How do you feel about using CNC?

[jpeter]

So whats the current take on guys using CNC? I often get the feeling that lots of old timers feel any work done with the aid of CNC is, well, "the computer made it" and therefore of little value. Is the current thinking that users of CNC are somehow cheating and are men of little skill? I got curious because in another thread I commented I'd drilled a series of holes accurately and done some other machining using CNC and got a response that he had drilled more holes just a accurately and hadn't had to resort to CNC, or stated to that affect. When I show my stuff at the local coffee shop I catch mumblings under someones breath that "it was made by a computer" so it doesn't really count. What's the general feeling about CNC?

 

[Rivergypsy]

Personally, as a time served instrument maker with 24 years experience in manual and cnc machining, I feel that both have their place in the scheme of things. Some jobs are far faster to do manually, others are faster and occasionally only possible using cnc.

I do love traditional engineering methods, don't get me wrong, and do take delight in ressurecting old and unusual technique of manual machining - this normally seems to get the cnc trained generation nicely surprised.

But conversely it is very satisfying to push a cnc or cad/cam & cnc system as near to its limits as I can and produce what can only be descibed as sculture.

Check out this link for an example of what is pure cnc - [ame]http://www.youtube.com/watch?v=QsmiIeAkE-o[/ame] - engineering p*rn!

 

[cfellows]

I would love to have a CNC setup, but it would just be an expensive toy. I also worry that the learning curve would be long and steep. Since I tend to be borderline ADD, it would probably sit on the shelf and gather dust...

As far as whether CNC is "cheating", my feeling is, whatever it takes to get the job done... and done well!

Chuck

 

[QSPSB]

Hmmm... Well this is one of them questions that have many answers!

One thing some people don't take into consideration is,,, The computer doesn't make the part...It all begins with the actual CAD rendering.. Now does it take skill to draw up a part in CAD or not... Sure it does.. Many folks that don't really know much about CAD think you just draw the part and it's done... Wrong!! The majority of your CAD drawings will have many layers to produce the part... Example.. 4-1/8'' holes= 1 layer, 9-5/16'' holes=1 layer, 3-1/4'' x 1/8'' x 4'' pockets=1 layer... Follow me!

Now some would say, well that sounds simple enough... and once you've learned to master your CAD program it is... Now... some would say... cool let's import this into the CNC controller program now and make this part... Wrong! Now you must save this CAD file as an DXF.. Import it into your CAM program and create all the tool paths per operation.. Once this is completed you will then create the G-code that will then be imported to your CNC controller program..

My point is... The computer doesn't do all the work for you.. It takes quite a bit of skill to go from point A to point B if you follow me

 

[kustomkb]

I have heard that it is "cheating", and I'm sure some have thought less of my work because of the use of it.
I cut my teeth on manual equipment and can spin the handles off of a Bridgeport with the best of them but when given the option, I will head for the CNC every time.

A quote from RManley's website; http://sites.google.com/site/halfsizedouglasmotorcycle/home/use-of-cnc

There seems to be this myth that CNC machines take all the skill out of it, I can tell you now, to get the machine to do what you want through a computer and then watch the cutter plunge into your material takes allot of time, care, preparation and nerve! Plus when doing complex 3D work, often the job doesn't come out completely smooth and alot of filing is required, therefore shapes produced by this method can be seen as accurate castings - is casting cheating?

 

[joe d]

I do not have any CNC equipment, and am not at all sure how one
gets all those little squiggly electrons to turn the dials ;D
but I do not sneer at those who use it, I just repeat to myself
that one day I'll figure it out.

Looking in from the outside,
it seems much harder than "traditional" machining as all that
code writing and button pushing is still "black magic" to a guy who
has barely graduated from hitting things with rocks....

Go for it, and enjoy yourself, that's what we are here for
( at least, as hobbyists)

Cheers, Joe

 

[jpeter]

Responding to the adhd guy: "Back in the day" I taught cnc programming to lots of students, some adhd. I have to say adhd guys often rose to perfection, especially when they took their medicine. Something about the computer got lots of them to focus in ways I couldn't.

 

[Tin Falcon]

This is a home shop board. The way one sets up his, or on a rare occasion her home shop is a personal matter. based on personal experience.
I have spoken with more than on model engine builder that just does not want to mess with the computer when it comes to model building. I respect that.

My background is I was taught as a manual machinist by the U.S.Air Force. manual. the air force does have cnc machines. But you learn the basics on manual machines first.

I will say that for me the step up to cnc in the home shop. has been a bit of a long and bumpy road. I am trying to learn cam on my own and things are moving slow.

