IE Research PAPER

 Topic: “Design for Inventory Management in Health Care using smart RFID”

Authors:  S. Moslehpour, K. Jenab* & N. Namburi

Abstract
Radio Frequency Identification (RFID) is used to identify the characteristics of an object wirelessly using radio waves. The purpose of this technology in this study is mainly focused on healthcare for inventory management and theft control replacing the manual logs. The storage and tracking of high-cost inventory items is developed. Automatic reordering and billing interfaces are designed for the inventory falling below the par levels. iRISupply and iRIScope are the two RFID systems developed to reduce the inventory costs, expired item costs and to improve the inventory management with easy reporting system

Introduction
The goal of this project is to design a SMART inventory Management System with Radio Frequency Identification.
Radio-frequency identification (RFID) is the use of a wireless non-contact system that uses radio-frequency electromagnetic fields to transfer data from a tag attached to an object, for the purposes of automatic identification and tracking. Some tags require no battery and are powered by the electromagnetic fields used to read them. Others use a local power source and emit radio waves (electromagnetic radiation at radio frequencies). The tag contains electronically stored information which can be read from up to several meters (yards) away. Unlike a bar code, the tag does not need to be within line of sight of the reader and may be embedded in the tracked object.
RFID tags are used in many industries. An RFID tag attached to an automobile during production can be used to track its progress through the assembly line. Pharmaceuticals can be tracked through warehouses. Livestock and pets may have tags injected, allowing positive identification of the animal.
Since RFID tags can be attached to clothing, possessions, or even implanted within people, the possibility of reading personally-linked information without consent has raised privacy concerns.
Data stored on the RFID tag is retrieved through the use of a reader. The reader has one or more antennas that emit radio waves and receive signals back from the tag. Once the reader receives the information from the tag, it then passed in digital form to a computer system. This is accomplished utilizing Radio Frequency (RFID) technology to manage the inventory levels and for patient tracking. Through the process of transmitting object data from tag to a reader, RFID enables the communication of information in a timely and accurate manner.

This explains the main processes using RFID technology in medical cabinets. Medical industries and hospitals are in need of a device that monitors the supplies and expensive equipment such as pacemakers, stents, drugs etc,iRISupply is designed to meet the needs of the medical industries and reduce the inventory cost by eight to twelve percent. These cabinets identify three things: what items are taken by whom and at what time. They even identify, when the items were returned. iRISupply- RFID solution

Hardware Development

Design methodology of the cabinet is an important concern to be discussed. The hardware and software developments for the iRISystems classified as iRISupply and iRIScope.  The design is concentrated towards its being patient centric which has several advantages. Some of the advantages are discussed below :
1. Increase patient safety by preventing equipment cross-contamination and reducing risk for proliferation or transmission of infection.
2. Improve care quality by enhancing compliance to protocols for equipment cleaning
3. Re- processing and utilization.
4. Optimize asset management by tracking equipment utilization and mitigating risk of equipment theft damage or misuse.
In addition to this, this provides easy-to-use solution that automates the workflows of nurses and technicians, responsible for endoscope utilization and reprocessing.
The key features for the same are discussed below:

1.      Cabinet-based storage units provide secure, yet easy access to all endoscopes

2.      Forced-ventilation within Cabinet units to dry endoscopes following reprocessing washes.

3.      Ruggedized RFID tags affixed to endoscopes that withstand the chemicals pressure and action of reprocessing stations including ultrasonic agitations.

4.      Reprocessing work stations that automate processes and data capture associated with cleaning protocols.

5.      Automated rules and alerts delivered to email and handheld devices for cross-contamination risk or equipment status concerns (e.g. scope out of system exceeds 24 hours).

6.      Web based reporting tools to support analysis of endoscope utilization reprocessing compliance instrument repair and operational indicators.

By eliminating the common problems associated with manually intensive approaches that use paper stickers, barcode scanning or button pushing iRISupply enables an increased level of automation and accuracy by removing the burdensome tasks, typically completed by clinical staff. Common benefits experienced by organizations implementing the technology include:

