Router vs. mill

Hi there,

I'm new to the world of CNCing and one thing I have been unable to figure out is, what is the difference between a CNC router and a CNC mill???

And also am I correct if I claim that a gantry is the "thing that holds the Z axis?

Tanks all

the way i understand it, a cnc router usually refers to a gantry style machine. the y and z, are moving on the x. the z moves up and down on the y, and they both move on the gantry which is driven by the x.

a cnc mill may be referred to a moving table type or a metal working mill style. like a knee mill, or a bridgport (search ebay for good pics). a sherline mini-mill could be considered a cnc-mill just on a small scale.

obviously this is what i have picked up- and i think i have the general idea of what everything is called- but there are those on this board that could probably give you the production history and all kinds of in depth knowledge of where and why the two styles diverge. so- this is all IMO

That and generally hundreds of pounds of difference with the mill being the heaviest...

A mill operates on torque, a router on RPM's.
Milling machines are mainly for cutting metal, although they will cut other materials. RPM's for a mill are usually around 3000-5000RPM.
Routers are generally for soft materials like wood and plastics. Routers operate at around 25000-30000RPM.
Milling machines are typically far more rigid and massive than routers.
colin

As others stated, routers cut wood and plastic, mills cut metal. Every other characteristic goes with the territory.

E.g. to cut a 1/2" slot in a piece of wood, you want your bit to run at ~20K RPM, vs. under 1000 RPM if cutting the same slot in steel.

Size is important as well. Plywood comes in 4' x 8' sheets, so many routers are at least that big. A small fraction of 1% of mills are that big.

As far as weight, many large routers weigh as much as 15000 lbs, so I wouldn't necessarily say that they're light duty by any means.

On the other hand a milling machine that will cut a 5' X 10' workpiece weighs about 90,000#

In the context of CNC'ing a router is a machine built to handle sheet goods. Contrary to what people have posted it is possible to use a high speed router on metal. Aluminum for the most part.

The term Mill is a catch all as you can have a number of different types of Mills for example Horizontal, Vertical, Planer, Multi Axis machining cneters and probably a few I've missed. Often these mills are out fitted for machining metal with low speed spindles and just as often with higher speed spindles. In fact many manufactures offer their machines with different spindle options depending on the material to be milled.

I suspect that the term router came from the fact that the "router" machines often replace manual labor doing the same thing. Also the machine may be very limited in what they can do, that is simple 2 or 3 axis stuff. Given that Planner and Gantry mills have existed for years that do the same thing that a router does. Part of the reasoning for the term router might also come form the light duty nature of the machines relative to a mill.

Dave

So would JRGO plans be good for doing metal parts.or is it more for wood?

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Originally Posted by ducattiman

So would JRGO plans be good for doing metal parts.or is it more for wood?

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Wood.

Hi !

I`m a noob in the forum and the cnc scene as well.
I`d like ask the same thing as Ugilten asked, and a few more.
I`d like to build a cnc mill machine , based the CNC_Router_jgro pdf file.
Can I mill with this type of router with simultanous 3 axis ? The difference between the mill and the router is a controller software/electronic ? and offcourse as you mentioned the spindle speed/torque.
I`d like to mill toy soldiers , and miniature scenery from 3d models.

Thanks everyone for a hopefully answer :)

I think your question is allready answered, cut it in wood, yes, in metal, no. A toy soldier is quite detailed, and when using a router in metal, the cutter tends to shatter. The software can be the same, ofcause pro. mills tend to have their own software, for the rest of us, most people uses mach3, both for retrofitted mills and for routers

To me:
Router - for cutting aluminum (soft metals), plastic, wood
Mill - for cutting anything a router can plus steel, titanium, hard metals.

There are just too may permutations of construction type to make a distinction based on configuration alone.

Thanks for the fast answer :)

I have to offer my own humble opinion on this.

When a machine is designed there are five primary considerations. Rigidity, precision, work envelope, function, cost and horsepower. Any machine is a compromise between these six considerations.

A milling machine is designed primarily for rigidity. This is so because they generally cut hard metals and need to produce precise parts that fit together well. There are exceptions of course, like portal mills which are designed to be able to make enourmous parts and machine them all over using 5 axis designs. Generally speaking though, mills are slow and very rigid with high horsepower for cutting hard stuff. Cost is a secondary consideration.

Routers are generally designed to maximize the work envelope for a given cost. This means they are more flimsy, but for a given cost they have a much much larger work envelope. This is OK because they also generally cut softer materials like wood and aluminum. That is the biggest difference as I see it.

Drawing the line between routers and milling machines would be very difficult.

Barry Young
Young Camera Company

Reviving this old thread. I am new to this site and CNC and would like to clarify regarding the difference again.

Since the difference between a Mill and a Router is basically rigidity and spindle speed/torque, can i assume that i can design CNC mill with a 'router-like' rigid gantry with a high torque spindle? Is there a difference between moving a work piece in X & Y axis ('mill-like') Vs moving the Y axis(gantry design).

I know this is an old thread but I'd like to know the differences from the accuracy stand point. Can a router achieve the same level of accuracy as a good router when machining plastics (i.e. Plexiglass)?

The acuracy is affected by components u use , if u use thk rails , ground ballscrew , then u get good acuracy 0.02 mm , if u use round rails , and chinese ballscrew ur acuracy is less about 0.1mm , but not big diference .