How do you determine procurement costs for product design, materials, and specifications? A superb way to get valuable insights and pinpoint design improvement and cost reduction opportunities is through a product teardown study. What is a product teardown?

In simple words, the process of disassembling a part to understand how it has been made and its functionalities are known as product teardown.

A product teardown process is an orderly way to know about a particular product and identify its parts, system functionality to recognize modeling improvement and identify cost reduction opportunities. Unlike the traditional costing method, tear down analysis collects information to determine product quality and price desired by the consumers. Companies can understand their competitor’s product, on what ground it differs from their own and manufacturing cost associated.

The three primary reasons for a product teardown study are:

• Breakdown and Analysis:

It involves understanding the current technology, functionalities, and components of a product as well as identifying its strengths, weaknesses, and establishing areas for improvement.

• Benchmarking:

Benchmarking is establishing a baseline in terms of understanding and representation of the product. It provides a comparison of new conceptual designs.

• Knowledge and product improvement:

It involves gaining engineering knowledge to enact new room for concept development.

The entire product teardown process can be summed up in five steps:

• Identifying the purpose of the teardown. This is to determine the models to be enacted as a result of the process
• Creating data sheet where all insights will be listed
• Gathering tools and documentation of the process
• Analyzing the distribution of product
• Disassembling of product, component measurement, and functionality assessment
• Creating a bill of materials (BOM), models, and function flow diagram

The product tear down study technique has proven to be suitable to obtain crucial data about the manufacturing method, components, build-up model, functionality and strategies of competitors to find for improvement and coming up with a more refined version of a product.

Material Selection

Material selection stands out to be one of the most crucial aspects of engineering design as it determines the design reliability in terms of industrial and economic viewpoints. A great design needs appropriate material combinations, or else it will fail to be a profitable product. Engineers need to choose the best materials for the same, and there are several criteria they rely upon, such as property and its reaction to given conditions.  

Some important points to be included are:

• Mechanical properties: A design needs to go through various manufacturing practices depending on the material. The primary goal is to prevent the failure of the product from a material viewpoint and ensure service fit. The materials are subject to stress, load, strength, and temperature variations.

• Wear of materials: Most of the time, chances are that materials are contacting each other in a product. It can be seen in the case of gears. The selected materials should be able to withstand wear and tear.

• Corrosion: This is a condition where the importance of material selection can be witnessed the most. It is evident in products open to the environment for an extended period. Materials like iron are highly prone to corrosion. So it is essential to make that the material is corrosion resistant and capable of being used for the product.

• Manufacturing: Although the material is fit to be used for a product, it has to be appropriate for the manufacturing process. Improper machining can lead to a faulty product, and incorrect machining stems from an inability to put manufacturing functions of materials.

• Cost: Cost is a crucial fact to consider while selecting materials. Certain metals are rare to obtain, considering their availability and lengthy refining process. Although the cost factor can be neglected when performance is given priority, overall associated costs should be considered nonetheless. There is a reason why plastics have massively replaced metals in the manufacturing process.  

 

 

The quality control and inspection process in reverse engineering usually take three steps to determine if the 3D CAD model of the part is available or not. Those three steps are as follows:

• The first step involves scanning the part and generating a computer model's point cloud format.
• The second step involves merging and aligning the two computer models (CAD and Scanned one) to validate the part's specifications.
• The final step, i.e., step three, includes visual computer model inspections and alignment of the merged models for any deviations in the geometry and dimensions.

The quality control outcome would be some recommendations for corrections, so the part meets perfectly with the blueprint specifications before the part's mass production.

Following are some uses of Reverse engineering inspection: 

• Reverse engineering inspection comes in handy while carrying out Zero Article Inspection or ZAI. Zero article inspection is a type of workflow where the upcoming physical part doesn't follow the master design model but rather a derivative of the master model due to fluctuations in dimensions and tolerances. The review of the last digital representation before downstream purposes is known as zero article inspection. In this case, reverse engineering inspection provides sufficient information, allowing the inspector to check tolerances, dimensions, and any other information relevant to such projects. It gives assurance and confidence to produce quality components.
• Reverse engineering inspection is an essential inspection of stylized parts/surfaces - where just dimensional inspection is not enough.
• Reverse engineering inspection is an essential player during First Article Inspection (FAI). During the part manufacturing process, when an issue is detected with the manufactured part, the notification of the same has to go back to its design. The purpose is to keep the 3D CAD model in sync with the actual piece as manufactured. The hybridization of reverse engineering and inspection makes such updates easy to convey and apply, plus keeps the feedback circle opens across departments.
• Reverse engineering inspection has found significant use in the additive manufacturing industry. Such a process helps bring down process-generated errors while calibrating & modifying building criteria to cut down the process itself's influence.