1.      Improved Charge Capture Accuracy

2.      Eliminated Product Expiration Costs

3.      Reduced Time Spent Managing Inventory

4.      Optimized On-Hand Inventory Levels and

5.       Improved Product Recall Management.

Hardware Design for Reliability and Safety
the hardware consists of PCB designing of the boards and the antennas that ate used in these. The PCB are designed with one of the sophisticated application known as EAGLE. The authorized users have an RFID tag on their ID and when the ID is scanned on the scanner attached to the cabinet, it detects the user and the status of the Cabinet. A touch screen console is designed to provide quick and easy end user interaction. Adjustable shelving to accommodate a variety of packaging sizes and shapes is provided in the Cabinet. Re-configurable Cabinets to adapt to changes in inventory mix. Easy-to-learn intuitive work flows that significantly speeds end user adoption and proficiency. Item-level product tracking including lot number serial number and expiration date. If any product reaches its expiry date that will be intimated immediately by email through cabinet console.
Hardware Design of Printed Circuit Boards

The design and circuitry are discussed while designing the boards. Joining the diverse line of RFID readers and the Intermec RFID antennas including antennas, specifically designed for fixed applications as well as vehicle mount applications. The shock and vibration can far exceed average industry specifications. Intermec RFID antennas provide the vital link between reader and tag serving as the conduit that moves data back and forth. The antenna in an RFID tag is a conductive element that permits the tag to exchange data with the reader. Passive RFID tags make use of a coiled antenna that can create a magnetic field using the energy provided by the reader's carrier signal.

RFID Antenna

The antenna pairs are on a PC board. The PC board includes an RJ45 connector which provides both power to the antenna assembly as well as a communication interface for the antenna assembly. The RJ45 connector could be used to provide the RF signals from the antenna to a reader. In a preferred embodiment, the loop antenna and the Figureure eight antenna are arranged about a common axis, referred to as the X-axis. The Figureure eight antenna is placed symmetrically within the loop antenna.
In the current embodiment, the antenna assembly has a layer with several coplanar antennas on side of the PC board. The first antenna layer has a loop antenna enclosing a first Figureure eight antenna. A second Figureure eight antenna is positioned within the perimeter of the first loop of the first Figureure eight antennas. Within the second Figureure eight antenna is a second loop antenna. A third Figureure eight antenna.
The resultant system has high accuracy detecting RFID tagged items placed on the shelf. Additionally, the shelves are easily movable, allowing a Cabinet or shelf system to be adaptable so as accommodate a variety of articles. These and other objects, advantages, and features of the invention will be more fully understood and appreciated by reference to the description of the current embodiment and the drawings.

Main Controller

The Main Controller performs the function of communication, control and command scheduling. It connects to the various payloads through a common interface depending on the role for which it is being deployed.

Test and Results

Both hardware and software tests are conducted to check its feasibility. Hardware testing is done for boards on the physical cabinet. Software testing is done for the application and reporting system that controls the cabinet.
After the board has been populated it may be tested in a variety of ways:

1.      While the power is off, visual inspection, automated optical inspection. JEDEC guidelines for PCB component placement, soldering, and inspection are commonly used to maintain quality control in this stage of PCB manufacturing.

2.      While the power is off, analog signature analysis, power-off testing.

3.      While the power is on, in-circuit test, where physical measurements (i.e. voltage, frequency) can be done.

4.      While the power is on, functional test, just checking if the PCB does what it had been designed for.

Conclusions

This paper describes the use of Radio Frequency Identification for simplifying the healthcare management. iRISupply is the system designed for tracking the inventory and patients. Hardware design was developed to store the inventory that was controlled by the application.

Reporting system of the inventory is simple and user friendly.

Tagging the products with RF tags was done with Synergy software. Overall, the system is simple with patient interface and reporting system.

Future enhancements for tagging procedures are being planned to reduce the time for tagging each product. Also, scan times of the antennas need to be reduced to improve systems speed.

 Presented BY

Choudhary Ritesh
roll no 24

Design of PISTON for BAJAJ AVENGER 220 DTS-I

                    Design of Piston

BY Choudhary Ritesh, 24
        Ashish Chaursasia, 18

 

The piston is a disc which reciprocates within a cylinder and is either moved by or moves the fluid which enters the cylinder. The piston of an I.C engine receives the impulse from the expanding gas & transmits the energy through the connecting rod to the crank.

Piston design is a challenging engineering problem which involves complex physics and requires satisfying multiple performance objectives. Uncertainty in piston operating conditions and variability in piston design variables are inevitable and must be accounted for. The piston assembly can be a major source of engine mechanical friction and cold start noise, if not designed properly.

