Solved Home and Z Offset Settings and Questions

Hey guys - I learning a tremendous amount this printer due to the great folks on here but I still have a few questions and thought I post a specific thread about them. To start I have a new Robo3d R1+ running stock Firmware (ROBOR3dR1+V2). The only thiung I have changed at allis the E-step value to calibrate the extruder. My questions are.
1 - Where is the home position? When I select home "all" it goes all the way down and to the left and front. So Z all the way down, X all the way to the left, and Y all the way forward (so the bed is all the way back). I would have thought it would go to the direct center. Is this normal? If not, what should I check.
2 - What is the default z offset supposed to be? Mine is -.7. I know this because when I home all, it tells me Z is at -.7. Is this normal, does it vary, does it matter?
3 - Z Offset. I need a Z-offset for dummies explanation. I have asked this question a couple of times and either I don't quite understand it, or MatterControl and this printer work differently. It has been explained to me that - values are above the board and poisitive values are below the board. So a negative z offset raises the print head off the bed while a positive z offset lowers the printhead. Additionally, the more negative - the higher the print head off the bed, and the more positive, the closer and lower the printhead gets.

Assuming that is correct, that is NOT how this printer is reacting. I am going to try a few tests just to check, but I am relatively certain, that the more negative value I put in, the lower it goes. Now this makes sense from a commons sense perspective, and it is also what is shown in the manual. Excerpt from the MatterHackers Manual
below, but is not how it has been explained on here.

"The distance to move the nozzle along the Z axis to ensure that it is the correct distance from the print bed. A positive number will raise the nozzle, and a negative number will lower it."

I definitely appreciate all the support I have received. Any thoughts on the above issues/questions? Id di use the search feature and found several threads, none of which address this.

 

Thanks Mark - Super fast response as always - you are truly an asset to this community. Some follow on questions based on your comments above:

You said the default Z offset is 1.0. If that is correct, why then wen I home does my screen show X:0.00, Y: 0.0, Z:-0.70? There is no 1.0 anywhere. Where would would I go to confirm what is actually entered for the default value of that offset?

Definitely understand your comments about the startup Gcode and M565 values. Do those values override anything else that is already stored in the software/slicer? In other words, if I change the startup M565 value, will the above numbers change when homing?

 

I was speaking of the Matter Controls "Control Screen." When you home, it shows you the position of your extruder. In my case, at home, it shows 0,0,-.7. It consistently shows this so I assumed it was set somewhere. It might not be, as you mentioned, and rather it might be calculated by the system, but it is the same every time.

How do I make sure the slicer is not adding any offset ont op of the value I enter for the M565 comand? Where would I find that?

 

Thanks to both of you.
Geof - I completely agree. I like the user interface of MatterControl, but it has issues. I'll be writing up a review of them later when I understand a little more.

Mark - thanks. Putting in zero for z offset when using the M565 command makes sense. Going to try it shortly. Any particular order the M565 command needs to be in the startup g code?

 

Well I ran some test first layers to compare. This was using only the z offset setting in MC. It was NOT using the Z offset M565 command. Note that the one that is 0 offset is actually just finished it's second layer. The others are only 1 layer. Here is the pic:


Based on everything I've been reading, including the first layer article here: https://cdn.shopify.com/s/files/1/0...t-layer-example-small.jpg?4263709265829532270

I think the correct offset here is -.1. It might actually be -.05. Looking at the samples above, the 0 offset has gaps in it. Additionally, the more negative the offset, the more pushed down the nozzle is and the less defined the numbers and letters are. See at -.8 how squished it is? Again, I realize that this is NOT what the M565 command supposedly does, but it is definitely the way MC handles those values based on these samples.

 

Thanks Mark. I know I've said it, but I couldn't have done it without you guys. I am looking forward to eventually doing what I can for others as well! I do plan on writing up a little MC for Dummies once I have this somewhat figured out.