Centroid Community CNC Support Forum

slodat wrote: ↑Fri Feb 07, 2020 12:49 pm What does forward/back on the Y mean? More specifically, where does Centroid want the table to be in the homed position? I'm assuming X0 is table all the way to the right. Still unclear where the saddle is.. at the operator or at the column?

Table closest to you is Y+
Furthers away (toward the column) is Y-

Centroid doesn't care where you home. It becomes the control Datum point.

Don't worry, you are learning.....ask all the questions you need to. You do need to square away your understanding of spindle movement.

First decide on what axis is what. The Z axis is your spindle and Z up, away from the work is Z+. You then decide which axis you want to call X. X+ and X-, and Y+ and Y- directions are then determined by the right hand rule.

With the axis names and directions determined. You home the table where ever YOU want to home the table. Once you decide on where you want the home position, you place the home switches so that they close in that spot. You can then add limit switches at the extents of your travel on each axis if you desire. Whether you use limit switches or not, you then need to set soft limits.

On the VCP, X+ is X+, Y+ is Y+ and so on. If the location of the X or Y arrows on the VCP does not coincide with YOUR axis designations, you can reverse the labels in setup.

You can home the table anywhere you want.

If you don't know what you want, then home it X- (table right / tool left) and Y+ (saddle forward / tool away).

The jog buttons arrows and directions represent tool movement across the part.

To make the tool move across the part in the X+ direction (left to right), the mill table has to move from right to left. You press the right-pointing (X+) jog button to make that happen.

To make the tool move across the part in the Y+ direction (from front to back), the saddle has to move toward you. You press the up-pointing (Y+) jog button to make that happen.

The minus limit switch is the switch that would be tripped if the tool moved too far in the minus direction (X-, Y-, or Z-). The plus limit switch is the switch that would be tripped if the tool moved too far in the plus direction (X+, Y+ or Z+).

You guys are awesome! Thank you so much for your patience and taking the time to help me out! I'm going to cross post this info in the other thread to make it available to the next guy.

I **think** I understand

Short video showing 200ipm rapids from far limits back to home. Thanks for the help! I made a little cheat sheet to help keep it all straight.

The video starts out with the table in X+ and moving toward X-
Though you have to be happy its starting to show signs of life!
Marty

Now I’m more lost than I was when I started.

If you don't know what you want, then home it X- (table right / tool left) and Y+ (saddle forward / tool away).

This is what I thought I did..

Is there a photo somewhere that shows how I’m supposed to set this up? I’m trying to interpret words and I’m still not getting it right.

Is x0 y0 supposed to be table all the way to the left, Y closest to the operator?

Right hand rule - thumb points towards X+; index finger points to Y+; middle finger points to Z+. On a machine tool directions are based on "cutter" movement. Even though on a knee mill the cutter only actually moves in the Z direction, we still pretend it does for X and Y as well.

Therefore, for the cutter to "move" X+, the table actually moves from right to left. For the cutter to "move" in the Y+ direction, the table has to move from the column towards the operator.

In your video, you start out with the cutter as far right (X+) as it will go and as far toward the operator (Y-) as it will go. As the table moves, the cutter is moving in the X- and Y+ directions.

Is x0 y0 supposed to be table all the way to the left, Y closest to the operator?

Machine zero (X0 Y0 in Machine coordinates) is where it homes to.

Part zero (a.k.a. WCS zero, the X0 Y0 that is the base point for all the dimensions in your part program) is wherever you choose to put it, using the Part Setup screens (F1/Setup -> F1/Part) or the G92 code.

On router tables it is not uncommon to set part zero once at some corner of the machine, and leave it there. On milling machines, you usually set a new part zero for every job, to a point on the stock piece for that job.

First, thank you all for your help. This is obviously new to me and seriously kicking my arse. I won't get to the machine until this evening. I do follow machine zero vs part/WCS zero. I use WCS on my router for many different setups.

To make sure I know how to do this, this evening.. Machine Y0 is with the saddle all the way toward me (the operator), away from the column, like in the video. Machine X0 is with the table all the way to the left, like in the beginning of the video? aka.. I currently have the X axis backwards?

For the life of me "picture the tool going through the workpiece" is not helping me figure this out. I just need get it right, move on and learn from there.