new member

[shipper506]

My experience with CNC started about 6 years ago, because I like to make my own tools for wood working (including but not limited to Panel saw, Dust collection, And others). When I saw the CNC on youtube, I new this would be the project for me. After much surfing on the web, I settled on the "Build Your Own CNC Machine" (a 2 foot by 4 foot model). I saw an expansion in my future (maybe 4 foot by 4 foot or larger) so I settled on four Nema 34 stepper motors 878oz. I know this is like putting a V-8 engine in a Volkswagon. The build went well. Long story short, the test did not go well. The Z axis lost steps on the up side. I ask questions in CNC message boards but was shunned and found no answers. After many weeks of trying the project was shelved. I have moved to the state of Florida upon retirement. I am in the process of re-wiring the CNC. I may have some questions later, for now I am reading the many threads here and look forward to interacting with you all.:welcoming:

[njhussey]

Welcome!!! I'm sure if you post up some picures of your build etc then the folks here will respond with suggestions as to why it's losing steps and any other questions you may have...

[JAZZCNC]

The build went well. Long story short, the test did not go well. The Z axis lost steps on the up side. I ask questions in CNC message boards but was shunned and found no answers. After many weeks of trying the project was shelved. I have moved to the state of Florida upon retirement.

I'll do a deal with YOU.? We'll help you get working again and on right track and You send US some of that lovely Florida Sunshine to UK.!

Welcome.

[shipper506]

I'll do a deal with YOU.? We'll help you get working again and on right track and You send US some of that lovely Florida Sunshine to UK.!

Welcome.
That is a deal I can live with. :smile:

[DrNik]

Welcome, I'd love some of that sun too

[routercnc]

From your introduction it sounds like you want to make a wood cutting machine and have fitted 4off Nema34 stepper but are loosing steps. Couple of things:

Nema 34 sounds a bit overkill for a wood machine - I've seen them specced for lifting the knee on a mill, but for a wood cnc machine you can lift a lot of weight with a Nema 23
Nema 34 needs lots of voltage to make them work. It is possible you are under driving them. I've seen them specced on this site to run at 70V DC minimum, with a preference for direct mains drivers.
Stepper motors can be wired in different ways (series, parallel) to change their output but only if the drivers can take the current

So without jumping to conclusions too early, I think the collective wisdom on here can help you out if you provide:

1. Stepper driver make, model, and most importantly voltage being used on each axis
2. Drive system - all-thread, trapedoizal screw, ballscrew, rack and pinion, belt, other
3. Linear motion - skate bearings, v-bearings, supported rail, linear profile rail, other

Also any photos of the machine, particularly the Z axis will be a great help.

[shipper506]

I'll answer the questions as best i can first, then the upgrades I've made, then pictures (if I can figure out how to add the pictures-including some of that Florida sun I promised)

[jamesgates1000]

Hi welcome to the forum, I have been a member for a while but only just started using it. The really knowledgeable people on here have been a great help to me so far.

[shipper506]

STEPPER DRIVER
1 pc Four-axis Driver Board HY-TB4DV-M (TB6560), 3.5a, 16 micsteps

STEPPER MOTORS
Nema 34 stepper motor 878oz.in bipoler - step angle 1.8, Rate voltage 6.4, Rate Current (A) 2, Phase Resistance 3.2,Phase Inductance (mH) 15, Holding Torque (oz.in) 878, Rotor Inertia (kg.e?) 1.7

DRIVE SYSTEM
Lead screws are 1/2 " 8 starts 1 turn=1"

Anti back lash on all axis

LINEAR MOTION
skate bearings

WIRE
18 gauge wire from driver board to stepper motors and 22 gauge wire to limit switches/e-stop

POWER SUPPLY
350W 36v

[njhussey]

Well the first 2 lines says it all....TB6560 (by the way you're brave running it at 36V, surprised you've not had the magic smoke from it yet at!!!!) and Nema34 motors.

See this thread...http://www.mycncuk.com/threads/1373-eBay-TB6560-Stepper-Motor-Driver-Boards?highlight=TB6560

You're never going to get any sort of performance running Nema 34's with a TB6560. Nema 34's need 100V plus to get any sort of performance.....

