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1

General Mach Discussion / Rewiring limit switches w/ shielded wire

« on: January 27, 2010, 05:12:08 PM »

All-
I'm trying to solve some erratic behavior with my router table by replacing the limit switch wiring. Limits are currently wired with 18 ga speaker wire. Good news is I'm coachable but bad news is I'm not an electronics wiring genius. I've attached two images that might help. Feel free to mark them up as needed and repost.
I have 22 ga two conductor shielded wire, and I can trace the existing wiring to connect them to the BOB correctly. What I don't know is where to connect the ground wire at both the switch end and the enclosure/BOB end. Do I attach the limit grounds to the BOB, or a common ground inside the enclosure? I can see what looks like a common grounding point inside the enclosure(marked on photo), but it's too far away from the actual BOB to use it as a grounding point for the switch grounds. Seems like a simple enough thing to do I just have no idea how to do it. Thanks to all who might be able to help.
I've also determined one of the switches on the y axis to be flaky; since our work never comes close to the limits on the y is there a way I can eliminate this switch from the wiring circuit until we can get a replacement?

2

General Mach Discussion / Router heads

« on: December 15, 2009, 07:07:06 PM »

I just burned a DeWalt 2-1/4 HP router up somehow, after three months of use. It had been losing RPMs during cycles; sounded like it was trying to work through a brownout at times. Tried to spin the tip and it has all but siezed. I'm cutting 3/16" polycarbonate on top of MDF spoil with a 3/16" Onsrud 65-018 upspiral bit. It has been working well, but the last week I would notice it bog down for a split second every now and then. Well now it finally crapped. So I'm wondering if I'm pushing a consumer grade tool too hard, is my feed rate too fast, etc. I have the router set at max speed 24k rpm, and the feed rate through LazyCam into Mach at 70. Router doesn't seem like it's going too fast, as I get no burning smells or blackened bits, and the router speed lowers slightly but not by much(ear test).
So I need a new router, obviously, and these things aren't cheap. What's a good one to use? Anyone have any insight as to why I burned this one up so quickly?

3

General Mach Discussion / Heellllllppp! Erratic router behavior.

« on: December 10, 2009, 02:01:06 PM »

My problem- new to Mach(of course), bought the home-fabbed table second-hand. Have actually used it to great success for my needs(polycarb sheet, simple 2D patterns). I know very little about Mach 3, apparently just enough to get by until now. More often recently the machine has begun to (1) just STOP at random whilst executing g-code (stop button flashing) (2) go off and do its own thing whilst executing g-code (3) go into a 'limp mode' where the ability to jog the tool head diminishes by more than half(no estop button flashing, no message)

Given the problem isn't exactly the same at each instance but similar in nature, I'm assuming that (1) the general Mach config and motor tuning is off(I performed no such procedures after getting the table, just using whatever settings the previous owner initiated) (2) the general plumbness of the table is off slightly off(home-fabbed out of steel, but very robustly built)

I have been using this table successfully with good accuracy and repeatability for a couple of months now. Just recently I have observed the nuts that center the rotating collar on the z-axis lead screw(not the Lovejoy things on the motor shafts but the collars around the lead screws) loosening due to vibration, with the corresponding screws and such that do the same for the x-axis loosening as well. I tighten them back and use a little locktite blue and go on. Usually I just jog the gantry back until reasonably close to the pillow blocks at the end, power off and use a framing square to make sure it's square-ish(x-axis has two leadscrews) and restart the program, reboot, or whatever and it works fine after that. I have a sneaking suspicion that the machine is binding on the x, y, or z. I think this coupled with incorrect mach setup and motor tuning and my general ignorance of things such as accel/decel, stepping, etc is causing my trouble. I'd like to kick this in the head and get to a real understanding of the machine but I find the Mach manual to not be a very good read.

specs:
Motors- SureStep 434oz/in x2 on the x, x1 on the y
           SureStep 276 oz/in on the z
Breakout board- Stepper3 S3BRK2R1
Drives- Gecko G203V x4
Leadscrews- X- Hilead 3/4 x .333 RH 84" OAL (x2)
                Y- Hilead 3/4 x .333 RH 60" OAL (x1)
                Z- Acme 1/2-8 RH x 24" OAL
DeWalt 2.25 horse router head
PC- Win XP home, Intel Celeron 2 GHz, 768MB RAM (nothing else is run on this machine, ONLY MACH- not even Internet Explorer & g-code generated on different PC) Mach 3 version R3.037 fully licensed

pics below, screenshots of tuning setup included






I included the a-axis screenshot even though I haven't the slightest idea what it does or what it could be for, since the table is only 3-axis. IF ANYONE has any help to offer I'd be very grateful, if any additional info is required for you to help me just let me know. Thank you very much.


             

4

General Mach Discussion / Mach 3 ignoring Z setting

« on: October 05, 2009, 01:18:05 PM »

Hello all, relatively new to Mach 3 - when I first power the machine on and start the software up, I set X, Y, and Z settings before running a gcode. When I hit cycle start, the tool moves WAY up above the z I had set and does its thing in mid air. X and Y stay put where I set them but Z goes up a few inches. This only happens when I first use the machine in the morning. It happens every time; I just hit the spacebar, reset the Z and reload the gcode and it runs as it's supposed to.  What am I doing wrong here? RTFM I know, but the manual for Mach 3 puts me to sleep and doesn't really answer my queries in a language that I can get my head around. Aside from minor issues I've been having I'm starting to get better with it. thanks

5

General Mach Discussion / jogging slow and limit switches won't work

« on: September 19, 2009, 10:32:47 PM »

Mach 3 seems to behave differently every time I turn it on. 1-  I can't jog full speed - Abnormal Condition light blinking CV vs full stop, and the log tells me a limit switch has been triggered, but hasn't. Also, the switches don't stop the machine when they are tripped. New to Mach 3; got the table & software from another person. Having depth setting problems as well. Using LazyCam to output Gcode; doing simple 2D AutoCAD dxfs to rout polycarbonate sheets .1875"(3/16"), 4.7625mm. not using this to mill anything complicated, yet I cannot seem to get it to run consistently. Constantly ruining material and wasting time and money. How do I reset the machine? How do I get my normal jogging back, with limit switches behaving properly? How do I set an origin point that the software will remember and start from without having to configure it every time I power it on? Also, whenever I want to drill a hole, it pecks at the hole twice with some holes, but only once with others. I'm a CAD pro but this software makes my brain hurt. Apologies for the serial questioning. Perhaps I need to reinstall the software?