New member seeking advice

[JAZZCNC]

Hi Rob and welcome.

Regards software it basicly goes like this. Parts are drawn in CAD then brought into CAM software which produces a file that gets loaded into the control software which drives the CNC machine.
CAM is where you define cutting stratagies called toolpaths, the paths are defined from your Cad drawing or model.
There are different stratagies depending on operation to be carried out IE: Profileing toolpaths, drilling, pocketing, roughing paths for quick stock removal, finishing paths etc. There are basicly 2 types of machineing 2D & 3D each with there own set of cutting stratagies(toolpaths) thou often you'll see 2.5D mentioned which is essentially multi level 2D using just 2 axis simultanously true 3D use's 3 or more Axis at same time.

You define toolpaths by selecting areas lines, holes etc or surfaces or full models if 3D from the CAD drawing then assign parameters such as cutting tool, speeds/feeds, direction of cut (climb milling etc) the options available will depend on type of stratagie selected.
Then the Cam software generates a G-Code file that you load into the control software which then follows the instructions.

The control software does nothing more than translate the G-code file into movement telling the motors how far and in which direction to travel and perform or monitor the actions of the machine using I/O's (inputs & ouput) signals.
These signals can be outputs to turn on external devices like spindles, vacuum, etc even the kettle if you so desire.!! Often outputs will be triggered using special codes contained within the G-code file but can easily be triggered by other actions like inputs, all this is configurable within the control software.
Typical inputs are E-stops, limit switchs, home switch's but again could be anything from a switch to a light sensor to a button again all setup and monitored within the control software.

Now regards CAD &CAM there is software that incorparates both CAD/CAM in one package which often helps makes things easier and gel better but it's not required just more conveniant.
To be honest CAD/CAM is a funny area and which software or package to use will depend greatly on what you intended to do with the machine.! Even then it's not always clear cut and you may find you end up using more than one package.?
I for instance use one package mainly for 2D stuff because it's quick and easy and another for 3D or V carving because that provides better cutting stratigies, both will do the same 2D/3D but one does some things better or easier than the other.
Often it's a personal thing as well because you just can't get on with it's interface or how it works.!!

Regards the motors, drives a basic run down goes like this.!

From the PC parallel port goes a signal cable to a Breakout board (BOB), this BOB takes the signals and redistributes them to defined pins, each pin then gets used as either an input or output thats becomes under the control softwares command.

Outputs are used for things like motor direction, step amount, as well as for controlling things like spindles etc. Same goes for inputs which are usually things like E-stop etc There are a limited amount of I/O's dictated by the parallel ports 25pins of which only 17 are available 12 outputs 5 inputs.

These I/O's are arranged on the BOB to perform different functions IE pin 2 & 3 will control the Step count and Direction for the X axis motor, 4 & 5 Y axis and so on upto the BOB's axis limit usualy 4 some times 5. Any spare are used for turning on spindles or what ever you assign it to do, often the BOB will have a relay connected to an output thats used to safely control high power devices like spindles.

From these output pins signal wires goto each drives signal terminal, 1 for step count 1 for direction, 1 drive per axis. There will also be a power cable from a separate PSU that goes to each drive, Each drive shares the same PSU and this will usually be sized to match the drives MAX voltage and Amp requirements.
Then from the drives come cables that go to the motors to power and perform the movements.

Also from on the BOB there are input connections that get connected to things like E-stops, limit switchs etc which the control software then monitors and if the pin state changes it performs an action IE: stopping the motors if E-stop condition is reported.

So basicly that's it in a nut shell.

You need:
BOB . . . . . . . . . . . . . to distribute signals
Drives (1 per axis) . . . to control motors
Motors. . . . . . . . . .. .to Errrr. . . move . .:)
PSU . . . . . . . . . .. . . to power drives which power motors
Small PSU. . . . . . . . . .to power BOB, some times can be taken form drive PSU depending on BOB

The size of motors/drives and PSU will depend on factors like machine size and mass it's going to move and best left untill you have arrived at a final machine design and decided on other components like type of linear rails, whether it will use ballscrews, timing belts ,threaded rod, Rack&pinion etc all of which play a role in motor/drive/PSU sizing and selection.

On this note can I strongly steer you away from building using MDF and if you do plan building look to stronger materials like steel and Aluminium. It will workout cheaper in the long run with far less stress belive me.!!

Anyway Rob I think that should give you enough to chew on and don't hesitate to ask if your unsure about anything. . . Enjoy.!!