3D Scanning – The process of collecting 3-Dimensional data from physical object through a variety of data acquisitions devices.

3D to CAD: The process of converting 3-Dimensional point to a dimensionally defined graphic model.

Accuracy: The extent of how close a measurement is to the recognized true value.

Annotation Models: A digital model containing specific coordinate locations verifying deviations from nominal data.

AS IS CAD: A CAD model that represents actual manufactured parts rather than a designed CAD model.

CAD (Computer-aided design): The use of computer technology to assist in the creation, analysis, or modification of a design.

CAM (Computer Aided Manufacturing): The use software that can support both machine tools and 3D CAD modeling capabilities.

Cone beam: A conical-shaped x-ray beam that produces two dimensional images of an object.

Design intent: The process of taking a manufactured part into account with inherent errors and modifying the same till it is true.

GD&T (Geometric Dimensioning and Tolerancing): System of languages and symbols used for defining and communicating engineering tolerances.

Hand held scanner: Portable camera that is used for capturing 3D imagery of objects with a laser or structured light based.

Hybrid Model: Combining two different modeling processes to accurately define 3D geometry.

Laser Scanner: A device used to capture 3D surface geometry, consisting of a laser output and a sensor to interpret the data.

LIDAR: A combination of the words: “Light” and “RADAR.” A LIDAR scanner employs RADAR’s technique of emitting a signal and measuring distances to objects based off of the signals reflection.

Long Range Scanning: Acquiring data at expansive distances from hundreds of feet away to miles away. Data can be captured through a variety of devices including LIDAR, Time of Flight and phase shift scanners.

Modeling: Digitally creating 2D or 3D object using CAD or data manipulation software, such as Polyworks, Geomagic or Solidworks.

NanoCT: Capturing images using CT (Computed Tomography), with a resolution of the images defined in nanometers.

Parametric Model: A sketch driven model that builds a design tree that can be opened in a CAD environment and allows the operator to manipulate the model.

Parametric Modeling: This process is taking 3d scan data and through the use of design tools, creating a sketch driven model with consistent relationships between features in the feature tree.

Phase Based Scanners: LIDAR Scanners that take measurements by sending laser pulses towards an object and measuring the phase shift of the pulses’ reflection off of the object.

Point Cloud: A set of points defined by X, Y, and Z coordinates that represent the external surfaces of an object.

Prismatic Modeling: Creating CAD geometry using basic geometry shapes, i.e. planes, cylinders, cones etc, to define correct shapes of the 3D geometry.

Re-Engineering: The process of modifying an existing part or assembly of parts digitally to improve its performance or use.

Repeatability: The variation in measurements taken with the same piece of equipment, under the same conditions, across multiple tests.

Reverse Engineering: The process by which a man-made object is dismantled to reveal its architecture, designs, or to extract knowledge from the object in order to know about its functioning and structural integrity.

SCAN to CAD: The process of collecting 3D data using 3D scanning hardware and converting the dimensional data to CAD format using a variety of software packages.

2D Drawings / Schematics: A 2D print that describes the physical characteristics of an object, how it should be made, assembled, handled, etc. These can be used to provide basic dimensional values to define its function.

Sectioning: The process of creating 2D profiles through sections of an object.

Short range scanning: A process used to collect dimensional data in 3D space from short ranges.

Solid Modeling: Defining an object with CAD tools such as extrudes, revolves, sweeps, etc. A solid model is enclosed and is said to have mass and volumetric values can be calculated.

Surface Model: An objects exterior skin defined by CAD features or NURBS surfaces.

Triangulation Scanner: Projecting a known pattern of light grids or fringe onto an object in order to calculate surface geometry by analyzing the distortions of the pattern.

White Light Scanner: A 3D camera projecting a known pattern of light grids or fringe onto an object in order to calculate surface geometry by analyzing the distortions of the pattern.