[shipper506]

Im confused, you say im not going to get any type of performance out of the 34's because they need 100v however they are not rated that high voltage and all but "Z" was working fine.

The upgrades consist of new limit switches/E-stop, rewire from 22 gauge to 16 gauge on the stepper motors, and new connectors between the two modules, what i call the brains (computer and breakout circuit (software)) and the working module (Stepper motors X Y Z and limit switches (hardware)).

[routercnc]

The rated voltage is much lower than the voltage you can actually drive them at using pulses (ie what the stepper driver voltage is)
I'm afraid Neil is correct and you have built a mismatched system. 36V is way too low for Nema34. You can either accept that or wait for someone to post the technical reasons why.
You are also running lead screws not ballscrew and have anti backlash. This all adds to the friction when lifting the Z axis. To add to it further they are on skate bearings although that should be a minor factor in terms of allowing a smooth lift.
The cheapest way to stop loosing steps would be to swap out the Nema34 on the Z to a Nema23, and probably turn the voltage down a touch to be kind on the chips. Keep the acceleration and velocity at modest levels and you should avoid loosing steps.
If your leadscrew pitch is 1" per turn then I think you would also benefit from a 2:1 pulley on the Z

[shipper506]

If i wait for someone to post the technical reasons, I probably wouldn't understand the post anyway.
I will go with the Nema 24 on the Z. for now.
Could you expand your thoughts on the pulley? Are there any pics of this system?
If i continue using Neman 34 (thinking about expansion) what would you recommend?

[routercnc]

Just noticed that I've typed Nema 24 where I should have said Nema 23 on my posts - corrected. I should also add that you need the lower inductance ones -I'm away from my computer but remember somewhere around 2-3 mH being a good choice. Hopefully someone can post up a good spec.
If you look through the build logs here you should see some of them using pulleys. Your screw pitch is very high putting a lot of load on the motor so the pulley ratio will give the motor more torque with less chance of stalling

If you want to stick with the 34s then you need to buy 4 separate stepper drivers and a break out board. This will be a lot more expensive than your current board and it's all because of your choice of motors which are a bit big for the machine you describe.
When I'm back at my computer I'll try to find the ones most people use. I think Kinko do some mains powered ones which will really make the best use of them.

This thread talks about using 34s
http://www.mycncuk.com/archive/index.php/t-8248.html

[JAZZCNC]

If i wait for someone to post the technical reasons, I probably wouldn't understand the post anyway.
I will go with the Nema 24 on the Z. for now.


I'll give it in simple Technical terms. Large motors have more Inductance or think of it as Resistance to flow of current thru it's windings and Current gives us Torque.
Then think of voltage as the force pushing current thru the motor windings.
So with higher inductance you need more Push to achieve the same speed as motor with lower Inductance. Then because torque mostly comes from current and your struggling to Push the current thru the windings then Torque is also lower.
Think of it as trying to drive a manual gearbox(don't think you have many of these in US . .Lol) Car Slow in too high gear!! Because your speed isn't enough then Motor stalls.

Now you have the worst mix match of components because Nema 34 motors have high inductance but you have Low voltage. Made worse by Drive/s that don't allow higher voltage and like has been said your very lucky you haven't fried them already running so close to there Max voltage.

Unfortunatly it gets worse when it comes to speed because you have high friction linear components in the form of Lead screw and Skate bearings.

This translates into Driving Car Slowly in high gear with the brakes Sticking and the end result motor stalls at lower speed.!!

[shipper506]

So my take on this is:

get a Nema 23 stepper motor to go on the Z axis and use what I have

or

get a larger power supply and stepper motor controllers?

The largest motor controllers I have found are 80v. Will they do?

[JAZZCNC]

So my take on this is:

get a Nema 23 stepper motor to go on the Z axis and use what I have

or

get a larger power supply and stepper motor controllers?

The largest motor controllers I have found are 80v. Will they do?

Well it's a close call really. .? . . . . Nema 23 motors are cheap and if you combine these with 2:1 ratio using pulleys then they will probably do the job with 36V. . . . Think personally in your position I would so go for this option as it's cheapest and easy.

