Move from home to XYZ zero

I have noticed a flaw that has cost me a few clamps and bits.
FYI I use inches as metric is like Greek.
It concerns the movement from machine home to XY zero, it always drops the z to .150 above the part first so that anything that sticks up more than that gets hit.

Might not be a problem if I could find where to set start point for the Z so that when I tell it to raise the bit it moves more than .15.

This holds true in Easel and UGCS.
However, if I write the code I can fix it per program or if I export, fix and then import I can avoid it but I do not always remember to do so.
I have been calibrating my X-Carve and have found issues with accuracy when cutting but when checking (no load) works fine.
I have cleaned all wheels, belts and tracks of debris and that helped. Then I designed and install dust shields for the Y track, X seems ok and am working on dust sucking.
I have a 1150 cfm sucker but the machine isn’t strong enough to drag a hose (2") and mill at the same time.

Any ideas?

In the software that you use to generate your gcode, there should be a safety height setting. I use vcarve and I tell it the safety height to ensure it clears my clamps.

This is not a problem with UGCS. UGCS only sends what the CAM program generates, or what you send it if you are programming in G-code.

I have only used a few CAM programs, but the ones that I have used have a specification for a “safe height” which is supposed to be set by the user to clear any obstruction (like clamps, etc.) in the work area.

Your CAM program seems to have a default “safe” height" of 0.15 inches. Look in your CAM program to see if you can find where to set the “safe” height.

In Vcarve Pro they call it “Rapid Z gaps above material”.

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I am referring to Easel.

Under the machine tab, click advanced settings…you will find the default 0.15"

That is what I thought. All this means is that hoops abound to jump through and nothing is easy.
I like GWizard Editor because it is easy to avoid those problems but Easel does the writing while all I need to do is place shapes.
I can edit the g code but that takes more time.
If Easel had a setting that allowed moving the XY axis before the Z that would solve the issue.
No full sized CNC mill drops the Z before positioning the XY plane, way to costly otherwise.
I guess I am complaining about Easel doing nonstandard things with the software.

I’m not sure I follow what you are saying here. I don’t use Easel, so I can’t speak to those issues.

You can change the safety height in Easel from .150" to something higher if you like, for avoiding clamps and such. My machine has always raised to the safety height from home to the first cut, and from the last cut back to home, I don’t understand why it wouldn’t be working for you.

As for the inaccuracies while cutting, it sounds like you’re losing steps. You may need to adjust belt tension, potentiometers, or check the pulley screws are seated fully. One of the best resources for troubleshooting that is this forum post: [Guide] Offset cutting, Lost steps, Positioning errors, etc

I guess I am not being clear here. I think I understand about safe hight on the Z but it would be a good idea that when starting at Home moving XY first before any Z move is better and safer.

I found that my dust removal was not doing the job and the wheels were binding along with excessive feeds.
Both problems have been addressed.
I haven’t changed the Z up move but will check into it.
Thanks for the help.

I don’t think moving XY before Z would be a good idea, especially since homing starts with the bit on the material. That’s a good way to break a bit and damage the material if it’s not perfectly level to begin with, especially if the bit is a small one.

Not what I mean at all. Most CNC machines have a home or start position and that is most usually no where the actual blank work.
I know that once XYZ zero is set in easel and all questions answered then it will raise the bit x amount. Then make a move on both XY, that is fine because there usually nothing in the way.
However, if one stats from the home position such as repeating parts then the Z drops and then XY moves rapid.
Happens in commercial shops with careless programing all the time. Home is not XYZ zero, home is machine zero, not the same thing.
From machine home moving the XY first clears all obstacles so that when the Z drops it has nothing to hit. Retracting is the opposite, first the Z to machine home then the XY move, again nothing to hit.
It could be selectable for those that like it either way.

If I write my own code I don’t have that issue but when I am not is reverts to default and that may not be a good thing.

You can do this with the G28(G28.1) mechanism in grbl.

First you move your machine to where you want the G28 location to be, then you enter the G-code command G28.1

That sets your G28 position. This position is held in EEPROM and is retained until you change it to something else.

Then in your start up G-code you can place a G28 command to move to that location via a different location.

For example, G28 X1 Y1 Z1

That command would move your machine to 1,1,1 and then go to the G28 position.

Thanks, that makes sense. I have been retired long enough to forget these things.

Gotcha. I usually set my home to the lower left corner of the material instead of machine home, so I haven’t noticed that problem.

In another thread (Some quick tips on cutting projects), @Mike drew up a good clamping triangle that’s helpful to keep in mind, regardless of where the home is set.

Hopefully it’s one of those things that a person learns from by the fourth or fifth time, like trying to move Z+11" because of fat fingers and rushing (something I hope I’ve learned after doing it 5 times… :smile:)

Th problem now is exporting a G code file from Easel into UGS and having the tool start somewhere sensible.
What it does is take off to the rear right corner, no idea why as I set the shape to the center of the circle I wish to generate.
I then tried the lower left and that made no difference.
I set the XY zero in the center and it will not accept that, it wants to put it somewhere else.
I set XY lower left and it does the same thing.
I have tried with Easel and UGS with same result so far.
Might be something I am doing and I am going over it one more time.
I am also editing the code so that my clamps stay clamps.


Post the first 20 lines of the (edited) G-code file here.

Solved it but out side the box.
I export the G code from Easel, import into GWizardE and edit, add a G28 and moves to the point I want it to start.
Problem solved.