We all know reverse engineering is an economical approach towards product development & innovation which is often utilized by manufacturers to evaluate and redesign competitor products. The method requires understanding the product design, system integrity and the manufacturing processes involved to realize the potential required to build a similar or an improved version of the product. The reverse engineering technique is best suitable for producing design data and related technical manuals for products that no longer have any design information available.

The entire work-process involves engineers studying every single design feature, associated manufacturing processes and tools needed for product development and storing information using CAD tools. After digitizing the entire information, suitable design modifications are carried out as per requirements.
However, to get things right one should have an efficient and dedicated engineering team, right software and hardware tools, etc. which seems difficult to have within the organization always.

Here comes the advantage of outsourcing reverse engineering projects where the activities can greatly reduce the cost of product development and burden on the engineers who can, then, put full emphasis on developing innovative design solutions for the product.

If one still questions outsourcing, some of the important benefits to outsourcing reverse engineering projects are mentioned below.

• Outsourcing can bring in a global pool of talent with the myriad of innovative ideas that can assist in product design and development without investing in infrastructure and resources.
• As the in-house resource can focus on R&D, it greatly helps in improving the productivity of an organization.
• Product development time reduces considerably.
• Hiring an outsourcing partner who matches requirement scale greatly enhances the organization’s capability.
• RE outsourcing presents a scope to develop the product at a competitive price since the development cost is considerably less.

 

You might be a seasoned design professional thinking “What do my bosses sit around and do all day while I do the real design work".

This section outlines and explores the various early stages of the industrial design process that a product goes through. It does serve as a reasonable account of the overall and general product design process.

• Ideating or initial ideas

Before any design work can begin on a product, there must first be a definition of what the product or product line might be. The idea’s genesis can be many factors such as:

Consumer demand – Reviews & feedbacks from the customers or even their ideas can help companies generate new product ideas.

Internal sources – Companies provide incentives and perks to employees who come up with new product ideas

Market research – Companies constantly review the changing needs, requirements and trends of the market by conducting plethora of market research analysis.

Competition – Competitors SWOT analysis helps companies to generate ideas.

• Idea screening

An idea can be excellent, good, moderate or very bad. Once a suitable product opportunity has been identified, a specification document or design brief is created to define the product. It is usually created by the higher management of a company who’ll have access to information, such as budgeting and buyer/seller feedback. This step involves filtering out the good and feasible ideas which maintains the technical integrity while staying within realistic cost expectations.

Features such as a mechanical specification or a reference to an existing invention the product might be based upon, are outlined. Expectations, uses, and underlying intelligence associated to the product are included as well. Electronics, including sounds, lights, sensors, and any other specific inputs, such as colors and new materials may also be mentioned. Finally, a few reference sketches or photo images can be added to convey a possible direction.

• Concept design & development

All ideas that pass through the screening stage are turned into concepts for testing purpose. A concept is a detailed strategy or blueprint version of the idea. In most companies, designers work up a design brief or product specification that guides their designs. It’s the designer’s role to make these ideas a reality. A professional designer has the ability to provide a large variety of designs in a quick and efficient manner. Many people can draw one or two ideas, but when asked to elaborate they often fall short. What separates the true design professional is depth and breadth of their presented ideas and vision in a clear and concise manner. Concept design generally means the use of hand-drawn or digital sketches to convey what’s in a designer’s mind onto paper or a screen.

• Business analysis

A detailed business analysis is required to determine the feasibility of the product. This stage determines whether the product is commercially profitable or not, whether it will have a regular or seasonal demand and the possibilities of it being in the market for the long run.

• Modeling

With the help of 3D modeling software (CAD – Computer Aided Design), the ideas/concept is rendered a shape, thereby creating a 3D model. The technical and engineering team has the biggest workload during this phase. These 3D models will often show up problematic areas where the theoretical stresses and strains on the product to be developed will be exposed. If any problem persists, it is a best phase of product development to handle the design errors and come up with modifications to address the same.

• Prototyping & pilot runs (preliminary design stage)

In this stage, prototypes are built and tested after several iterations and pilot run of the manufacturing process is conducted. This stage involves creating rapid prototypes for a concept that has been deemed to have business relevance and value. Prototype means a ‘quick and dirty’ model rather than a refined one that will be tested and marketed later on. Adjustments are carried out as required before finalizing the design.

