[knightridar]

Hi Everyone,

I am working on a project that requires a CNC with 4 axes of movement and a 200w fiber laser has to be mounted to it.

It will be used to cut features in stainless steel tubes.

Below is a link to the preferred method of movement I need.

http://www.youtube.com/watch#!v=EMDq...eature=related

I have experience with G-code and CAD/CAM. However, I don't have experience with the controls of a CNC (i.e. servo motors, controller cards, hardware interface, etc)

Are there any good books/websites out there for the items mentioned above?

One option is to create a CNC like machine with 4 axes from scratch. i.e. using a gantry table or building 4 axis of movement via linear slides and a rotary stage (capable of product feed through).

Our other alternative is to use a HAAS vertical machining center ( TM-1 SERIES) and hook up the laser via a serial cable interface. A 4th axis will be added on to it by HAAS to rotate the stainless steel tubes. We are also considering to get a bar feeder to hook up to VMC so that an operator doesn't need to be present to load stock tubing (12ft) into the machine.

We need tolerances within +/- .001, and the main concern is to get this laser to turn on and off at the right time and interface with the CNC.

Any idea if the vertical machine center has any logic control connections.
(I am having trouble finding the types of connections available on CNCs)
I know they have serial port connections, but how do you interface with them?

The laser has the following connections:

ttl trigger/gate
pl5 - machine interface
serial port
usb port
ethernet port
sk11 - customer interlocks
sk10 - remote control boxx

THANKS!

[Tweakie]

Hi knightridar,

I don't mean to be disrespectful here but you are talking about a mega bucks project, (this is no hobby bench-top CNC) and you say that you don't have any experience with the electrical / mechanical side of things.

I think you would be well advised to look for someone with the electrical / mechanical CNC knowledge otherwise you could make (or be talked into) some pretty costly mistakes.

Tweakie.

[knightridar]

Hi, well any response is better than no response.
Thanks!

I agree. Well I am still keen on learning the controls of a cnc.
i.e. servo motors, building your own cnc.

It would be nice to start building my own cnc as hobby and plus it would help in terms of building my knowledge of cncs.

Any good books out there?

I don't like the few I saw on Amazon.

[ame="http://www.amazon.com/Build-Your-Machine-Technology-Action/dp/1430224894/ref=sr_1_12?ie=UTF8&s=books&qid=1282332554&sr=8-12"]Amazon.com: Build Your Own CNC Machine (Technology in Action)…[/ame]

But then again I previewed this one and the table of contents looks thorough
however, I don't want to assume that alone will make it a good book.

[Konstantin]

Imho the best book on hobby cnc is this forum.
For the tolerances you require I think you will need to spend the money on a professional machine.

So what is your situation exactly, what hardware do you already possess? A 200w laser head? What type of laser?

The connection types of a CNC.... hmmm ..... I guess you are talking about proprietary connectors like those in HAAS machines, if so then the only the manufacturer documentation will shed light on it.

As for the 98% of hobby cnc machines there is only one connector, the parallel port. Usually hobby laser cnc uses a pwm to control laser output, perhaps the laser head you have needs a proprietary controller.

As for general idea about cnc is this:
the gcode is sent over the parallel port in 2 pulses for the axis, a direction and a step, the motor drive will move the motor one step in the direction specified. There are some standalone controllers made with micro-controllers like Arduino but it is not widespread yet.

So for a simple cnc you need:
a.- motor drive (servo or stepper)
b.- motor (servo+encoder or stepper motor)
c.- break out board (connects the drive to lpt)
d.- some linear motion components (linear bearings and belts/screws)
Mix the above to meet your needs (amount of axises, table size, tolerances, etc)
e.- software to execute gcode (Mach, Turbocnc, EMC, etc)

[knightridar]

Hi,

it's a 200W fiber laser, which we are planning on getting. so we don't possess any hardware yet and I wouldn't want to at this point of the project either.

first we are checking to see how feasible this is.

From what I've researched, the A3200 controller from aerotech is popular for the laser applications.

However, I was assuming that most commercial CNCs have some type of PLC output/input capability.

http://www.machinemate.com/FullListCodes.htm

The website above has some interesting 300 series g-code for lasers.

I was considering to get a HAAS TL-2 and hook it up to a bar feeder from IEMCA, but I don't even know if this lathe is capable of taking bar feeders.
HAAS's website isn't descriptive enough about that.

Then we were going to mount the laser as a tool piece and have the spindle index.


two questions:

What do you mean by pwm?

What does lpt mean?

thanks! btw for the basic controls info.

[joe perry]

You know Knight, I'm learning ALOT building my own CNC by following the Reprap project. RepRapWiki PWM (if you haven't found out yet) is Pulse Width modulation. In my little brain's understanding, it's turning on and off an electric pulse at a specific rate. One of the functions that a reprap uses PWM for is heating up nichrome wire in the plastic extruder. The extruder controller sends these pulses to the nichrome wire at a specific rate. The higher the frequency of the pulses, the hotter the heater gets.
The machine you (might try) to design and build sounds exciting! Have you considered a screw machine? I work with Haas vf 2 and 4 VMC's but we don't have the function enabled that allows them to move an axis simultaneously with the 4th or 5th axis. I didn't know you could use a bar loader on a VMC. How would you move the Y axis with bar loader attached to the 4th axis?

[knightridar]

hi thanks for the response.

yeah definitely can't put in the bar feeder in the VMC at the moment.
ditched that idea as soon as i realized that the y-axis is moving along with table (chair) .

now i am considering building a bar feeder and have it integrate with a plc that acts along with a 4 axis cnc. the cnc will be custom. it will use a linear slide to push the bar and a 4th axis indexer.

definitely using a cnc ball screw.

check out k2cnc all. they got some nice machines. thanks again!