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Gunsmithing How to learn CNC?

Bryan27

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Full Member
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Jul 31, 2007
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Not that I'm going to go out and buy a CNC mill in the near future, but I'm a little bit curious as to how/where you learn how to operate one of these machines. The local tech school that I took a class at has one CNC mill, but the instructor is old school and only teaches you how to use the manual machines, the CNC just sits there gathering dust. Is it something that you can teach yourself? I am not the most computer savvy person, so it always seams like there is some voodoo at work when those in the know start talking about G code and writing programs and such. Is it something that would be practical to learn on your own or do you need a course to get it done?
 
Re: How to learn CNC?

The best bet IMO is to learn a modeling program like Solidworks. Then you can use an intermediate program to convert to G codes. Haas builds very reasonble machines that will support production work. I would recommend finding someone that uses one and have them show you how they work. However, unless you are useing for production, CNC can be very costly for single parts. As far as use goes, if you can draw it, you "pretty much" just hit the go button.
 
Re: How to learn CNC?

i have been teaching myself g-code over the last couple years. there is a lot to learn and every project i do, i learn something new that can be done. i have been using peter smid's book "cnc programming handbook" to learn from. in my opinion, it is well written and easy to understand.

teaching yourself is probably not the best method. taking a class would be better and faster. for the hobby cnc user that does not have time for class, self teaching g-code can be done.

what i have a hard time with is learning cad. i can't for the life of me figure out any of the programs. i am eventually going to need to make time to take a class or hire someone to sit down with me and teach me the basics. for now i am limited to 2-1/2 d and very basic 3 d parts on my machine. even with a good cad and cam program, you will still need to know g-code so personally, i would start with learning that.
 
Re: How to learn CNC?

I agree with 300sniper. Get someone to teach you or better yet take a class to learn G codes. Not every CNC machine is the same so it will be best to have a good kniowledge of G codes.
 
Re: How to learn CNC?

I agree. Find a Haas. These are very easy to learn on. A Haas will get you up and programming in just a few hours at most. Alot of shortcuts on those machines. Makes a person with no experience start their own business(I worked for one of these individuals ONCE. lesson learned on my part).
 
Re: How to learn CNC?

One thing that is lost starting out on CNC's is all the practical applications you learn doing jobs on manual machines. Do yourself a favor and spend some time with manual machines then learn G codes and CNC machining.

You'll be light years ahead of "CNC programmers"
 
Re: How to learn CNC?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Luvman</div><div class="ubbcode-body">One thing that is lost starting out on CNC's is all the practical applications you learn doing jobs on manual machines. Do yourself a favor and spend some time with manual machines then learn G codes and CNC machining.

You'll be light years ahead of "CNC programmers" </div></div>

Thats EXACTLY what you need to do. Learn how to be a machinist then learn how to be productive with a cnc. G code is simple, there is no easy way or book that will teach you what you need. the best way is to start with manual machines, master them first then you will already have a good idea of what a cnc will be able to do. You need to know that before programing. You can get a g code simulator off the net that will verify the program for you and actually draw it out so you can see it.
CNC's are not something you want to just jump on and learn before knowing what machining is and how cutters react with different material and what tool does what. .002 seconds can cost you the price of a new pickup or worse..

That "old school" instructor is priceless if you want to learn...CNC's just the next step and i dont blame him for not letting everyone play with the CNC. good on him for teaching and not just showing..
 
Re: How to learn CNC?

i bought my cnc machine without ever touching any milling machine before. i had never even seen a manual or cnc mill in use. so far i've only crashed a few tools. usually it is because of misplaced decimal and other times because i didn't z up enough to clear a clamp. manual experience wouldn't help much with that. i have wrecked cutters by improper feeds/speeds and or depth of cuts though. my machine has a 60ipm rapid speed so i have a bit more time to catch mistakes during a trial run vs. some of your fancier high dollar/high speed machines. about 75% of what i do could be done on a manual machine and would probably be faster. the other 25% cnc is required and would be near impossible to do on a manual. i got the cnc first because a project i wanted to do was in that 25%. now in the near future i am going to be in the market for a nice manual knee mill. i had to and still am learning cnc and machining at the same time. that probably isn't the easiest way to go about it but it can be done.

this was my very first project on my mill. the program was written manually using g54-59 and i designed the fixture. all the holes were drilled and the back side counter bores were done on the first side. then the plate was flipped over and bolted to the fixture. then the profile and chamfer were done.

