[tivoidethuong]

Hi! I want use AC 3 phase motor control by VFD. How many hp i need to cut steel?

[RotarySMP]

Sorry, you haven't provided enough information for anyone to give you a meaningful answer. What size tooling do you intend to use to make what size parts in what steel?

[lakeside]

also your spindle speed will need to be very low rpm

[tivoidethuong]

Thanks for your reply
i want build spindle sames Tormach PCNC 1100. Any have it. Take some pic of spindle motor.

[dkowalcz]

Rule of thumb for steel is 1 hp per cubic inch removed per minute.

Be aware that the shaft hp for a VFD controlled motor is only valid at the full load speed of the motor or above (1800 rpm or whatever). Less than that, and it's basically constant torque only.

[Mcgyver]

like dk said, power equates to removal rates and changes by material. a child can remove steel by hand (say with a file or engraver) so its not that its steel that is the constraint, its how fast you want to remove it. careful though, you can't scale the above rule of thumb or quickly the rest of the machine (rigidity) won't keep up!

[tivoidethuong]

my CNC machine speed max is 800mm per min, too slow uhu?

[tivoidethuong]

like dk said, power equates to removal rates and changes by material. a child can remove steel by hand (say with a file or engraver) so its not that its steel that is the constraint, its how fast you want to remove it. careful though, you can't scale the above rule of thumb or quickly the rest of the machine (rigidity) won't keep up!

thanks you. I know that power equates to removal rates and changes by material . But i want my machine can cut steel, or alium. I don't know how many RMP motor 3 phase can run?

[NC Cams]

Please provide more specific information as follows:

What thickness steel???

Full face cut (plunge) or simple light facing???

What grade of steel???

How hard is steel???

What size cutter (diameter) do you plan to use???

How many flutes???

What is cutter material???

How fast in ft/min or mm/min do you wish to cut???

These are just starter questions. If you don't know spindle size, thus bearing sizes, you may not have capacity/rigidity to do real heavy cutting.

Care to start over????

By the way, generally speaking, typical spindle motors for mills run from 1.5 to 2.5hp and some as large as 4-5hp.

If you can't answer quesions in sufficient detail, use about 2.5hp as a decent, "fits all" starting point. This much power should cut whatever you want to cut....

[mxtras]

I concur. You could get by with 1HP but 2HP would be more capable.

Scott

[tivoidethuong]

i want mill part same part on the background of www.bobcad.com.
May i connect direct moto saft to spindle saft or use belt?

[tivoidethuong]

some pic of part i preprair for my machine

[tivoidethuong]

and this is hardware

[RotarySMP]

Just note that round shaft material supported only at the end does not make a very rigid machine, and rigidity is everything when working with steel. The picture of the gantry mill you have included (Isn't this Jon Fettig's model?) showed linear bearings which is a much better approach.

Those ball screws look nice.

[dertsap]

if your using those steel rods for your slides , i don t think your going to be cutting steel at any heavy cut or speed ,if any cutting at all ,that looks like 3/4 and 1/2" or 19mm 12mm round bar am i correct , steel will destroy any tool if there is any kind of vibration ,or play anywhere

[tivoidethuong]

Please provide more specific information as follows:

What thickness steel???

Full face cut (plunge) or simple light facing???

What grade of steel???

How hard is steel???

What size cutter (diameter) do you plan to use???

How many flutes???

What is cutter material???

How fast in ft/min or mm/min do you wish to cut???

These are just starter questions. If you don't know spindle size, thus bearing sizes, you may not have capacity/rigidity to do real heavy cutting.

Care to start over????

By the way, generally speaking, typical spindle motors for mills run from 1.5 to 2.5hp and some as large as 4-5hp.

If you can't answer quesions in sufficient detail, use about 2.5hp as a decent, "fits all" starting point. This much power should cut whatever you want to cut....

i hope my machine can mill same part in the pic

[RotarySMP]

Is this a troll thread? That looks like an aluminium aviation fitting.

If you are serious, then no, a little machine with the round shaft ways is not going to be able to hog this out. No way. Sorry!

[tivoidethuong]

RotarySMP, i think it was weld, the round shaft with ball linear not good for cnc machine??. i see alot comerical machine use it, but this is wood router machine. May be heavy machine use linear rail???

[tivoidethuong]

and how about this part? can i router it with 1HP ac motor?

[sdantonio]

since the thread originator doesn't seem to be filling in any of NCCams questions I thought I would take the oportunity to fill in a few and possible get a real answer (yeah, I'm hijacking the thread for one post... evil me).

In my case I am building 2 machines based on Joe's plans (http://cnczone.com/forums/showthread...light=joe+2006) The machine destined for metal work will have a 12in X 24in cutting surface, 270oz motors and a 2.25hp variable speed router (8000 to 30Krpm).

What thickness steel???

possibly as much as 0.5in.

Full face cut (plunge) or simple light facing???

Both

What grade of steel???

Standard hardware store mild steel (I will also be cutting a lot of aluminum, but that is a different endmil and different speeds, etc.)

How hard is steel???

Mild

What size cutter (diameter) do you plan to use???

mainly 0.25in

How many flutes???

per your recomendation

What is cutter material???

solid carbide (could use TIN if you think it would be better)

How fast in ft/min or mm/min do you wish to cut???

As per your recomendations.