4th Axis Learning Curve

[HollowPoint]

I've had my new hobby mill for a few months now. About two and half of those months was spent waiting for Back-ordered parts.

After the obligatory crashing and breaking of at least a hundred bucks worth of End-Mills and Drill bits, I think I finally have a handle on it.

Thanks to some of the guys over on the CNCZone forum I think I'm ready to start using the 4th Axis rotary table that came along with my package deal.

My problem is that I have a very difficult time absorbing the information I need from just reading it. I'm not sure why but, that's the way it's always been for me. I'm more of a hands on kind of learner. I have to see it being done before it really clicks in my brain.

That being said; I was wondering if any of the CNC users here might direct me to some internet tutorials regarding the setup an use of a 4th Axis rotary table? My particular machine is a Tormach 770. I use SolidWorks CAD software and SprutCam CAM software to generate my tool paths.

I've checked out most, if not all, the video tutorials on YouTube. I'm hoping someone knows of some others that might help me climb that Learning Curve without to many slip ups.

I'd like to use it to try to get better results when making my own cherries and such.

Thanks in advance.

HollowPoint

[Casting Timmy]

If you're unsure about the program, turn down the speeds and offset your Z axis back so it can't crash as it will be to far back to machine. You can bring back your Z axis after running the program without a part.

[HollowPoint]

Greetings CT:

This is basically what I did when I first started learning to use my mill itself. It's like running the part without the tool in the spindle.

What I'm needing to learn now is how to create my tool paths correctly, setting up my rotary table and indexing my part; step by step from beginning to end.

HollowPoint

[kywoodwrkr]

We use blocks of machinable wax in the shop for the learning curve side.
We use cylindrical wax for the lathe and blocks(6x6x2) in the mill.
We have vaccums for the wax and recycle, using cake pans as molds.
I can guarantee you this does not mean you will not break a mill!8-)
YMMV

[LEADHOPPER]

HollowPoint,

When I program for a 4-axis, I use the center of rotation as my "Z" and "Y" axis offset. Your tool paths should not be any different then 2 or 3 axis toolpaths, assuming that you are using the 4-axis to position your part, and are not trying to cut as the 4th axis is rotating. That opens a can of worms that you don't want. If you know the codes for a rotation you can manually punch them into the program. Just make sure that you put in a "Z" retract that would let the 4th axis clear the tool, no fun when a 4th axis rotates and snaps your tool.

LH

[HollowPoint]

Thanks guys:

My CAM software has an integral simulation mode that aids in minimizing tool breakage. When I started practicing with my mill I used sheets of styrofoam insulation as my materials before actually moving to metals. I cut them into small sections to fit my work envelope.

Even with the Simulation feature and the Styrofoam I still managed to snap my share of bits and end mills. I still haven't completely overcome the "Pucker-Factor."

The wax concept makes sense. I think initially I can use some cheap dollar-store candles to experiment with before moving on to the hard stuff. I may even have some candles laying around somewhere.

I'm very slowly getting to a position where I can begin to see some light-at-the end of this tunnel with the 4th Axis learning curve. It's the same situation I found myself in when I first started learning CNC in general.

When you've never done something before it can seem like a daunting task to try to learn it. Only in hind sight can you see how hard it was or wasn't.

I'm more or less self-taught so alot of the technical CNC nomenclature just flies right over my head.

At this point, dreaming it up and drawing it up are a whole lot easier than machining it up. Luckily that hasn't stopped me from trying.

Many thanks for your input gentlemen. If you think of anything else that may be of help please don't hesitate to let me know. Good video tutorial are always a big help for me.

HollowPoint

[W.R.Buchanan]

HP: I have seen this many times in the past. It is called learning on too steep a gradient.

I once did a demo for a company that was selling a friend of mine a 3 axis CNC mill.

My friend was an extremly well versed gunsmith with 40+ years in the trade. but he was not a well versed machinist.

He wanted to go directly to making double rifle receivers as soon as he could turn the machine on. I tried to tell him that he needed to make a bunch of simple parts to learn the machine before taking on more complicated jobs. He wouldn't listen, and basically got so frustrated that he just let the machine sit.