• Test marketing

Apart from continuously testing the product for performance, market testing is also carried out to check the acceptability of the product in the defined market and customer group. It is usually performed by introducing the new product on a very small scale, to check if there are any shortcomings. This helps to know in advance, whether customer will accept and buy this product on launching in the market. Test marketing is a powerful tool indeed.

• New product launch

This is the final stage in which the product is introduced to the target market. Production starts at a relatively low level of volume as the company develops confidence in its abilities to execute production consistently and marketing abilities to sell the product. Product manufacturing expenses depend on the density of the product, if there are numerous parts, material selection etc. The organization must equip its sales and customer service entities to address and handle queries. Product advertisements, website pages, press releases, and e-mail communications are kept on standby on the launching day.

Product development is an ever evolving fluid process and cannot be summed up in a few steps. The entire procedure sees insertion of additional stages or even eviction of a crucial part, depending on the nature of the project. Each group of professionals, whether designers, engineers or marketing, sales; has their role to play in this methodology. It is the company’s responsibility to continuously monitor the performance of the new product.

Sometimes, situations arise where you don’t have access to a part’s original design documentation from its original production. This might be due to the absence of the original manufacturer altogether or stoppage on the production itself.

Reverse engineering empowers us to analyze a physical part and explore how it was originally built to replicate, create variations, or improve on the design. The goal is to ultimately create a new CAD model for use in manufacturing.

Let us take a look at the steps involved in reverse engineering. Commonly, it involves careful executions of the following steps:

• Scanning

The first step involves using a 3D scanner for collecting the geometric measurements and dimensions of the existing part quickly and accurately using projected light patterns and camera system. Generally, the types of scanners used for such execution are blue light scanner, white light scanner, CT scanner and /or laser scanner. The former two captures the outward dimension and measurements while the latter two is capable of scanning the entire inside out.

• Point Cloud

Once a certain part is scanned, the data gets transformed in the form of point clouds. Point cloud is a 3D visualization consisting of thousands or even millions of points. Point clouds define the shape of a physical system.

• Meshing/Triangulation

This stage serves involves conversion of point clouds to mesh (STL or Stereolithographic format). Mesh generation is the practice of converting the given set of points into a consistent polygonal model that generates vertices, edges and faces that only meet at shared edges. Common software tools used to merge point clouds are Polyworks, Geomagic, ImageWare, MeshLab. The meshed part is then run for alignment in the mentioned software tools.

• Parametric/Non-parametric Modeling

After the meshed part is aligned, it goes through either of two stages. The first option involves applying surface modeling on meshed part in tools such as Polyworks. It results in the generation of non-parametric model (IGES or STEP format). An alternate option is creating a sketch of the meshed part instead of putting it through surfacing. This work-process is known as parametric modeling (.PRT format). For a non parametric model, predicting future data is based on not just the parameters but also in the current state of data that has been observed. For a parametric model to predict new data, knowing just the parameters is enough.

• CAD Modeling

The next stage consists of transferring the data through CAD software tools such as NX, Catia, Solidworks, Creo etc, for applying functions such as ‘stitch’, ‘sew’, ‘knit’, ‘trim’, ‘extrude’, ‘revolve’ etc for creation of 3D CAD model.

• Inspection

This stage includes visual computer model inspections and alignment of the merged models against actual scanned parts (STL) for any discrepancies in the geometry as well as dimensions. Generally, inspection is carried out by using tools such as Polyworks or Geomagic. Reverse engineering inspection provides sufficient information to check tolerances, dimensions and other information relevant to the project.

• Documentation

Documentation of 3D stage model depends solely on one’s technical/business requirements. This step is about converting 3D model to 2D sketch, usually with the help of tools such as inventor or Isodraw/Coraldraw, citing measurements which can be used for reference in the future.

 

As we have seen during the introduction, the first step to reverse engineer a product is through scanning with the help of 3D scanners. Early eras have seen the painstaking task of obtaining dimensions of an existing product. These methods were time consuming and needed attention to details from the very first stage.

However, with the rapid development in the scanning technology, the inception of a product has caught speed and the chances of errors have reduced dramatically which has made 3D scanning and measurement an important part, starting from design stage to inspection stage.

3D laser scanning is the technology to capture a physical object’s exact size and shape using a laser beam to create a digital 3-dimensional representation of the same. 3D laser scanners create “point clouds” of data from the surface of an object.