This is 2011. Computers are a way of life. CNC is the way professional machinist make things. As time goes on CNC components are more available to the hobbyist.
CNC is one way of making parts it takes computer skills , knowledge of machining ,knowledge of metals etc. manual machining is another way and also requires a large skill set.
I say cnc is different way of machining. But it it still takes time thought skill and work to produce a part. granted once you make part 1 ,2-10 are easy.
Tin

 

[George_Race]

Just a few comments from a novice at engine building and machining in more conventional ways. (This metal working is all new to me)

I think there is a middle ground where CNC crosses over with more conventional milling and drilling. For example, if i need to put 8 holes in an object, have the holes line up with another object, then CNC sure does save me a lot of work. I do a simple drawing of the layout that I want, send it to the CAM program and then pass it on to the mill in the form of G Code. Could not be any easier and the whole process would not take more than about 15 minutes to get done. Simply index a common point on the two pieces, clamp them down and let the CNC controlled machine drill the holes. When done they will match perfectly.

Now, using the same CNC Machine, I can manually mill parts as well. The mill has computer aided control, so if I want to take off a thousandths or two from a piece of stock I can. Using the keyboard I can mill away to my hearts content, and there is no guess work as to where I am milling or to what depth. All the numbers are displayed on the computer screen and it only does exactly what it is told to do. No oops because I cranked the mill a bit two far as I was cutting, or set the cutter depth incorrectly at the start of the pass. (My mill does not have a single crank to turn)

My retirement hobby job is making parts for Experimental Airplane builders. All the pieces that I design and build are uniformly cut and sized. If someone needs 6 or 8 3 1/8 inch Instrument Bezels I am assured by the CNC process that they will all be identical and fit properly the first time. And, all I have to do is clamp down the material and wait for it to finish the job.

Later this year, when it warms up out in the shop, I am going to attempt to build my first model engine. Some of it will be done by CNC from drawings. Some will be done by hand, measuring and cutting as I move along. When finished I would like to think that the model building community would not look on the finished product any differently because some of my building was CNC aided. I don't have a machinist background. My expertise has been in Computers and Software. It just seems natural for me to move more in the direction of CNC, than not.

My final thoughts, I think there is room for both techniques and you always need to apply the skill set you are most comfortable with to any task.

Hopefully my comments have not offended any "Real Machinists" out there.

George

 

[kvom]

I do both. For a 1-off CNC part I'll spend much more time with the CAD/CAM than at the machine. But for multiples and parts with non-linear sections, it's hard to beat the CNC mill.

I break a lot more tools though.

 

[90LX_Notch]

The people who state that with cnc the computer does it are ignorant. They don't understand it; therefore, they criticize it. They are the same guys that can't work on today's cars; but "give them a car from the sixties or seventies...." I laugh at guys like that. If you know what you are doing, today's cars aren't any harder to work on.

Back to the cnc-

One place I work parttime in the summers is a perfect example. They had a big aluminum casting to machine. They had hired a cnc wizard from one of the machine tool mfg companies. They could never get the part right. The excuse was that castings are a ***** to machine. I pointed out to the owner that 100 years ago everything was a casting and they would of machined it no problem.

 

[Lew Hartswick]

The way I look at it is, it depends on whether it's the finished product youre most
interested in or the fun of "doing" it. To me I enjoy turning the cranks and the
design of the part or tool. Having it after is just a "by-product" of the fun. So for
me I wouldn't touch a CNC machine [Unless I was mass-producing an object for a
money making endeavor]
...lew...

 

[ieezitin]

I am strictly manual in training and my machine inventory is the same, making parts from the layout bench to the machine then milling and or flipping chips takes a lot of skill and attention to details especially when you consider the volume of steps taken all of which could inject an error.

I am 48 and computers have come into my life as much as you all, I look at them with my analytical mind and know they work on pure logic, but find I have to work as hard (mentally) to be able get the results I want, so while I have absolutely no experience in Cad and Cnc I see and appreciate the skills required to design, input and produce a part.

I too like many others am interested in filtering this system into my shop so I can take advantage on what it has to offer (repetitive parts being one example) and in full blown retirement I want to have that goal established.
All I know is this, my generation (I graduated my apprenticeship in 84) and people before me were trained to a high level in using manual machines, tool making techniques and overall detailed work environments which gives us such a broad range of hands on experience, taking a kid today pumping him full of math and computer science and letting him loose on a million dollar 4 axis CNC is to be fair to the kid wrong, as I firmly believe we have installed some unjust confidence, code error or software glitches the youngster would solve in a flash, chatter marks, loss of power or just plain dimension irregularities the kid would probably scratch his head.

If old man future was wise, he would devote time to training in the hands on mantra song of old (here’s a problem kid now go figure it out) then train for the state of the art equipment.

