Paper ID #15398

Developing Servo Indexing System Using Timing Screw for Automatic LiquidFiller in Manufacturing Environment

Dr. Akram Hossain, Purdue University - Calumet

Akram Hossain, Purdue University Calumet Akram Hossain is a professor in the department of Engi-neering Technology and Director of the Center for Packaging Machinery Industry at Purdue UniversityCalumet, Hammond, IN. He worked eight years in industry at various capacities. He is working withPurdue University Calumet for the past 27 years. He consults for industry on process control, packag-ing machinery system design, control and related disciplines. He is a senior member of IEEE and heserved in IEEE/Industry Application Society for 15 years at various capacities. He served as chair ofManufacturing Systems Development Applications Department (MSDAD) of IEEE/IAS. Currently, he isserving a two-year term as the chair of the Instrumentation of ASEE (American Society of EngineeringEducation). He authored over 29 refereed journal and conference publications. In 2009 he as PI receivedNSF-CCLI grant entitled A Mechatronics Curriculum and Packaging Automation Laboratory Facility. In2010 he as Co-PI received NSF-ATE grant entitled Meeting Workforce Needs for Mechatronics Tech-nicians. From 2003 through 2006, he was involved with Argonne National Laboratory, Argonne, IL indeveloping direct computer control for hydrogen powered automotives. He is also involved in severaldirect computer control and wireless process control related research projects. His current interests arein the area of packaging machinery system design & control, industrial transducers, industrial processcontrol systems, modeling and simulation of Mechatronics devices and systems in virtual environment,programmable logic controllers, programmable logic devices, renewable energy related projects, wirelesscontrols, statistical process control, computer aided design and fabrication of printed circuit board.

Mr. Nirjhar Das Sharma, Purdue University - Calumet

Nirjhar Das Sharma pursued his passion for engineering from his early childhood while he was goingthrough High school education. He completed a four year B.Sc. course in Electrical and Electronic En-gineering (2008-2013) from Chittagong University of Engineering & Technology, Bangladesh. The lasttwo years of the Bachelor study introduced him to some real-life learning along with a lot of importantexperiences. He personally believes that the Industrial training at TICI (Training Institute for ChemicalIndustries), Narshingdi was the most valuable tour where he experienced about the Industrial ProductionTechnology, sensing and control systems. This training made his decision easier to become a Graduatestudent of Mechatronics Engineering Technology at Purdue University Calumet, USA (from August, 2013till present). His enthusiasm developed for learning Electrical controls, PLC Ladder logic (Allen Bradley),HMI design, Robot (Motoman) programming and Motion controls helped him to accomplish the integralpart of his research projects. Moreover, he has been a dedicated Instructor for an undergraduate levelcourse ’Electricity and Electronics fundamentals’ from January, 2014 to June, 2015 at Purdue UniversityCalumet. At present, he is also working as an Electrical Engineer at Plastipak Packaging Inc. experi-encing different technologies like Injection Molders, Blow Molders, High Speed Vision System, Roboticpalletizers in a packaging environment. His strong belief about all of these experience and educationwould create excellent opportunities for him and flourish his knowledge in the future.

Mr. Gautam Agarwal, Wynright Corporation

c©American Society for Engineering Education, 2016

Developing Servo Indexing system using

Timing Screw for Automatic Liquid

Filler in Manufacturing

Environment

Abstract

In the world of automation, one the most significant topics for industrial manufacturing

technology is primary packaging of products and machine design which can be considered as the

integral part of new products development process. Servo motion control is one of the most

promising solutions for primary packaging industries. This research article will present a

servomotor driven indexing system using timing screw in a filling machine which can be

described as an efficient application of precise motion controls. In addition, the research is

focused on the Integration of the indexer with an automatic liquid filling machine developed

from industrial prospective. It also emphasizes on more advanced features of an indexing system

of a generic filling machine. The servomotor driven indexing system using timing screw offers

the premium method to index containers or bottles in order to design a fast and efficient

production in an automatic liquid filling system. Servo encoder feedback can provide the closed

loop control on the process and save the product from wastage with the help of a feedback signal.

