Questions for those experience in CNC machining

[redlaser666]

I am a hobby machinist. I learned a few years ago how to do manual lathe and milling machine operations and have come to understand my machines well.

My questions relate to converting this machines to CNC capabilities. I have already researched everything I would need to do to turn a manual mill to CNC.
The question is how do I create parts after the conversion?
I have read that MACH3 is a good controll software, but it just proceses G code ???
How do you guys draw your designs and then convert them to said G code??
What do you draw in?? Autocad?? What do you do after?????

Thanks for any help!

[renie]

where to start?
there are lots of different cnc operating systems, most of them use G-code but that does vary from machine to machine.
Fanuc operating system i would say is the most popular and easiest to learn

software wise you have a large choice Solidworks and Inventor seem to be the most popular choice for 3D work.

as for CadCam there are lots solidworks has a plugin which is quite good, theres edgecam mastercam etc etc
I use Onecnc which is a cracking program, but it all depends what u want i would hit the cnc forums :)

[redlaser666]

where to start?
there are lots of different cnc operating systems, most of them use G-code but that does vary from machine to machine.
Fanuc operating system i would say is the most popular and easiest to learn

software wise you have a large choice Solidworks and Inventor seem to be the most popular choice for 3D work.

as for CadCam there are lots solidworks has a plugin which is quite good, theres edgecam mastercam etc etc
I use Onecnc which is a cracking program, but it all depends what u want i would hit the cnc forums :)

Ok so if im getting this right this is the stuff i would need:
- Solidworks to draw the part
- Solidworks plug in to convert the drawing to code
- Machine operationg system to run the code and make the part

What is a "cracking program" ???

[renie]

Ok so if im getting this right this is the stuff i would need:
- Solidworks to draw the part
- Solidworks plug in to convert the drawing to code
- Machine operationg system to run the code and make the part

What is a "cracking program" ???

Pretty much though some cadcam programs can do 3D modellling too :)


Im over the pond.... "Cracking" is a British slang word for "Good" :)

[redlaser666]

Thanks for your input. I did see the Onecnc website and it look to be a really nice and able to do both the drawing part as well as simulate the tool path. Can it also drive the machine itself?
Lastly is the matter of cost, being this is not going to a production machine. do you know how much does the license cost?

[renie]

Thats the expensive bit

Not sure on prices exactly but somewhere in the region of:

Solidworks $6-8000
Onecnc $4-5000

you may be able to get these cheaper

The cadcam software will give you g-code which your machine control reads.
i.e i pressume MACH3 will proceses G code and send the information to your axis etc etc

personally ive not used it as the cnc machines i use are all built in.

[OPBN]

Thats the expensive bit

Not sure on prices exactly but somewhere in the region of:

Solidworks $6-8000
Onecnc $4-5000
.
And people wonder why milling services using CNC are so expensive....

[OneSelfLost]

I used to build CNC machines at my last job (and other crazy robots with lasers!)

We used Solidworks, Mach3 and a SmoothStepper

http://www.warp9td.com/

[y0da900]

I'm doing a CNC conversion at the moment too. Some good deals to be had on ebay that have Mach3 and Bobcad V21 bundled with a Gecko driver and 3 or 4 steppers.

[athomas]

Mach 3 is one of the nicest cnc operating systems that you can get and is better than a lot of systems in a much higher price range. The free version is fully functional with all the bells and whistles of the full version except the number of code lines are limited. You just have to do the work in batches. The number of lines of code is quite a bit though. The fully licensed version isn't that much to spend if you don't want to worry about code limitations.

You can get a few nice 3D drawing packages that aren't very expensive or are free. Alibre is a nice package and is available for free. Their pro versions come on sale for half price all the time if you want more. Some even have the cam software built in.

The CAM software is the most expensive part of the cad-cam milling cost. It is the brains that converts the drawing to G-code so the controller can read it and run the mill. There are free ones or less expensive ones out there, but they don't work really well, especially if you want 3D. For 2D or 2.5D some work fine.

