CNC LATHE OPERATION

Is this a school project? If it is you might be able to get a free seat of demo software from Mastercam, Surfcam, or a variety of others depending on where you are. Those software packages have verification ( simulation ) features. If you are in Europe Delcam is also one of the best. Do you have a machine to work with? Are you at a company that has a lathe with the GE FANUC control? If so they should have a manual. The other question is: do you know how to run a manual lathe? If not, you should learn this first before messing with a CNC. You can do a lot of expensive damage very quickly if you crash that machine not to mention the danger. Learning to program is actually the easy part. It is learning to be a machinist that takes time. Any FANUC control whatever the number uses basic G-code programming. There are loads of websites with this info. The differences from one machine to the other are learned at the machine and you should have someone who knows the machine to train you.

Thank you Mr.Gary Ceng for your comment,this ain't a school project,actually I've just finished 2weeks training in cnc lathe machine basic operation & programming to update my skills in machine shop but as of now I have not gone on the job training so I'm gathering info on the net for as much as I can.As for manual lathe operations,I have almost 12 years of actual experience on that field,can you please give websites where there are sample of programming w/ simulation because I find programming confusing,2weeks is not enough for me so I'm self studying & your input is one of my references.By the way our program was GE FANUC SERIES 21 T,I'm also planning to take up cnc milling & I've learned that it is a bit different because it uses 3 axis unlike on cnc lathe where only 2 axis are used,I hope you could give me those websites it would be of big help.Thank you & good day!

Most of ths software for somulation that I am familiar with comes with cad/cam programs wuch as mastercam or surfcam and they are very expensive. I spent 12 years programing with a pencil and calculator and then 14 years using the above softwares. I usually only use the verification software if I am doing something complex. I did a google search using the words "cnc lathe simulation free" and got these: toolingu.com and cncsimulator.com.. There were many others if you want tofollow up on them. You might also try the search using the word verification instead of simulation. I have not tried either of these, but there they are and they say they are free. I have not done lathe programming in a long time and then very little although I may be getting a cnc lathe soon. Good luck with your learning. If you are still having trouble when you get to the milling and would like some help you can contact me.

Gary

Thanks for the info Mr.Ceng,I'll search for the links you gave me.If time permits I/ll be taking up cnc milling,as of now Im in the process of completing my requirements for possible migration to canada.They hired me as mechanic but they also learned that I have experience in machining so I opted to study cnc lathe coz' I think they don't use conventional machines out there or maybe some,I hope to get in touch w/ you especially if I were to to take up cnc milling.Time for me to sleep now it's already 2am (Philippine time),thank you!

As the above poster mentioned, Fanuc 21 series controls uses G-Code programming. Once you have mastered G-code you can enter it line by line and process the part you desire. On a simple 2 axis lathe, it may be possible to learn from experience in a shop in a couple of years. However, with advent of better and better CAD/CAM programs, even skilled programmers are becoming obsolete. My opinion is to learn CAD/CAM programming and basic machining (2 axis lathes are much simpler than mills) which will include G-code programming.

Fanuc utilizes some standard M codes which will have to be entered to make your program work, even with a simulator or CAM. You can enter these in most CAM programs for such things as door open/close turret movement, coolant off/on bar feeders and other things that are machine specific. These will be found in the Manufacturer's Owners' Manual or Operation Manual. Fanuc controls are a "one size fits all" control. The manufacturer takes separate outputs from the Fanuc I/O when the "M" code is processed and causes peripheral devices to actuate or operate or change state. Most of these are standard in the machine industry (ie: "M8" coolant on) but others are different. The Fanuc Manual will not tell you what your machine M codes are. The operation manual will give (rather difficult to follow)intruction on G-Code which will not be of much value without practice time on the machine and as the poster above alluded to; Someone to teach the basics (tool selection, metal identification, spindle speeds and feed speeds, English and Metric precision measurement and application along with advanced math skills, tool path or sequencing in a lathe, chuck safety use and operation and finally troubleshooting part process discrepancies, etc just to name a few) and safety. An improperly run lathe can cause death, so it's important to learn these things along with the programming.

