Sainsmart Genmitsu 3020-PRO MAX

About the Machine

Sainsmart no longer sells this model, but it remains fully supported in Easel. The Genmitsu 3020-PRO MAX has a 300 x 200 x 72 mm working area, a 300W spindle (12,000 RPM), and steppers rated 1.5 A (X/Y) and 1.8 A (Z).

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 3020-PRO MAX's 300W spindle tops out at 12,000 RPM, near the middle of the chart. It has more torque than a small brushed 775 motor, so it holds speed better under load, but it still loses some torque near the top, so favor the middle of its range for hard materials and only push toward 12,000 for softer ones. 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. Linear rail guides on all axes and a lead-screw drive give this machine more stiffness than Sainsmart's smaller kits, but it still isn't rigid enough for full bit-width depths, so keep passes moderate. 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 12,000 RPM, so run 12,000. With the bit maker's 0.025mm per tooth (0.0010 in): 12,000 x 0.025 x 2 = 600 mm/min (24 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.