TECHNO.PST not proper.

Hi folks,
I've been out of circulation on cnczone for a long time because I got locked out of my account.

I forgot the password and it just wouldn't reset. Thankfully it finally did after all these years. But that's another story.

I have an older Gantry III machine. It's a 130 about 4x4.
It uses an ISA card in the pc that's connected to an amplifier box which in turn is connected to the SERVO motors.

I use Mastercam V8.11 to program with, and the pc that drives the machine uses G-code Ver.105c for the controller interface.

The problem is with the TECHNO.PST post processor file.

/// My configuration in G-code 105c must always be set to [X] OVERRIDE PROGRAM SPEED. If not ticked, it will lock up G-code Ver.105c as soon as it encounters a feed rate command. \\\

This means that I cannot use Mastercam to control the feed rate.

This is definitely a post processor issue. I know this because I have another post called MPTECHNO.PST and if I use that post I can untick [ ] OVERRIDE PROGRAM SPEED in G-code Ver.105c and enjoy the benefits of variable feed rate machining that Mastercam has to offer, namely "Highfeed Machining" as they call it.

However, I like the TECHNO.PST much better because it does not add extra tool motion to the beginning and end of the file the way the MPTECHNO.PST does.

Both posts are intended to be modified, but that's where I'm stumped.

I was hoping to find someone with a similar rig to shoot me a post to try, or if someone has any ideas on how to modify my existing TECHNO.PST to properly allow for Mastercam to control the feed rate thus enabling.me to untick [ ] OVERRIDE PROGRAM SPEED safely in the configuration for the G-code Ver.105c interface program.

When you [X] OVERRIDE PROGRAM SPEED the machine goes at a constant feed rate no matter what. I wanna take the training wheels off this thing but I don't want to compromise by having to use the MPTECHNO.PST to do it.
This is a simple post hack folks. It can't be that hard.

Attached is a Zip file containing both posts. Note that the MPTECHNO.PST despite being designed by CNC Software, homes X and Y at the end of the run. This is a potentially dangerous situation if you happen to have a clamp between your last move and X0,Y0. It also adds what I feel to be unnecessary tool motion to the beginning of the file which too presents a hazard. Another thing I don't like is that it does not add the stuff that I like to see at the beginning of the file such as; date and time stamp, name of program, size of tool, etc. So once you have it loaded you click once and the run starts. Better watch it with that clicker!

By contrast the TECHNO.PST let's me step through the code a couple of times with no machine motion so that I may verify the program name and tool size before clicking again to start the run. But more importantly it doesn't add potentially dangerous moves to the beginning and end of the file. I like that, and this TECHNO.PST is definitely the preferred post. I especially like the fact that it just lifts the Z at the end of the run and does not add extra tool motion to the beginning of the run.

But it needs a little help to properly execute the feed rate command. Anybody out there familiar with customizing a post?

Thanks,
Alex

Watching this with interest. Might be easier to remove the extra commands from the mptechno.pst than to troubleshoot and correct the other one.

Yea, I can easily do that with the code it spits out but I'd prefer if the post itself was configured to do it automatically.

BTW if you still intend on watching with interest, I'm cutting and pasting this thread to the Mastercam portion of the forum. So stay tuned over there.

Mastercam techno isel posts are easy enough to figure out what to delete.....techno is a very simple post, but there is a lot of crap (probably) in the post you will never use....just print it out and save a copy and delete what looks right. Mastercam checks the post for errors, and air cut tests would be the rest of the way.

Keith, I assume you got my techno post? If not, I can email it.....it's basically unchanged from when I moved to Mastercam 9 I think, just updated as I got newer versions of Mastercam (which I have finally pulled the plug on this year, Vectric for me now). Not sure how it compares to the posts mentioned here.

Greg

The thing is these two posts operate completely differently. For some odd reason the one I like won't allow me to let the gcode determine feed rate.

Does anyone have a Techno .pst file I could try out???

Someone at cnc software said they did a few months ago but never sent me no file.

Quote:

---

Originally Posted by dart70ca

Watching this with interest. Might be easier to remove the extra commands from the mptechno.pst than to troubleshoot and correct the other one.

---

PROBLEM SOLVED!!!

Hey dart70ca,

I finally figured out how to fix this annoying problem and I'd like to share it with the world of Isel Techno users who still use the old ISA cards.

