Clueless Noob Computerization?

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MCRIPPPer

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hey guys. i have a sieg SX2 mini mill and want to go cnc. i find milling rather tedious and i think i have put enough hours in on manual mode to move onto some computerization. :thumbsup2::rubbinghands:


im not too worried about the mechanical side. it should be no problem. but i am clueless in the software department but im pretty good with electrical hardware. i have the setup for programming PIC microcontrollers so i am able to make my own electronics, but i dont want to have to design the whole thing. i was looking at the planet CNC USB system because i could build one myself.

im not fully clear on how the whole thing works. i know i have stepper motors, and drivers for each motor, but then i guess there is a controller that tells each driver what to do? what other hardware is there to interface to the PC?? :thinking:

i want to use USB to communicate with the machine. i dont want to have to find a machine with parallel ports :panic:

so the software seems like its weird. it seems like some websites say i need a cad, a cam, and a control software. all of them cost 100 bucks. i know i need cad (unless i want to write Gcode directly :nervous:)


but then what happens after the CAD stage?
 
Really good questions.

First lets define the terms:

CAD = Computer Aided Drafting (software)

CAM = Computer Aided Manufacturing, converts CAD drawings to G-code. (software)

G-Code = Code that the Controller uses to drive the machine (software)

Controller = Converts the G-code into machine motion commands and monitors the progress (software and hardware)

Drive(s) = Takes the motion signals from the controller and outputs the proper speed and direction to the axis motors. (hardware)

Depending on the system, some of the above functions are combined into one platform. There is a bit more to it, but this is a high level overview.

There are controllers that will take a USB, serial, or Ethernet input.

From here, the sky is the limit.

There is CAD/CAM software that allows you to draw the part, then in the same software create the G-code from the drawing. But it is really two separate processes. It is possible to skip the CAM process, but it is tedious to manually write G-code from drawing dimensions, I know, I have done it many times.

I'll be happy to continue if you have questions, entire books have been written on this subject.
 
MCRIPPPer said:
hey guys. i have a sieg SX2 mini mill and want to go cnc. i find milling rather tedious and i think i have put enough hours in on manual mode to move onto some computerization. :thumbsup2::rubbinghands:


im not too worried about the mechanical side. it should be no problem. but i am clueless in the software department but im pretty good with electrical hardware. i have the setup for programming PIC microcontrollers so i am able to make my own electronics, but i dont want to have to design the whole thing. i was looking at the planet CNC USB system because i could build one myself.

im not fully clear on how the whole thing works. i know i have stepper motors, and drivers for each motor, but then i guess there is a controller that tells each driver what to do? what other hardware is there to interface to the PC?? :thinking:

i want to use USB to communicate with the machine. i dont want to have to find a machine with parallel ports :panic:

so the software seems like its weird. it seems like some websites say i need a cad, a cam, and a control software. all of them cost 100 bucks. i know i need cad (unless i want to write Gcode directly :nervous:)


but then what happens after the CAD stage?
Click to expand...

the most similar machine I used to what you are talking about building was a CNC sherline mill..it worked like this:

3 stepper motors, one for each axis

each stepper motor connects a a control "box" that had the driver electronics in it...

the driver electronics box connected to the computer using the parallel port

running on the computer was LinuxCNC...which basically takes the G code and converts it into pulses on the parallel port

LinuxCNC and Mach3 basically do the same thing..convert G code to hardware pulses for motors. LinuxCNC is free and very simple. Mach3 costs money and I think has more features, perhaps even stuff to generate simple G code for shapes or something.

So LinuxCNC and Mach3 would be considered "control" software.

So then, you need something to make the G code.

Thats where "CAM" (not CAD) software comes into play. Stuff like MeshCAM, Surfcam, CamBam, Camworks, etc..etc..range in price from free to $50k+. I would recommend MeshCam which is EXTREMELY basic, which you should outgrow in a few weeks and at that point I'd recommend CamBam or possible on of the free 2.5 axis packages like HSMworks or whatever they call it these days.