If it doesn't work then I would say Start again with new drives, Nema 23 motors and PSU that match better and sell your existing stuff.

[shipper506]

What do you think about a new "Z" axis like this one ( http://www.ebay.com/itm/CNC-Z-axis-Slide-DIY-CNC-PLASMA-OXY-ROUTER-linear-motion-NEMA-23-Reprap-3D-mil-/281410051552?pt=LH_DefaultDomain_2&hash=item4185589de0 ) to replace the one i have? would this work?

[njhussey]

It's less than ideal as it uses unsupported rails so will flex when cutting giving a poor finish. Depends on what you're wanting to cut really...

[JAZZCNC]

What do you think about a new "Z" axis like this one

Not a lot.!!

It's just too whimpy for a good router, It uses round unsupported rails and thin aluminium plate so will flex and vibrate giving a poor finish. The bearing and motor coupling design looks poor so chances are accurecy is on lower side. Also poor design with how it connects direct to motor will shorten motor life.
The screw is 16 turns per inch so thats a high pitch(1.6mm) so your Max feed will be lower, 8 turns(3.175mm) would have been better choice.

But if you are just doing light work in softer materials then it will probably be ok.

Just be aware thou the motor isn't included in this sale.!

[shipper506]

Ok Ill keep trying - how about this combination for my existing unit? Ship from USA WAREHOUSE 3Axis Nema 34 Spindle Shaft & Nema23 Stepper Motor CNC (http://www.ebay.com/itm/200866349459?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) . Ill use my existing 36VDC power supply for one of the stepper motor driver - DM542A so each Stepper motor driver will have its own power supply. (if someone explains how to attach pics, I will attach some)

[Clive S]

(if someone explains how to attach pics, I will attach some)

Have you tried using the (Go Advanced) button and then attachment paper clip symbol. ..Clive

[JAZZCNC]

Ok Ill keep trying - how about this combination for my existing unit? Ship from USA WAREHOUSE 3Axis Nema 34 Spindle Shaft & Nema23 Stepper Motor CNC (http://www.ebay.com/itm/200866349459?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) . Ill use my existing 36VDC power supply for one of the stepper motor driver - DM542A so each Stepper motor driver will have its own power supply. (if someone explains how to attach pics, I will attach some)

Well no not really because it's still using low quality components. For instance the motors have 9 & 22mh inductance which is way to high with only 36v & 60V.

Personally I'd forget the nema34 motor and go with nema23 all round. Buy drives that can handle 70-80v and run all motors from one 60-65Vdc PSU.
Forget buying a Kit and buy individual parts that match each other best. Kits are nearly always a Mis-match of components.

Adding pictures can be done from Quick reply by selecting 3rd from end icon on toolbar at top. Then uploading.

[shipper506]

Ok that sounds good - Where am I buying these components from?

[JAZZCNC]

Ok that sounds good - Where am I buying these components from?

If you want to stay state side then try Kelling cnc http://www.automationtechnologiesinc.com/

[shipper506]

yet another question - How do you pick the resolution to use (microsteps) for carving wood? Example: I have 2 DM542s and one DM860. DM542 range from 2 to 128 Microsteps and 400 to 25600 Step/rev.(for 1.8* motor). DM860 2 to 256 Microsteps and 400 to 25600 Step/rev.(for 1.8* motor).

[JAZZCNC]

yet another question - How do you pick the resolution to use (microsteps) for carving wood? Example: I have 2 DM542s and one DM860. DM542 range from 2 to 128 Microsteps and 400 to 25600 Step/rev.(for 1.8* motor). DM860 2 to 256 Microsteps and 400 to 25600 Step/rev.(for 1.8* motor).

Ok well first 2 to 128 and 400 to 256000 are the same thing just using a different notation. Let me explain.!!

Typical Stepper motor needs 200 FULL steps for one revolution. (360/1.8=200) These FULL steps can be broken down into micro steps by the drive electronics.
So first notation uses 2, 4, 8,16, 32, etc which means 2 x 200=400 micro steps or 4 x 200 = 800 microsteps etc.
The second notation uses 400, 800, 1600, 3200 etc which is the result of the above calculation.

Both mean the same thing.