We will go through point clouds in later sections.

3D Scanning Technology

3D laser scanning efficiently takes the measurements of contoured surfaces and complex geometries which require huge amounts of data for their accurate description because doing this with the use of traditional measurement methods is impractical and time consuming. It creates accurate point cloud data by acquiring measurements and dimensions of free-form shapes.

The basic working principle of a 3D scanner is to collect data of an entity. It can either be:

• an object
• an environment (such as a room)
• a person (3D body scanning)

In reverse engineering, laser scanner’s primary aim is to provide a lot of information about the design of an object which in the later stages gets converted to 3D CAD models, considering the compatibility of 3D scans and Computer Aided Design (CAD) software. 3D scans are even compatible with 3D printing which requires some specific computer software.

3D scanning technologies varies with different physical principles and can be classified as follows:

• Laser triangulation 3D scanning technology: In this category, the laser scanner projects a laser beam on a surface and measures the deformation of the laser ray.

• Structured light 3D scanning technology: This technology acquires the shape of a surface by measuring the deformation of a light pattern.

• Photogrammetric technology: It is also known as 3D scan from photography. It reconstructs an object from 2D to 3D and has specific computational geometrical algorithms for the task.

• Laser pulse 3D scanning technology: This unique process collects geometrical information by evaluating the time taken by a laser beam to travel between its emission and reception.

Contact based 3D scanning technology: This process requires contact between the probe and the object, where the probe is moved firmly over the surface to acquire data.

Types of scanners

Apart from scanning technologies, there are various types of 3D scanners. Some are built for short range scanning while others are ideal for medium or long range scanning. The built and usage of specific scanners hugely depend upon size of the object to be scanned. The scanners used for measuring small objects vastly differ from the ones that are used for large bodied objects, such as a ship.

Here is a brief summary of types of 3D laser Scanners:

1. Short Range 3D scanners: Short Range 3D scanners utilize either a Laser triangulation technology or Structured Light technology.

2. Laser based 3D scanners: Laser scanners work by projecting laser a beam or multiple laser beams on an object and capturing its reflection with sensors, which are located at a fixed distance from the scanners.

3. Structured light 3D scanners: These are also known as white light scanners. However, most structured scanners use blue or white LED light. The light pattern usually consists of a certain geometrical shape such as bar or block or any other shape, which is projected onto the object. The sensors consider the edge of the pattern to determine the 3D shape of the object. Blue or white light scanners are generally used to obtain outward dimension.

4. Medium and Long range scanners: Long range 3D scanners are used for large objects such as buildings, ships, aircrafts, and military vehicles. These scanners rotate and spin a mirror which reflects the laser outward towards the object or areas to be 3D scanned.

5. Arm based scanners: Arm based scanners are very useful when measuring small minor parts, as it can be maneuvered by attaching it to the arm and is generally portable.

Benefits of 3D Laser Scanners

3D scanners have contributed a lot over the years and needless to say, it comes up with many benefits. Some of them are as follows:

• Able to scan tough surfaces, such as shiny or dark finishes.
• This is strictly for the handheld or other portable scanners. But given their importance, it is safe to say that the portability of scanners has played a great role in easing up engineering.
• The scanning technology has made it possible to capture millions of point in a considerably less time.
• Scanners are less sensitive to changing light conditions and ambient light.
• Scanning of complex contours and geometrical figures have become more convenient with the invention of groundbreaking scanning technologies.
• Nowadays, laser scanners have become so diverse that they are produced depending upon variety of projects or the objects to be scanned.

During the lifecycle of a particular product, companies tend to review the existing design to look out for ways to reduce production cost. Even when coming up with a new product, so many manufacturers go for analyzing the same during its design phase so that it requires an optimum level of cost to produce. This is where Value Engineering comes in.

Value engineering is an organized method to improve the “value” of a product or service in the lowest of cost.

VE is a systematic approach aimed at obtaining the necessary functions in a product, process, or system at the minimum overall cost, thereby maintaining the quality, reliability, performance, and safety. It provides the substitution of materials and methods with less expensive alternatives, without jeopardizing the functionality. It is emphasized totally on the functions of various components and materials, rather than their physical characteristics. Value engineering is also called value analysis.

