X-axis work offsets on a lathe problem

[sam]

Hi again,

Having a hard time getting it to work. Have researched the topics here https://www.masso.com.au/forums/topic/help-with-x-axis-lathe-setup/ and I think perhaps the problem I have is that my x - axis can only go from 0.000 to 136.00 as when assigning a work offset it goes to the z position set no problems but the x is always hitting the soft limit at 0.00 where it homes to.

So should my x - axis be when homed - 68.00 (1/2 of the 136.00 to soft limit)?

If so how do I set it like that? Because if I set my soft limits to + 68.00 to -68.00 it will never reach + 68.00 because of homing switch hard limit and only go half the distance it should going the other way.

Thanks,

Sam.

Edit: Sorry I should point out that the machine co-ordinates of the x axis go to +136. The DRO. up top goes to -136.

Also: If I am to do a boring operation do I need to change the tool calibration option to back facing?

 

[ecs]

Hi Sam,

These are the settings i use on my lathe.

You dont need to change to back facing when doing a boring operation.

Josh

 

[sam]

Ok, Thanks for that @ecs. I have now the range -68 to +68 sorted, though my invert on the x-axis settings has to be not inverted or everything goes the wrong way.

Unfortunately this doesn't fix my problem with the work offsets. To add to the description of what is and what isn't working. If touch off a tool, I can run a nc. routine and all works no problem. Everything is going the right direction, except the x-axis is off by around 7mm - to far out. I can just shift my tool post back 7mm and get the job done. But when I go and change a tool I will have to move the tool post again, since it will be in a new location. This I gather is where the offsets should come in, but when ever I set 1 and then hit the go to work origin it is always stopping from an x- axis soft limit fault. But then there is no setting for x-axis for lathe work offsets either. Nor can you Zero it on the DRO. The axis barely moves if at all from the home position when the soft limit fault is raised. It's about as far as actually hitting the soft limit as it can get...Unless its going the wrong way past the Homing switch.

One thing I suspect / not sure of is that my x-axis increments for the machine co-ordinates form - to +, where as the DRO up the top increments the opposing way from + to -(see last 2 pics). I assume that its the machine co-ordinates that need to in the positive direction, away from the user. Is that correct?

 

[ecs]

@sam - take a look at this post. I've already gone through what your going through now. It will just be your settings around the wrong way.

https://www.masso.com.au/forums/topic/setting-a-lathe-up-for-the-first-time/?part=1

Have a read through all the posts and you'll find some useful info there about the directions.

Your z axis should also mirror the x axis. -50 and +50 for travel and home position.

You need to get the machine going the right way with the keyboard before you even try run any gcode.

 

[ecs]

@sam - we'll work on the offsets once the machine is setup correctly.

 

[sam]

Have read that forum thread before, and used it for my initial set up. Obviously there are are some things I am unclear of though. I assumed the settings for the directions that the axis was talking about was for machine co-ordinates. I still do think that, but the DRO up top going the other way kind of has me scratching my head still so to speak. The Z axis doesn't.

I have split each axis 50/50 now as you said.

The settings I have now are:

Homing : - Z-Axis axis not Inverted, X-Axis Inverted.

- X-Axis Homing position = -68 mm,

- Z-Axis Homing position = +222 mm.

X-Axis : - Not Inverted,

- Min. = -68 mm,

- Max. = +68 mm.

Z-Axis : - Axis Not Inverted,

- Min. = -222 mm,

- Max. = +222 mm.

And the machine co-ordinates run like in the Lathe-Co-Ordinates.pdf.

Edited: From Am post and is working as it should now. The thing that was messing with my head with work offsets was the tool loaded and its x value causing the (X-Axis soft limit fault).

So have now made tool T0 a dummy for going to work offsets. Now it all makes sense

Just have remember to load the T0 tool dummy before going to any work offset.

Thank you for taking the time to help, much appreciated.

PS @Masso

Maybe this should be in the doc's for old slow newbies such as myself. Especially when going off how to use offsets from the Mill docs, which is all there seems to be currently ( which are great by the way)....Unless I'm slower than even I thought I was and missed all together. If I did miss it, sorry about what I just said.

Cheers,

Sam.

 

[ecs]

@sam - Glad you got it working.. Time to make some chips!!

 

[sam]

Thanks ECS, Have made a lawnmower blade hub and a back plate for a four jaw. They turned out really nice. I did have to change the distance per rev on the x-axis, for diameter mode Masso uses( that's where the 7mm off was coming from). and now it's -140 to 140 instead of the -68 to 68. It has since occurred to me why my x-axis is the other way around also, it's because my motor is mounted back side, so the signals are turning the screw the other way to yours.

With the offsets, I realise now that there are numerous ways to go about it. You can set up a tool on each work offset, with each tool having to be zeroed and offset in that work offset or do what I do now and setup all tools on G54 then another with the dummy tool for it to go to a tool change position. My method may not work as fluently for everyone though, as I have macro in the post processor so I just have to hit cycle start on tool change an it goes to G55 and off to the tool change position automatic, Hit cycle start again once the tool is changed and it goes back to G54 with the new tool, off to the next sequenced operation.

Anyway Thanks again for your help.

Cheers, Sam.