Messages

1

General Mach Discussion / Re: Bridgeport Knee Mill Conversion?

« on: December 30, 2017, 04:02:17 PM »

If you want to use the knee for tool length compensation the tool length would simply need to be passed to the knee axis to move it up or down by that amount BEFORE a tool is actually changed so you have room for it at your normal tool change Z height. Then the program sees all tools as the same length.

You'd probably want to compare the two offsets, and only move if the new tool is longer, as you don't really want the knee cranking up for some short tool after running some long tool, before you've changed the tool.

Slowly making sense, thanks

So in the code all tool length compensation would be turned off and I would likely be editing the M6 Start ??

That's actually a good question.
You still need to use tool length compensation, and use the tool lengths in the tool table to move the knee, but how does Mach handle that?
Not using compensation would work, if you know the knee will move to Z in the right position.
Other option is can mach combine the position of the knee, with the quill?

2

General Mach Discussion / Re: Z Axis Air Assist

« on: December 24, 2016, 04:35:38 PM »

They should use a venting regulator.
The regulator lets in pressure when the pressure drops i.e the cylinder extends, and vents pressure out when the pressure increases i.e. the cylinder retracts.

3

General Mach Discussion / Re: Strrange sound of stepper motor Mach3

« on: December 22, 2016, 06:29:22 PM »

Do all the axis do it at the same time?
If they are, it could be a power supply issue.

4

General Mach Discussion / Re: Custom Machine Servo Motor "Stall/Catch" (Both Power On and Power Off)

« on: December 06, 2016, 07:38:31 PM »

Dirty/sticky/worn brushes could quite easily cause enough of a problem to cause the drive to fault.
If checking them has cured the problem, then that has probably been the problem.

If it hasn't, the next thing I'd be trying would be to start swapping bits between axis. Motor/encoder/drive in some form of logical order, starting with whatever is easiest to change. Once the fault moves, you should of found the problem. If it never moves, then you're looking at a wiring problem.

5

General Mach Discussion / Re: Question on Plasma THC control to users of this facility

« on: November 27, 2016, 06:29:59 PM »

Around 2003 would probably be about right.

Your plan sounds reasonable.
I suspect you'll need to add a bit filtering/smoothing to the input, otherwise your up/down relays will likely do nothing but chatter.

6

General Mach Discussion / Re: Physical buttons for plasma

« on: November 27, 2016, 06:00:17 PM »

The problem is, if it's the continual movement that was overheating the motor, then the same will likely happen with a larger motor.

It'll be a case of striking the balance between moving too much that the motor overheats, and moving too slowly the torch height doesn't respond quick enough.

7

General Mach Discussion / Re: Question on Plasma THC control to users of this facility

« on: November 27, 2016, 08:06:40 AM »

I was going to convert it to CNC, but after much deliberation, I got the chance of a CNC lathe, then an even bigger mill, which led to another CNC lathe, which led to a ready to run CNC mill, and am currently retrofitting yet another mill.
In amongst that, the mill I bought from you got sold (I think I still have the wiring diagram from when I worked out exactly how the rapid cycle worked). I still have my original Harrison mill, which is currently setup to do second ops.

You could increase the supply voltage to your existing driver, however you really want to be using a linear supply.
I suspect the real reason you kept blowing controllers, was under deceleration, the drive dumps energy back into the power supply. Switch mode power supplies generally don't like that and have little capacity to absorb it, with the result you see a voltage surge, which and the TB chips just don't handle going over their rated voltage. Linear supplies on the other hand, with a reasonable sized capacitor will quite happily absorb the surge.
The other option is to add in a reverse energy dump, which will dump any energy from the drive into an external resistor (check the stepper motor basics guide over on gecko drive for examples)

8

General Mach Discussion / Re: Just when you think you are finally getting there....

« on: November 27, 2016, 07:43:42 AM »

I'm going to guess that's around where the axis speeds starts/finishes changing speed for/after the corner?

9

General Mach Discussion / Re: Physical buttons for plasma

« on: November 26, 2016, 06:59:41 PM »

I would expect a servo to handle those kinds of moves, if tuned well. Could it be a case of the short/sharp moves, combined with a bit instability in the tuning causing the problem?

Could you try reducing the max current/acceleration?
You obviously don't want to reduce it too much that it's not fast enough to respond, but dropping it slightly might be enough to take the edge of the moves which are causing the heating.

10

General Mach Discussion / Re: Question on Plasma THC control to users of this facility

« on: November 26, 2016, 06:50:16 PM »

Just had a quick scan through the thread on mig-welding. Are you the Adrian H who happened to sell a rapid cycle Harrison mill a number of years ago?

The basic older TB drivers are not great. They're ok if you don't push them near their limits, but lots of implementations have woeful heatsinking, which compound their limitations. For not much more money, I'd buy some newer individual TB6600 drives (search ebay for TB6600 - there are plenty options), which use far better chips, and would allow you to run a higher voltage power supply. You also get the benefit that if you do blow one up, you only need to replace that one.
For plasma, you need speed, and the main way to get speed from steppers is by increasing the power supply voltage.