Nevertheless, this type of indexing system can offer cost benefits and a high degree of precision.

The idea presented here is of an automatic filling system relates to the indexing method of

different types of containers and more particularly to an electromechanical control system and

method for controlling servomotors that are a part of an indexer of the filling machinery. This

type of bottle indexing & filling mechanism plays very important role in the medical, beverage

and wine industries. These machines are used not only for filling and capping but also to reduce

the labor operator or manual operation in the industry. A traditional process contains filling the

bottle by hand or by a semiautomatic machine having questionable accuracy will create lots of

wastage of filling product. There are several important factors that are necessary to be brought up

while discussing about Automatic Liquid Filling system such as the type of liquid, the size of the

container, the throughput of the system, filling method etc. The traditional process takes lot of

preparation time. This means, first of clean the bottle, second, determine whether the bottle is

crack or not. In this way, the work setting time is more as compared with the filling time of the

bottle. So due to this problem the idle time of the process is more as compared to the working

time of the machine this will results in the low productivity of the machine and also it requires

many worker for this process. This affects the overall efficiency of the machine. In turn this also

reduces the throughput due to the more idling time. The goal of this research was to achieve the

design, testing, and implementing an entire working machine in a shortest possible time. Thus,

machine design and controls programming including engineering method was implemented from

conception through the completion.

Problem Description

At present many methods are popular in the manufacturing industries for liquid filling machines

for the purpose of placing a container in the fill group area and as well as assurance of the

product dispensing in the right container with right positioning. Some of these design methods of

indexing might be expensive to build and complicated in case of operation and maintenance. So

the main objective of this research is focused on following concerns:

1. What is the advantage of using timing screw for this automatic filling system?

2. How much efficiency based on production and cost we can retrieve using timing screw

indexing?

The purpose of this research was to design an automatic indexing for an industrial liquid filling

system which is basically a piston filler system. The automatic indexer was achieved by a timing

screw from “Morrison Container Handling Solutions”, driven by an Allen-Bradley servo motion

control system. The system can inspect the desired number of containers to be filled, accept to

feed into the timing screw also perform appropriate mapping of the presence of the bottle or

container in the fill group area. The perfect mapping or inspecting of the present bottles is simply

achieved as a result of servo feedback loop and proper operation of photo eye sensors. The

reason for this inspection is to save product from dispensing if there is a missing container in one

of the screw pocket in the fill area. The system encompasses a regular conveyor system for

taking the bottles to feed into the indexer and also discharging from the indexer simultaneously.

The filling portion of the entire system is definitely driven by electro-pneumatic operation. The

system is able to demonstrate successful automatic indexing with industry grade motion control

system, electrical and pneumatic controls systems. In order to initiate the design and

development of the servo-driven timing screw indexer for the automatic filling system, few

assumptions can take place.

1. The system is designed to be capable of being integrated with actual inline packaging

processes. However, this system was built as a separate unit in a laboratory environment. At

that point it was assumed that the performance of the system would remain constant in the

event of integration with other divisions of a packaging process such as capping, labeling and

stacking etc.

2. The timing screw indexing system had to be deployed in a smaller scale to fit at the

Mechatronics Laboratory in Purdue University Calumet. The assumption made at that point

was that the results obtained from the indexer/filling system would not vary depending on the

variable of throughput or machine size at a different production environment.

3. The prototype was developed to perform at a very low speed in order to overcome challenges

with motion control for precise movement of the containers/bottles.

However, in any occasion of being deployed in an actual industrial environment, the system

should perform properly at higher speed with few modifications of machine design and position

commands with respect to lower speed.

