A little confused

[Cold Fusion]

Alright, I've been reading all about the software side of cnc and I think I'm confused I know that everything starts as Cad, which I can make myself easily. Then it goes into a cam program? After the cam program does it go to a program like Mach1? Is it possible to skip the cam program and go straight to Mach1 with an Iges or Step? Also, how do I do drill cycles? Here are all the bits needed in one run of chassis. Carbide Cutter, 1/8 drill bit, 5/32 drill bit, 3/16 drill bit, end mill, and countersinking bit. I know that the more expensive Cam programs have all the features to do this, but I can't afford it. Sorry for the ignorance but I need someone to someone to lay it out for me

[turkgeltz]

After you've drawn it in cad, you use the cam software to toolpath it and convert it in to g- code (machine language). Then you use the software like Mach1 to co-ordinate it with the hardware on the machine(motors and controller).

[Scott_bob]

with a good CAM system, who needs a CAD system.

On the subject of lowest cost approach to CNC mfg:

As far as im concerned the point of a CAD system is to design your part.

But, the CAD data is usless to a CNC machine.
CAM systems talk CNC language, CAD systems do not.
So, Eliminate the CAD system (for entry level Design/Mfg).
You practically can't do much CNC programming without CAM.

There are some very good CAM systems that will prolly do everything you need to do...

Regards,
Scott_bob

[ger21]

Those CAM systems are probably way more than he wants to spend, too. I posted a link the other day to a free CAD program, Intellicad. This will let you save you're files as .dxf's. I believe Mach1/2 can convert you're .dxf files to g-code. You can also use ACE converter to convert .dxf's to g-code, which is also free. Available from http://www/dakeng.com. With all those different size holes, the easiest thing would be to use a cutter no bigger than the smallest hole and mill all the holes with the same tool you're cutting out your parts. It would probably be easiest to countersink the holes on a drill press while the next chassis is being run. Otherwise, you'll be spending more time changing tools than making parts.

Gerry

[Cold Fusion]

Ok, I've got all my Iges chassis files converted to Dxf. I have decided to drill all the holes with a 1/8 bit then go back and enlarge and countersink with my drill press. Now I have three problems left.

1: I need to make a 1/8 deep pocket in the chassis

2: I need to be able to switch the drill bit with a routing bit.

3: I need to have 6-8 chassis per sheet. Can I get that done in G code?

I can not afford to buy a fancy cam system right now. Someone on the boards offered to make my G code for me for a small price. I like the idea of this until I can do it myself. If it doesn't work out with him is there anyone else who wants to make some money generating code for me? I would have at least 7 jobs to start with and probably 10 more later on.

Btw, which do you prefer, Mach2 or Master5?


Here is a picture of the chassis I do.

[buscht]

Hi Cold Fusion, It looks to me that you don't have any problems just possibilities.

First, reread Ger21's post carefully, I think that his idea about using the smallest router bit and routing out the larger holes is a very good way to do this.

You should not have to do any hand work on these parts other than maybe the countersink. I am assuming that they are 3/8" or less in total thickness and you can route the whole thing with a 1/8" diameter cutter.

1. Your pockets are easily cut, just set the Z height correctly and step the cutter over many times.

2. Switching out a drill and router bit. You may want to take a look at www.precisecut.com. They have bits with collars on them. That way when you exchange bits they allways go into the collet the same distance. This is vital for your pocketing. You need to know where your Z depth is located.

I noticed from various postings that you want to make your own machine. One advantage of this is that you can make it the way you want. There is no law saying that you can only have one router in the Z axis. I think that MACH 2 can handle at least 6 axises.

Make two Z axises and mount them right next to each other. One would be the drill and one would be the router. Under program control you can have your cake and eat it too. Let's say that you have 6 inches between the two centerlines of the Z axis's, then you just have to make sure to add an additional 6" to the appropriate X or Y axis. When programing, you just use the fixture offset to set the 6" offset.

This would give you a true production machine for only a couple of hundred more dollars.

3. Can the G code make 6-8 parts per sheet.? No problem! You have to look at this differently. How big is your sheet? Can get that big of a sheet on your router?

You show 4 parts in your photo. Is this the entire variety of production pieces? and are they always produced in these quantities? Meaning kits of one each?

Depending upon your answers to these questions will determine how you go about nesting the parts on a sheet.

Let's assume that you only make these 4 parts, but they are not related. I would then take the geometry for one of them (in CAD) and lay it out on your sheet. Copy this and put as many as you can on the sheet.

