Need Help!- Teaching CNC operators

[cncwhiz]

After many years of headaches and dumming down my programs, the big bosses have decided to let me train the machine operators. Some or most of these guys are green as can be. Some came from Walmart etc, you get the picture. I will have different levels of triaining as that some people know more than others. I will be teaching only the "G and M" codes that we use here in house. They will be learning what and how to do work and tool offsets and basic reading of programs. After almost 30 years of machining I'm sure there are things I will overlook. I will be showing them the difference between a dull and sharp cutter etc. I would like to teach them what dull and sharp tools sound like but how to do this and how much time would it take to do this? I am looking for input from people who have or are doing this in the "real" world. I will be doing this in both the classroom and at the machine.

TIA

[electromech31]

Start by finding out exactly what you need to teach. Second find out were you students are at with their skills. I have found a great site http://www.jjjtrain.com/vms/, I have used it for examples to my students. Also look for some industrial standards, http://www.nims-skills.org/downloads/downloads.htm, so you can say that the students were taught such and such. (save your ass later)

[ImanCarrot]

The jjjtrain site is tops for general info.

What a sharp/ dull tool sounds like- What I do is use a microphone which I took apart and blu- tacked to the spindle housing. I use headphones to listen to the tool cutting- it's a huge advantage. I daresay you could stick the output into your PC or even a tape recorder to play it back to your students?

[cncwhiz]

electromech31,
That first link is good stuff. I will be using it a lot. That second site is pretty good too. There is so much to think about for this issue as that not everybody is at the same level. You don't want to waste production time training someone that could be making parts that allready knows the topic that you are teaching at the time.

ImanCarrot,
Your idea sounds pretty good if all things are taken into the sound ie; tool type, material type etc...

[MazakMikeO]

One of the ways I have used in the past to train apprentices is to show them a certain task, say taking a tool length offset, then let them try. Usually they won't pick it all up straight away, but as they are going through, I would watch for a mistake, and if it won't do any damage let them carry on, then stop them, point out the mistake and start again.

The best way to learn things like this is by doing, and doing again in my experience. Let them make mistakes, but not ones that damage anything. But you definately need to sort out different levels first.

That in my opinion is the hardest part.

[cncwhiz]

I'm starting to get an idea of how I need to go about this task. These guys all push buttons everyday, so I think the first order of business is to actually learn the basic concept of what the program is doing. They have a very general idea as that they are running the machine.

[tauntdesigns]

One thing alot of mill operators seem to have problems with, is making workpiece offsets. Some have to look on the machine at the labels (X+, Y+, etc..) and then use their hands to help them try and picture in their mind which way to go... and some still make the wrong change. Some think it matters what type of machine it is (table moves or spindle moves) which I say it doesn't matter.

If you're running part and you have a 1 inch dimension from the left edge of the part to a hole and it checks .990. I look at as the feature (hole, web, etc) needs to move right .010. When you move right on a X,Y graph, that's in the plus(+) direction, so make a plus offset in X workpiece offset. It doesn't matter what type of mill machine you're on.

So, if a feature needs to move right(X+), left(X-), up(Y+), down(Y-), deeper(Z-), and less deep(Z+)

Now I'm confused
Jack

[cncwhiz]

I'm always the spindle, this makes it better for me to understand. It gets worse for those kind of people in my shop. We use hex tombstones and machine two parts and six sides for most of our setups. We do not have verticle machines in our shop so it can get a little crazy.

[tauntdesigns]

Being the spindle is same as I was saying... to get a feature to move to the right you'd have to move the spindle right. All mills are programmed like a X,Y graph... even horizontals.

Right(+), left(-), up(+), down(-), in(deeper(-)), and out(less deep(+))

Horizontals are basically a vertical laying on it's back. The X,Y graph is taken in from the operator's positions, point of view.

The only difference I've found with Horizontals are the direction table rotates. Some I've run rotate clockwise with (+) direction and some counter clockwise.

[cncwhiz]

tauntdesigns,
That will be down the line for most of these guys. Like I said in the begining of this thread, most of these guys arn't even button pushers. My main idea at this point is to have them understand what the programming is doing so they can set an offset or start the program back up after the weekend or intrruption. I use "G10's" so they won't be setting to many work offets. My programs use subroutines and are all over 2,000 lines.

[tauntdesigns]

cncwhiz,

Do they mount their own tools, if they do.... this was something we addressed with some of our button pushers. How to draw the end mill up in the holder with the set screw so if the tool holders set screw loosens up a little the tool has a better chance of not cutting to deep. I know it sounds simple but ........... Do you G10 the tool offsets too from a tool pre-set area or do they set them on the machine.

Cheers,
Jack

[Mitsui Seiki]

One thing that helped me when I was new to this and the ones I have trained is this, -(Minus) = more chips , +(Plus) = less chips.