CNC Knee Mill: Model 3VK

Travel X=31" Y=14.5" Z=4" Table size 10" X 50" 2, 3 or 4 axis

Atrump's entry level CNC machine is stuffed with features that turn new CNC operators into part making machinist in the shortest possible time. Of course, for the accomplished CNC machinist this easy to use tool just makes his work load that much lighter. Every metalworking machine Atrump builds has been laser compensated to provide the best machine accuracy possible. Machines in Motion only quotes complete ready to use machinery. None of this "low ball pricing" served up with that last minute "list of options" needed to actually make your new machine useful. Click Here to download our 3KV quotation. We do our best to clearly spell out what is included with your new machine purchase. Page 2 is a list of machine & CNC control options. No surprises here. If your work requires a particular feature you can include it right up front. You can also purchase any of the control software options later when you do need it. No service call is required to upgrade your Centroid powered CNC machine. You can find more detailed information about each control option by Clicking Here.

Lower cost Open Bed Mills

Atrump's model ??FC milling machines include the quill style spindle. Sometimes it is desirable to have one mill that performs both manual operations and full 3 axis CNC programmable machining. Smaller models can be delivered with R8 taper or NTS#30 taper spindle nose most models come with a NTS#40 taper spindle as standard. The head on a FC model machine may resemble the type found on a typical knee mill, HOWEVER, these machines are built with specially engineered, oversized castings and quills. The B8FC uses a 7 1/2 horse power spindle motor.

Note:
A very nice feature of the Centroid controller is the way it handles the back gear on a quill type head. Atrump installs a back gear sensor switch and the control will automatically know when to reverse the spindle motor. Your M3 "spindle on" will always spin your tool in the clockwise direction. Also, the programmable spindle speed is recalculated for the different gear ratio.

The primary characteristic of Atrump's model ??EC machine is, each mill is built with a 40 taper, machining center style cartridge spindle. These spindles come with 2 pulley ratios, normal and high torque. Large diameter cutters like shell mills and face mills require a greater amount of torque, usually at lower speeds. Atrump mills have provided for this. Hogging steel bases can be handled well with this model. The 40 taper cartridge type spindle is much more durable than the quill style. If you are planning to place your machine into a production situation or heavy metal removal Atrump's EC version machines are a better choice.

OPEN BED MILLS (typically in stock)

With Manual quill	With cartridge spindle
E5FC Travel X=35" Y=18" Z=20" Table size 10" X 54" 5 H.P. 40 taper spindle	B3EC Travel X=31" Y=16" Z=20" Table size 10" X 50" 5 H.P. 40 taper spindle
E6FC Travel X=41.7" Y=22" Z=24" Table size 14" X 52" 6 H.P. 40 Taper spindle	E8EC Travel X=50" Y=22" Z=24" Table size 18" X 56.7" 10 H.P. 40 taper spindle
Other sizes available in 6 to 8 weeks. Built per your specifications.

DC Vs. AC Servo Motors

Often the question comes up:

"Should I order my machine with DC servo motors or the new AC brushless servos?"

The choice is easier than you might think.

DC servo motors have been around for decades. They are well proven and reliable. Out of a few hundred customer machines I replace less than one DC type servo motors each year.
These motors have more torque at feed rate speeds than the same sized AC servo motor.
Finally the cost of these simple motors is considerably less than a properly sized AC brushless servo motor.

AC brushless motors do have their place in modern machine building.

AC servo motors produce higher working speeds. This gives your machine quicker acceleration and faster rapid speeds. A feature that can be important in time sensitive applications.
The costs for AC brushless motors become much closer to that of the DC motor in the higher output sizes.
The overall size and weight of an AC brushless motor is considerably less than the same sized DC type servo.

Larger Atrump mills will come with AC brushless motors as standard equipment. The machines listed on this page all come standard with 29"/lbs. or 40 "/lbs. DC servo motors. If higher rapid speeds are justified for your application then we can build your new Atrump milling machine with AC brushless servos.