Feed rate commands posted with the TECHNO.pst are obeyed by the Ver.105c controller if they are pre-processed and run using continuous motion. It won't work in regular step mode. But that's okay. The mptechno.pst will work in either.

It doesn't matter much to me as I tend to use continuous motion most of the time anyway because it smooths things out considerably. Not that the machine can't be made to run fairly smoothly in regular step mode with a little tweaking of the acceleration rate. But now I have the added benefit of constant material removal rate because of the programmable variable feed rate found in Mastercam V8.11 (highfeed).

So yes, feed rate can be controlled by the posted code. But only if run in continuous motion.

So as usual, who do I have to thank for all the help?

ME, that's who!

You know, you turn around one day and find that it's been 20 years (and I did just the other day) and not one person seems to be willing to lend a hand except to stretch it out for payment.

That's just sad.

Hopefully someone will benefit from this information FREE OF CHARGE to the general public.

The mistake that I made was assuming that the pre-process function only works for a set feed rate. Well guess what? It doesn't! In fact, you can insert a feed rate change in the code wherever you want right at the controller, pre-process for continuous motion, and you will get smooth motion and variable feed rate.

~Alex

Well, my apologies for not asking that particular question previously, glad you figured it out! After 20 years of one method (ok, not all of them with servo controls but as far back as I can remember), I would have never have considered anyone way using step mode and not preprocessing, especially a guitar maker.

Greg

The thing is Greg,

When you preprocess, it tells you that file has been preprocessed for such and such a speed. Therefore someone with limited capacity (such as myself) simply assumed that the act of preprocessing locks the controller into that particular speed that was set prior to the preprocess.

In reality however, this is not the case.

Although [ ]Overide Program Spd has been unchecked and the gcode has been properly posted to call out feed rate changes, the controller will still report back that it has been preprocessed for a set speed as shown in the pictures.

There you have it in a nutshell. I always thought the only way to vary the feed rate was to put it into step mode. I was duped!

Nevertheless and despite the false reports of the controller, the machine obviously shows variable feed rate and continuous motion.

When the depth and width of cut increases, the machine slows down. When the depth and width of cut decreases, the machine speeds up. When the machine comes close to a corner, it slows down. The machine will then increase speed after it exits a corner. All of this is programmable.

Success baby!

Next challenge: G64 P
From my understanding this is a call to control the accuracy of the cut during continuous motion.
Is that even possible with this setup?

Ah, I see,

I never saw that confirmation....maybe a different version (edited as I saw you had servos, thought maybe this confirmation was a stepper thing)

Also, I would hope that G64 isn't necessary as one would hope that the reason it pro-processes the files at all is to allow good accuracy in the continuous motion file. I also doubt it supports G64 at all, there should be a list of g-codes supported though somewhere on the net....now this thread is one of those places (see attached PDF).

But, no G64. The techno g-codes supported is very limited. Glad to here that variable speeds worked from the post though. That's the beauty of posts, they can make these few g-codes do a lot more....at the expense of long programs but do-able.

Today was a milestone day and I just figured I'd mark it.

After much testing, I successfully cut pine at varying feeds from about 20ipm to 100ipm with an 1/8" two flute endmill. I ran a pocketing toolpath with a conservative stepover of 20% of the tool at a depth of cut of 1/4" and a spindle speed of 16,000 rpm.

It was glorious!

When the tool did a full slot, the feed rate dropped to a crawl. When there was hardly any engagement it accelerated quickly to top speeds. As the tool encountered more material of my previously machined part, it slowed down accordingly. It took hairpin turns gracefully by slowing down and speeding up taking into account the varying amounts of wood it was plowing through. It just ran like a well oiled champ and smooth as butter!

After the cutting was done I inspected the carbide bit and found it to be only slightly warm to the touch, cleaner, and it almost seemed sharper!

I guess I let my imagination run away with me just a little. But today is a landmark day! One for the history books, and all I can say is...

Yea, baby! Constant volumetric material removal rate is the bomb! I would have never put an eighth inch tool down a quarter of an inch below the deck, or even fathomed running it at 100ipm unless I was testing with foam. Are you kidding me? The rule of thumb is half the diameter of the tool. Not anymore.

The rules have changed!