Engraving Text on OD (Mill Turn)

[Mick]

Hi there,

 

We are engraving the part number on the outside diameter of a coupling. The text rolls around the diameter, so we are using Axis substitution.

 

However, the backplot looks fine, but when posted, the code actually has the engraving being machined "backwards" around the OD.

 

When I encountered this on a A axis mill a while back, I was able to change the CW - CCW switch, and the code as output correctly. However, on this machine (a Mori Seiki MT253), changing the CW - CCW function makes no difference. There is no option in the post to change the C axis direction either.

 

Can anyone offer any suggestions? At present, the only way to resolve this is to actually mirror the text, then toolpath it. This gives us the correct code, but we shouldn't have to do that.

 

Can someone offer any suggestions?

[DavidB]

What if you use the opposite TCplane?

[J Coulston]

Had the same problem on a Mori NL2500SY. Ended up projecting the text to the far side ID instead of the OD of the cylinder to get good code. Text was not mirrored.

I hope this makes sense.

text->()coded backwards

(text->)coded correct

[Mick]

If I use the opposite T/C plane, (I'm using Top, so it would be bottom), it returns the error "Top Tool Plane Must Be Used For Axis Substitution".

 

John, I'll give the "Far Side" option a go

[Bryan Johnson]

The post needs to be modified for the rotary direction.

When you changed the "CW - CCW function", did it have any effect on the output. If not, keep looking for what is setting direction. My guess is that it will be in the PST file.

[Mike@Apollo]

I've had this same problem in the past. All other rotations will output fine.

 

I just mirror the text and move on.

 

If anyone figures it out, please post the fix.

[Mike Mattera - TFM]

 

This should change the direction of the "wrap".

 

Mike Mattera

[bigjohn]

quote:

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This should change the direction of the "wrap".

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What???????????

 

 

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[Mick]

Nope. Changing the CW/CCW changes it in Mastercam, but the posted code is the same. As far as I could find, there is no switch to change the direction of the C axis.

 

I did encounter this issue on a VMC post a few years back, but I had a Rotary Axis direction switch int he post I could change, and it made it work fine. But this MT post doesn't have that

 

I used "J Coulston Idiot"'s suggestion of projecting onto the lower surface, and it worked.

(Thanks J Coulston!)

 

Now, I do have to say, that really sucks. There surely has to be a better way. Hehehe, guess I am off to Tech Support

[crazy^millman]

Does your post require you to use Back as C0. ??? Then it might be a matter of how you are setting it up from the beginning. Top is really C90. or C270. depending on your machine and if you are using the back Plane from Mastercam your post says Ok I will use it, but make it like it is in Mastercam and not like it is on the machine. I would try making my own back plane if this is how you are having to program your machine to make C0. come out correctly on your machine.

 

Also a bug in the software still in X3 is if you are in Right view and rotate 90 deg it will keep the plane right. You have to go to ISO Gview, then Top C-plane and then rotate and it will make a new C-plane. I sometimes forget this until I need a good C-plane then it clicks back into my memory.

 

I also have had to project to the bottom of a part to get engraving to coming out correct when doing it the way you are doing it. I have found wrapping the text around what I want to engrave and not using C axis toolpaths, but curve 5 axis with point to center to give me the best most predictable results. I can provide you an example if you need.

 

HTH

[Bryan Johnson]

Send me a z2g that includes the post and I will take a look at it.

[Philcott]

quote:

---

I also have had to project to the bottom of a part to get engraving to coming out correct when doing it the way you are doing it. I have found wrapping the text around what I want to engrave and not using C axis toolpaths, but curve 5 axis with point to center to give me the best most predictable results. I can provide you an example if you need.

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I would like to see this Ron. I have not tried this before and it sounds interesting.

 

Phil

[BrianCNC]

When I did this last I also had a problem with the text being mirrored. I had to create the text in the bottom view, but chain it in the toolpath in the Top since axis substitution only works in the Top plane. I then set the Misc. Variables to use G107 command. This was on a Mori NL3000Y.

[mike_f]

if your text is actually mirrored I don't think this will help you but I have a lathe with a sub spindle that rotates opposite of how mastercam sees it. I thought I could change that in the MD but apparently it doesn't work that way. so I put a switch in my post using a mi.

code:

---

  if mi5$=1, cabs = -cabs

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this reverses my g-code output for my c-axis when mi5=1.

I'm not a post guy, this fix works for me to reverse my c-axis output when I need it to. It might screw up your output. I would listen to Ron first.

[Mick]

I did get a response from tech support:

 

"In some Mill post, you can change rot_ccw_pos to change the rotary axis direction, but in lathe post, you don’t have this switch. You can program the post to do that, but it might be too much work. In the toolpath parameter settings, you can use CCW as rotary direction, or project the geometry to the other side of the stock. Both ways will give you mirrored toolpaths, which will post correctly. I think this is the easiest way around this problem."

 

Unfortunately, it is really a "fix". Having to project the curves to the lower surface, results in Mastercam displaying the toolpath "backwards", but the posted code is correct. Without Vericut, we would never have picked this up, until we ran it on the machine.

 

I tried 5 Axis curve, and that does work, although in reality, we should be able to use standard Axis substitution for this.

 

I did try it in X3, but I get the same results.

[crazy^millman]

Phil super busy right now, but when I get sometime I will add it to my help people list.

[Philcott]

At your leisure, Ron.

 

Thanks in advance.

 

Phil

[bigjohn]

This problem has been around for years in C Axis and no one seems to have a satisfactory answer. I was using MCV9 and I was getting mirror image output on face and diametre end product. I put the question in the forum a couple of years ago and someone gave me the right answer. Here is what I was given.

 

code:

---

 csav = - csav   #to reverse the direction of C axis rotation 

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In the post here, MCV9 Post:

 

code:

---

 # --------------------------------------------------------------------------

pxyzcout #Perform calls for mapping coordinates and shifts

pplane_mod

if cuttype = one, pxyzcout0 #Turning

if abs(cuttype) = two #Right/Left Face cut

| cuttype = three, pxyzcout2 #Cross cut

if cuttype = four, pxyzcout4 #Y axis substitution

if cuttype = five, pxyzcout5 #Multisurf Rotary

csav = - csav #to reverse the direction of C axis rotation ##JV inserted line

#C axis control modifications

if posttype <> two,

---

I have not tested it in MCVX2, but right now I'm getting mirror image in diametre, and not on face.

 

 

If this make any sense to you guys, good luck to you, but I would kike to know the solution too.

 

 

John

 

 

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