Looking to get started with CNC...

[alank2]

Hi,

I've looked through the forum listing and I don't see one that is a catch all forum for beginners. If this isn't the right one, please feel free to move my post to the correct one.

I've been cutting a plastic enclosure (1599HBK made by hammondmfg, 8"x4"x1") by hand using some wooden forms with drill bushings, but I'd like to get into CNC. I drill 4 5/8" holes in the top and need a 1" x 6" rectangle. But the thing is I also need to cut a rectangle and have a round hole in the bottom edge and left edge as well. The left edge is going to be 8" above the "table" for example and I'm not sure how much of a problem this would be.

Do you guys have any directions I should start looking?

Thanks,

Alan

[jckstrthmghty]

First thing is budget. How much are you willing to spend? Are there any other projects you have in mind? If it's only the one then cnc is not the way to go. Be far cheaper and perhaps faster to make a few cutting jigs. What size of table, what kind of accuracy are you looking for.

[alank2]

Hi,

First thing is budget. How much are you willing to spend?

I saw the Zen Toolworks kit over at Amazon which is what peaked my interest in CNC. I've never really looked or read about them too much. To get one that would do the work I need, I can probably go 1K-1.5K, but less is more. One thing that would be important to me is durability.

Are there any other projects you have in mind? If it's only the one then cnc is not the way to go. Be far cheaper and perhaps faster to make a few cutting jigs.

I am a project type of guy and it always seems I'm wanting to work on a new one. So, while something that could machine the cases I need would be a great help, the ability to do machine other things over the long haul is what is exciting. I love a new hobby and CNC looks like an awesome one. One of my existing hobbies is electronics, microcontrollers, designing pcb's, so I am familiar with that already.

What size of table, what kind of accuracy are you looking for.

Don't even know where to begin. I do have wooden forms now that I am using with drill bushings. I use a trim router with these wooden forms to cut out any rectangular openings I need. I'm not sure what type of accuracy I have with these.

Thanks,

Alan

[IBBruin]

I've done the manual router bushings, templates and such and there is some degree of satisfaction with that. But I LOVE drawing in AutoCAD, exporting a dxf into lazycam, opening up the gcode in Mach3, picking the multilayer wizard in Mach3 and cutting an exact pattern in something using the machine/electronics/software I chose and put together. It's hard to describe it.

[flojor10]

Hi,



I saw the Zen Toolworks kit over at Amazon which is what peaked my interest in CNC. I've never really looked or read about them too much. To get one that would do the work I need, I can probably go 1K-1.5K, but less is more. One thing that would be important to me is durability.



I am a project type of guy and it always seems I'm wanting to work on a new one. So, while something that could machine the cases I need would be a great help, the ability to do machine other things over the long haul is what is exciting. I love a new hobby and CNC looks like an awesome one. One of my existing hobbies is electronics, microcontrollers, designing pcb's, so I am familiar with that already.



Don't even know where to begin. I do have wooden forms now that I am using with drill bushings. I use a trim router with these wooden forms to cut out any rectangular openings I need. I'm not sure what type of accuracy I have with these.

Thanks,

Alan

So if you are interested in Cnc would you built or buy? You could probably built a better machine than if you buy a kit. If your always working on projects and know a little bit about electronics your at a big advantage and a Cnc router is probably for you. Looking foward to seeing what happens
-George

[alank2]

Hi George,

So if you are interested in Cnc would you built or buy? You could probably built a better machine than if you buy a kit. If your always working on projects and know a little bit about electronics your at a big advantage and a Cnc router is probably for you. Looking foward to seeing what happens
-George

I am open minded on build vs kit, but leaning slightly towards kit. I think I have so much to learn. I've been doing some reading here and at Wikipedia.

Is G-code something that the computer would send to a control board? Or does a computer interpret G-code and translate it to lower level signals a control board needs?

What does CAD/CAM software do? What is the difference between CAD and CAM?

How does a CNC machine know where it is? Does it have to go home and use limit switches to know?

What is the difference between a stepper and a servo?

Given my needs to cut a plastic box on 3 sides, am I really looking at 3 distinct jobs, each with the surface I want to work up? With one surface up, it will be 8" tall, how can I deal with this?

What is the difference between a CNC mill and a CNC router?

