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Haas vf-o

drom68

Cast Iron
Joined
Jan 13, 2013
Location
VA, USA
I have a job shop with all manual machines. I am moving into the cnc world and purchasing a VF-O with low hours and clean. It has tooling and the owner is easy to work with.

That aside, I started looking into G-code. I started reading the manual and a few other items I found here on PM. I get it, but of course I don't get it.

I looked at youtube videos and remembered that I am visual person and learn much quicker if I see the process vs reading.

- I'm looking for a video series that is well laid out and not done on someone's spare time with bits and pieces. I wouldn't mind buying a series as long as it's actually useful.
- Tool off sets. I need more information to wrap my brain around and not break anything.
- Tool Height. Which is better, going off the cnc table or the actual part.

Thanks for any assistance.
 
not a video ( although haas has a series of videos that go over some of the basics) the haas manual to me is 2nd to none on walking you through all of your G, M codes. check it out ! It lays it all out in very simple terms, and is easy to follow and use. even has program examples using multiple G code at the same time to commonly programmed parts.
 
Go to Haasautomation.com and look around.

Then find their Tips of the Day videos. All professionally done, simplistic,yet informative.

Think they are also listed on U-Tube


Yes read the manuals but seeing is a big step forward.

It was "hands on" when it all started to click for me. Then again that was before U-tube and the internet came into play
 
The first step to coding is to understand what the codes do. In CNC G code is defined by groups. You can have many different G codes in one line of code but if they are from the same group you will alarm out.

Then you have to realize they are Modal, they stay active even after a reset is depressed. This is where things can go horribly wrong horribly fast.

A good example of this is absolute and incremental. Most people end a segment or program with a line like G0 G91 G28 Z0. This takes the Z axis to the machine reference/home position. The problem here is G91 sets the machine in Incremental mode. Now without canceling this out with a G90 at the next motion the machine will move incrementally to the called position. Lets say you rapid down to your R plane and then have a G1 telling Z to go to Z-1.0 with a feed move. this will not take you to the actual Z-1.0 you commanded but rather it will be -1.0 from the R plane. OK, so far no big deal, your cut will just be shallow. Now lets say your G54 work offset is XY 0 center of part, The part is 10" long and your using a .5 end mill. You want the machine to go to X5.25 before making its cut along the end. So in Absolute you would just say G1 X5.25 F?? and it would cruise on to the end before making the Y move. In Incremental it's only going to move 5.25 before making the Y shift thus slicing through the center of the part.

The programmer could have completely avoided the risk of this happening by not using:
G0 G91 G28 Z0
but rather a simple
G53 Z0
Less code and still in absolute mode.


I know you posted looking for vids, and that's a good way to get started I agree but before getting to deep you Need/Must understand the Modal groups.

  • Group 1 (motion): G00, G01, G02, G03, G80, G81, G82, G84, G85, G86, G87, G88, G89
  • Group 2 (plane selection – XY, YZ, ZX): G17, G18, G19
  • Group 3 (absolute/incremental mode): G90, G91
  • Group 5 (feed rate mode): G93, G94
  • Group 6 (units – inches/millimeters): G20, G21
  • Group 7 (cutter radius compensation – CRC): G40, G41, G42
  • Group 8 (tool length offset – TLO): G43, G49
  • Group 10 (return mode in canned cycles): G98, G99
  • Group 12 (work coordinate system selection – WCSS): G54, G55, G56, G57, G58, G59)

Autodesk does a great job of explaining this.

Getting Started with G-Code | CNC Programming | Autodesk
 
Thanks for the replies. Very helpful.

I downloaded the manual which is full of great information. Then I started watching videos which helps it tie in.

I watched a few of the Hass videos, very well done. I like them, but I bounce around and would like to go through a step by step.

It's not hard to see how easy it will be to crash the machine. The modal groups is what I was not "seeing" so far.

I'll read through Autodesk and continue with the Haas manual. I don't mind the reading, but actually seeing a hands on approach really ties things in for me.

Thanks again, great info!
 
Listen up...


Your already telling me your smart enough to know you do not know enough.


A great place to be.


Now let me tell you a machine without a vise on the table and without a tool in the spindle cannot crash. Read that again.


So when your machine is up and running enjoy and play around with it...it cannot crash.

Now take a short gauge tool holder and toss a pencil in it, use the tip as your tool tip. Piece of paper on the table. Touch off part origin, tool offsets. Program a few moves that you can see in simulation, then with pencil on paper. You can do all of this with NO CHANCE of crashing...you can destroy a .25 pencil...or break a tip...but that's about it.

Take the pressure off and relax...get to know your machine.

I think I did the above for about a few minutes before a bunch of what I had read started to really click. After that I played with plastic for a short bit before getting into steel. That too I soon realized wasn't all that necessary.

For me...reading the work position coordinates along with reading the next line or two ahead had me knowing where the machine was going BEFORE it got there.
 
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Now let me tell you a machine without a vise on the table and without a tool in the spindle cannot crash. Read that again.

Haha, How many times have you went through a long setup only to get that spine tingling alarm saying "Z over travel"? My Cincinnati's were the worst with 7.2" of gauge height......
 
"For me...reading the work position coordinates along with reading the next line or two ahead had me knowing where the machine was going BEFORE it got there."
- SIM

This sentence sums it all up. When you can single block or feed hold then compare WORK position to tool and part and be confident it is correct before pressing the green tool breaker button.. that's when you got this.

I used a wood dowel to trace the details and drill points of a part. I made 4" lengths of 24" stock and had 3" left when I got the concept of reading the position with changing offsets and tool lengths. Even then mistakes will happen. Always turn down feed rates and single block on a new program. If your brain says "That does not make sense." listen to it - stop and review.

 
Another way which might be simpler is to get a CAM program. Import your geometry and set up the tools then select geometry to cut around. There are a lot of parameters that need to be input. Once done you can post the output then look at what the machine should be doing. Programs such as GibbsCAM have a 3D plotter showing the tool's movement.
I touch off the tools to the part with the shank of a broken end mill, usually 1/2" and put 0.5" in G54 as my Z work offset. Part origin is usually an easy point to reference on the stock material, say, upper left on the drawing. Useful when the stock is held in a vice and the stationary jaw is toward the back of the machine.
 








 
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