CASE STUDY: INTELLIGENT MANUCATURING VIA AUTOMATION TOOLS AT HYUNDAI TRANSLEAD

CASE STUDY: INTELLIGENT MANUCATURING VIA AUTOMATION TOOLS AT HYUNDAI TRANSLEAD

AZNIZAM BIN ABDULLAH

Maizul Afzairizal bin. Mohd Adnan

Mohd Fuad bin. Ibrahim

Mohamad Taufik bin. A. Rahman

1.0  Introduction

Hyundai Translead is one of the companies own by Hyundai Motor Company Korea that run in United States. It produces trailer manufacturing. Although Hyundai is known for their advance in robotic automation, however Hyundai Translead is not using robot on line H. Hyundai Translead is a leading manufacturer of dry and refrigerated van trailers, domestic containers, container chassis and converter dollies for the North American transportation industry. It was established in San Diego, CA in November 1989 by the name Hyundai Precision America Incorporated with manufacturing facilities in Tijuana, Mexico.  [1]. 1996, the company was the first major trailer manufacturer in North America to receive ISO: 9001 Certification, which was awarded for consistent and documented quality in manufacturing, and has earned re-certification every year since.

Hyundai Translead was established in San Diego, CA in November 1989 by the name Hyundai Precision America Incorporated with manufacturing facilities in Tijuana, Mexico. In March, 2001 the company had changes its name to Hyundai Translead and by November 2002 the company has come out with two US patent: new redesigned variable height gooseneck patent and new method for fabricating reinforced sliding gear track holes. In October 2004, HT has come out with prototype testing capabilities expend with the additions of increase strain gauging, photo stress technology and finite element analysis modelling. In March 2005, with new warehouse building and the re-engineering of sub-assembly component manufacturing area, the company production capability was increased by 25%.   Here, the case study at Hyundai Translead is used to see the element of intelligent manufacturing. There are three cases will be discussed and elaborate shown in Figure 1

 

2.0  Why did the company opt for other forms of non-intelligent tool?

In 2001, the company has bought two robots but later neglected them. But they stop using the robots since they are not worth compare to technology changing. According to them, instead of using the robot, they use the tools that already provided by the Korean operations. It is cheaper than using robots and the tools is already installed in the plant. The robots are outdated before the cost of purchasing can be obtained.  Robot failures are costly and difficult to diagnose [2]. It also cost in maintenance and need highly trained personnel to operate the robots.

Hyundai Translead is headquartered in San Diego. Its manufacturing plant is in Mexico, and the parent company is Korea. Here, we believe the HT uses expert system based on available data from parents company at Korea. The data mining alread available at parent company as quoated below:

When Hyundai Translead began to plan its new 154,000-square-foot building for high-speed production of dry-freight van trailers, the manufacturer had a ready source for ideas — its parent company.

This is because by application of knowledge based manufacturing strategy will make manufacturing a simple straight forward.

Production rule base:

IF production planning and control very complex, THEN no chance of developing the system that will solve production problem. Computers DO supplying data, WHILE the decisions should be made by people.

As reported in the [1] among the fixtures and equipment found in the H line that help Hyundai achieve those objectives:

·         Greater use of scissors lifts.

·         Automated roof assembly machine.

·         Improved mounting stations.

·         Balancing devices that can move heavy loads with fewer people.

3.0 How did their manage bottleneck?

HT used a conventional cart system instead of using a conveyor. In their opinion, using cart system can eliminate bottleneck. The bottleneck came from the failure. When something goes wrong at the conveyor, whole production will stuck. But if there a problem at the cart, they just been rejected. It is more flexible compare to conveyer. They also did not use forklift. According to them, by throwing the conveyer and forklift the efficiencies of line H are better compare to other line. They also declare that by using the system they can avoid bottleneck. The fundamental is the factory plan in holistic view we can see:

If used conveyor THEN all production line is connected and fixed.

If used CART, DO divide and concoquer THEN the the production line is MODULAR/FLEXIBLE

 

4.0  The Reason behind the Prohibition of Forklift.

The main reason behind the prohibition of forklift is maybe because of it is not suitable with the work at H line.However, there are other disadvantages of using the forklift. Most forklifts are powered by electricity or propane, but some also use gas and diesel. Electric forklifts have a few disadvantages. Some of them include recharging, battery weight, and power. There are about 5 disadvantages of using forklift. There are recharging, weight, charging station, location and power. 