It was Lawrence Miles who came up with the concept of finding substitute materials for parts unavailable.  It was found that substitutions not only reduced cost but aided in a better-finished product. It was this new technique that evolved into value engineering today.

The value in VE means two components:

• Function: The measure of performance abilities
• Cost: The resources needed to achieve the function

The function of a product is the specific task it was designed to perform, and the cost refers to the cost of the item during its life cycle. The ratio of function to cost denotes that the value of a product can be increased by either improving its function or decreasing its cost. In value engineering, the cost related to production, design, maintenance, and replacement are included in the analysis.

If we take an example of a new tech product which is being designed and is slated to have a life cycle of only two years; the product will be designed with the least expensive materials and resources that will live up to the end of the product’s lifecycle, saving the manufacturer and the end-user money. This is how product value is improved by reducing costs. It is evident that with the increase in function value and decrease in price, the overall product value increases. 

Stages of Value Engineering

There are three main stages to value engineering, which are:

• Planning: Gathering product information, and understanding its primary goals, identifying the functionality of the product.
• Design: Designing alternative ways to incorporate in the product which enhances the value rather than affecting its function and quality
• Methodology: Reduce the action list as much as possible. Developing alternatives to feasible plans. Allocation of costs.

Benefits of Value Engineering

Value engineering helps an organization in numerous ways:

• Lowering O&M costs
• Improving quality management
• Improving resource efficiency
• Simplifying procedures
• Minimizing paperwork
• Reducing staff costs
• Increasing procedural efficiency
• Optimizing construction expenditures
• Developing value attitudes in staff
• Competing more successfully in the marketplace 

Value engineering concepts apply to business as well as technical situations and consequently lead management to informed, result-oriented decisions. Value engineering has to be treated as a future investment for gaining technology leadership in the industry.

During the last few decades, with the developments in technology, manufacturers have been enabled to source parts globally. More and more manufacturers have entered the competition as it grows fierce. Companies in developing nation market offer products at lower prices. To sustain business and achieve growth, many manufacturers are coming up with new products to cater to the consumers and widen it as well. They must be very marketable and of high quality. The Design for Manufacturing and Assembly (DFMA) method enables firms to develop quality products in lesser time and at lower production costs.

Design for Manufacturing and Assembly (DFMA)

Design for Manufacturing and Assembly or DFMA is a design process that targets on ease of manufacturing and efficiency of assembly.

Simplifying the design of a product makes it possible to manufacture and assemble it in the minimum time and lower cost. DFMA approach has been used in the automotive and industrial sectors mostly. However, the process has been adopted in the construction domain as well.

DFMA is a combination of two methodologies which are:

• Design for Manufacturing (DFM): DFM focuses on the design of constituent parts to ease up their manufacturing process. The primary goal is to select the most cost-efficient materials and procedures to be used in production and minimize the complexity of the manufacturing operations.

• Design for Assembly (DFA): DFA focuses on design for the ease of assembly in the product. The aim is to reduce product assembly cost and minimize the number of assembly operations.

Both DFM and DFA seek to reduce material, labour costs associated with designing and manufacture of a product. For a successful application of DFMA, the two activities should operate in unison to earn the most significant benefit. Through the DFMA approach, a company can prevent, detect, quantify, and eliminate waste and manufacturing inefficiency within a product design.

Design Failure Mode and Effect Analysis (DFMEA)

Design Failure Mode and Effect Analysis (DFMEA) is a methodical string of activities to identify and analyze potential systems, products, or process failures.

Design Failure Mode and Effects Analysis or DFMEA focuses on finding potential design flaws and failures of components before they can make a significant impact on the end users of a product and the business distributing the product.

DFMEA identifies –

The potential risks introduced in a  new or modified design,

 The effects and outcomes of failures,

The actions that could eliminate the failures, and

provides a historical written record of the work performed. 

DFMEA is an ideal process for any sector where risk reduction and failure prevention are crucial, which includes:

• Manufacturing
• Industrial
• Aerospace
• Software
• Service industries

 

The previous sections dealt with the initial and middle stages of reverse engineering. This section highlights a stage which is undoubtedly crucial for product development. After a meshed part is aligned, it goes through either—surface modeling in tools such as Polyworks, which generates a non-parametric model (IGES or STEP format) or parametric modeling where a sketch of the meshed part is created instead of putting it through surfacing (.PRT format). The resultant is generally called, 3D computer aided model or CAD model.

