Lunyee 4040 Pro

About the Machine

The 4040 Pro is a compact all-metal CNC router with a 400 x 400 x 90 mm working area, a 100W spindle (0 to 10,000 RPM), and Nema 17 stepper motors (1.68 A, 0.55 Nm torque). Its Z-axis rides on dual HG15 linear guides with a 1204 ball screw.

Cut Settings on this Machine

Every cut starts with one formula: Feed Rate = Spindle Speed (RPM) x Chip Load x Number of Cutting Edges (flutes). Chip load is the thickness of material each cutting edge removes in one revolution of the bit. This number comes from the manufacturer of the bit, which publishes a chip-load chart for each bit diameter and material. Look up your exact bit and material, start from the middle of the published range, and you have the third number in the formula. The chart below shows the recommended spindle speed for each material and bit type.

The 4040 Pro's 100W spindle tops out at 10,000 RPM, below most of the chart, and it has the least power of Lunyee's router lineup. A small spindle like this loses torque fast under load, so leave it near its top speed for everything and control the cut with feed rate. Depth per pass is where the machine itself matters. A truly rigid machine with a powerful spindle can cut as deep as the bit is wide in a single pass, but that takes real spindle torque, a drive train and clamps that hold firm, a gantry that will not flex, and enough mass to soak up vibration. This machine falls well short of that bar, so keep passes shallow: push too deep and the bit deflects and chatters, leaving scalloped edges, or it rubs instead of cutting and burns the material. The fastest way to dial in a cut is to see what has already worked for other people.

Worked example for feed rate: 1/8in (3.175mm) two-flute solid carbide end mill in hard wood. The chart says 16,000 RPM, but this spindle tops out at 10,000 RPM, so run 10,000. With the bit maker's 0.025mm per tooth (0.0010 in): 10,000 x 0.025 x 2 = 500 mm/min (20 in/min) feed. For depth per pass, start shallow and check Community Cut Settings in Easel for what works on this machine. If the cut sounds strained, reduce the depth, not the feed. Slowing the feed below the chip load makes the bit rub instead of cut.

Community Cut Settings shows the spindle speed, feed rate, and depth per pass other makers actually run for your machine, material, and bit.