Optical QC: spindle servo, 100 W StepperOnline A6-RS kit

User, 18 Oct 2026, asked about the StepperOnline A6-EC100L2A1-M17
(100 W EtherCAT kit).

- The motor fits: torque about 0.02 N m needed at the motor through a
  1:6 belt (0.32 rated); the belt brings the load inertia (about 25 to
  35 kg cm2, estimate; record 20.5) to about 28x the 0.03 kg cm2 rotor.
- Take the pulse/RS-485 twin A6-RS100L2A1-M17 (USD 108.78): its drive
  outputs the encoder as divided A/B/Z pulses for the line-scans and
  takes pulse/direction from the planned PLC. The EtherCAT drive has no
  divided output (A6-EC manual, CN1: 5 DI, 3 DO) and needs an EtherCAT
  master.
- inline-optical-qc.md: spindle servo paragraph, sensor table, BOM
  group; BOM line 109 to 250 (was 300 to 700). Total USD 16,073 to
  32,734, THB 0.53M to 1.08M.

docs/equipment/inline-optical-qc.md

@@ -224,6 +224,37 @@ belt crosses that line:
 - **Lift drive:** the lift is a guided pneumatic cylinder, and the
   spindle is belt-driven from a servo set to the side. That keeps the
   bottom camera's view cone clear, which the elevation shows.
+
+**Spindle servo.** A 100 W AC servo kit is enough:
+StepperOnline A6-RS100L2A1-M17, a 40 mm motor (0.32 N·m rated,
+1.12 N·m peak, 17-bit magnetic encoder, 0.03 kg·cm² rotor) with the
+A6-200RS drive for pulse, RS-485 or analog control. It costs USD 108.78
+from the China warehouse
+([StepperOnline](https://www.omc-stepperonline.com/a6-series-100w-rs485-ac-servo-motor-kit-3000rpm-0-32nm-17-bit-absolute-encoder-ip67-a6-rs100l2a1-m17),
+October 2026).
+
+- **Camera clock:** the A6-RS drive puts the motor encoder out as divided
+  A/B/Z pulses, up to 4 Mpps
+  ([A6-RS manual](https://www.omc-stepperonline.com/download/A6-RS_series_servo_drive_manual.pdf)).
+  They go straight to the encoder inputs of both line-scans (Basler racer
+  2 encoder control,
+  [Basler](https://docs.baslerweb.com/encoder-control)), and the PLC
+  drives it by pulse and direction.
+- **Belt ratio 1:6** (for example 15 to 90 teeth). The record alone is
+  about 20.5 kg·cm² (180 g at 150.8 mm radius); with the spindle head the
+  load is about 25 to 35 kg·cm² (estimate). That is about 1,000 times the
+  rotor direct; through 1:6 the ratio comes down to about 28, inside the
+  drive's tuning range. The motor then runs at 360 rpm for one turn a
+  second.
+- **Torque is no limit.** Reaching one turn a second in 0.15 s takes
+  about 0.13 N·m at the spindle and 0.02 N·m at the motor (our
+  arithmetic), well under the rating.
+- **Not the EtherCAT twin.** The A6-EC100L2A1-M17 (USD 123.29) has the
+  same motor, but its drive has no divided encoder output: CN1 carries
+  five inputs, two of them touch probes, and three outputs (A6-EC
+  manual). It also needs an EtherCAT master, which the planned PLC is
+  not. It only fits if the whole station moves to EtherCAT, with a
+  separate spindle encoder for the cameras.
 - **Thermal camera (option):** hangs at the tunnel entry. It only makes
   sense at a press-side station; cooled records show no temperature
   pattern, so the launch setup leaves it out.
@@ -237,7 +268,7 @@ PLC needs to run the station. Lights, drives and cylinders are in the
 | 4k monochrome line-scan camera, GigE, 50 mm lens | 2: top and bottom | Basler racer 2 r2L4096, Hikrobot MV-CL042-91GM | inspection zone, on opposite radii (top 330 mm above the record) | surface: non-fill, stitching, flow lines, specks, bubbles, under dark-field, bright-field and transmitted light on alternate lines; eccentricity from the groove spiral | 857 to 1,088 (Basler web shop); lens 300 to 800 (estimate) |