But, what is CAD?  

CAD is the acronym for Computer Aided Design. It covers different variety of design tools used by various professionals like artists, game designers, manufacturers and design engineers.

The technology of CAD systems has tremendously helped users by performing thousands of complex geometrical calculations in the background without anyone having to drop a sweat for it. CAD has its origin in early 2D drawings where one could draw objects using basic views: top, bottom, left, right, front, back, and the angled isometric view.  3D CAD programs allow users to take 2D views and convert them into a 3D object on the screen.  In simple definition, CAD design is converting basic design data into a more perceptible and more understandable design.

Each CAD system has its own algorithm for describing geometry, both mathematically and structurally.  

Different CAD models

Everything comes with its own varieties and CAD modeling is no stranger to it. As the technology evolved, CAD modeling came up in different styles. There are many methods of classifying them, but a broad general classification can be as follows:

• 2 dimensional or 2D CAD: The early version of CAD that most of us are aware of. These are 2-dimensional drawings on flat sheet with dimensions, layouts and other information needed to manufacture the object.
• 3 dimensional or 3D CAD: The purpose of both 2D and 3D models is the same. But what sets 3D models apart is its ability to present greater details about the individual component and/or assembly by projecting it as a full-scale 3-dimensional object. 3D models can be viewed and rotated in X, Y, or Z axes. It also shows how two objects can fit and operate which is not possible with 2D CAD.

3D models can be further classified into three categories:

• 3D Wire-frame Models: These models resemble an entire object made of just wires, with the background visible through the skeletal structure.
• Surface Models: Surface models are created by joining the 3D surfaces together and look like real-life objects.
• Solid Models: They are the best representation of real physical objects in a virtual environment. Unlike other models, solid models have properties like weight, volume and density. They are the most commonly used models and serve as prototypes for engineering projects.

Types of CAD formats

Different professionals use different software, owing to different reasons like cost, project requirements, features etc. Although, software comes with their own file formats, there are instances where one needs to share their project with someone else, either partners or clients, who are using different software. In such cases, it is necessary that both party software understand each other’s file formats. As a result of this situation, it is necessary to have file formats which can be accommodated in variety of software.

 CAD file formats can be broadly classified into two types:

• Native File Formats: Such CAD file formats are intended to be used only with the software it comes with. They cannot be shared with any other software which comes with their own CAD formats.
• Neutral File Formats: These file formats are created to be shared among different software. Thereby it increases interoperability, which is necessary.

 Although there are almost hundreds of file formats out there, the more popular CAD formats are as follows:

STEP: This is the most popular CAD file format of all. It is widely used and highly recommended as most software support STEP files. STEP is the acronym for Standard for the Exchange of Product Data.

IGES: IGES is the acronym for Initial Graphics Exchange Specification. It is an old CAD file format which is vendor-neutral. IGES has fallen out lately since it lacks many features which newer file formats have.

Parasolid: Parasolid was originally developed by ShapeData and is currently owned by Siemens PLM Software.

STL: STL stands for Stereolithography which is the format for 3D information created by 3D systems. STL finds its usage mostly in 3D printers. STL describes only the outer structure or surface geometry of a physical object but doesn’t give out color, texture and other attributes of an object.

VRML: VRML stands for Virtual Reality Modeling Language. Although it gives back more attributes than STL but it can be read by a handful of software.

X3D: X3D is an XML based file format for representing 3D computer graphics.

COLLADA: COLLADA stands for Collaborative Design Activity and is mostly used in gaming and 3D modeling.

DXF: DXF stands for Drawing Exchange Format which is a pure 2D file format native to Autocad.

Use of CAD

Computer-aided design or CAD has pushed the entire engineering process to the next level. One can actually mould or fold, modify or make a new part from scratch, all with the help of CAD modeling software. The many uses of CAD are as follows:

• CAD is used to generate design and layouts, design details and calculations, 3-D models.
• CAD transfers details of information about a product in a format that can be easily interpreted by a skilled professional, which therefore facilitates manufacturing process.
• The editing process in CAD is very fast as compared to manual process.
• CAD helps in speeding up manufacturing process by facilitating accurate simulation, hence reducing time taken to design.
• CAD can be assimilated with CAM (Computer Aided Manufacturing), which eases up product development.