basic questions about CAD and CAM...

[max90272]

HI THERE,

I am a CNC hobbyist. In fact I am still finishing fabricating my machine as we speak so I am very new at all this. I am using Kcam, although it is been only a few weeks, I find it really good.
Forgive my ignorance, but I have a really basic question in regards to CAD and CAM....

KCAM imports Gcodes and make the mill follow them and thus cut material right??... How do you generate gcodes.... Is that what the CAD softwares do? For instance if I want to make a part, would i just design it in a CAD software and export it as a gcode into KCAM? If so, what CAD software would you recommend for hobbyist who are just kinda "messing around" with their home made CNCs? Something easy to learn, decent and cheap...

I also have a question in regards to spindle set up. HOw do you set up the spindle with the software and the parralle pins? I have an AC motor that makes my spindle turns with the help of a belt. I have just a simple on/off switch for it, but started noticing that KCAM offers some spindle options such as CW and CCW as well as ON/OFF, through the use of one of the parrarel pins. How would i set that up? Do i need a controller specifically for the spindle motor before i can set it up in KCAM?



thank you for all your help
MAX

[jalessi]

Max,

There are several ways to turn the spindle on or off, a simple method would be with a solid state relay connected to your breakout board.

In order to control the speed of the spindle through software a VFD would be a good choice.

Welcome to the Zone

Jeff Alessi

[max90272]

Jeff,
Thanks a lot for the quick response.
Are you by any chance the famous/talented motocross racer #801, brother of Mike???? (google him/youself, you will know what i mean)

Anyways, i wonder if you would be kind enough to send me a link of a solid switch relay (remeber I am using an AC motor) that I could use with perhaps some instructions on the wiring (sorry, i am just starting out).

The same for the VFD... What the heck is that??? A link to one would be greatly appreciated.

THANKS AGAIN JEFF

[ImanCarrot]

Your CAD program is used to make a drawing (Computer Aided Design).

Your then import this into your CAM program (Computer Aided Manufacturing).

You set things like your tool diameter, speeds and feeds in your CAM software (turn the coolant on etc) and the CAM software reads your CAD drawing and figures out where to send the tool.

You the hit the Post Process button and the CAM software generates the G-Code for your machine (each machine has a different Post Processor cos they mostly have different G-Codes so you need the right Post Processor for your machine).

You then take the G-Code file to your machine by floppy or direct transfer.

Upload the G-Code to your machine, dry run it with the tool well away from any metal to make sure you're not gonna ramp into the machine table, then cut some parts

[jalessi]

Solid state relay info:

http://tinyurl.com/4ywwvo

http://cnc4pc.com/Tech_Docs/C8-AC_RELAY_Manual_Rev2.pdf

VFD Wiki:

http://en.wikipedia.org/wiki/Variable-frequency_drive

I know the Alessi Motocross brothers, however I don't ride Motocross.

Jeff...

[max90272]

THANKS GUYS, that is very useful.

As far as for controlling the speed of the spindle, you mentioned using a VFD as per your link. Could I just use a regular dimmer switch like we use in homes for lights?

One more thing in regards to spindle speed... Is the CAM software supposed to control the speed or is it completely separate from it?

thanks again,
you guys are great teachers.

MAX

[ImanCarrot]

The CAM software should control the spindle speed, but on my machine (and I suppose many others) it doesn't. I have to manualy adjust the spindle speed.

[jalessi]

Max,

Are you using Mach3, if so it has provisions for spindle speed control, however without a VFD or some other method of interfacing the spindle to the computer it wont be of any use for spindle control.

I wont comment on the use of a dimmer switch to control a ac motor because there are far to many variables that may cause problems.

Jeff...

[max90272]

Jeff,
Actually I am using KCAM. Somehow i think i cannot control the speed of the spindle with that software but i may be wrong.
thanks again

[jalessi]

It will support a relay to turn it on and off.

Supported M Codes
M Code Description
M00 Program Stop
M01 Optional Program Stop
M02 Program End
M03 Engage Spindle Relay
M04 Engage Spindle Relay
M05 Disengage Spindle Relay
M06 Tool Change
M07 Mist Coolant On
M08 Flood Coolant On
M09 Mist and Flood Coolant On
M13 Engage Spindle and Coolant
M30 Program End and Reset
M60 Program Stop
M98 Call Macro subroutine

Jeff...