Design Methodology

This research study is highly motivated with industrial and mechatronics methodological

approach. This type of approach is generally implemented by three following phases:

a) Modeling & Simulation

b) Prototyping

c) Deployment and Life cycle

First step should be the recognition of need. To follow the first step the primary need of this

research is to choose and design a timing screw dedicated for a bottle of specific size and

dimension. The concept should be developed as the first step is completed. It is also very

important to specify the functional requirements of the system for this research.

Selection of the right driving components for the timing screw indexer should be the second step

in this example. For this research, a servo motor and servo drive along with safety integration

was chosen. Third step was definitely to optimize the design to be able to simulate the actual

hardware.

Sometimes the design approach of this type of system may require development of software or

program coding where life cycle optimization can take place. Deployment of a design is the final

touch in this methodological approach. Concurrent way of engineering technique should be the

main key of the design phases for this research. The indexer selection should company the filling

mechanism as well as the fill cycle calculations and simulation etc. The conceptual framework of

this study started with the machine design and component selection. To follow the Industrial

standards of this specific type of research, selection of component as well as cost effective bill of

materials plays a very important role. There was also another factor to maintain the Mechatronics

methodological design approach. Basically this research is developed to focus, guide and walk

through a combination of Industrial practices and design phases of mechatronics technology. The

design of filling machinery basically begins with the container to be filled with the liquid product

to be used. As this research is based on a Laboratory environment, so the liquid products are

actually not involved here. The integrated machine was built based on a very general liquid like

drinking soda or water.

Type Boston Round

Diameter 1.75”

Height 4.5”

Table 1: Container Dimension and Specification

Figure 1: Container used in the research

This information about the container is the first step to begin the machine design. Depending on

this, the selection of the system conveyor will be decided and the other mechanical components

for the filling operation. As soon as the mechanical design was established for both indexer and

the filler, the electrical controls design was the next approach to be done. Moreover, there were

controls programming Logic, Operator Interface and Testing the operation which were very

important tasks to get a complete result. The timing screw design and calculation is the most

value added because the design parameters of the timing screw determine the overall efficiency

of the indexing system as well as the filling operation. First of all some information are to be

decided prior to the calculation of Design of the timing screw.

1. Size of the container= 1.75” Diameter

2. Desired throughput for the research is 40 containers per minute. As this research is built

based on a laboratory environment, so the design was meant to as compact as possible

and also the speed or throughput was not significantly higher due to some safety purpose

of the students and equipment.

3. Pitch of the timing screw = 2.5”; the pitch of the screw is actually the distance or gap

between the Centre of two containers sitting together.

Figure 2: Determining pitch of the timing screw.

1. Length of the timing screw = 36”

2. Diameter of the timing screw = 4”

All these screw parameters are dependent on the size of the containers.

Pitch=2.5”

1.75” 1.75”

Figure 3: Timing Screw Initial Assembly Drawing

After the screw pitch and diameter is determined, the next step is to design a drive assembly

system which is basically used for mounting the timing screw with the feed through conveyor

system. Also the drive assembly system will determine the direction of rotation or the direction

of travel of the containers. Sometime a proper calculation and sizing drive to have a gear reducer

for the servo motor to rotate and operate the timing screw. Although in this research, gear

reducer was not used but suggested rear ratio is 7:1 (Calculation was done from Motion

Analyzer, Rockwell Software, and Rockwell Automation). The other advantage of having a gear

reducer is to avoid the inertia mismatch between the servo motor and the load; also it is useful

for resulting in higher speed in comparison to the input power or torque of the motor. So, this

drive assembly system can operate the machine in a greater throughput and increase the line

efficiency a lot more than the desired speed.

This research was focused on the automatic indexing features rather than the speed of the filler as

it was indicated before. So gear reducer was not used but the drive assembly system is well

attached to drive the timing screw as a travel direction from left to right. When manufacturing

the drive assembly it is important to use guarding over the system to have the safety from any

kind of hazardous situation. It is better to use a stainless steel industrial standard guarding for the

drive assembly system. Designing a timing screw also refers to some calculation which starts

from the desired speed of the system (40 containers per minute). The time for fill stop should be

determined to know what maximum speed the timing screw needs to be rotating.