He never made anything with that machine.

This is my advice. Since you said you need hands on type of learning structure then I suggest you start by making many 2 axis parts IE drill hole patterns, make some slots, pockets etc.

Then add the 3rd axis and profile some half spheres and things like that. By then you will have familarized your self enough with the more basic functions of the machine, that you can add the 4th axis and you won't have to cope with all the other things going on.

Understand that 4th axis capibility is way up the food chain from where you're at. I have been doing this for 25 years and the only 4th axis I have in my shop is a Manual Hardinge Head I use to drill holes around the perifery of a part. This is infrequently done at best and I can live without the automated function very nicely.

Start out simple and progressively make parts that are more and more complicated.

It is the best and really the only way to learn how to run your machine.

Hope this helps you in some way.

Randy

[HollowPoint]

Hi Randy:

I completely agree with your assessment of this "Learning Curve;" and in fact that's exactly what I've done thus far.

I've already made several parts with my new CNC mill. Some more complicated than others. A few of them I've even posted here on this website.

Now it's time I learn how to setup and use my 4th Axis. That's the reason for my OP.

I know there are more than a few guys that frequent this site who have vastly more CNC experience than I do. I was just hoping that one of you had some beginner's information in the form of video tutorials or maybe written so that a two year old could understand. Lot's of pictures is helpful for me; lots of words just tend to complicate simplicity.

I do appreciate the bits of information I've received thus far. Believe it or not, these bits of information are much easier for me to digest than long drawn out technical explanations. Even when those technical explanations are exactly the answers I'm needing. I can't explain why that is. For me, that's just the way my brain works; or doesn't work.

HollowPoint

[W.R.Buchanan]

HP: always remember you must tell the machine every single move that it must make.

Then,,, what you do is make the part in your head, IE watch the machine run in your head taking into account every move that must be done in the order it needs to happen.

Then write the code.

If you are using a Cam program to write the code then you must run the proof program and find insert all of the missing lines which are usually rapid traverse moves, and administrative commands like coolant on/off, spindle on / off , speed changes etc.

Most programs on my CNC Lathe are simple parts so I write programs one line at a time.

Doing programs this way will establish YOUR personal "format." IE the way you write programs.

After you have become familiar with what programs should look like, it will be much easier to edit them and remove slow sections and see thngs that will crash you.

This is why I say to start out simple and work up. Being able to ferret out moves that are out of sequence, will help with your broken tool costs.

Adding the 3rd and 4th axis adds layers of complication to your quest. If you have 3 axis movement figured out then all you are doing is adding another layer with the 4th axis. Those 4th axis moves will be inserted into the program where they are appropriate,and will intermingle with the existing 3 axis moves.

Hope this further explains what you need to do. There is no generic tutorial that I know of that adds the 4th axis. It is just like adding another 3rd axis. IE moves that you must include into your program to execute the tool path you seek.

Randy

[Cap'n Morgan]

Hollowpoint.

To begin with, don't think of the 4th axis as a moving axis, but more as a sophisticated vice, capable of positioning your part at whatever angle you want and then using the other axes to do their job. A lot of parts can be made this way. If you need to actually use the fourth axis as a "live" axis, you'll most likely be swapping it for the "Y" axis. There's rarely, if ever, any need to run more than two axes simultaneously when doing 4-axis milling and the 4th axis should only be used perpendicular or at an angle to the Z-axis. A rotary table parallel to the Z-axis is redundant on a 3-axis CNC mill -

I use a CNC mill with a 4th axis (and a 5th as well) on a daily basis and I have never used any dedicated 4th axis software to generate programs, except for a macro on the machine which will swap the Y or X axis with the rotary axis - great for engraving on curved surfaces, but even that could be done with a calculator if so needed.

I think the most important thing is not to be daunted by seemingly complicated parts, but instead analyze the part and try to break the operations down into individual jobs which can later be chained together if necessary.