To sum up, computers and cnc and such are just as imperative as manual is, as long as the operator is versed in both.

Anthony.

 

[Kmot]

I am curious to know if classrooms teaching young people today to be professional machinists teach them to do manual machining first before they teach them the computer machining technology and programming skills?

CNC items are always perfect looking.

There is zero doubt in my mind that manually machined parts were -----> TYPO(not) absolutely perfect as well, during WWII when manual machinists were building aircraft engines, for example.

 

[1hand]

I am curious to know if classrooms teaching young people today to be professional machinists teach them to do manual machining first before they teach them the computer machining technology and programming skills?

CNC items are always perfect looking.

There is zero doubt in my mind that manually machined parts were not absolutely perfect as well, during WWII when manual machinists were building aircraft engines, for example.

My son is 14, and his first machining class this year is a CAM class. I'm still glad that he is interested any how.

"CNC items are always perfect looking."

You haven't seen mine :big:

Cnc has increased my broken endmill collection, scrap pile, HMEM log in time, and my tobacco in take.

Matt

 

[GWRdriver]

I often get the feeling that lots of old timers feel any work done with the aid of CNC is, well, "the computer made it" and therefore of little value.

I don't think there is or can be a "general" feeling on CNC, except to each his own. Each of us will have his or her own opinion of it. Here is mine, and your word Value is the basis for it. I will say however that there is a slippery slope involved . . . where is the line drawn between what is a hand tool, or when some tool artificially enhances your skills or replaces them. The discussion rages on . . . .

Metalworking is my hobby, I'm not in it to produce quantity against a clock. I also consider what I do to be a "craft" as much as anything else in that my objective is to make things with my hands and basic tools, some of them power tools. That being the case using CNC would run me afoul of my basic objective. However if someone's objective is producing quantity against the clock then he should help himself with any means available.

As for the Value part, I value most the things made by a skilled pair of hands by manual means. The best way for me to explain is . . . let's say I'm at a show or meet and two gentlemen display identical projects or objects and both are well-made, and both are worthy of admiration. Let's say one project is made using CNC and one is made by conventional means. The project and individual who will get most of my attention and admiration will be the one who used conventional means, because I Value those skills more than I do the skills required for CNC work. That isn't to say that the CNC guy is a bad dude, or that his work doesn't have value, it's just the result of my individual value system. Simple as that.

The other thing in play here is ego and self-esteem. The most virtriolic arguments I've ever heard over CNC vs non-CNC have been because one party or the other demanded respect and admiration from the other. That approach to anything is a recipe for disappointment because there's no assurance that will ever happen. Respect yourself, do what you do because it makes you happy, don't worry about what some else thinks. That's much easier said than done I know.


Have I ever thought about just baggin' it and having someone CNC some particularly difficult part for me, such as a locomotive driver pattern? Sure, a number of times. But between time and cost and wanting the challenge of doing it myself I haven't so far. Life is long, one can never tell what might happen.

 

[mu38&Bg#]

I think there is much to be said about the feedback you get from sound and vibration when manually machining, that you may not get from a large CNC machine.

If you're paying attention to the machine, the feedback is the same manual or CNC.

CNC items become perfect looking because the designer and operator know what it takes to make it so. You can easily design something that simply can't be machined (consider inside radius and tool reach issues in a mill for instance). And without appropriate knowledge of the machine, tooling, and metals, a fabulous design will still be garbage.

Garbage in garbage out. I don't think it matters if human hands are on the dials or computer keys. The one off or multiple issue needn't be considered in a hobby shop. For me two pieces of work one by CNC one manual, doesn't even matter. The quality and "value" is in the finished product. Would you spend even twice as much on a bag of plastic cups in the grocery store if you knew the mold was made by manual means? Probably not.

I like CNC and I use it. It doesn't matter what you think. ;D Anyone want a T-shirt?

 

[kustomkb]

I think there is much to be said about the feedback you get from sound and vibration when manually machining, that you may not get from a large CNC machine.

I spent a couple of years working in a CNC production shop with a deaf guy. He would have his crotch pressed up against the machine in order to "hear" any chatter and feel how the machine was running. -Great guy.

 

[Noitoen]

There is also the DRO. Isn't that cheating too?

 

[Tin Falcon]

I think we all need to realize the objectives here.
What are the goals.
here is what I see others may shuffle the order and that is fine.
Have fun !!
learn:1) about machining
2) about building engines
3) about engines and mechanical things.
4 )about ourselves and limits and learn to change them a bit.
5) other things related to machining and model building
make and collect tools (part of the fun)
teach and encourage others about the above.

If a hobbyist wants to learn about cnc machining and converting machines to cnc that is part of the fun.
Tin