Industrial CNC Routers
& Gantry Routers

How accurate is a gantry milling machine of this class?

For the Kegema FKS 2513, the manufacturer states a positioning accuracy of ± 0.07 to 0.1 mm and a machining accuracy of ± 0.08 mm. That covers contour cutting, grooving and nested panel work. Based on these figures, the machine is not intended for fits in the range of a few hundredths of a millimetre.

These figures follow from how the machine is built:

• X and Y drive: helical rack and pinion. The angled tooth engagement spreads the load across more tooth flank than a straight-cut rack and therefore runs more smoothly.
• Gantry drive: four servo motors in total, two of them on the Y axis, so the gantry is driven on both sides rather than pushed from one.
• Z axis: Taiwanese TBI ball screw instead of a rack, since infeed in Z directly determines cutting depth.
• Guideways: 20 mm linear guides (Taiwan) on all axes.
• Reduction: Japanese Shimpo precision gearboxes on the servo axes.
• Frame: reinforced steel frame construction, with an automatic central lubrication system supplying the guideways to limit wear over the machine's service life.

The servo motors are Leadshine RAL AC units rated at 750 W each, distributed one on X, two on Y and one on Z.

What power supply and floor space does a gantry milling machine need?

The Kegema FKS 2513 runs on a 380 V three-phase supply. The manufacturer states a total connected load of 19.5 kW, split between the spindle, the vacuum pump, the dust extraction unit and the four servo motors, with the vacuum pump and spindle accounting for the largest share. Fusing should therefore be agreed with an electrician before delivery.

At around 1,250 kg gross, this is not a machine that gets moved around during production. The permitted operating range of -20 °C to +45 °C at 5 to 75 % relative humidity also covers unheated workshops. The twin-bag extraction unit needs its own space next to the machine, both for installation and for changing bags. Installation dimensions and the operating and maintenance clearances are not part of the data sheet and should be requested before delivery is scheduled.

What is this machine suited for, and what not?

The Kegema FKS 2513 is designed around flat workpieces: 200 mm of Z travel, hold-down by vacuum and T-slots, working feed up to 20 m/min and 30 m/min rapid traverse. That suits sheet material, contour cutting and nesting. For some jobs, however, the published specifications show it is not the right machine.

• Suited to: panel cutting and contour milling up to 1300 × 2500 mm, optionally up to 2000 × 4000 mm, plus 2D and 2.5D work with a repeating set of tools.
• Workpiece height limit: Z travel is 200 mm. After tool length and clamping, less usable height remains, so tall three-dimensional parts are outside its range.
• Tooling limit: ER32 with a maximum tool diameter of 20 mm. Larger cutter heads cannot be mounted.
• Tool change limit: the tool sensor is manual, so programs with many tool changes add operator time.
• Coolant limit: the data sheet lists no coolant system. Any work that requires flood or mist cooling has to be clarified beforehand.
• Accuracy limit: ± 0.08 mm machining accuracy. Tighter tolerances call for a different class of machine.

One point on hold-down: the smaller the individual part, the less surface area the vacuum has to act on. In that case the T-slots in the table take over the mechanical clamping.