[James Wisner]

W.R, and Capt are right on there regarding ANY CNC mill operatations, The learning curve is only one way, STRAIGHT UP.

Start out with the simple 2 and 3 axis parts, and then work into any 4 axis program, the feed rates are differnt regarding the rotation of the table, and the interpoleation of the G2 and G3 arcs.

We have two retro fitted Boss 5 Bridgeports we have run now for about 10 and 12 years. I am still learning things about the programs. We have over 900 parts we make, only about 12 of them are on the 4th axis.

Many, Many parts can be made simply by three axis movements, and then sawing the part off from the base material. Then refixuring if needed for any more cuts.

Good luck on your endeavor.

James Wisner

[HollowPoint]

Thank you gentlemen for your input.

I finished a rudimentary drawing of a four-fluted reamer yesterday just to have something to practice with.

Right now I have no problem making parts on my machine; it's figuring out exactly how to incorporate my 4th Axis when generating my tool paths using my present CAM software that's giving me grief.

Setting up my 4th Axis on the mill is relatively simple.

Yesterday was the closest I've come to getting my software to output a tool path of any kind using a 4 Axis. I called the SprutCAM software support people for some help but, apparently they were swamped by all the other callers seeking help. It's an excellent CAM software; just overly complicated to learn.

Their tech support is pretty thorough. It's waiting in line for help that's frustrating.

I faced the same frustrations when learning to use this same software for general CNC milling. Once they talked me through it a couple of times it finally clicked in my brain. From then on I was able to dissect and analyze the G-Code it produced and learn from there.

They actually called me back later on in the day yesterday to help me out but, I was working so I wasn't able to go to my computer and have them walk me through the process.

I have a day off next week. I'll give it another shot then.

I know it may sound like I'm at a stand still but, I am making progress. Progress never seems to come fast enough though.

HollowPoint

[W.R.Buchanan]

If you are trying to make a reamer then the 4th axis moves are simple indexing moves that are done in between the flute cutting routines. This should be pretty easy to insert, then do the flute routine, index, flute routine,,,Etc.

If I was doing this on my 2 axis machine I would use my hardinge head as the material holder. I would cut a flute, index the Hardinge head manually, run the flute routine again, index etc. This is how I slot Levin "D" style collets I make. Slot, index, slot, index etc.

You are doing the exact same thing except you are giving the machine a command to index for you. This should be no more complicated than giving it a G code and a value, after each flute routine is ran.

Randy

[HollowPoint]

W.R.B:

It would be easy if I knew what I was doing but at this point what I want to do is figure out how to let my CAM software make the calculations and post the code for me. That's why I bought it in the first place.

Once I have the G-Code I can then go back and "Reverse-Engineer" it; so to speak. If I can study the Code, I can then figure out how to write it or tweak it myself.

I know enough G-Code to edit it when necessary but, I want to learn how to use this software so that I don't have to write the code myself. I can already do it with general 3-Axis CNC milling but, adding in a 4th-Axis has still got me slipping and sliding on that learning curve.

HollowPoint

[W.R.Buchanan]

HP my point is you will always have to edit the code to include those items. The software will only write tool paths. You still have to get the tool to the starting point, and remove it when it's job is done. The software doesn't know how to make parts, all it can do is generate tool paths. You have to fill in all the blanks.

Also the software, no matter how sophisticated, doesn't know when to turn the coolant off and on and a variety of other little things as well. The software can't think.

If it could there would be alot more guys with CNC machines happily making parts in their garages as no skills other than using a program would be needed. We ain't there yet.

The whole idea is you have to learn how to make parts first. Then you learn how to tell the machine to make all the moves you would have made had you made the part manually. Then software can help, but it doesn't know how to make parts. It doesn't understand the sequence of events necessary to make every part or for that matter any given part.

This is why you need a person.

This is the main thing people don't understand about CNC machinery, you still have to have a person who knows how to make the part writing the programs and making the machine go.

When machines are able to think for themselves this may change. They also may decide they don't want to work for us any longer. Just like the ones in Arnold's movies did.

Then we are in trouble!

Randy