MODEL OF ENGINE CHOOSEN FOR STUDY:

BAJAJ AVENGER-220 DTSI

 http://www.hastingsmfg.com/ServiceTips/piston.htm

        I.            GIVEN DATA :

                                      Displacement=219.89cc

                                      Maximum power=19.03  Ps @8400rpm

                                     = 14 kw

      II.            SOLUTION:

                                   Volume = π/4 d2 *l

                                  219.89=π/4 d2*1.5 d        {Assuming l=1.5d}

                                  219.89=π/4 *1.5 d3

                                  D=5.174cm=6cm=60mm

1.  PISTON HEAD OR CROWN:

The thickness of the piston head or crown is determined on the basis of strength as well as on the basis of strength as well as on the basis of heat dissipation and the larger of the two values is adopted.

(a)  Thickness(tH) of piston head on the basis of strength

Material Selection:  selecting material for piston as aluminium alloy.

Permissible bending [tensile] stress

σ=50 to 90 MPa

th=σ                                                   {taking p=45kg/cm2  f=500 kg/cm2}

tH=0.78cm=7.8 mm

2.  HEAT FLOWING THROUGH THE PISTON HEAD:

H=C*HCV*m*BP

C= Constant representing that portion of the heat supplied to the engine which is absorbed by the piston.

It varies from 5 to 20 %

HCV= higher calorific value of the fuel  47*103 KJ/BP/hr for petrol

m= Mass of fuel used in kg/BP/sec

H= 0.05*47*103 *41.7*10-6 *14

 =1.37 kW

{Taking c=5%                 m=0.15 kg/BP/hr= 41.7*10-6 kg/BP/sec }

(b)Thickness of piston head on the basis of heat dissipation

                tH=(1.37*103)/(12.56*174.75*75)

                            tH =0.0083m=8.32mm

Taking the larger of two values

              tH=8.32 mm

k= thermal conductivity factor 174.75 W/M/ 

[Tc-Te]=temperature difference  = 75 

3.  RADIAL RIBS:

Assumption:  (a)  3 compression  rings

                         (b) 1 oil ring

Radial thickness of piston rings  t₁ = σ 

T1=0.388=3.88mm

                 Taking pw=0.7 kg/cm2

                  σt  =500 kg/cm2

                  t2=0.7t1=0.7*3.88=2.716 mm

        The minimum axial thickness of the piston ring

                tr =D/10nl=6/(10*4)=1.5 mm

                Axial thickness of the piston ring as already calculated [tr=2.7] is satisfactory.

                Distance from the top of the piston to the first ring groove,i.e. width of top land

                                b1=(1 to 1.2)tr = 1.2*8.33=9.99≈1 cm

                Width of the other ring lands

                                b2=(0.75 to 1)t2 =2.7 mm

                The gap between the free ends of ring

                                G1=[3.5 to 4]t1

                                G1=4*3.8=15.2 mm

                Gap when the ring is in the cylinder

                                G2=[0.002 to 0.004] D

                                G2=0.004*6=0.024 cm=0.24mm

4. Piston Barrel

                Radial depth of the piston ring gloves

                b=t1+0.4

                  =2.21+0.4=2.25mm

Maximum thickness of Barrel

                t 3=0.03D+b+4.5

                    =(0.03*45)+2.25+4.5=8.1mm

Piston wall thickness towards the open end,

                t 4=0.25 to 0.35 times t3

                t4 =0.30*8.1=2.43mm

5.Piston Skirt

                Let,l=length of the skirt,mm

The maximum side thrust on the cylinder due to gas pressure

R=µ*π/4*d2*p

                  =0.1*π/4*2025*4.414

                  =702.02N

Taking µ=0.1

             P=45*9.81*(1/100)=4.414N/mm2

Side thrust due to bearing pressure on the piston barrel (Pb)

                R=Pb*D*l

                   =0.45*45*l   taking Pb=0.45Mpa

                   =20.25l N

20.25l=702.02N

    L=34.67mm

Therefore total length of the Piston

L=length of the skirt + length of the ring section + top land

  =l+[4(ti)+3b2]+b1

 L =34.67+[4*1.5+3*2.7]+10=58.77mm

6.Piston Pin

                d0=outside diameter of pin,mm

                l1=Length of pin in the bush of the small end of the connecting rod,mm

                Pb=Bearing pressure at the small end of the connecting rod bushing in N/mm2

                      For bronze bushing=25 N/mm2

Load on the pin due to bearing pressure,

                =Bearing pressure * Bearing Area

                =Pb1*d0*l1

                =25d0*0.45*45            [l1=0.45D]

                =506.25 d0 N

Maximum gas load =π/4 (D*D)*P

                                =π/4*2025*4.4

                                =6.998 KN

therefore 506.25 d0=6998 N

                             d0=13.824 mm ≈14mm

inside diameter of pin d1=0.6*d0

                                                =0.6*13.824=8.3mm

                d1=9 mm

Let the Piston pin be made of heat treated alloy steel for which the bending stress (σb) may be taken as 180 NPa

                To check induced bending stress in pin

Maximum bending moment at center of pin

                M=P*D/8

                    =7*45*10^3/8=39375

Also,the maximum bending moment

                39375=π/32[d04-di4/d0]σb

                93300= π/32[14^4-9^4/14] σb

σb=176.48 N/mm^2

Since the induced bending stress in the pin is less than the permissible value of 180 Mpa.

