supply had shat itself it maybe because it was under rated. There were a whole heap of higher capacity PS's on ebay which I was contemplating on purchasing before I found the real cause of the fault which was the bad soldering.

Do you still have the PSU ?  Could you take a picture of the label area?  There are fake Mean Well units out there.