Thanks for the help!

Alan

[jckstrthmghty]

I definitely think some reading/research is in order. First I think you should look at the joes2006 sub forum. That would fall into your budget and is an excellent machine available in a kit.

A bit higher would be a extrusion build like CNCrouterparts but those will take you out of the stated budget.

Then there's something like what I have. A jgro which can be built with hand tools which will be under your budget if you plan well.

As for a fully built machine, don't think that's feasible unless you are willing to double your budget.

If your cutting area is 8x11" or smaller look at microcarve's thread. Absolutely a smoking value for a super precise kit.

[louieatienza]

There are not too many routers on this forun that have enough Z travel to cut an object 8" on end. Usually this would be the domain of the mill.

You might want to look into a Taig or Sherline CNC mill, which are very durable and capable of machining hard metals as well. Of course you still need a way of fixturing your box to machine it on end.

As for knowing where the job is, well it is you that must tell (or show) the CNC where the orogin of your job is. You normally locate 0,0,0 whether it be the center or a corner of your wok, depending on how it's set up in your software. You could have the CNC probe the center or edge of your work, but you'd still need to get it in the proximity first.

I would do your job as three separate programs. This way, if you're doing a batch of boxes, you can do one face, before tearing apart your setup/fixture to do the next face.

For stepper vs servo check the mechanical section. Though for most applications here steppers are fine.

Routers and mills come in vavrious forms, and line between the two can blur. I would say routers have a larger table format, than mills. Routers are generally not used for milling hard metals, though there are commercial tables more than capable of doing so. The spindles on mills usually run slower, with more torque, though there are mill with high speed spindles.

[flojor10]

Hi George,



I am open minded on build vs kit, but leaning slightly towards kit. I think I have so much to learn. I've been doing some reading here and at Wikipedia.

Is G-code something that the computer would send to a control board? Or does a computer interpret G-code and translate it to lower level signals a control board needs?

What does CAD/CAM software do? What is the difference between CAD and CAM?

How does a CNC machine know where it is? Does it have to go home and use limit switches to know?

What is the difference between a stepper and a servo?

Given my needs to cut a plastic box on 3 sides, am I really looking at 3 distinct jobs, each with the surface I want to work up? With one surface up, it will be 8" tall, how can I deal with this?

What is the difference between a CNC mill and a CNC router?

Thanks for the help!

Alan

G code is made in you cam software and then sent to you post processor(mach 3). Then signals are sent to your motor driver board. Your motor driver amplifies the signal so it can moves the motors.


CAD software stands for computer aided design, you use it to make a solid model of what your going to cut. Cam is Computer aided machining, you use this to create toolpaths from the design made in the CAD software.

You don't need limit switches or touch plates, if you don't mind you could visually zero the axis's.

Servos are more expensive and usually aren't used in hobby Cnc. But they are more accurate than stepper motors and more powerful.

To cut a 8" high box you need to have a long and sturdy z axis. You could also make a fixture that held the piece you are cutting below the table so you wouldn't need a long z axis.

A Cnc mill is meant mostly for ferrous metals and its spindle has slower speeds with more torque. A Cnc router is used more for wood, plastics, and aluminum cutting.

Sorry for the bad grammar, I was writing in a rush. If you have any more questions feel free to ask.

-George

[alank2]

Hi,

You could also make a fixture that held the piece you are cutting below the table so you wouldn't need a long z axis.

I was thinking about this direction as well.

Thanks for all the information everyone, I'll get to some reading!!

Alan

[arizonavideo]

The micro carve would work but for the 6" box if you do a lot of them then you could cut a hole in the table or make the Z travel longer.

What do you put in the box?

[alank2]

Hi,

The micro carve would work but for the 6" box if you do a lot of them then you could cut a hole in the table or make the Z travel longer.

I emailed John of microcarve and he even send me a BMP of how it could be done!

What do you put in the box?

Here is what I build : SA Development Press Monitor

It is a monitor for ammunition reloading presses. You can't see the bottom or left machining, but here is the face.



Can you cut labels with CNC too? What about the 5/16" holes? I usually use a punch for this and it is a pain to clean up the hole with an xacto... I was thinking if you could press a label between two thin wood layers could it be cut with a spindle?

Thanks,

Alan