Therefore, the dimensions for the pin as calculated above (i.e.d0=14 mm & di=9 mm)are satisfactory.

 Design considerations that are considered

1. The piston must have the strength to resist the impulse and inertia forces.

2. Ability to disperse the heat of combustion and avoid thermal distortion.

3. Sealing the gas and oil

4. Sufficient bearing area to work for large number of reciprocating cyles

5. Minimum weight

6. Smooth noiseless operation

7. Provide adequate support for piston pin

1) Introduction to Piston:-

 The piston is a disc which reciprocates within a cylinder and is either moved by or moves the fluid which enters the cylinder. A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder. In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder wall.

The Crown:

The crown is the top most part of the piston. It is subjected to high temperature in the combustion space and the surface is liable to eroded/burn away. For this reason material for which is made up of must be able to maintain high strength and resist corrosion at high temperature.

The Ring lands:

Are the reliefs cut into the side profile of the piston where the piston rings sit. The ring lands are typically taller than the ring thickness which allows the rings to move and rotate in the bore. It

also allows combustion pressure to contact the entire piston ring top face inside the ringland pressing it down (and out in some designs) improving ring seal.

The Skirt:

The piston skirt is the extension of the side profile of piston which controls the piston movement in the bore preventing it from wobbling around and controlling the angular forces present on the piston walls from the angular rotation of the crankshaft.

The Underside:

This part of the piston is exposed to the crank case and houses the wrist pin (connecting the piston to the rod) and exposed to the engine oil in 3 ways:

Oil collected by the oil retention ring (the bottom most piston ring) is routed through holes in the side of the piston to the underside to drain back into the crank case.

Oil sloshing around in the crankcase due to the crankshaft counterweights dipping in and out of the oil sump as well as oil forced up through the connecting rod up to lubricate the wrist pin (on forced oil pins).

On engines equipped with oil squirters under the piston, where oil is squirted on the underside to help cool the piston mass for longevity or racing applications, which in some situations may also allow for an overall thinner crown without sacrificing the strength of the piston and while reducing the overall weight of the package.

PISTON NOMENCLATURE

 

 

PISTON MATERIAL:

Materials used in piston are, for the most parts, either aluminium alloy or some form of cast iron. Various alloys of cast iron are used including the special form Meehanite.  A few engines use malleable cast iron. Pin carrier inserts are generally cast iron but sometimes are made of heat treated steel forgings. A few large assembled pistons have a separate crown made of either cast steel or a steel forging.

 The coefficient of expansion, the increase in size per degree of temperature increase of aluminium is approximately twice that of cast iron. This fact must be taken into account when determining minimum piston clearance.

 The heat conductivity, the rate of heat flow, of aluminium is approximately three times that of cast iron. The result is that an aluminium piston has less variation in temperature from top to bottom.

The density of cast iron is three times as much as aluminium. This does not mean that an aluminium piston weighs only a third as much as a cast iron piston because strength and heat transfer problems dictate that the metal sections of an aluminium pistons be made proportionately thicker.

Manufacturing:

Die Casting of Aluminium

Casting is the beginning of the piston. At the foundry the die is prepared by heating it to operating temperature for approximately one hour. This process allows the die to readily accept the molten material when it is poured.

   Process starts by heating the material to 700 degrees Celsius. This is well above the melting point of the aluminum, but below its boiling point. The material is then scooped up with a ladle from the crucible (the pot that holds the molten material). This is then poured into the die through the sprue. The material is then allowed to cool before it is removed from the die and placed into a bin of hot water. This water is used to facilitate a more even settling of the hot metal.

After the castings have had time to cool they are placed into a heat treatment plant overnight. This process tempers the casting and ensures the piston will have improved qualities.

After it is removed from the heat treatment the casting has its runner removed.

Process Parameters:

Dies used are 5 piece and three piece.

