OpenParallelGripper — XL330 version

Plan for machined and purchased parts

The XL330 BOM separates printed housings and adapters from an aluminum claw pair, a purchased rail and two racks. It strongly recommends metal printing for the 20-tooth gear and says the author used SLM. The design therefore is not an all-plastic desktop print: price metal fabrication, the XL330 servo, the SSE2B6-100 rail, two RGEAL0.8KA-55-A5-B10-C10-D10 racks, fasteners and electronics separately. The BOM lists quantities but no current delivered total. [S003]

The linked claw STEP path in the BOM omits the stp directory; the preserved file is XL330_version/hardware/cnc_miling_parts/stp/Claw_50mm.step. An assembly STEP and individual STEP/STL files are present. The project README still says the assembly instructions are not available, so use the model and BOM to plan fit checks rather than assuming a complete assembly sequence exists. [S002] [S003] [S009]

Reconcile the serial settings before commissioning

The documented control choices are two LITE 6 tool digital inputs for open/close, or Modbus-RTU over RS485 for intermediate positions. The reference electronics use OpenRB-150 and an RS485-to-TTL module, with soldering and a crossed Grove TX/RX connection. The electronics guide warns that connections may be unstable; it also retains an ATOM Lite/debug-board sentence despite describing OpenRB-150 elsewhere. Check the XL330 wiring diagram against the selected board instead of combining the two versions' instructions. [S004] [S005]

There is a concrete mismatch in the pinned Modbus examples: the OpenRB sketch initializes Serial2 at 57,600 baud, while the Python example actively requests 115,200. These must agree before the pair can communicate. The sketch uses servo ID 1 and example targets of 0 and 250 degrees; reconcile those limits with the assembled mechanism before enabling motion. The software README lists Dynamixel2Arduino, modbus-esp8266 and the xArm Python SDK, but a matched dependency build and hardware calibration have not been verified here. [S005] [S006] [S007]

The MIT-licensed repository includes mechanical files, wiring documentation and example control source. That does not make the purchased servo and boards open manufacturing designs. The LITE 6 documentation supports a platform-interface tag; the README's suggestion that other cobots might work is not evidence of Universal Robots or delta compatibility. No physical assembly, gripping performance or safety certification is claimed. [S001] [S004] [S008]