I will differ from you on only one point and that is the statement that "even skilled programmers are becomming obsolete". The best software in the world will not make you a machinist. If you don't know how to cut metal, you have no business programming machine tools. I know of a guy who had a reputation for pushing machines to the limit and then backing off just a bit to run his jobs. He got a lathe tool holder in the face and had to have his whole mouth and jaw reconstructed. In my experience (mostly milling) people who start programming without first having machining experience have a lot of crashes, break a lot of tools, and send parts flying across the shop.

We seem to be pretty much on the same page. I have to be careful or I will get up on my soap box. I never cease to be shocked by the ignorance that comes out of some schools. I have actually encountered people who think you can just scan a drawing into a machine and it makes parts. I even saw job ad for a person who could "automaticaly" turn drawings into g-code. I couldn't resist. I wrote and told them that the technology did not exist to do that. That is why they were hireing a programmer. I could go on and on and I bet you could also.

Agreed 100%, Garyceng. The programmer must know the true characteristics of the behaviour of materials while they are being carved to shape, and have knowledge of workholding methods for odd-shaped parts. Only through becoming an accomplished machinist or toolmaker can this knowledge be gained. Anyone who has a basic knowledge of CAD or similar software can be easily and quickly trained to write CNC programmes. Whether the programme as wrritten will be successful without rework depends greatly on the knowledge of material, tool, and machine selection and interaction.

Reminds me of many years ago when I learned and then taught CNC programming at a technical school. My question to a student-"How do you quickly find the feed override knob?" Answer-"It's the one with all the paint worn from around it due to faulty programmes!"

Ing. Robert Forbus

We don't really differ, I just used a term that could be understood different ways: Obsolete.

Many of the production shops that are not really fabrication or prototype or one piece or part production shops are (and have been since the advent of CAD/CAM) phasing out the real machinists, and especially journeyman, who are paid top dollar. Instead, they keep one (or two in a big shop) he becomes the shop foreman and he proves the programs that he (or a CAD/CAM/Draftsman) sends to the machine once the foreman sets the part vices or fixtures and they agree on tool path etc. Then, they hire cheap help (button pushers, mostly high school grads) to load parts into the machine, change tooling call the shop foreman when the part doesn't work in the "go, no go" gauge. They don't want them to learn anything because; first, they will want more pay because they can do more with the machine, but they can also screw things up more (ie. forgetting decimal in tool offset screen, changing .012 to 12 *Fanuc* older controls causing a crash.) Second, they will be worth more to another company who will pay more, and they will lose them and have to hire someone to replace and retrain.

What happens to the journeyman machinists that were let go? The job market in a given area where production shops are working, may advertise for "experienced machinsists" and there will always be signs and ads for such ones, but the pay and benefits are seldom commensurate with their experience and usefulness. The prototype one-off part shops are not hiring much in the slow economy and if they are hiring, the pay is seldom what it was before. Many of these guys open their own shops and do overflow work for bigger shops, the government (Navy, Air Force etc.) and the new high tech start-ups du jour. Or they retire, or do something else, including going to school to learn CAD/CAM.

So no, they aren't obsolete but the schools and job shops aren't training the number and quality of apprentice machinists as in the past. It seems the "basics" are now encumbered with decisions that have to be made as to whether it can be done faster and better on a CNC with CAD/CAM instead of learning that there is more to a machinists job than making chip$.

My opinion.

Yes, CNCdoc, It is very frustrating isn't it? Recently I was in the unfortunate position of having to be an employee. I programmed for a shop with 25 CNC mills. There were 2-3 setup guys and the rest were button pushers, not because some of them were not capable but because they were not allowed to learn. Years after I closed my shop in California, I did some contract work for a former competitor. He said that he would usually hire people who had previously worked for me because he knew I had taught them something.