The number of fill heads used in the filler also plays a vital role to determine some of the

important calculation. In this research the preliminary proposal was to have 4 fill head nozzles

but later on it was eliminated to 2 fill heads to make the machine more compact. These

calculations are definitely done from some of the mathematical equation to understand the filler

stop time and this stop time can be used for the filling the containers with the expected liquid

product and achieve the ultimate throughput with the machine.

Controls System Design

The idea of this research was initialized with different perspective of the controls system where

servo motion control was more complicated. The idea was to build a controls system for a

walking beam filling technology which is based on three axis servo motion cam profiles. But

later on, the research goal was motivated into a different path yet the control system of this

research is surely able to build a machine with 4 axis motion. Besides, this electrical control

system was built to demonstrate laboratory experiments. As a result, the electrical design and

load calculations are based on both the “Indexer and Filler” and laboratory training criteria. In

this research, one of the very important software tools is DMAT (Drives and Motion

Acceleration Toolkit Wizard) by Rockwell Automation which leads the design and simulation

phase of the procedure. Firstly, a Multi-Axis Kinetix 6000 Servo Drive with LIM (Line Interface

Module) was chosen as the dedicated components for the research. So, this DMAT software tool

was really helpful building the preliminary Bill of material (BOM), Electrical Schematic, Panel

layout footprints and other layout drawings. Later on, all of these software created documents

were needed to be modified according to the exact application of the research and the laboratory

Table 2: Calculation for the Indexing Operation, Morrison Container Handling Solution

training module. The Electrical controls system of this research is called ‘Kinetix 6000 Servo

Trainer Panel’. Most of the components were pre-selected and then it was easy to start with the

application and also I/O points of view for the research. To build a trainer panel, a well-designed

cubic structure was built with keyboard and monitor mounting hardware for the trainer computer.

Figure 4: Front View

Figure 5: Top View

Figure 6: Side View

Figure 7: 3D View of the Trainer

Process Description

The working principle of the timing screw Indexer is simple to understand. The first index cycle

after transitioning to Automatic Mode should index the first container on the conveyor to the

most downstream fill head. In this case, the screw will make an absolute movement to index the

first bottle to the most downstream fill head. The following containers will then align below the

earlier fill heads as both screw pockets and the fill head assembly are designed according to the

specific containers dedicated to this research. The next fill group will already be situated in the

following pockets, so the screw need only proceed by the number of pockets of the timing screw

in each fill group. This motion can be achieved with relative movements of the servo axis.

Figure 8: Basic Operation of an Indexer using Timing Screw.

This process is illustrated above where the gray rhombuses are indicating the screw pockets. The

first transition indexes a total of 4 pockets ahead to fully index the red container. Every

subsequent index would then only move 3 pockets ahead. This First Group Indexing will occur

for the first index cycle anytime Automatic Mode is activated. The location of the containers is

unpredictable if the machine transitions out of Automatic Mode. Another important study of this

research will provide the application of a fill shift register to track the bottle present within the

indexer to be able to prevent from wasting of the products. This bottle tracking operation is

defined as ‘No Bottle No Fill’ or N.B.N.F operation for this research. The N.B.N.F operation

will be controlled directly from the logic program of the controller which is basically a bit shift

operation triggered by the actual home position of the servo-indexer. This way it is easy to

register if a bottle is actually present under the fill heads and ready to be filled or not.

Filling Mechanism Path Flow

Priming Sequence

The priming sequence of the Indexer was one of the most challenging procedures in order to

achieve the research objectives. The priming sequence is the Automatic order of operation that is

held just before the first indexing of the group of containers. This operation is definitely

controlled by the program coding as a part of the combination of PLC and servo motion

programming. Nevertheless, a priming of the indexer needs to have some input signal conditions

to complete the sequence which actually also measures the number of screw rotations or

revolutions needed to get the containers right before the fill group area. In this research two

diffused type of photo eye sensors drive the conditions for priming sequence.

