Usage of limit switches is rather ridiculous as they are never accurate

We’re getting away from my question(which Ron refuses to answer for some reassign). So I’ll ask again.

HOW Do you use G55 without ever at some point using mechanical switches to find machine zero?

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This made me LOL

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Who cares about Machine Zero, the machine doesn’t. So why should you? All you need to care about is where the edges of your work material is in X and Y. After that you need to determine the offset for your cutting tool in Z is and what your rapid clearance is. Other than that your machine Co-ordinates don’t mean a damned thing. As long as your using Soft Limits along with Jigs and a Fixture Table and BASIC GCODE!!!.
As far as Not a Stepcraft or whatever other thingy. Mach 3 has been around for over 20 years whereas Easel has been available for what 4 years. On top of that a fair number of Corporations have modified Mach3 to suit their own systems.

And another thing I really don’t appreciate the uninformed comments from a bunch of boobs. Especially considering that I haven’t Flown a Stealth Fighter either. The one thing I do know is that I’ll be damned if I try and help anyone else out of a predicament when their machines electronics go wonky.

By making this statement, you care about where Machine Zero is. Without Machine Zero as a reference point your “edges of your work material in X and Y” are undefined to the G-code and software you used to create your G-code.

You also care about Machine Zero, as Soft Limits don’t work without it. They also depend on Machine Zero as a reference point.

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Point is bub. If you turn off your machine it forgets where it is. When you start it back up it assumes it is at machine zero. Then when you send G55 it goes to where it believes that is. So if your not ever homing your machine. Then your leaving it at he same spot or on all the time. If it doesn’t know wher machine zero is at then your soft limits are as useful as your help in this forum. If you leave your machine at say 10X and 10Y. As your G55 And turn it off for the night. Then when you turn it on in the morning it thinks its at zero. And soft limits ARE directly dependent on MACHINE ZERO. So if you have 30 inches of work area and soft limits at 29.5 then you just ran your machine 10 inches past your rail. Congratulations your an idiot.

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And that "boob"as you referred to him has helped probably everyone on this forum at one time or another and has put out some pretty amazing stuff. So he must be doing something right.

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And that stepcraft thingy is what UCCNC was optimized to run on. Just a little info for ya.

Your right my bad. I apologize @RonaldLambier. I was trying to understand your method. Then things got Dark.

If you do not have homing switches, you have to zero to a reference point on the part.
If you have homing switches, you set the piece in the jig and hit start.
So, cons:
They cost $20 max more.
They are less accurate (but good enough).
Pros:
It’s slightly faster to zero.
It’s much faster for repeat-ability.

Zero machine, put in carving foam, run test carve, swap for final material, zero machine, run final carve.
Worth it in my book.

Less accurate than what?

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Less accurate than zeroing to a ref point on the part, or using a computer vision system for alignment.

You can zero to a reference point with accuracy better than 0.001 inches?

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Am I missing something here? I realize some of you are trolling, but the few of you that aren’t really seem to have unrealistic expectations from a <$1500 machine. I’m using bump stops to line up material, and switches to get a close repeatable zero. I’m probably within 0.030" from carve to carve - the thickness of a credit card. I would put money on your x and y dimensions being more than 0.030" off if you carved a max area square (roughly 9.8" x 9.8" on a 500mm) on any size xcarve. Variances in belt length due to variances in belt tension will throw the machine off more than a few thousandths, as will belt stretch over time.

Ronald - here’s what I’m getting at. Some of us don’t want to tinker with gcode. some of us want to turn on a piece of equipment and get simple, repeatable results. Sure we will take the time to dial it in to the best of our ability, but then we want to be dumb, clueless appliance users. The switches allow us to do that. Sending a gcode command every time is something I don’t have to do. If the carve is simple I can design it in easel, click a single radio button when I go to output and the software takes care of it for me.

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Phil, cool carve, but the ripples in the vertical fins have me a bit puzzled - are the an optical illusion or did you carve them separately and then glue them into place?

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Phil - I haven’t measured my tolerances yet. Probably way under 0.030" but that’s the worst I’ve seen. No surprise the z is crazy close - screw drive and 2.5" of usable travel means not much room for variance to creep in. That, and I’ve seen some of your mods.

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A quick search of the internuts gives:
Automated Visual Measurement

With a claimed accuracy of 28.6um (0.001125984")

Mechanical Limit Switches
http://www.cnczone.com/forums/diy-cnc-router-table-machines/29746-limit-switch-repeatability.html
With a claimed accuracy of 0.010-0.002mm (0.00019685039")

Touch probes

1um (0.0000393701")

Couldn’t find any specs for:
Opto Limit Switches
Hall Effect Switches

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I dont see any fins ? I dont see a head or arms either !
@steveprior are we looking at the same carve :slight_smile:

Someones got a woody…

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Man that came from left field and almost a year ago. Must have been trying to figure out how to use a homing switch. Let’s see. Phil. Or this guy? Hmmmm tough choice.

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Did the moderator delete several posts here???

I nearly split my side reading this thread earlier bc I was laughing so hard. When I went back to read it again a great portion was gone…

Granted the deleted posts had nothing to do with the original post but it just goes to show that if you don’t know what your talking about, don’t offer up inaccurate information. And when you get called out on the BS advice being given don’t be a rude @-hole and lash out.

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