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Messages - neptune

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General Mach Discussion / Re: Y-axis "creep"
« on: December 29, 2011, 04:20:14 AM »
Yes, config, ports and pins, motor outputs. Make sure that all your axis motors (X, Y & Z) step and direction, are either all active high or all active low.

I have found that if you have a mixture of some active high and some active low, it results in the creep which you are seeing.


General Mach Discussion / Re: Y-axis "creep"
« on: December 26, 2011, 04:49:57 AM »
I have had this problem in the past. Solved it by changing the active hi/lo on the affected drive.


General Mach Discussion / Re: Safety First
« on: July 10, 2011, 10:19:38 AM »
Thanks for all your comments.

Jeff, it is a bad idea to have a shelf behind the lathe. It's just that in a home workshop many of us are limited for space and there is a temptation to use every available bit of wall, but it has made me think about re-arranging things.

Sam makes a good point.

Actually being able to focus your mind into hitting the E-stop in a time of panic is no easy feat.

When these things happen, your brain seems to work in slow motion. You are thinking, how do I stop this thing - oh yeah, hit the big red switch. You don't want to be thinking, where did I put the mouse when it was in the way just now, why is the mouse pad cluttered up with tools so that I can't move it, why can't I see the monitor from where I am trapped or why has Mach chosen this moment to freeze, etc, etc.

Seconds really count in such circumstances.

Thanks again

General Mach Discussion / Safety First
« on: July 07, 2011, 01:13:49 PM »
Hi Guys

Having just read a recent post about operating Estop button with mouse, I thought I would add my advice to that of many others who say that you really must have a hard wired emergency stop switch which is easily accessible, cuts off all power to spindle and drives and is independent of software.

I have 30 odd years experience as a machinist and should really know better, but we all do stupid things sometimes. The other day i was turning a large piece of bar in the lathe. The chuck jaws were protruding well beyond the diameter of the chuck which was peventing me from fully closing the chuck guard. I was in low gear running only at about 100 RPM, but with lots of torque.

As I reached over the lathe to get something from a shelf, my Teeshirt slipped out of my waistband and was immediately caught up in the jaws of the chuck. This twisted me around and pulled me down towards the ground with the chuck jaws pounding against my back. I aimed a good hard blow at the mushroom switch which is my emergency stop button and all power was immediately disconnected. Unfortunately, in my panic I slammed my knee into the machine. The result of all this was a badly bruised back, a broken leg and 3 days in hospital.

However if I had to rely on getting to the mouse and finding the Estop icon on the screen, it could have been a lot worse. Experienced machinists will know that you should not wear loose clothing whilst operating machinery. It is also not a good idea to reach over moving machinery, but above all you need a reliable way of stopping the machine quickly in the avent of an emergency.

I hope my experiance may be of benefit to newcommers to machining and perhaps just a reminder to everyone else.


SmoothStepper USB / Re: MDI
« on: May 26, 2011, 01:01:51 PM »
It shouldn't be the case, but I had the same problem as you when I converted from parallel port to smooth stepper around 10 months ago. Not everyone is seeing this problem and I do not know why some are. The good news is that the work around is very reliable and I have been using the machine daily without any problems as long as I start off with a G code program loaded.

Perhaps if others are experiencing the same thing and they report it on the forum, it may throw further light on the root cause.

SmoothStepper USB / Re: MDI
« on: May 23, 2011, 12:23:58 PM »
Are you using a smooth stepper? If so, switch on your machine, open up mach 3, accept re-set if it is flashing, then before you do anything else, load a G code programe, (Any program), then try to run a command from MDI.

Hi Don and welcome to the forum. Go to General Mach Discussion and select "New Topic" you will then be able to post your question and I am sure someone will be able to help you.


General Mach Discussion / Re: Steppers slightly "jitters" when idle
« on: January 12, 2011, 05:24:12 PM »
I had this problem a couple of years ago, It was resolved by selecting low active for the axis motor drives in ports and pins. Now using smooth stepper it doesn't appear to matter whether they are active high or low.


General Mach Discussion / Re: Using the the taig mill to turn parts...
« on: October 26, 2010, 05:13:55 AM »
Before I had a cnc lathe I did a lot of turning on a milling machine. Initially I had a simple set up with a chuck mounted onto a motor shaft with the motor mounted onto the table of the mill. The tool was held in the mill spindle with the spindle locked. It wasn't a very good arrangement but it did turn out a few parts with care.

Later I built a lathe type headstock which was mounted on to the table of the mill. I then had a tool holder clamped to the column with gang tooling mounted onto that. This was very successful and I made several thousand parts using that method. I also had limit switches mounted on brackets at various locations with strikers fixed to the table. The limit switches were configurable and could be set to change the speed or direction of the motor or to apply a brake to the motor so that cross drilling could be carried out using the mill spindle in the same setting.

The main limitation was rigidity as the the tool overhang was quite long, but after experimenting with various arrangements a reasonable comromise was achieved.

The pictures show the general arrangement, they are looking a bit worse for wear now but they did a good job when I needed them


General Mach Discussion / Re: Feed problem
« on: October 21, 2010, 12:06:33 PM »
G94 is feed per minute mode. G95 is feed per rev of the spindle. When you write a G code program, you can specify which mode to use in the first line of the program and it will stay in that mode until you change it. If you enter a feedrate into the MDI box the mode will be whatever was previously specified.

During testing of your machine, I would suggest you stay in G94  so if you enter a feed rate of 50, the axis will travel at 50mm per minute. If you were in G95 mode the axis would try to move at 50mm per rev which would be much to fast.

It is not necessary to enter a feedrate into the MDI box everytime. If you have already entered F50, it will stay at that rate unless you specify differently. When you start up Mach each time, the feedrate is defaulted to a low value (I think 6mm per minute)

The maximum feedrate is dependent upon the velocity as set for each axis in motor tuning (your rapid feedrate)


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