Furthermore, in article reported in [1] and [2] Hyundai Translead has released a new dry van trailer with an extended scuff rail to prevent forklift damage. If a forklift hits the lower inside rail of the HT Composite XT Dry Freight Van Trailer, it will hit the aluminum bottom rail and not the composite sidewall panels, reducing downtime, the company said.

i.                    Recharging

One of the disadvantages of electric forklifts is the amount of time they take to recharge. It takes about six to eight hour to recharge and take another eight hours to cool off before it can be use for six hours.

ii.                  Weight

The weight of the battery is also a disadvantage of electric forklifts. The battery can weigh as much as 3,500 pounds. It a bit difficult to charge the battery in a routine since the battery is very heavy. Therefore, special battery hoists just to change the batteries where it will involve with more expenses.

iii.                Power

Another disadvantage of electric forklifts is their power. Forklifts with internal combustion engines are capable of generating more torque and power. However, electric forklift can’t handle more than 15000 pounds load.

iv.                Charging Station

Another disadvantage of electric forklifts is that they require a charging station. Area that houses the charging station for electric forklifts must be dry, ventilated, and has a controlled temperature. Other types of forklifts don't need a charging station as they can be refueled practically anywhere

v.                  Location

One of the final disadvantages of electric forklifts is that they should rarely be used outdoors. The fact that they generate no emissions makes them perfect for indoor use, but this does you no good if you need a forklift that can be used outside. However, you can sometimes use electric forklifts outdoors only if you use them on a well-paved location. Also, you need to make sure you don't use them in the rain because doing so is very unsafe.

These are some of the disadvantages of electric forklifts. They will only provide power for six hours before needing to be recharged for eight hours. The batteries used for electric forklifts are also considerably heavy, so a special crane just to change the battery.

5.0  How did Hyundai maximize its operation efficiency

HT has come out with the objective of maximizing the efficiency. Among the fixturesand equipments found in the H line is:

·         Greater use of scissor lifts

·         Automated roof assembly machine

·         Improved mounting stations

·         Balancing devices that can move heavy load with fewer people.

·         Material flow is straight, and subassemblies are produced close to where they are needed on the line. For example, the side table is located at the beginning of the assembly line. It feeds directly into the assembly line.

·         Front walls are built in the same area. Completed walls are loaded onto a cart that is capable of delivering six completed front walls to the line.

·         Floors also feed directly into the line.

·         They did more external process rather than internal process. The assembly line is not the place for fabrication.”

·         Gang drills, punching, and rivet machines reduce much of the time required to fasten flooring, side sheets, and extrusions.

6.0  Intelligent manufacturing via automation tools

In October 2004, HT has come out with prototype testing capabilities expend with the additions of increase strain gauging, photo stress technology and finite element analysis modelling

6.1 Finite Element Modeling

Engineering analysis of mechanical systems have been addressed by deriving differential equations relating the variables of through basic physical principles such as equilibrium, conservation of energy, conservation of mass, the laws of thermodynamics, Maxwell' sequations and Newton's laws of motion[3]. However, once formulated, solving the resulting mathematical models is often impossible, especially when the resulting models are nonlinear partial differential equations. Only very simple problems of regular geometry such as a rectangular of a circle with the simplest boundary conditions were tractable.

The finite element method (FEM) is the dominant discretization technique in structural mechanics. The basic concept in the physical interpretation of the FEM is the subdivision of the mathematical model into disjoint (non-overlapping) components of simple geometry called finite elements or elements for short[3]. The response of each element is expressed in terms of a finite number of degrees of freedom characterized as the value of an unknown function, or functions, at a set of nodal points.

The response of the mathematical model is then considered to be approximated by that ofthe discrete model obtained by connecting or assembling the collection of all elements.The disconnection-assembly concept occurs naturally when examining many artificialand natural systems[3]. For example, it is easy to visualize an engine, bridge, building,airplane, or skeleton as fabricated from simpler components. Unlike finite differencemodels, finite elements do not overlap in space.

6.1.1 Finite Element Analysis

Some information that software system required in finite element analysis are:

·         Nodal point spatial locations (geometry)

·         Elements connecting the nodal points

·         Mass properties

·         Boundary conditions or restraints

·         Loading or forcing function details

·         Analysis options

Because FEM is a discretization method, the number of degrees of freedom of a FEMmodel is necessarily finite. They are collected in a column vector called u. This vector isgenerally called the DOF vector or state vector. The term nodal displacement vector for uis reserved to mechanical applications[3].

6.1.2 FEM Solution Process

Procedures

·         Divide structure into pieces (elements with nodes) (discretization/meshing)

·         Connect (assemble) the elements at the nodes to form an approximate system ofequations for the whole structure (forming element matrices)

·         Solve the system of equations involving unknown quantities at the nodes (e.g.,displacements)

·         Calculate desired quantities (e.g., strains and stresses) at selected elements

6.1.3 Basic Theory

The way finite element analysis obtains the temperatures, stresses, flows, or other desiredunknown parameters in the finite element model are by minimizing energy functional.Energy functional consists of all the energies associated with the particular finiteelement model. Based on the law of conservation of energy, the finite element energyfunctional must equal zero[4].