the back side of the parts completed prior to flipping:

cnc005.jpg


the parts after the plate was flipped over and bolted to the fixture:

cncboltdown.jpg


six completed parts still bolted to the fixture:

cncchamfered.jpg


back side of completed parts:

cnc017.jpg


front of completed parts:

cnc016.jpg


one assembled part:

mastercylinderadapter.jpg
 
Re: How to learn CNC?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: heatseekins</div><div class="ubbcode-body">
That "old school" instructor is priceless if you want to learn...CNC's just the next step and i dont blame him for not letting everyone play with the CNC. good on him for teaching and not just showing.. </div></div>

Oh, I agree with you there. I took a night class a while back and will take another when my schedule allows, just because I think it's kinda a good way to relax and learn something I'm interested in. He is all about doing things the hard way in the name of learning and that's what I take the class for. If you are working on a project and you need a screw or bolt you can't just buy one from the hardware store, you make it. If you are making something that calls for a .500" round pin, you can't just cut off a peice of 1/2" round stock and call it good, he hands you a peice of 3/4" square stock and tells you to make it. The school has a 2 year degree program that I have considered doing and then learning gunsmithing afterwards. I just find it strange that they have the CNC mill but don't teach it's use in a 2 year program, especially since most of the guys in that program are in it for a career and not a hobby. I learned a lot in the night class, 2 days a week for 3 hours each, so I am considering taking the 5 day/3 hour class and see how that goes. I like the way the instructor teaches and he's pretty flexible with the projects especially if you finish all your semester projects early you can pretty much finish the semester making whatever you want to as extras, just give him a blueprint to grade it from.

Do most colleges/tech schools teach some type of CNC programing and CAD? I live about 5 minutes from University of Memphis and State Tech is 5 minutes the other direction. I would think that their engineering departments would teach this stuff, but my brother has his masters degree in mechanical engineering and said he never learned anything about the actual manufacturing process, he knows solidworks and some CAD though.
 
Re: How to learn CNC?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body">i bought my cnc machine without ever touching any milling machine before. i had never even seen a manual or cnc mill in use. so far i've only crashed a few tools. usually it is because of misplaced decimal and other times because i didn't z up enough to clear a clamp. manual experience wouldn't help much with that. i have wrecked cutters by improper feeds/speeds and or depth of cuts though. my machine has a 60ipm rapid speed so i have a bit more time to catch mistakes during a trial run vs. some of your fancier high dollar/high speed machines. about 75% of what i do could be done on a manual machine and would probably be faster. the other 25% cnc is required and would be near impossible to do on a manual. i got the cnc first because a project i wanted to do was in that 25%. now in the near future i am going to be in the market for a nice manual knee mill. i had to and still am learning cnc and machining at the same time. that probably isn't the easiest way to go about it but it can be done.

this was my very first project on my mill. the program was written manually using g54-59 and i designed the fixture. all the holes were drilled and the back side counter bores were done on the first side. then the plate was flipped over and bolted to the fixture. then the profile and chamfer were done.

the back side of the parts completed prior to flipping:

cnc005.jpg


the parts after the plate was flipped over and bolted to the fixture:

cncboltdown.jpg


six completed parts still bolted to the fixture:

cncchamfered.jpg


back side of completed parts:

cnc017.jpg


front of completed parts:

cnc016.jpg


one assembled part:

mastercylinderadapter.jpg


</div></div>

I've seen some of the projects you've posted and have been impressed, you do good work and it shows that you've thaught things through when you do them. What's that part you made for?
 
Re: How to learn CNC?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bryan27</div><div class="ubbcode-body">

I've seen some of the projects you've posted and have been impressed, you do good work and it shows that you've thaught things through when you do them. What's that part you made for? </div></div>

my mind is always thinking about some project and how to go about it. if i finished 5% of the things that go though my mind i'd be rich!

the part is an adapter to mount a 1 ton chevy master cylinder onto a toyota pickup brake booster. i was going to start a business manufacturing misc. parts for offroad vehicles. i didn't think that fully though. after i got started and found out how much insurance and other expenses were going to be, i decided it was not going to work for a part time gig. i couldn't make the commitment to turn it into a full time deal either.
 
Re: How to learn CNC?

