Messages

61

Show"N"Tell ( Your Machines) / Re: Zero gravity Z

« on: December 02, 2013, 09:50:21 AM »

I had a similar problem on my home built mill. With the new spindle and the Y axis mounted to the Z the total weight is about 50 lbs and the Z started slowly drifting down. I just installed 2 50 lb gas springs hose clamped together to give an 18" stroke. About $40 total from Mcmaster Carr.

Gas springs have about 2000 psi of nitrogen in them. It takes the rated load to start compressing them. Then the load increases by only about 10% over the full stroke. So the 50 lb cylinders put out 55 lbs of force at the bottom of my Z stroke. They are also filled with oil so provide damping too.

I considered going that way at first but thought the lifespan of the gas springs may be limited (i thought of the tailgates of cars that have to be propped up because the spring(s) was worn out).  How has it worked for you?

62

Show"N"Tell ( Your Machines) / Re: Zero gravity Z

« on: December 02, 2013, 09:36:03 AM »

neither of these would allow Z to go out of control, it sounds wierd!

What kind of "mill" are you talking about that you have?  This is a gantry router I have.  Doesnt sound like you are familiar with the concept.

63

Show"N"Tell ( Your Machines) / Zero gravity Z

« on: November 30, 2013, 07:59:36 PM »

Estop cuts power to the motor, which puts it in free fall. The air cylinder keeps it suspended. It's balanced just right too. I know that because estop does not kill power to the encoder board and the position continues to be monitored even during estop.

64

Show"N"Tell ( Your Machines) / Re: Zero gravity Z

« on: November 30, 2013, 07:01:26 PM »

Not a particularly safe system if Z drops at all. How is it moved and held in normal use?

You may want to set the air pressure a bit high so that in the event of estop or losing the axis for any reason it rises out and clears the cut. Just my thoughts

Huh?  I think you missed the point.  The Z does not fall because of the air cylinder holding it up.

65

Brains Development / Re: Activate Output with M0

« on: November 30, 2013, 05:27:07 PM »

This works:

IsStopped-->No-Op-->
                                AND----->Output
RUN-------->No-Op-->

66

Brains Development / Activate Output with M0

« on: November 27, 2013, 06:09:07 PM »

I'd like to activate an output when Mach stops for M0 (program stop) but I'm not sure how to go about it.  Suggestions anyone?  If there is a conditional LED or something in a pull-down in Brains, then I missed it.  Thanks.  -Nick

67

General Mach Discussion / Re: Here's our setup - and we've got some questions

« on: November 22, 2013, 01:14:41 PM »

Bah!  Nothing to read here.   

68

General Mach Discussion / Re: Here's our setup - and we've got some questions

« on: November 21, 2013, 02:10:27 PM »

We haven't purchased the router yet - any tips on that would be welcomed. We'll be working mostly with wood, periodically with long run times.

Whats the price range?  On the cheap side, I like Porter-Cables only because of the collets available here: http://precisebits.com/products/equipment/porter-cable_0429_collets.asp?tsPT=!!!Porter-Cable_0429!!!Collet!!!PG!!!

However the bearings in the P-C's don't last all that long.

69

Show"N"Tell ( Your Machines) / Re: my diy fixed gantry

« on: November 20, 2013, 10:40:53 AM »

Looks stout.  It's even painted! 

70

General Mach Discussion / Newcomer question soft limits

« on: November 13, 2013, 04:49:30 PM »

Great! Cheers.