Now like most things CNC which is best isn't straight cut thing.? There are several factors which have to be considered and they don't relate to the type of work your doing with the machine.!! The things that affect micro stepping setting are the PC your using or better put the motion control device your using ie parallel port and the Machine it self.

The strength of the machine and Resonance can play a big part in what micro stepping works best for your machine and the motor/drive relation ship so resonance doesn't affect them and some trial and error can be needed to match your motors best.

Then you have the PC to consider, or more important the Max number of pulses your parallel port or motion control devise can reliably give out.! This is a very important consideration for relaibilty, accurecy and performance you'll get.
If you set the micro stepping high then you'll require many many times more pulses to reach the same speed as a lower micro stepping setting. For instance a setting of 400ms will require 6666.666 pulses per second to reach 1000rpm at the motor. For the same 1000rpm with 1600MS you'll need 53,333.333 pulse per second
If your pulse device ie parallel port then you'll only have limited amount of pulses available which with standard mach3 setting will be 25,000 pulses per second per axis.
Has you'll see this is fine for the 400ms setting with some pulses to spare. But with 1600 you'll only have half the number needed to reach 1000rpm so therefore the Max speed you'll achieve is 500rpm. So going too high can limit speed depending on the Pulse rate the Motion control devise can output.

So you'd think OK I'll keep MS low but again it isn't always that simple as the closer you get to the FULL step of the motor the rougher the motor tends to run and resonance becomes a problem. This is why the Minimum MS amount is 400 or 2 x 200 as running full step isn't fun.

So higher MS helps to smooth out the motors and deal with resonance. The trick is picking a MS setting that suits the machine and resonance to give a nice smooth motor without stressing the pulse device.
If you stress the pulse device and overtune the motors you'll lose steps and accurecy.

Common Setting is or starting point is 800ms or 4x and if the motors stall easily or sound resonant and rough running then try different setting.
Remember every time you change MS setting you'll need to adjust the Steps per setting so machines moves correct distance.

Sorry for long explination but your better knowing why than just wondering why.!!

[shipper506]

For some reason the thank you message did not go through so here it is - Thank You for that information. You have explained it well. The next problem I am having is setting up Mach3 Ports and Pins "Motor Outputs". The simplest way to ask this question is: Is there a way to determine which pin is motor and which pin is direction for each motor? What is printed on the breakout board is as follows:
Pin Label
2 Dir + X
3 Dir - X
4 Dir + Y
5 Dir - Y
6 Dir + Z
7 Dir - Z

I have assumed the "+" is the "Step Pin#" and the "-" is the "Dir Pin#".
(again Thank You All for listening to the ramblings of this old man)

[JAZZCNC]

Ok well you should have Dir and Step + & - for each axis. Or at least Dir & Step plus one more connection for either ground or 5V (often marked Vcc) depending on the connection type you choose on the drive. common Anode(NPN) or Common Cathode(PNP).

What BOB and Drive are you using.? I'll take a look for you.

[shipper506]

OK if this worked you see what i call the brains of my CNC machine: pic1 is in it's sleep mode - pic2 working state - pic3 is the Dell computer - pic4 is the slide out that holds the power supplies, CNC stepper controllers , and the breakout board - pic5 is the breakout board.

[shipper506]

correction to previous post it is NOT:
2 Dir + X
3 Dir - X
4 Dir + Y
5 Dir - Y
6 Dir + Z
7 Dir - Z

it IS:
2 PUL - X
3 Dir - X
4 PUL - Y
5 Dir - Y
6 Pul - Z
7 Dir - Z

[JAZZCNC]

correction to previous post it is NOT:
2 Dir + X
3 Dir - X
4 Dir + Y
5 Dir - Y
6 Dir + Z
7 Dir - Z

it IS:
2 PUL - X
3 Dir - X
4 PUL - Y
5 Dir - Y
6 Pul - Z
7 Dir - Z

Ok well those pics are about much use as fart in space suit but I think I get the problem.!

The BOB will have a 5V output supply. Take a wire from this to each of the Step & Dir (+) on the drives. This should get you working.

