Brad, there is typically a contactor on the VFD input, but this is used for the morning switch-on, evening switch-off and e-stop only. It is not used for starting up the spindle every time you make a cut.

Anyway, I don't know what other VFD does, but if you put a relay in front of the my type of VFD, it won't start the spindle (not in a million years) & it can't switch off the spindle at the instant you cut the power to the VFD...

Hi Gerald,

That was my originally thought on how to wire a VFD.

Thought this site some say E-stop and >>>> some say E- stop meaning what I would call a reset. Maybe we should call a RESET a reset a not E-stop and an E-stop an E-stop.

At least, being a novice, the like terminology confuses me on occasions, as I am sure it does others.

This stop/reset example of how I made error in judgment error since we never make mistakes.

I am offering this in a positive way, this is a great site.

Thanks,

Al

(E)mergency-stop is only used for smoke, flames, blood and screams.

Do those screams include the ones from the wife yelling to get other things done instead of playing with the machine?:)

Depending on your VFD, a large braking resistor can be installed that can stop the spindle within a half turn (so they say, I have no way to measure that).

The braking resistor on one of our mills looks like the coil from an electric stove (it could well be). The moment you hit the E-Stop, the VFD dumps all the power into that coil.

Check your VFD owners manual on installing and sizing a braking resistor.

My dad says that braking resistors in mills used for tapping will stop the spindle in a quarter turn - but you are tapping much slower than milling.

He says a 1 second stop time might be a more realistic number, maybe longer for a really high speed spindle.

Thanks all.

Made all the wiring changes. Now. I like how the VFD reacts. Made several cuts, like I can cut half of the roadrunner only because I did not recieve my licence from Mech3 and cannot load all the code>>>>> I hope. It cut nice, starts and stops with the code comands M3/M5 commands, can stop and start Spindle on the touch screen.

Now Brad how do I contol the Spindle speed on screen?

Anyway it finally cuts and I think I made a record of the longest build time. tust shy of 36 months

Now comes the hard part How does it run? Hopefully less than 36 months.

Once again thanks all.

Al Drouin

Seems like I didn't get my point clear.
To rephrase.
The VFD display takes about 6 seconds be fore it starts blinking & another 4 seconds for it to get ready for operation after the VFD is connected to external power & to get the spindle turning, one need to press the ON button on the VFD or receive a signal from the PC after the VFD display is ready..

Hence, "if you put a relay in front of the my type of VFD, it won't start the spindle (not in a million years) "

The VFD display will only black-out after about 6~7 seconds after the power supply is disconnected to external power.

Hence,
" it can't switch off the spindle at the instant you cut the power to the VFD..."
& I've not got to the spindle breaking stuff yet...

All this is before we even consider talking about the physical breaking.

Pictures , Pictures , Pictures :D !!!

Al, you need an optoisolator, two resistors, one capacitor and a small hobby circuit board. You use a spare output pin from the PC, and treat it as a PWM output; one resistor is the current limiter for the input side of optoisolator; the optoisolator protects the PC and VFD from each other, and the remaining resistor and capacitor form an RC filter on the output from the optoisolator to create a 0-10v control voltage that goes into the VFD.

I'll try to run the actual calculations and draw a circuit picture a little later - I'm not at my desk right now. What is the make and model of your VFD?

Recieved Mech3 licence now>>>> we have a full roadrunner

Attachment 13101

Attachment 13102

Show the machine:)

I will do that

He did,

Here
and
Here

Now all he needs is a serial Number! Congrats Al! :)

SaWeeeet - Congrats you get #95 ---- Can I hear 5 more .... I know your out there :D !!!

Nice build !!

Builder's Log Update
 

Al,

Congratulations on completing your MechMate and earning Serial #95.

Here is the Updated Builder's log.

As a guess, I've included the US MDF sheet size ( 97" X 49" ) as the dimensions. Please let me know the actual cutting dimensions of your MechMate.

Please review your Builder's Log entry and let me know any changes you want to make.

Congrats, Al

Way to go AL

Congrats Al!!.. Nice build...

Good morning,

Today my goal is to make a dust shoe; I designed a base in v-carve. Loaded the file in the machine. Cut shoe and the holes are out of round. I know some where in this site I saw something about out of round holes but can’ t find it know that I need it.

It repeats all cut passes exactly.

I am not sure if it is motor tuning, programming, or noise. I have de-bounce down to 100.

Here is a picture of the piece.

[ATTACH]13116

Al

Hi, Al

Check up to tighten the screw of gear wheels on shaft of a step motors.

Loose grub-screws and too much slack on the z-slide (tighten eccentrics).

Dmitriy and I posted together. . . . we have seen those circles before! :)

Thanks

found posts in trouble shooting "out of round holes and read.
i have read and will try this morning

Thanks
al

Found the "A" stepper motor mount was a little to tight and had bound up not allowing the spring to pull it up to enaged with rack in essance running on just the "X" stepper. Grubbers were all tight. Ran a quick cut circle, 3" was off by about 1/16". Much better. On the "Z" one roller in five not making proper contact will adjust play again later today.

Wish I didn't have to work for a living.

Thanks

Al

Alan, believe it or not, you quickly diagnosed a "new" cause for bad circles......one of the gantry motors not fully meshed with the racks.

Gerald,

Don't give me that much credit all the help within this site did more than I did.

I tightened up the lose Z roller and it is now cutting to within 2 thousandths across the diamiter.


Attachment 13117

Thanks

Al

Hi Al,

Problems solved in 8.15 hr. You should start a bussiness!

@Al; I just had a similar problem to yours today, my small circles ( 1/2" in diameter) do not look like circles, but 3 and 4" circles look almost perfect (notice I said *almost*). I been fighting the correct "Pulses Per" setting within Mach3 and tomorrow I am going to look at all the springs and Z rollers as never thought about looking at the Z..

Nice machine Al, congrats! I am not too far away from you in lower fairfield county.

Been away for a wile.

Brian you are welcome to come to Mystic anytime.

Miguel I did have a a miner problem and I tightened up the springs a little and sprayed the nylon washers with lubricant and all was fine. Do check setscrews on the gears i had to put locktite on mine.

al

Al,
Are you using two set screws 90 deg apart or just the one? I think Gerald had recommended that at one point.

Heath,

I am just using one set screw on the flat of the shaft it's been ok for about 15 hours cutting so far will do more cutting this week now that I am back. If I have a problem again I will add another.

If your motor shaft only has one one flat face, don't be shy to file/grind another one 90 degrees away.

It has only one flat now. If I have any trouble at all it will be done.

Thanks Al

Alan

You could also put another two grub screws at 90 and 180 degrees to the original grub screw on the flat.
What this gives is three points where the grub screws load against the stepper shaft.

Look carefully at post 708 on my thread http://www.mechmate.com/forums/showt...&postcount=708 and you can see the way the grub screw bites into the stainless shaft.
The other grub screws are biting in "on the round" and will miss the shaft on the "sides" opposing the direction of rotation.
This means that they will not resist the rotation as well as the screw on the flat but it will provide a good extra measure of fixing anyway.

Somewhere on the forum a member posted "do them up, undo them, then do them up again" as a method of seating the screw.
Good advice when you see how they cut into the stainless steel.

Ross

A few things I have been cutting. Learning>>>



Attachment 13208

Attachment 13209

Attachment 13210


AL

Great work.

Brad, a wile ago you said you may have a drawing for a spindle speed control.

I think I am ready for the next step. Spindle speed control. My VDF is a AC Tech Model # M 12100c .

Does controler work on the Mech 3 screen or does it need modification?

Thanks in advance

Al