The sad thing now is that shops all want to hire experienced people but refuse to train the people they have. Then the big companies try to hire engineers to do the job. The unfortunate engineer who gets the job finds that he has to learn a whole new profession with no one to teach him. Of course the guy who actually has the experience will never get interviewed because he doesn't have a BSME.

Ok, now I on a roll. I can't stop. Lets not forget the public school system which looks down its collective nose at manufacturing and therefore doesn't encourage kids toward the many great carreers they could have while they phase out most industrial education programs. And the public wonders why our manufacturing base is being shipped off to other countries.

I agree (warning possible thread hijack). It's one of the downsides of capitalism. The schools teach, the rock videos teach and the guy down the street with the Hummer teach kids that there are those who can make more money than the the others by doing something or learning something with the end goal of gathering money,and lots of it. Anything less is unacceptable. (Who is working at McDonald's in Silicon Valley, where it is impossible to make a living there doing so?) A short cut to wealth is the more worn path now, and the machinist and his equipment and know-how are fast becoming a "means" to an end, instead of a career where one finds enjoyment in the work of his hands.

To add something relavent to the discussion: There are several online auctions where older CNC equipment ends up going pretty cheap. If I were wanting to learn G-code programming in a hands-on environment, I would buy one of those for a few grand and hire a retired machinist to tutor me a few days a week. If the manual actions performed by the machine in manual mode are learned, it would be a simple transition from that to the G-code programming that would be, in effect translating the actions of a skilled machinist, instead of the logical numeric output of an equation based on the fastest feeds, speeds and tool path of a CAM program. Once CAD/CAM is learned, then you could be the judge of whether the product measures up to what it should be as an extension of the machinist's skill, instead of a crutch for the unskilled to use as a way to bypass the actual skill needed in the process as the untested engineer's calculations are stated in CAD, translated in CAM and then produced on the CNC machine.

The problem with that is that the tool selection and speeds and feeds are usually taken from the tooling brochure, where cut depth, speeds and feeds are always optimistic and over stated as are the precision operations and production capabilities of the machine manufacturer. As a result, the under-educated CAD/CAM programmer, is often disappointed in the outcome of his programming because he causes the work to be under-bid and under-scheduled. Then, after the tooling salesman and the machine manufacturer have been consulted and it's discovered that the tooling guy blames the machine manufacturer for not being able to fully use the tooling and the machine manufacturer blames the tooling for not being "good enough" for the machine. As a result, production has to be non-stop. Machine maintenance suffers and tooling is stretched to it's limits to avoid higher costs. Eventually heends up losing money. A good machinist would have easily been able to render a more feasible production operation based on real life experience.

Some things can only be done just so fast. These guys just can't get that through their heads!

In my experience, G-code programming is the last thing you learn to be able to use a CNC, unless the machine offers high-speed machining or other multi-axis and tool-path short cuts or nesting procedure, which usually comes along with the machine training if that is the one you are learning on for the first time.

I used to work for a machine manufacturer (several) and I taught G-code, re-engineered, worked in R&D, installed, retrofit and repaired CNC machines of all kinds. There are now 3-D digitizers that input real-time data with precision scaling into the better 3D CAD programs, which can be output to several quite functional CAM programs. Not quite a picture, but pretty close. Still, guess who made the original?

The newer simulators are useful for finding programming errors and learning G-code, but IMHO, learning it hands on is the best, easiest and fastest way to learn G-code. Unfortunately, the thread starter didn't ask about that.

hi, if you want an answer find, then can you ask to adylengyel@yahoo.com. he is a very "technical" man.

best regards.

hi,

let me share some of my exprience on cnc lathe .basically cnc works on the principle that,it is controlled by numbers which include G-code M-code and N-code. G-code are the preperatory code that guide the machine for initial set-up and preperation before actual machinig then followed by n-cone which actually guide the machine to perform the machining and required tool path to be followed.then the M code for closing the operation.You need to have the knowledge of all these code to write a program.