Figure 9: Filling Mechanism Process Flow

Priming

Sequence

Start a New

Cycle

Filling the

indexed

containers

Head Dive

Auto Indexing of

the containers

Photo eye 1: Containers Available

Photo eye 2: First Screw pocket recognition

Figure 10: Positioning under Priming Sequence of the indexing

The procedure is little complicated because both of these sensors has to be satisfied and

obviously the priming sequence has to be triggered from the Human-Machine Interface (HMI).

There is another time the priming sequence can take place if the power cycle is occurred and the

controller is in its first scan of the program code.

Auto or JOG Mode

The Indexer of the research set up can be operated in two modes of operation.

1. Auto Cycle Mode

2. JOG Mode

Auto Cycle Mode initiates the indexer to run in Automatic mode. So the first thing the controller

will try to find out if the priming sequence is done. And then fulfilling the input signal conditions

and HMI buttons are pressed, the Auto cycle mode takes place. The first step of the Auto Mode

is to complete the indexing which means to bring the containers under the dedicated fill group

area and two fill heads will be aligned from the Centre with two containers respectively. This

step is completed with the dedicated motion instruction being done and starts the pneumatic air

driven Head dive process. After the Head dive is done, both the dive system and the indexer will

wait for a time to be elapsed to reset the cycle. The final step is to send recognition to the

controller that a cycle is completed and based on given condition start a new cycle. This is

basically the theory of Auto mode of operation.

JOG mode of operation is nothing but a manual operation for the machine outputs of the

research. This mode of operation does not run any cycle but allows the operator to determine the

possible situation by changing manual speed, acceleration time, deceleration time etc. of the

servo motor or the indexer. Moreover, this operation helps to set the pneumatic components to

function with precision and nearly accurate positioning.

Fill Cycle

Fill cycle of the machine exactly follows the process flow or process mapping of the filling

Mechanism. This is actually the basic reflection of the Auto Mode of filler operation along with

indexing of the research.

1. First step is to check if the priming sequence is complete.

2. Second Step is to make sure the first group of containers completed indexing.

3. Third step is to check if the Fill heads are down or if the Head dive has been occurred.

4. Fourth step is to initiate and complete the fill to the set volume within a specific amount of

time into containers.

5. Last step is to complete the fill and restart a new cycle or go back to the first step.

Fill Shift Register:

Fill Shift register is an operation that is occurred during the fill cycle by the controller logic of

the system to determine the presence of bottle under each fill heads. The photo eye located at the

First pocket of the screw generates the soft pulse inside the code and triggers a bit with the help

of the Homing position pulse of the servo motor. This way the shift register starts shifting a bit

from right to left each time the sensor get a false to true transition by the presence of a bottle. As

a result, fill shift register helps to find out whether the product needs to be dispensed or not. This

operation is very useful to save products from wasting that are expensive or save products that

are harmful to be exposed in the environment.

Figure 11: Explaining Fill Shift Register operation during the fill cycle

Fill Cycle Reset

Fill cycle represents the total operation starting from indexing through the fill completion of one

group of containers within a certain period of time during the Automatic mode of operation. Fill

cycle time means the time spent for one complete cycle. So, after each cycle completes, the

controller will look for a signal to be high inside the code which is the Fill cycle Reset flag.

There might or might not be a delay time for the cycle to be reset and restart a new one.

