To CNC or not

[magicniner]

CNC is fun, there's no doubt about that, On the other hand, Its really great for making 5,000 whatzits. If you're a hobbyist, you don't need that many.

I used to think like this until I discovered that CNC is excellent for onesy-twosey parts with compound curves and 3D features which would be impossible with manual equipment or would take so many set-ups with custom fixtures that they wouldn't be worth doing.

This is a .20 cal rotary magazine I made for a target air pistol, the central mag advance ratchet feature has areas where the cutter must be less than 0.8mm diameter



Even with a rotary table, multiple custom fixtures and a high speed spindle I suspect it would be a bit of a pig to machine with 0.6mm or 0.7mm end mills

 

[Robert LaLonde]

I bought and set up a small CNC mill several years ago and was fooled by all the model engineer forum content on hand coding into thinking I needed to learn to write G Code. CAD/CAM is still a fairly steep learning curve, choosing something with a supportive community forum will be a big help.

CamBam has the BEST support community of any on-line community I have seen. Its also one of the easiest CAM programs to learn. No its not the only one I know or even the first. That being said some basic knowledge of code can be helpful even if you do zero (0) hand coding. Nice thing about Mach 3 is all the basic G&M codes are available along with descriptiuons right from the home screen.

Mach 3 will do exactly what you want with simple holes, series of holes, etc. There is a tab called Wizzards in there and it takes you to it. No coding, simple to understand

Look at this youtube and search more for yourself:

I pretty much only use the NFS Wizards. They are consistent in style and layout and work quality. One or two of the others left me wondering what was wrong with my machine.

Isn't it limited to 3-Axis?

Yes, and no. You can always use your other axis for indexing. Realistically very few projects actually require simultaneous 4 or 5 axis motion. I see lots of very high end machine videos on YouTube where they have a 5 axis machine basically doing 3 axis work, and just using the 4th and 5th for indexing. Sure there are a few doing real 3+axis machining, but not many. Usually I see it in carving machines where the the spindle has the multi axis mount rather than the work piece.

 

[magicniner]

Yes, and no. You can always use your other axis for indexing.

Bob, I've suggested manually adding indexing tothe code to a guy on another forum who wants to 3D carve some things but doesn't have CAM that supports a 4th.
Does it allow adding an indexing feature in the 4th axis so you can toolpath one feature then simply add another 7 copies at 45 degree intervals to get 8 identical features around an object by selecting the option and filling index angle and number of copies? That's how I added the locking slots on the periphery of the magazine on that mag. It would be easy enough to copy and paste 8 copies of the path and manually add indexing but it is nice not to have to ;-)

 

[Karl_T]

I have a little machine shop CNC mill, operating system is mach3
...

Are there programs for mach3 software that would help me make simple circles and squares. I seem to need precision holes in pieces a lot. Ive done a number of 1000 hole holes and whittled some nice squares with my big manual mill but doing so with a CNC mill sitting on a shelf makes my head hurt.

...

I'm going to offer a contrary opinion. For some CNC almost becomes a religion - the answer to everything.

Looks like your need is for accuracy in bored holes. That large manual machine with a quality DRO is going to do a better job than a little CNC mill. IMHO, I'll take a rigid machine over wimpy one that has CNC added any day. Remember, CNC just turns the crank for you.

Now, I am a big CNC user. But I do find my huge Supermax manual mill gets nearly all the high accuracy drilling and boring work.

I also think CNC will just frustrate you, unless you are willing to take the time to bust through the learning curve. Worth it once there, but can be a steep one for some, not so much for others.

Just my two cents

Karl

 

[JimDawson]

Isn't it limited to 3-Axis?

No, Fusion 360 Ultimate is 5 axis. Not free, but I think it's about $300/ year. Still pretty inexpensive. There is also reference to multi-axis machining in the standard version but I have never used it.

 

[RJSakowski]

My primary reason for getting a CNC mill was to machine parts that couldn't be done by any other means. I have done jobs with up to 100 parts but those are rare for a hobbyist. I my particular case, the machining could have been farmed out to a local job shop but the cost would have been close to what the Tormach CNC cost.

As far as getting your feet wet, it doesn't take all that much effort. Conversational programming will allow you to do some fairly complicated machining and you can be proficient at that in a matter of minutes or hours. There are a variety of CAD and CAM packages available for little or no cost. There will be a learning curve but it needn't be too difficult.

The point is that the CNC gives you added capability. It may sit idle for some time but at some point, you will have a job that cries for the CNC and you will be glad that you have the resource at your disposal.

 

[Robert LaLonde]

Bob, I've suggested manually adding indexing tothe code to a guy on another forum who wants to 3D carve some things but doesn't have CAM that supports a 4th.
Does it allow adding an indexing feature in the 4th axis so you can toolpath one feature then simply add another 7 copies at 45 degree intervals to get 8 identical features around an object by selecting the option and filling index angle and number of copies? That's how I added the locking slots on the periphery of the magazine on that mag. It would be easy enough to copy and paste 8 copies of the path and manually add indexing but it is nice not to have to ;-)

Which software? I am more familiar with CamBam than Fusion360. I know in CamBam, I could just copy/paste the machine operation and add a line of code in the operation header of each operation to advance the 4th axis. Because you are doing it before CAM generates code its pretty easy. In the operation parameters there are fields for entering code manually at the beginning and end of each operation.

CamBam also has a 4th axis plugin, that effectively swaps one linear axis for the rotary axis. Sort of like CNC Wrapper, but better.

I have read that Fusion360 has basic 4th and 5th axis indexing capability, but I have never used it. I just use Fusion for its adaptive clearing in 3D. Often I will generate that part of the code in Fusion, and then drop it into CamBam as an "NC MOP."

 

[magicniner]

Bob,
I think he was experimenting with deskproto

 

[Robert LaLonde]

I used DesKAM (Deskproto) a very long time ago when I didn't know anything. I seem to recall it was pretty hard for me to do anything with it, but that may have just been my ignorance. Still, you can always edit a code file in a text editor. If its a single operation it would be pretty easy to copy paste it with an appropriate G00 A(xxx) manually entered at the beginning of each new paste.

 

[ozzie34231]

Guys, this is 2018 and you're talking Mach 3. Mach 4, a copy of their Mill Wizards, and Fusion 360, (free for hobby or small business), is a 2018 way to go. You don't need to ever learn a bit of G-code.
My recommendation is to download a trial copy of Mill Wizards and it very soon reveals what you can do without knowing G-code, or having a Cad/Cam program..
You can also download a trial copy of Mach 4 to see what it is about.
You can download Fusion 360, but that will take a little time to learn. There are however, many, many Youtube videos to help you learn.
The comments about a big machine accuracy vs CNC are silly. If you're talking a knee mill vs a tabletop CNC, yes the knee is more accurate. But the fact is that CNC can be more accurate than manual comparing like size machines.
I have a knee mill built in the 1970s running Mach4 and it can machine to .0001" accuracy, and then with a probing sequence measure the work. If it had handles, I'm not sure I'd know how to use them.