These dies are made from cast iron

Temperature: 700 degrees Celsius 

Pin Boring

At this stage of the piston manufacturing process the casting has the gudgeon pin hole rough machined and the locating bung machined. This process is where the casting is machined on the base to allow placement of the casting in other machines. This is carried out on a simple lathe.

The pin bore

    Pin boring is done in conjunction with the bung turning, as one casting is removed from having the bung face machined it is placed on the pin borer.

The pin borer is only a rough machining process which allows the reamer to enter the gudgeon hole later.

CNC Turning

Turning of the casting is carried out on CNC (Computer Numeric Control) machinery. This equipment is the most accurate and fastest available for this application with very tight tolerances and extremely fast spindle speeds.

        The castings are placed in the lathe on a bung and held in place by a solid rod through the gudgeon pin hole. A draw bolt is activated in the chuck which draws the rod toward the chuck and holds the piston in place.

    The lathe is then started and the machining cycle begun. This cycle is programmed into the lathe in a basic language called G-Code (this code is not the only one available). G-Code has basic commands to tell the lathe to move to certain positions (X,Y,Z co-ordinates), at particular spindle speeds (eg S2500 means spindle speed 2500rpm), at particular feed rates (eg G01; rapid traverse) and other commands such as M01 (repeat programmed) and others.

After the piston is machined it is removed from the lathe and the part number stamped on the crown (top) of the piston.

Machine specifications:

Machine used : CNC Lathe ECONO CNC 26.

Maker : HMT

Height of centres : 260 mm

Swing over bed : 575 mm

Swing over cross slide : 340 mm

Distance between centers : 1000 mm

Speed range : 40-2040 rpm

Process parameters:

Rough turning:

Speed : 25 m/s

Feed : 0.5 mm per rev

Depth of cut : 0.4 mm

Drilling

The first stages of the finishing process include drilling, slotting, valve and crank relieving.

Drilling

Drilling includes all oil holes in places such as the gudgeon pin bosses and oil ring grooves.

Slotting

Slotting is where slots are placed in the skirt or in the oil ring groove.

Valve relieving

This process is done on a mill and involves setting the machine up for the process, choosing the correct cutter and completing the job. Since there are so many different types of valve reliefs it is impossible to have a specialised machine set up to do one job.

Crank relieving

Crank relieving is carried out on a specialised machine which scallops the skirt of the piston to the required shape and depth by using two opposed cutters placed on a common shaft.

Grinding

    This process involves the final size being machined on the piston. The grinder machines the skirt of the piston only and in the majority of cases is cam ground. Cam grinding ensures the piston will "grow" evenly in the bore of the engine. A perfectly round piston will expand unevenly during use because of the uneven placement of material in the casting (gudgeon pin bosses and ribbing used for strengthening).

Machine specifications:

Machine used : CNC Grinding machine - PMT-AWH-100

Maker : PMT

Grinding length (max) : 1000 mm

Height of centres : 450 mm

Grinding diameter (max) : 450 mm

Grinding wheel diameter : 350 mm

Process parameters:

Rough Grinding:

Speed of wheel : 20 m/s

Feed of workpiece : 1 mm per min

Depth of cut : 0.05 mm

Finish grinding:

Speed of wheel : 40 m/s

Feed of workpiece : 0.5 mm per min

Depth of cut : 0.02 mm

Reaming

    Final machining process for the piston is that of reaming. This process involves the piston being placed in a bath of oil and reamed at different sizes to reach the final size required. Since the pin boring process is only rough it is necessary to ream the pin bore a number of times to achieve the surface finish and size required. Reaming is not a fast process and is only partially automated (there are automatic feeds on the reaming machines). Tolerances achieved on the finished reamed surface is 0.4Ra. 

Radial drilling machine is used for performing reaming operation.

Machine specifications:

Machine used : Radial drilling machine - KML -40A

Maker : KML

Drill capacity (in steel) : 40 mm

Drill depth : 180 mm

Taper spindle nose socket :MT-4

No. of speeds and range : 6 (45-660 rpm)

Drill power : 10 KW

Process parameters:

Drilling:

Speed : 20 m/s

Feed : 0.1 mm per rev.

7.Pin Fitting and Final Inspection

At this stage the piston is cleaned, fitted with the appropriate gudgeon pin, stamped with the pistons' oversize and any other markings, and then sent to despatch.

8.Despatch

Finally, the piston is wrapped and placed in the shipping container with the ring set and sent to the customer.

References:

http://www.jp.com.au/Made.html

http://www.superchargerperformance.com/supercharger-power-parts/introduction-to-piston-design-for-forced-induction-engines