The expected cycle time can be calculated very easily. To know the fill cycle time is very

important because that is the best way to know exactly what time after the system needs to

complete the cycle and start a new fill cycle. At the starting of the Methodology, it was stated the

desired throughput of the system is 40 containers per minute. This system has 4 fill heads. That

simply shows the number of cycle needs to be done within 1 minute or 60 seconds. For this

research, Number of cycle in 1 minute is equal to 20 (Expected throughput/ Number of Fill

heads). Therefore for each cycle it will get 3 seconds to complete each cycle (Expected

throughput/ Number of Fill cycles in 1 minute).

Human Machine Interface

The Human Machine Interface plays the lead role for the operator as this is accessible path to

modify any variables, timers, counters and other motion parameters to the program. Sometimes

selecting different mode or START-STOP control gives the operator a versatile advantage to

improve the existing process. The following figure represents one of the main displays of the

HMI design of this research.

Figure 12: The Indexer Set up screen from the HMI design.

Limitation & Future Improvements

The design and fabrication, intended to be accomplished in this research, was a smaller scale

prototype of a real-life automatic filling system. In an actual industrial environment, the system

may require modifications/improvements for the variables related to the motion control system,

perfect signal conditioning from the photo eyes and other controls components. Besides this,

depending on variation of bottle, the mechanical arrangements would need to be revised or

modified. In addition, the actual Indexer and the Piston filling system machine may need to go

through some additional stages in a real packaging facility. The purpose of this research was to

accomplish an industry grade indexer in a filling machine line based on successful articulation

between servo motor driven timing screws, electro-pneumatic piston filling system. Therefore,

implementation of servo driven indexing systems or filling operation cannot be fully automatic

as there were no options for staging or feeding the containers into the conveyor. This research

was completed successfully by the proper output configurations and desired stable system as a

combination of servo-driven Indexer and Piston filler.

A research should always have the door open for the future process improvement and

opportunities for analysis. This research has a versatile controls system involved which was built

by keeping in mind about the possible future improvement.

1. This system is capable of driving 4-Axis with separate servo motors. As a result, the control

panel can be applied to build a Walking beam continuous filler.

2. The filling mechanism of the machine can replace any other method of filling. As an

improvement work, the higher technology like Mass flow meter filling techniques can be

adopted with the existing controls system.

3. Finally, the servo trainer panel has the room for more up gradation if necessary with two

PowerFlex®

V.F.D units to run two more A.C Induction motors.

Conclusion

Integration of an automated filling system with an Automatic indexing sequence for industrial

applications was initiated with the aim to accomplish a diversified industrial automation and

controls modular learning system for the Mechatronics Program at Purdue University Calumet.

Successful implementation of the Filler Indexer line would deliver the following educational

focuses for the learners in this program:

1. System design approach for industrial packaging problems.

2. Problem solving methodologies through development of automated machines.

3. Selection and sizing of electrical, pneumatic, controls and mechanical components

depending on the requirements for a certain application.

4. Electrical controls panel schematic drawing and wiring skills according to industrial

safety standards and requirements.

Substantial programming approaches for automation technologies (e.g. PLC, HMI, Motion

control etc.) for effectively automating industrial production/packaging machine lines in order to

enhance the end product quality and machine throughput. Integration of a Servo-driven Indexer

and an Industrial Dual Head Automatic Piston Filler was the main objective of this research. The

research also focused on the safety standards that are practiced in the industries for the

integration of Electrical Engineering, Mechanical Engineering, Electro-pneumatic, Motion

controls and PLC technology. The other goal of this research was to build a servo trainer panel

which will serve the purpose of laboratory environment. This multi-Axis drive and controls

system enables the students to obtain the bird’s eye view of the industrial machines and enhance

their learning in terms of wide range of mechatronics methods, components and the integrated

applications. The System Design approach is an effective method of research as it emphasizes on

maximum involvement which develops enthusiasm to investigate and learn about the

Mechatronics systems. The automatic Indexer developed in this research could also be

implemented to improvise the process and convert it to Walking Beam continuous filling system.

Regardless of the limitations, the main objective of the research was accomplished with proper

care and necessary steps maintaining all Industrial standards.

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