Save this whole thing as a DXF and it becomes the program. The router or G code doesn't know or care if this is one part or 10,000 parts. Its totally up to you as how you want to make them.

You said that you cannot afford a fancy CAM machine. Again, no problem. http://www.artofcnc.ca/Mach1.html

He states that MACH1 has a direct DXF import feature. I don't know how it works, but it might just be a matter of calling out layer names in your DXF file.

Another cheap option is to simply write the G code by hand. Your parts are very simple and if you learn the G code you can simply type the instructions in NOTEPAD and save the file as a TXT file.

This method is very error prone and I wouldn't want to do it all the time, but the cost is right.

Having someone else right the code might work, but I think that you both would have to be pretty good at reading each other's mind. Either that or your directions to him would have to be so specific and your understanding of your needs so good as to give clear directions that you will have the skills to do this yourself.

T

[Cold Fusion]

First, I am building my own cnc router. A couple of people have told me to start small on my first machine. That's good advice for a casual hobbiest who might not finish a complicated machine. But I view this as something I have to have. I spend so much on machining these parts that if I had started earlier I could have payed for the whole router. Here are the the specs I want right now:

All Aluminum gauntry and frame
1.25 Thomson Linear Rails and Bearings
Porter Cable Router
250oz or higher steppers
7amp 3 axis controller (maybe a 4 axis 6 amp)
6 inch aluminum z axis
42x24x workbed


With this size workbed I could get about 13 chassis per sheet.



Is the only advantage of dual Z axis speed? I don't really care if if it takes 20 minutes longer. After all, it will be in my garage and probably be working only 10 hours a month.

[balsaman]

How are you doing the pockets right now?

Those parts will be easy to program. Looks like simple 2D drawings are all you need, then convert with Ace Converter.

I would use a 1/8" endmill and have it cut the holes to whatever diameter you want. No need to redrill.

Turbocnc does support tool changes if you must change tools. It's best (a must) to have fixed tool lengths then tho.

Mach2 is better. It is the latest release.

Turbocnc version 4 is almost ready and will be VERY good. I am a beta tester. Cheaper too.

Eric

[steveald]

Hi,

In regards to changing from drill bit to router bit...why? I just use a 1/8" endmill for holes smaller than 1/4". For plastic, you could use one 1/8" bit for everything except countersinking (you were going to do that on a drill press anyway) so no toolchange required. I think most controller software will import DXF, just remember that you need to create a DXF toolpath, not a DXF outline of the part. (use CAD to offset the part outline by 0.0625" for a 1/8" bit, and save the offset lines to import into controller) It looks like you want to cut the same part many times, so it won't be a real time waster to spend the extra time to create the G-Code, you could even do it manually and use something like the Flashcut CNC demo program to verify it. You can even use the Flashcut demo to create G-Code from DXF, edit it and verify (you just can't control your machine with it without the signal generator.) This route might violate the Flashcut demo software license, you'll have to look int that yourself, but my point is there are ways to avoid purchasing expensive CAM software. My parents bought a house for less than a MasterCAM license, it was a long time ago mind you

Good luck, and Happy New Year,

Steve

[ger21]

I think the best thing to do is spend more time reading and learning how how the different controllers and software packages work. Learn how to write g-code manually, so that you understand what's going on when you're parts are'nt being cut write. Download the Mach 2 manual from http://www.artofcnc.ca and read every page in it. Then read it again. It's VERY informative. Once you have a good handle on the processes involved, download the free CAD software I posted here:

http://www.arch.adelaide.edu.au/~twyeld/ftp/intellicad/

Then learn how to draw the toolpaths you're going to need for you're parts and use ACE, or the Flashcut DEmo, or whatever else is out there to write your g-code.

If you spend some time up front learning exactly how everything works, it will save you from making a lot of scrap when you're machine is done.

Gerry

[Cold Fusion]

The manual doesn't work. Could you email it?

[HuFlungDung]

Cold Fusion,

Yes, don't spend a fortune on software to cut parts like those. Bobcad (or equivalent) would suffice, and is not free, but at least it has the basics of a cadcam system. It will help get you on the right footing to branch out into other fancier stuff later on, should you need to.

I've never tried the route that a lot of the guys are recommending with dxf file convertors, but you'd still need to edit in a lot of stuff to make a program (I guess). At least something like Bobcad has the toolup/tooldown, and various other gcode macros handy to insert.