So CAM software takes in your CAD model and lets you make toolpaths for it. Yes, making toolpaths is complex enough (most of the time) that you need a whole other category of software for it.

So to make the CAD model, thats where you need CAD software. Solidworks, Alibre, Sketchup, etc... I am pretty sure there are some great free CAD software these days, I'd recommend sticking with parametric modelers like Solidworks or similar, if you are serious about machining in the long run.
 
so the hard part for me is knowing what combo of things will actually function. the steppers and drivers are not an issue really. it seems like most of the controller hardware is designed to work with a specific software, like mach3 or whatever. so why do we need CAM again? doesnt the CAD output DXF and doesnt mach 3 read DXF?
 
MCRIPPPer said:
so the hard part for me is knowing what combo of things will actually function. the steppers and drivers are not an issue really. it seems like most of the controller hardware is designed to work with a specific software, like mach3 or whatever. so why do we need CAM again? doesnt the CAD output DXF and doesnt mach 3 read DXF?
Click to expand...

Let's start with the last question first. No, Mach3 nor any other controller software that I know of will directly read an output file from any CAD program, DXF or otherwise. You need the the CAM program to to translate the CAD output file into toolpaths, and then Post Process the tool paths into G-code that the controller can read.

Mach3 is probably one of the most widely use controller software packages and therefore many hobby type controllers are designed to work with Mach3. There are a number that will work with LinuxCNC. There are other controller software/hardware packages that require their own proprietary software. For instance my CNC controller software is free, but will only work with Galil hardware, unfortunately that hardware is out of the price range of many hobbyists.

The controller software normally does all of the motion path determination, based on the G-code, and provides a user interface.
 
MCRIPPPer said:
ok. anyone tried this one?

http://www.planet-cnc.com/index.php?page=software

it seems like a good solution. i would only need 2 software systems for this right?
Click to expand...

I read through the specs on that software and I'm not sure it will actually generate tool paths (CAM Functionality). It says you can import tool paths from various software, the specs reference a number of third party CAM packages. It does look like it does convert DXF to G-code, but the DXF would have the tool paths already generated. As far as the controller functionality, it will probably work OK. I have no personal knowledge of this software or the hardware.
 
Just a few more thoughts on hobby class CNC systems in general. One thing to consider is the support available for the system you choose. There are a lot of systems out there, but in general when getting started I would stick with the those that have wide market acceptance, and thus better documentation and help availability.

There are many CAD programs available, some free, some low cost, and then of course the high end stuff. This is also true of the CAM and controller software.

This is not an endorsement of any of the following:

Design Spark Mechanical is a free CAD program from Allied Electronics. It will generate both 2D and 3D models. Well written, and a lot of features normally only found in the higher end solid modeling software. Good documentation and help videos. It will also helpfully direct you to Allied products when it can.

AutoDesk has some free (I think) cloud based CAD and CAM software. Their CAM360 software has Post Processors for several different controllers, including Mach3. Documentation and support is pretty good.

CamBam is one of the more popular CAM programs, and it also has reasonable, if a bit clunky, CAD functionality. The download is free, and it will give you 40 full featured evaluation sessions. I'm not sure what happens after the evaluation sessions have been used. There are a number of user forums available.

Mach3 is probably the most used controller software, and there are a lot of free add on plug-ins for various controller hardware. The download is free, and is full featured for some period of time, then it reverts to a limited number of G-code lines (about 500 lines I think) and continues to operate. There is an amazing amount of support for Mach3 through their documentation, and many user forums. There is a lot of controller hardware available that will accept a USB connection.

LinuxCNC is free, and there are a quite a few controller hardware packages that are compatible, and there are a number of user groups and forums available.

There are a number of others available, but they are somewhat less popular, and thus do not have as much support available. My apologies to any vendors that I missed here.
 
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