 | 8 MP colour area camera, GigE, 16 mm lens, ring light | 2: top and bottom | Basler ace 2 a2A2840-14gcPRO | label gate, 520 mm from the infeed | right label on the right side, print, label centring; the top camera also reads the stamper number in the run-out | 1,119 (Basler web shop); lens and ring light 300 to 800 (estimate) |
 | Laser distance sensor | 2 | Micro-Epsilon optoNCDT 1420 | under the record, at 90 and 130 mm radius | warp: height traced round two circles during the turn | from EUR 470 list; ILD1420-25 about 1,600 at a reseller |
-| Encoder of the 200 W spindle servo | 1 | Delta ASDA-B3 class | spindle drive | angle of the turn; clocks both line-scans and the lasers | in the servo, 300 to 700 (estimate) |
+| Encoder of the 100 W spindle servo (17-bit) | 1 | StepperOnline A6-RS100L2A1-M17 kit | motor, 1:6 belt to the spindle; divided A/B/Z output from the drive | angle of the turn; clocks both line-scans and the lasers | in the kit, 108.78 |
 | Diffuse photoelectric sensor | 3 | any industrial make | looking up through the open centre: infeed, label trigger, outfeed | a record at the infeed starts the cycle; the trigger fires the label cameras; a full outfeed holds the next record | 50 to 150 (estimate) |
 | Through-beam photoelectric sensor | 1 pair | any industrial make | across the conveyor at the inspection position | the record's leading edge; stops the belts over the chuck | 50 to 150 (estimate) |
 | Cylinder position switch | 6 | SMC D-M9 class | lift (up, down), reject pusher (home, out), mandrel (open, clamped) | confirms each move before the next step | 25 to 60 (estimate) |
@@ -290,11 +321,11 @@ By group, per station:
 | Frame | 0.8k to 1.6k | 32 m of 40 × 40, 3.8 m of 40 × 80, angle brackets, feet |
 | Enclosure and guards | 0.3k to 0.7k | black panels, polycarbonate, door switch |
 | Conveyor | 0.5k to 1.4k | round belts, pulleys, slide strips, drive |
-| Handling | 2.0k to 4.9k | guided lift cylinder, 200 W spindle servo, spindle head with mandrel, rodless cylinder, pneumatics |
+| Handling | 1.8k to 4.4k | guided lift cylinder, 100 W spindle servo kit, spindle head with mandrel, rodless cylinder, pneumatics |
 | Vision | 7.7k to 12.5k | 2 line-scans, 2 colour cameras, lenses, 2 coaxial, 4 dark-field and 2 backlights, 2 ring lights, controllers |
 | Sensors | 1.4k to 4.3k | 2 laser distance sensors, presence and stop sensors, cylinder switches |
 | Control | 3.5k to 7.8k | PLC, edge PC with GPU, HMI, safety, cabinet and wiring |
-| **Total** | **16k to 33k (0.54M to 1.10M THB)** | thermal camera (USD 2.1k to 3.0k) not included |
+| **Total** | **16k to 33k (0.53M to 1.08M THB)** | thermal camera (USD 2.1k to 3.0k) not included |
 
 **Open points for the machine builder.**
 
@@ -422,7 +453,7 @@ simulated.
 
 | Item | Estimate |
 |---|---|
-| Hardware per station, from the [bill of materials](inline-qc-station/inline-qc-station-bom.csv) | USD 16k to 33k (0.54M to 1.10M THB) |
+| Hardware per station, from the [bill of materials](inline-qc-station/inline-qc-station-bom.csv) | USD 16k to 33k (0.53M to 1.08M THB) |
 | First station: frame build and machined parts, lighting trials, software, training data | 2 to 4 person-months, USD 15k to 40k (our own team with a local machine builder) |
 | Launch plant: one station for both presses, after cooling | the hardware above, USD 16k to 33k, plus the first-station work (about USD 31k to 73k in all, 1.0M to 2.4M THB) |