Messages

361

Works in progress / Re: New IPS (Interactive Programming System) Professional Screen for Turn

« on: October 10, 2012, 04:35:34 AM »

Too bad you got the feeling there was not much interest, Wes I was still waiting for the finished version.

Dan

362

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: October 09, 2012, 07:40:59 AM »

Ah... They are so evenly spaced and bright (I would have expected the grain be darker than rest) that it didn't occur to me it was the grain

Dan

363

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: October 09, 2012, 07:17:45 AM »

Hi Tweakie,

Why are there vertical lines on the last one?

Dan

364

General Mach Discussion / Re: Encoders config

« on: October 08, 2012, 02:34:57 PM »

This is way too low. Try a 100k resistor. I think it's picking up noise and amplifying it.

Dan

365

General Mach Discussion / Re: Encoders config

« on: October 08, 2012, 02:01:31 PM »

I assume you're not using the line driver version, because the manual says it outputs 5VDC.

I would try removing the transistors and putting in resistors in series. Or try using a larger value resistor in series with the base of your transistors. It could be it's too low.

Dan

366

General Mach Discussion / Re: Encoders config

« on: October 08, 2012, 01:46:00 PM »

Don't know how encoders work with PP, but did you try playing with the debounce setting? I tend to agree with Terry that there is some problem with your circuit., picking up noise.

Dan

367

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: October 08, 2012, 09:42:58 AM »

Torque and HP are essentially the same thing. HP is just torque over time, and the relationship is linear.

Not exactly. Power is torque times rotational speed. And saying that the relationship is linear is a bit confusing as the speed (RPM) is not a constant itself. Take a stepper motor for instance - peak torque is at zero RPM, where the power is zero, while peak power is at some mid point RPM where torque is substantially less than its peak value.

Hence, the way Terry put it, is the correct way. You are essentially transferring torque. Power has absolutely no meaning here. I could have a 6kW high speed spindle putting out the rated power at 30,000RPM, which means only 2Nm torque, whilst a tiny NEMA 34, 25 watt stepper would have twice that torque at zero speed. Power is the amount of work you can do over time, so obviously the 6kW spindle would do more work in a given time at its lower torque than the high torque stepper.

Dan

368

Mach SDK plugin questions and answers. / Re: Impact engraving plugin

« on: October 08, 2012, 07:53:34 AM »

Hi Pasquale,

I don't have a working system. I attempted to build an electromagnet for this purpose some time ago but not completely understanding the physics behind it and wrongly assuming that it ought to be powerful to be able to engrave, I built a strong one. Then I saw that the plunger was too heavy and the coil had to much inductance and I couldn't drive it any fast.  I reduced the plunger and the coil but it still was not enough. Haven't touched it ever since.

Not sure why you said PWM. I was asking about the practical current control in the circuit. What component will be controlling the MOSFET gate voltage? Only way I know of in the configuration you laid out is an Op Amp. But I built such a circuit and found it struggling to pulse the MOSFET at frequencies higher than about 10Khz. I think that possibly the specific Op Amp model was not suitable although it was 1Mhz band width I think.

Regarding the frequency divider, I think that Tweakie and Andrea were getting good results without this. So again not sure why you need it.

Dan

369

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: October 07, 2012, 07:05:10 AM »

Yes, I have an Emco F1 bench top mill and it uses BT30 holders without the flats and the spring force is sufficient to hold the holders not allowing them to slip.

It would be helpful to know the application.  There is a lot of distance between driving 1/4 roughers thru aluminum and pushing a big face mill across an interrupted cut on stainless.

8mm roughing mill full diameter 4mm deep in aluminium. I am sure I could do twice that depth and the tool wouldn't slip. Don't use face mills on that small machine. Do use slitting saws and had a few times it jamming, but again it's not really a reference as it was stalling the undersized spindle motor (around 5Nm at the spindle).

Dan

370

Show"N"Tell ( Your Machines) / Re: A few of my projects..

« on: October 07, 2012, 05:06:03 AM »

Can you attach your images instead of linking to them as they dont seem to load or atleast not for me, I get a wee bit at the top of each then it seens to stall.
Hood

Yes. The same is here.

Dan