Ausprobiert: T8 Mini CNC

Under the name T8 Mini CNC is now in many technology dealers a product - especially the sellers from the Far East undercame almost daily with new offers. However, the devices differ significantly in terms of features and price: The more metal is installed, the more expensive the machine.

Probably the cheapest option costs about 130 US dollars (plus shipping and customs) and is different than their conspecifics: Instead of shaky constructions or expensive milled aluminum, this CNC machine relies on parts from the 3D printer. The slide, the tool holder, the Z-axis construction, the holders of the linear bearings of the table - everything is printed from PLA, big, solid, perfect fit. The rest of the construction - as with the other variants of the device - made of metal. But because just these hard-to-construct parts are cheap and off-the-peg, this is reflected in the low price.

Since the machine is either not suitable for working hard metals, the choice of construction material for the individual parts is hardly noticeable, because to mill or engrave wood, acrylic, ABS or board material, the stability is always sufficient. If it's just about cutting balsa or plywood, the steppers can also run faster. If you like, you can also swap the spindle motor for a laser module, the controller has suitable connections ready.

Solid construction

Three NEMA17 stepper motors with 8 mm trapezoidal threaded rods and backlash-free nut / lock nut designs provide neat power and accuracy. A GRBL board with Arduino Nano and three A4988 modules provide the drive. The A4988 modules are already pre-set. The frame construction is made of solid aluminum profiles with aluminum angles. All parts of the axles are attached to the frame with aluminum parts. The table is a single, 160 mm × 100 mm aluminum professional piece with T-slots. The tester also included screws, nuts, T-slot nuts, thumbscrews and washers to build one or more object fixtures.

GRBL 0.9 is preinstalled. A 755 motor with 24V / 60W is used as the spindle motor, an engraving insert (60 degrees, 0.2 mm, 1/8 ") is included.With the CNC mini cutter two power supplies were supplied: One of them can range from 6 to The second is intended for the operation of the Arduino and came with a solid, American power plug into the house It was replaced by an existing one with identical values.

Resilient in practice

The milling results are impressive. Especially when engraving circuit boards or signs made of fiberglass, acrylic or aluminum, the machine showed no weaknesses. Repeatability was better than 0.05 mm, no play was noticeable. After about 20 hours of operation, however, it was time to provide the screws on the stepper motors with safety lacquer. They had relaxed a few times, especially on the Z-axis. It is also important to remember to set the zero position manually before starting an order - this machine has no limit switches. But for their price, the T8 Mini CNC machine is a real cracker, even if it comes along at a glance, a little half-finished. But it just works as expected. 

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