One of the biggest mistakes people make when constructing a cnc mill/lathe is that they go for power over speed. Most of the aftermarket stepper motors are plenty powerful for not that much money. Use the proper lead screw for you setup. I would prefer a 5 turns to 1 inch ratio over a 20 turns to 1 inch ratio. For most small setups it will allow you to keep your motors working in the most optimum speed range without skipping steps. However, most small setups come with 20 turn ratios because they ship with tiny little motors if you get the cnc upgrade.

[redlaser666]

Mach 3 is one of the nicest cnc operating systems that you can get and is better than a lot of systems in a much higher price range...

You have been of much help sir!

I have not decided on how I am going to build the machine just yet since I need to learn about all the software involved first.
For sure I will use Mach3, and I will look into the 3d modeling software but seems solidworks is a common one so I may go for that.

What options are there for the CAM? Cheap for 2.5d may work for my intended aplications (mostly mouting adapters and other mostly flat things) but any sugestions for a good one that doesnt break the bank might do as well.

[renie]

you can get some free cam software not sure what its like?
Try google ? :)

[redlaser666]

I think I will use Bobcad for the CAD/CAM.
I found the ebay reseller that sells the steppers and software that y0da900 was mentioning. The kit I saw was for 3 steppers and both Mach3 and Bobcad for $550.

[y0da900]

Yeah, that's the package I got. Not just the steppers, but the Gecko G540 driver as well. A separate power supply is needed though - only electronic piece not included.

Gecko and software should be here tomorrow. They email a license file for Mach3 and send the license for Bobcad through the mail with the software. I've already gotten a call from Bobcad to help me get everything set up and to answer any questions I might have. Not a lot of use until I have the software ready to install, but a call from the actual software company was reassuring that it wasn't pirated (caller ID had the company name and the phone number listed on their site).

[redlaser666]

That is good to hear. I think I will go with that kit as well once I am ready to take the plunge. I will first need to get settled in my new duty station and then get myself a nice machine to convert.

[athomas]

One thing to consider is a 4th axis. That will allow you to put a rotary table on the mill and cut nice even cuts on circular/round objects. Even with 2.5D cam software, you can lay it out flat and cut it around a tube. You can cheat with 3 axis systems by using one of the other axis as the rotary but you lose some flexibility (its really only good for perfectly round pieces).

You want to keep the ability to use manual control. Make sure you get dual shaft motors (preferably with flats already cut) You can cut your own flats though with the mill, but definitely do cut the flats. You'll get your handles stuck on the ends of the motor shafts if you don't.

[redlaser666]

For my applications I will not need the 4th axis, but if its an available upgrade I may consider it for a future upgrade.

Why is keeping manual control important?
Do you normaly have to use the manual controls for something or is a just-in-case thing?

[athomas]

Sometimes it is just quicker/easier to set things up manually than it is with automated controls. Then, you can reference that point from your home switches for accurate automated control of your cuts. A jog controller works, but involves more tapping keys and checking position.

For example, if I don't have an accurate measurement for the position of a hole in a part and I want to guide the cutting head down inside that hole, I would far sooner run the head down manually and feel whether is is lined up rather than trust that it looks lined up and end up hitting an edge. I could use gauges and measuring devices, but that takes time and it could be a simple cut that I need to make quickly.

Most motors these days have the option of dual shaft for no additional cost. It is just a nice feature to have. You don't need to keep the handles on the shafts all the time if you don't want to.

[redlaser666]

I think the ebay kit comes with double shaft motors so when I do this I will keep all the sugestions in mind.
Thanks!

[y0da900]

After I ordered they sent me a message asking if I would prefer single shaft or dual, so they definitely give you the choice.

[redlaser666]

Cool! Looks like they offer just what I need then. Thanks for everyones input!