Help with X axis lathe setup

mattjoy

mattjoy
Hello

I am getting really confused with my lathe X axis setup. I believe its a mixture of several things and i could possibly work it out eventually but its doing my head in ... lol

firstly why does the screen show that moving away from me is the positive direction and moving towards me is the negative direction? Can this be reversed? ... is it because of my home axis position? see picture below

Any help would be greatly appreciated ..
 

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breezy

Arie
Staff member
Quote from mattjoy on November 23, 2019, 2:13 am

firstly why does the screen show that moving away from me is the positive direction and moving towards me is the negative direction? Can this be reversed? ... is it because of my home axis position? see picture below

Now I'm not a lathe user but I googled this statement

For an N/C lathe, the positive cutting tool motion directions are away from the headstock, usually to the right (Z-axis), and away from the spindle's axis (X-axis). For tool-in-the-rear machines, the X-plus direction is away from the operator. For tool-in-the-front machines, the X-plus direction is toward the operator.

So my guess is that the setup of your X axis is "backwards" but without knowing what you have setup I can't advise what to change. So if you can provide a screenshot of your X axis and homing setups we the group can then advise how fix your problem.

How have you set tool position "front" or "rear"?

What values do you have in Max & Min travel? (any negative values)

Regards,

Arie.
 

mattjoy

mattjoy
Quote from Breezy on November 23, 2019, 8:59 am

How have you set tool position "front" or "rear"?

What values do you have in Max & Min travel? (any negative values)

Regards,

Arie.

Hi Arie, Thank you for your response.

My tool position is at the front

homing

I have managed to resolve the setup, however there is one issue I would like the MASSO team to look into. That is the fact that when you move the tool in the positive direction it is actually moving in the negative direction.

you would expect this because as you can see on the screenshot of the interface, it shows the X - is at the lower screen and X + is at the upper section of the screen, technically speaking it is working as is shown, but of course it is incorrect for a front toolpost. so when using the pendant, positive direction moves into the work piece, this is incorrect. Also, all my programs (hundreds of them) are doing my radius/arc in the wrong direction.. flipping the X would resolves these 2 issues I believe. I really do not want to rewrite all those programs :(



see pictures attached
 

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breezy

Arie
Staff member
@mattjoy

What happens when you change X axis setup to,
  • Min Travel to 0 (zero)
  • Max Travel to 840
  • Invert direction (may not be required)

and Homing setup to
  • Home position to 0 (zero)
  • Remove the X direction invert checkmark?

To me, setting to these values will move the position of the tool post from the "negative" to the "positive" side of the spindle centerline. This is assuming that the X axis homing switch is relative to the spindle centerline.

As I said before I'm not a lathe user, so I may be totally wrong here.

Regards,

Arie.
 

ecs

ECS
@mattjoy - I had similar issues when i first setup my lathe. But it comes back to the settings you have entered. The x values should be more -420 in the min and 420 in the maximum. Which will give you the total of 840mm travel. As your tool post is at the front the -x is closest to you and when feed in will go in the +x direction. So if your homing switch is place at the front of the machine this would be -420 when it homes. You need to check that when you press the x+ on the jog screen the machine moves towards the centre once the settings are set. If it doesn't you'll need to invert the axis. You'll need to do the same for the z axis. -z is at the chuck and +z is tail stock end.

Once you have this setup you'll need to check tooling is set to front on the tooling tab. And once you run a program it should go the correct way.

If you dont understand let me know and i'll take some screen shots of mine for an example.

Josh
 

mattjoy

mattjoy
Thank you for the info.. I will give it a go in a couple of hours and let you know later today



Cheers

Matt Joy
 

mattjoy

mattjoy
@ecs
@breezy

Ok, I have tried the above methods and I get the same results. Lets call this topic closed, because the machine is behaving as expected. The tool is moving in the correct direction and did not need to be reversed. once the tool is set everything behaves as it should.

