Annin Robotics Community

The AR4-MK5 mechanical assembly is progressing through the main transmission elements: motor, bearings, timing pulleys/gears and belts.

I approached this phase from a Quality Engineering perspective, treating each assembly step as a small Quality Gate.

Motor: Check fastening, shaft/pulley interface and cable routing. Any misalignment introduced here can later affect belt tracking and bearing loads.

Bearings: Tapered roller bearings require different installation methods:

• Outer race → aluminium housing: heat the housing uniformly to slightly expand the seat, then press the race squarely into position. Never hammer it.

• Inner bearing cone → shaft: warm the bearing/cone assembly to slightly expand the inner ring before fitting it onto the shaft. If force is required, apply it only to the inner ring, never through the rollers.

After pressing the outer race, verify seating depth at 0° / 90° / 180° / 270° with a digital caliper. This is a practical QC check of uniform seating and parallelism, while also considering measurement repeatability.

Thread locking / retaining compound

• LOCTITE 222: low-strength threadlocker for removable threaded fasteners, used on M4 and larger screws as specified by the AR4 manual.

• LOCTITE 648: retaining compound for cylindrical fits; use only if an outer race is slightly loose in its housing, not as a general installation aid and not normally between inner ring and shaft.

Gear / pulley: Check seating, axial position and pulley alignment. Small offsets can cause belt tracking issues and additional bearing loads.

Belt: Tension must prevent backlash and tooth skipping without overloading shafts, bearings or structures.

Final QC: Before closing the covers, manually check:

smooth rotation, correct belt tracking, no abnormal friction, controlled preload, no excessive play and no interference.

The key lesson is that:

Motor → Bearing → Gear/Pulley → Belt

should also be a sequence of Quality Gates.

Detecting an incorrect bearing seat, pulley misalignment or excessive belt tension immediately is far easier than troubleshooting the defect after the robot is fully assembled.

#PaMiLoCELL #PaMiLoLAB #AR4MK5 #Robotics #QualityEngineering #RobotAssembly #Bearings #TimingBelt #LessonsLearned

A good assembly also depends on using the right tools for each operation.

Some of the equipment being prepared for PaMiLoCELL and AR4-MK5 assembly:

• Drill press and rotary/power tools

• Soldering and electrical work tools

• Precision screwdriver and bit sets

• Wire stripper / crimping tool

• Digital caliper for dimensional checks

• Tweezers and cutting tools

• Loctite 222: low-strength threadlocker

• Loctite 648: retaining compound for cylindrical parts

• Liquid electrical insulation coating

• Bearing / bushing / seal installation kit

The objective is simple: assemble correctly, measure, verify and avoid damaging components.

Right tool → Better assembly → Better reliability

PaMiLoLAB

Following the initial kitting phase, the next step of PaMiLoCELL has been to prepare the physical environment that will progressively host the complete robotic system.

The development started from a hand sketch, followed by several iterations and technical discussions supported by ChatGPT, to define a preliminary cell layout integrating:

• AR4-MK5 robotic arm

• PLC and industrial automation system

• Electrical and Safety Panel

• Overhead camera

• RGB-D camera

• Diffuse LED lighting

• AI Vision hardware and software

The concept then evolved into preliminary mechanical and electrical documentation covering cell layout, component positioning and a first wiring architecture.

Current project status

Everything is still preliminary and conceptual.

The drawings, layouts and wiring architecture are a development trace to guide the next steps. They are not yet fully verified against the final physical configuration and may contain assumptions, inconsistencies or technical errors.

That is part of the challenge: study the system, build it step by step, identify what does not work, verify assumptions and correct the design as the real cell develops.

The goal is not to present a finished engineering solution, but a structured path where each step can be reviewed, tested and improved.

Development sequence:

Concept & preliminary layout

Initial sketches and system architecture.

Cell preparation

Mechanical environment and spaces for robot, PLC, Safety Panel and Vision devices.

AR4-MK5 installation

Robot positioning and verification of real workspace, reachability and clearances.

PLC & Safety integration

Installation, wiring and verification of automation and safety architecture.

AI Vision integration

Positioning and calibration of overhead camera, RGB-D camera and controlled lighting.

Risk Assessment & Safety Validation

Once the AR4-MK5 is installed and the real cell configuration is available, the project will move to:

PaMiLoCELL_Risk_Assessment_Safety_Validation_Rev0

This phase will evaluate actual hazards and required safety functions, including robot movements, cell access, emergency stop, interlocks, electrical risks and safety architecture.

The project will evolve iteratively:

Concept → Build → Verify → Identify Errors → Correct → Integrate → Validate

The key point is not to assume the first design is correct, but to use each step to learn, challenge assumptions and progressively improve the system.

PaMiLoLAB

During one of my previous hobby projects, assembling and programming the open-source AR4 robotic arm, supported by the Annin Robotics open-source community and AI tools such as ChatGPT and Codex by OpenAI, my perspective gradually moved beyond the robotic arm itself.

That experience led me to explore how Robotics, Industrial Automation, Functional Safety and AI Vision can be integrated into a complete robotic system, with potential applications in Production, Quality and HSE.

This is the starting point of PaMiLoCELL, the first technical development project within PaMiLoLAB.

The first phase is focused on kitting and system preparation: identifying, selecting and organizing the hardware required to build a compact robotic cell around the AR4-MK5.

The planned architecture includes:

• AR4-MK5 robotic arm

• PLC and industrial automation components

• Electrical and functional safety system

• Overhead camera

• RGB-D camera

• Controlled LED lighting

• AI Vision computing platform

• Mechanical enclosure and integration hardware

The objective is not simply to assemble individual components, but to progressively integrate them into a complete, documented and functional robotic cell.

Next steps will cover mechanical assembly, PLC integration, electrical safety, machine vision and AI-based object handling.

PaMiLoLAB

Intermittent disconnect from PC (COM5). I’ve removed and checked the diode and it test OK. Polarity is correct. Resetting the HMI 5v IO Board Com Port back to COM5 works for a little while longer. Seems to always be on D0 off. New install - never worked correctly.

MK3

HMI v6.3

Nano Sketch v1.3