[shipper506]

If you look close at pics 4&5 you will see a brown wire with a white stripe on one side (looks almost like a white wire) going from the 5vdc+ on the breakout board to the PUL+ and a jumper from PUL+ to Dir+ on each controllers. I have put a volt meter on all three and they all have 5vdc power. I also checked all three power supplies and they all have the proper power output. I rechecked all connections and wires to be sure they are all in the proper places.

[JAZZCNC]

correction to previous post it is NOT:
2 Dir + X
3 Dir - X
4 Dir + Y
5 Dir - Y
6 Dir + Z
7 Dir - Z

it IS:
2 PUL - X
3 Dir - X
4 PUL - Y
5 Dir - Y
6 Pul - Z
7 Dir - Z

Right then you have it wired correctly. So now just enter the corrected pin numbers into mach3 motor outputs for step and direction of each axis. Don't forget the port number which will most likely be 1. Also make sure enabled is ticked.

[shipper506]

I have to work the next 7 days strait so i will not be able to physically work on the machine but i will be reading about the setup and maybe i missed something. I'll let you know how it goes.
A side note: I did notice the X and Y steppers get warm when its on for more than an hour or so. I set them all for half power when stopped.

[Clive S]

I have to work the next 7 days strait so i will not be able to physically work on the machine but i will be reading about the setup and maybe i missed something. I'll let you know how it goes.
A side note: I did notice the X and Y steppers get warm when its on for more than an hour or so. I set them all for half power when stopped.It is normal for them to get warm so that's fine. ..Clive

[shipper506]

A thought has just occurred to me (and before you ask no it didn't hurt much LOL). On the breakout board should i be able to take a volt ohm meter and verify the pin numbers are correct?

[shipper506]

PART !:
all of the limit switches work and the E-stop works. I have no motor control - i will attempt to explain how everything is connected and show pictures - maybe i'm missing something. the schematics i used to wire everything is pic-1, 2, 3 and 4 (exception is there is a power supply for each motor driver)

[Clive S]

PART !:
all of the limit switches work and the E-stop works. I have no motor control - i will attempt to explain how everything is connected and show pictures - maybe i'm missing something. the schematics i used to wire everything is pic-1, 2, 3 and 4 (exception is there is a power supply for each motor driver)Looking at the bob where the 5V power is connected does it need 5V connecting to the VDD terminal ? ..Clive

[JAZZCNC]

Remove the wire going to the Enable on the drives you don't need that. This won't be your problem as it's not going to ground but still remove it.

Other than that it looks correctly wired. So if your still not getting any motor movement then you must have the control software set wrong.
The VDD Clive mentions is if you use 10V I think and you have to change a jumper on the board if using 10V.

One more thing is take off the tie wrap cable ties. It's not a good idea to strap signal wires together with power wires as you'll get cross contamination on the signals from EMF electrical noise.
Also if the wire your using for the motors isn't shielded and the shield correctly grounded then you could end up with problems from electrical noise causeing false e-stops or worse missed steps etc.

Show some screen shots of how you set the Motor outputs in control software.

[Clive S]

The VDD Clive mentions is if you use 10V I think and you have to change a jumper on the board if using 10V.Of course I stand to be corrected by my mentor:apologetic: but I have a similar bob (but not the same) and that has to be connected to enable the bob. ..Clive

Edit: looking at the schematic and the picture of the bob they are both different in that the schematic shows : 5V gnd gnd 10V but the pictures shows 5V gnd gnd 5V

[routercnc]

I have exactly that BOB - it came free with the DQ860MA drivers which I notice the OP is also using.

15325

I used the 5V (upper most one in the picture) and adjacent ground to supply the BOB (from a 5V feed from the PC power supply). When it was switched on out of interest I also checked the voltage at VDD (lower one in the picture) and it was also 5V.

Board worked fine and from what I can tell in your pictures was wired up how you have it wired up (except i didn't use the enable connection on the drives).

The reason I ended up using it (for now) was because the other one I bought -
15326
could not be made to work despite checking with scope, multi-meter, all sorts of diagnosis. My conclusion was that it was a faulty board. So whilst you run through all the good advice about settings etc. (which hopefully is the problem) you should be prepared for the board to be faulty if all else is ruled out.