I may have made this post confusing because I mentioned several issues at once.
  1. not understanding the relationship between homing position and X maximum and minimum limits (resolved)
  2. Why X + direction on the keyboard and pendant is moving away from the operator (you would expect that on a rear mounted tool, but not on a front mounted tool)
  3. And why my G02 and G03 are reversed. (I am not entering "I" or "J" values; but still they're technically only moving in the correct direction for a rear mounted tool)



Regards,

Matt Joy
 

breezy

Arie
Staff member
Quote from mattjoy on November 25, 2019, 11:40 am

Why X + direction on the keyboard and pendant is moving away from the operator (you would expect that on a rear mounted tool, but not on a front mounted tool)

And why my G02 and G03 are reversed. (I am not entering "I" or "J" values; but still they're technically only moving in the correct direction for a rear mounted tool)

@mattjoy

You still have something reversed!!!!

For a front mounted tool pressing X+ should be moving the tool towards the operator. From the quote I posted in post#2

For tool-in-the-front machines, the X-plus direction is toward the operator.

Josh pointed out something that I missed, that the tool post should be able to travel to the negative side of the spindle centerline, therefore the X axis travel should be set with a negative value in Min Travel and a positive value in Max Travel.

So forget about homing for the moment, you need to get the tool moving in the correct direction first. Based on your earlier photos could you please try the following setting on the X axis
  • Min Travel = -420
  • Max Travel = 420
  • Invert direction ticked

Test to see if X+ direction request moves the tool post towards the operator, if not then remove Invert Direction tick and test again.

When you get the correct direction of travel we can set the homing. Now depending on where your homing sensor/switch is located, you need to enter either of the following
  • Home position to rear = -420
  • Home position to front = 420

Then tick/untick the Direction Invert to get the tool post moving the correct direction when it is positioned in the center of its travel.

When you have these things sorted then G02 & G03 will work in the correct fashion, it is because X is travelling the wrong way that reverses these moves.

Regards,

Arie.
 

breezy

Arie
Staff member
Quote from mattjoy on November 25, 2019, 1:02 pm

Doh! I'm going to get out of bed and try this immediately!

Sorry to drag you out of your comfortable resting spot, I'm about to head of to mine!!!!!!!

Regards,

Arie.
 

mattjoy

mattjoy
@breezy




Quote from Breezy on November 25, 2019, 1:47 pm

Sorry to drag you out of your comfortable resting spot, I'm about to head of to mine!!!!!!!

Regards,

Arie.

Thats ok ...



I have made the changes and the movement in the correct direction is working, but the screen still shows X minus at the bottom? see picture

Arc/radius still the same :(



Regards,

Matt Joy
 

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mattjoy

mattjoy
Quote from ECS on November 25, 2019, 9:58 pm

@mattjoy - You drawing to me looks crazy. What are those big arcs doing in the middle of the job?

@ecs Hi Josh. It's just a test piece .. I will read the post you have mentioned right now. Were your arcs reversed until you sorted it out?
 

ecs

ECS
@mattjoy - Not sure what you mean by arcs but my machine would run backwards yes. It was a matter of getting the machine to run correctly just in jog before trying to load a gcode file or homing the machine. You need to put in the correct min and max in the axis settings. Then using the jog feature make sure the x - goes towards the operator and x+ go towards the job. The z - should go towards the chuck and the x + should go towards the tail stock. If any of them go the wrong way use the invert to change the direction. Once this is setup then you can move onto homing. Once homing is setup them move onto tooling.
 

mattjoy

mattjoy
Quote from ECS on November 25, 2019, 10:22 pm

Then using the jog feature make sure the x - goes towards the operator and x+ go towards the job. The z - should go towards the chuck and the x + should go towards the tail stock. If any of them go the wrong way use the invert to change the direction.

@ecs I have had it in that direction.

Ok, I will do one bit at a time ... let me change X plus towards the job
 

ecs

ECS
@mattjoy - make sure your z axis is also correct with the min and max set. Note you'll need a - value on the min. Then check that when you jog -z goes towards the chuck.

Then modify your homing if necessary.
 

mattjoy

mattjoy
Quote from ECS on November 25, 2019, 10:47 pm

@mattjoy - make sure your z axis is also correct with the min and max set. Note you'll need a - value on the min. Then check that when you jog -z goes towards the chuck.

Then modify your homing if necessary.

@ecs done.. Z moves in the correct direction
 
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