Custom Filling and Capping Machine

Summary

Lumis Automation was tasked with creating a custom machine that would fill the customer's cartridges with a highly viscous fluid, apply a cap to the top, and then output them. The fluid needed to be heated to lower the viscosity and allow it to flow into the cartridges. The customer wanted to be able to load all of the cartridges, caps, and fluid at the beginning of the day and have the machine run continuously for at least 7 hours with zero or minimal human intervention.

What I Accomplished/ Learned

  • Mechanically designed a custom machine from scratch in SolidWorks

    • Created drawings for machined parts

    • Utilized both pneumatic actuators and stepper motors

  • Programmed a custom machine from scratch

    • Used ladder logic to program a PLC

    • Designed HMI screens

    • Set up Ethernet/IP communications between PLC and peripherals (remote IO/ solenoids, stepper drives)

  • Assisted in electrical design

    • Created an IO list and bill of materials

My Responsibilities

  • Project Manager

  • Lead Mechanical Designer

  • Lead Programmer

  • Assisted in Electrical Design

Customer Specifications

  • Cartridges and caps are loaded into the machine automatically

  • Cartridges are filled with an accuracy of ±2%

  • Temperature of fluid cannot exceed 120°F

  • Throughput ≥ 1 unit every 5 seconds

  • Run 5000 units in a 7 hour with zero or minimal human intervention after startup

  • Easy for an entry-level employee to operate

  • Fluid pumps and reservoirs need to be easily replaceable to avoid cross contamination between different variations of fluid

  • 120Vac 20A Power and 90 PSI 10 SCFM Compressed air available

Design Solution Overview

After some group brainstorming sessions we decided that a rotary table design being fed by vibe bowls would be the most effective solution. A high-level outline of the stages can be seen above. The 6 stages are:

  1. Cartridge Loading

  2. Dispense 1

  3. Dispense 2

  4. Cap Loading and Seating

  5. Cap Press

  6. Machine Output

The stages mainly utilized pneumatic actuators while the rotary table and dispense stages used stepper motors with feedback. AutomationDirect parts were utilized on this project due to longer than usual lead times across the industry.


Mechanical Design Steps

  1. Each station was designed in SolidWorks as an independent subassembly

    • Rapid prototyping by 3D printing parts that would be machined

  2. Identified necessary motion components (motors or pneumatic actuators) and sensors

  3. Integrated the sub-assemblies into one main assembly

  4. Designed the frame and base to tie the sub-assemblies together

  5. Identified which parts needed to be machined and which could be purchased or 3D printed

  6. Created drawings for parts that would be machined

  7. Sourced parts from a machinist

Programming Steps

  1. Wrote drivers to simplify communications from the PLC to the pump motors, rotary table, HMI, and remote IO via Ethernet/IP

  2. Created test screens on the HMI to verify operation of COMMs and IO

  3. Wrote subroutines for each subassembly

  4. Wrote safety aspects of machine (what happens on E-Stop, etc.)

  5. Wrote a main program to call each subroutine in the correct order

The project was written in ladder logic.

Electrical Design Steps

  1. Create IO list based on inputs and outputs specified during mechanical design

  2. Collaborated with an electrical engineer to specify components for the control panel

    • This included the PLC, HMI, power supply, circuit protection, and remote IO

  3. Reviewed and signed off on the electrical schematics and panel layout created in AutoCAD

  4. Performed a point to point inspection of the electrical panel

Part List

  • PLC: AutomationDirect P1-540

  • HMI: AutomationDirect EA9-T10WCL

  • Remote IO & Pneumatic Solenoids: Nitra PAL

  • Pump Motors: Applied Motion STM23XIP-3DE

  • Pump Gearbox: SureGear PGCN23-1025

  • Rotary Table: Oriental Motor DGM130R-AZAC (actuator) and AZD-AEP (drive)

  • Pneumatic Actuators: AutomationDirect, SMC, and AirTAC

  • Sensors: Panasonic and Banner

Challenges

The main challenges we faced are listed below:

  • The highly viscous fluid required heating in order to dispense properly, and we had to try multiple pumps before finding one that could provide the accuracy the customer required.

  • In order to heat the pump assemblies, and allow them to be easily removeable, we had to design an oven that could hold a precise temperature, open wide, and support the pump assemblies.

  • The customer changed the design of their cartridge halfway through the project which required us to make changes to make hardware and software changes.

Documentation Created

  • User Manual: describes the how the machine works, the sequence to start the machine, and the show down sequence

  • Maintenance Manual: maintenance required at specified intervals to keep the machine running properly

  • Pump Cleaning: describes the process to disassembly the pump assembly and clean the internals thoroughly

Results

The project was successful overall. The machine has a throughput of under 4 seconds per unit and easily produces 5,000 units a day as the customer requested. The machine also reduced labor by around 90% compared to when the process was done manually.

The project fell slightly behind schedule due to longer than usual lead times and scope creep, but the customer was not on a tight schedule. The only complaint that the customer had was that the replaceable pump assemblies were expensive. Initially they had planned to buy around 10 additional pump assemblies (2 for each different variation of fluid), but they decided to only use the 2 that came with the machine and wash them thoroughly before changing fluids. Overall the customer was satisfied with the machine, and we are currently developing another custom machine for them.