Very nice 300. Id like to think I may be able to learn CNC after gunsmithing school without paying for more classes. Either by an apprenticeship or just diving in and reading.
 
Re: How to learn CNC?

I started getting paid for my apprenticeship in the mid 80's.
All manual, and NO digitals! (good way to learn about backlash.)
I was lucky to grow up in a family of toolmakers, tool and die, die casters, moldmakers, and machine builders.
Cnc came later.

There is no class that can teach all of that.

As for fixture offsets, some machines may require you to put them in sub programs, while other machines may hold more than enough.

Online training, at your own pace, try this.

http://www.toolingu.com/default.aspx

They changed their site, but used to offer a test to help you get started.

Hope this helps, and feel free to mail me.
 
Re: How to learn CNC?

Here is a free 3-D Parametric program for free, that can be used to program in Gibbs.

Drivers fault.
Not enough load.
Code took 45 min per side to load in machine.(9600 baud)

We use side jobs as training, when work is slow.
High flow intakes also hold bigger turbo too.
http://www.youtube.com/watch?v=TZu6Y6RpVgU
http://www.alibre.com/

We are being asked to make, even with crude toolpaths.
 
Re: How to learn CNC?

Having a basic machining knowledge is more than benificial. The book referenced above by Peter Smid is in the bottom of my tool box. It is a good reference when needed and a good book to teach others with.
Start out simple with simple parts to get comfortable with G and M-code programming. The codes are not that difficult, it is the easiest "Second Language" you will ever learn, the rest is just math/geometry. FWIW I barely got through high school math, introductory algebra was it. You will just have to play catch up if you fucked off in school like I did. Being able to recite trig calculations isn't needed, but eventually you will need to understand how to look them up, do the figuring, and as important is how to apply them.

Starting out with a CAD/CAM system will ruin you in my opinion, You won't be able to have an intellegent conversation with a programmer. A CAD/CAM system isn't needed for simple stuff, often I can program parts manually faster than I can figure out what the software wants/needs in order to do it like I want it done. When your part geometry gets more complex (non-symetrical hole patterns, profiles, 3D, etc.) the CAD/CAM really shines. CAD/CAM software is just another tool.

There is also "Conversational" programming, I like to call it "Argumentitive". Conversational works but you have to understand it's language, along with it's limitations. Here again you may know how you want to do something and the controller has a different idea about how to go about it. If you want facemill from left to right, front to back, it will do it the opposite more often than not if you don't tell it otherwise.
You explain what you want to do (drill, tap, face mill, cut a circle, cut a pocket ,cut a boss) using it's vocabulary (Fill in the Blanks) and it will construct a tool path for you.



5 Golden Rules of Metal Working...
1) You can't cut what you can't hold.
2) If you don't know what the material is you can't cut it.
3) You can't fool Mother Nature.
4) A tool will cut on the path it is sent on.
5) If you don't know what Parameters to run...LOOK THEM UP.

If the 5 rules don't make sense to you now, they will.
 
Re: How to learn CNC?

If you get using CNC without having a fair knowledge of conventional equipment,your missing out on a huge learning curve. It would be almost like teaching a child everything on a computer from the day they start school,learning to type instead of write and doing childs arithmatic on a calculator instead of learning to add and subtract. By all means learn about programming but stick with the basic conventional stuff for as long as you can and learn as much there as you can before you go at the CNC game. Also remember theres 2 aspects to CNC machining,theres the programming and the operating side and both are 2 very different things. I know guys that are excellent programmers but absolutely useless operators and vice versa. The guy thats well used to conventional machining usually gets on well on a CNC.
 
Re: How to learn CNC?

It's been a long time since I worked as a machinist -- in the 1980's -- but back then it was clear that engineering schools DID NOT teach engineers shit about how things can be/are actually made in a shop vs. theory.

A lot of parts were designed initially that really couldn't be made and you would work with them to modify the designs to match with what could actually be done with the materials in question.

This was with one-off onesey-twosey parts for experimental devices and electron microscopes, etc. Not you general production parts.

My favourite
wink.gif
was a piece of ceramic given to us by some PhD who wanted it machined for some hot stage specimen holder design for an electron microscope. I'm sure some of you can guess what came next -- several tools ruined as that #$%&! piece of ceramic was not the sort that could be machined. We didn't know, and neither did the PhD.

I would be curious if today's university engineering programs now cover machining and manufacturing principles.