_Draft (round 14): the text is being written; the sections may still grow._
The MC-1 as it is designed: the figures in this chapter are design values. Each built machine is to be measured at commissioning, and its twin set to what was measured (see Machine profiles).
The MC-1 is a desktop three-axis mill for aluminium, brass and engineering plastics. Its gantry is fixed; the table moves in Y, the gantry's carriage in X, the spindle in Z.
| Travels X / Y / Z | 200 / 150 / 80 mm |
| Table | 300 × 220 × 35 mm, M6 tapped holes on a 25 mm grid |
| Size, width × depth × height | about 508 × 490 × 564 mm, with motors, cable chains and levelling feet, without the control box |
| Mass | about 57 kg, without the control box |
| Frame | 6061-T6 aluminium plates, bolted |
| Linear guides | HIWIN HGR15 rails (6), HGW15CC flange blocks (12) |
| Ball screws | SFU1204 (12 mm, 4 mm lead), C7, on BK10 / BF10 supports |
| Motors | NEMA 23 closed-loop steppers, 1.2–1.3 N·m (3), with jaw couplings |
| Spindle | 800 W, water-cooled, Ø65 × 195 mm, ER11 collet |
| Control box | a separate box beside the machine, on its right |
Each axis is a closed-loop stepper driving its ball screw directly through a jaw coupling. The drives report a fault on one line: the three drives' alarm outputs are wired in series to the controller's motor-fault input, so a drive that faults, or loses its power, stops the machine with an alarm.
The design's fastest moves are 3000 mm/min in X and Y and 1500 mm/min in Z.
Five M8 inductive switches mark the ends of travel: one at each end of X and of Y, each on its own input, and one on the Z slide for both ends of Z. The switches are normally closed: a broken wire or a loose plug reads as a triggered switch, so the controller raises an alarm and refuses to home instead of driving into the end stop.
Homing runs Z first, then X and Y, each towards its positive end (X+, Y+, Z+). The machine must be homed after power-on.
The Z slide carries the spindle, about 6.35 kg. While the drives are powered they hold Z. When they are not powered (after an E-stop, a drive fault or a power cut), Z with the spindle can creep down.
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Commissioning includes a test with the drives switched off: if Z creeps, the machine gets a Z motor with a brake, or a counterweight.
The spindle is a water-cooled 800 W motor spindle, Ø65 × 195 mm with an ER11 collet, two poles, up to 24 000 rpm. A Huanyang HY01D523B drive (VFD, single-phase 220 V in) runs it; the controller sets its speed and reads its state over RS-485, through an isolating module. A water pump cools the spindle.
The controller is a Teensy 4.1 on a T41U5XBB carrier board, with opto-isolated inputs. It runs the Twinwright controller (kernel), compatible with the Grbl 1.1 serial protocol, and it connects to the computer over USB.
| Input | What is on it |
|---|---|
| Limits | X−, X+, Y−, Y+ and Z, five inputs |
| Probe | the tool setter and the touch probe |
| E-stop | the E-stop button's second contact |
| Motor fault | the three drives' alarm outputs and the spindle drive's fault relay, in series |
| Cycle start, Feed hold | the buttons SB2 and SB3 on the control box |
Mains goes through a circuit breaker. A 24 V supply is always on: it feeds the controller, the sensors and the control circuit, so the controller stays connected to the computer and reports the E-stop. A contactor (KM1) switches the 48 V supply of the drives, the spindle drive and the pump.
Four Ø22 buttons on the control box's door, seen from the front:
| left | right | |
|---|---|---|
| top row | SB1 power on (green) | SB0 E-stop (red) |
| bottom row | SB2 cycle start (green) | SB3 feed hold (yellow) |
!) does: the axes stop under control, the spindle keeps running. It sits under the E-stop, so a hand that misses the E-stop hits feed hold, not cycle start.~) does.
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The tool setter sits at the table's left rear, held by two M6 screws in the grid; it takes the corner of the work area at about X 0–57, Y 130–150 mm. The tool setter and a touch probe share the controller's probe input.
With Z at the top, the tip of a tool that sticks out 15.5 mm from the collet is 80 mm above the table, and the spindle's nose 130 mm. A longer tool's tip is lower by its extra length. A touch probe held in an ER collet is usually 60–90 mm long from the nut to the stylus tip: with Z at the top, such a probe clears only low setups, about 20 mm above the table for a 70 mm probe.
Studio checks this for you: when you set up the work, change a tool or edit the tool table, it compares the setup's highest point with each tool's tip at the top of Z and says which tool does not clear and by how much.
The table's M6 holes on a 25 mm grid take clamps, a subplate or a vise. The twin knows a 75 mm self-centring vise on a 10 mm aluminium subplate, parallels, strap clamps, double-sided tape and a V-block.
The design values above are to be checked on each built machine, and its twin set to what was measured:
How the twin takes the measured values: Machine profiles.