The finite element method obtains the correct solution for any finite element model byminimizing the energy functional. The minimum of the functional is found by setting thederivative of the functional with respect to the unknown grid point potential for zero[4].

Thus, the basic equation for finite element analysis is

Where F is the energy functional and p is the unknown grid point potential (In mechanics, the potential is displacement) to be calculated. This is based on the principle of virtualwork, which states that if a particle is under equilibrium, under a set of a system offorces, then for any displacement, the virtual work is zero. Each finite element will haveits own unique energy functional.

As an example, in stress analysis, the governing equations for a continuous rigid bodycan be obtained by minimizing the total potential energy of the system. The totalpotential energy P can be expressed as:

whereΩand εare the vectors of the stress and strain components at any point, respectively, d isthe vector of displacement at any point, b is the vector of body force components per unitvolume, and q is the vector of applied surface traction components at any surface point.

The volume and surface integrals are defined over the entire region of the structure Ω andthat part of its boundary subject to load Г. The first term on the right hand side of thisequation represents the internal strain energy and the second and third terms are,respectively, the potential energy contributions of the body force loads and distributedsurface loads[3].

In the finite element displacement method, the displacement is assumed to have unknownvalues only at the nodal points, so that the variation within the element is described interms of the nodal values by means of interpolation functions[4]. Thus, within any oneelement, d = N u where N is the matrix of interpolation functions termed shape functionsand u is the vector of unknown nodal displacements. (uis equivalent to p in the basicequation for finite element analysis.) The strains within the element can be expressed in terms of the element nodal displacements as ε= B u where B is the strain displacementmatrix. Finally, the stresses may be related to the strains by use of an elasticity matrix(e.g., Young’s modulus) as σ= E ε.

The total potential energy of the discretized structure will be the sum of the energycontributions of each individual element. Thus, where Π_e represents the totalpotential energy of an individual element.

The physical significance of the vectors u and f varies according to the application beingmodeled.

Application Problem	State (DOF) vector d Represents	Forcing vector f represents
Structures and solidmechanics	Displacement	Mechanical force
Heat conduction	Temperature	Heat flux
Acoustic fluid	Displacement potential	Particle velocity
Potential flows	Pressure	Particle velocity
General flows	Velocity	Fluxes
Electrostatics	Electric potential	Charge density
Magnetostatics	Magneticpotential	Magnetic intensity

6.2 Stress Analysis bythe PhotoStress Method

PhotoStress is a widely used full-field technique foraccurately measuring surface strains to determine thestresses in a part or structure during static or dynamic testing. With the PhotoStress method, a special strain-sensitiveplastic coating is first bonded to the test part. Then, astest or service loads are applied to the part, the coating isilluminated by polarized light from a reflection polariscope. When viewed through the polariscope, the coating displays the strains in a colorful, informative pattern whichimmediately reveals the overall strain distribution and pinpoints highly strain areas. With an optical transducer (compensator) attached to the polariscope, quantitative stress analysis can be quickly and easily performed.

Permanent records of the overall strain distribution can bemade by photography or by video recording[2].

The advantages of using photostress are:

•          Instantly identify critical areas, highlighting overstressed and under stressed regions.

•     Accurately measure peak stresses and determine stress concentrations around holes, notches, fillets, and other potential failure sites.

•         Optimize the stress distribution in parts and  structures for minimum weight and maximum reliability.

•     Measure principal stresses and directions at any pointon the coated part.

•     Test repeatedly under varying load conditions,without recoating the part.

•     Make stress measurements in the laboratory or in thefield — unaffected by humidity or     time.

•     Identify and measure assembly stresses and residualstresses.

•     Detect yielding, and observe redistribution of strains in the plastic range of deformation.

PhotoStress coatings can be applied to the surface ofvirtually any test part regardless of its shape, size, ormaterial composition.

PhotoStress has an established history of successfulapplications in virtually every field of manufacture andconstruction where stress analysis is employed, including:automotive, farm machinery, aircraft and aerospace, building construction, engines, pressure vessels,shipbuilding, office equipment, bridges, appliances, plusmany others[2].

Reference

[1]        ........,2012. About Hyundai Translead [online]

Available at:http://www.translead.com/php/1_abo/1_abo.php [retrieved at 20 November 2012]

[2]        ........,2011. Introduction to Stress Analysis by the PhotoStress® Method [online]

Available at: http://www.vishaypg.com/docs/11212/11212_tn.pdf [retrieved at 20 November 2012]

[3]        .........,2012.Finite Element Analysis [online]

Available at: http://usa.autodesk.com/adsk/servlet/item?siteID=123112&id=17670721  [retrieved at 20 November 2012]

[4]        Starr.A.G., et al.2005.Failure Analysis of Mature Robots in Automated Production.Journal of Engineering Manufacture.August 1, 1999 213: 813-824

1