Applications of virtual reality technologies in design and development of engineering products and processes

Virtual reality (VR) technologies support and accelerate product design, facilitate actualisation and delivery of ideas, and are highly helpful for discussions and collaboration [1]. It is known as a new dimension in manmachine communication that combines real-time (3D) computer graphics direct intuitive interaction in 3D space [2]. They are one of the main mechanical engineering tools helping to obtain better results designing new and improving already designed products [3, 4]. Significant benefits on efficiency and flexibility of processes as well as functionally of products serve as the reference point for using such technologies in other engineering operations [5, 6]. Short production terms, often being the case even manufacturing complex products, make manufacturers to involve engineers of various specialisations. In such situations, quick, creative, and integrated activities are needed in order to find and integrate efficient solutions. The use of virtual technologies in various product design or manufacturing stages requires various abilities and skills, such as the understanding of what is requested, using computer and software, converting and processing data, understandable presentation of the information; also insight, experience, curiosity, and talent. The better the engineer at each stage of the chain understands what is requested from him/her and the more understandably he/she delivers his/her requests, the smother the following stages of product design go. This is also applicable to the ability of collecting data that later will be used for designing virtual 3D prototypes and further development of the products; and skills of creating and improving virtual 3D prototypes that later will be used for designing CNC and other programs and preparing questions and proposals. The most important aspects of the application of VR technologies [7, 8] discussed in the article: Novelties: the article describes the method which allows accelerating many stages of product design, development, and manufacturing; putting into effect solutions that can hardly be actualised using classical methods. This method originated from multiple attempts to use VR technologies in the area of products design and develop in Mechanical Engineering Company; the result was achieved due to contact development of mechanical processing technologies, tight collaboration supported by an IDEF0 diagram of corporate specialists and divisions, and goodwilled cooperation between the manufacturer and the client [9]. Scientific value: cross-disciplinary communication enables developing new information, transferring and accepting knowledge and experience, acquiring and improving skills, accumulating experience and so on. Practical value: improved technical communication and more rapid generation of alternative ideas. Designing spherical elements and implementing them into the existing 2D drawings is complicated and time consuming process. It requires the creation of additional technologies that extend the time and increase the cost of production. Besides this, the 2D technology requires using several reference points that influence manifestation of setting (measurement) errors.


Introduction
Virtual reality (VR) technologies support and accelerate product design, facilitate actualisation and delivery of ideas, and are highly helpful for discussions and collaboration [1].It is known as a new dimension in manmachine communication that combines real-time (3D) computer graphics direct intuitive interaction in 3D space [2].They are one of the main mechanical engineering tools helping to obtain better results designing new and improving already designed products [3,4].Significant benefits on efficiency and flexibility of processes as well as functionally of products serve as the reference point for using such technologies in other engineering operations [5,6].Short production terms, often being the case even manufacturing complex products, make manufacturers to involve engineers of various specialisations.In such situations, quick, creative, and integrated activities are needed in order to find and integrate efficient solutions.The use of virtual technologies in various product design or manufacturing stages requires various abilities and skills, such as the understanding of what is requested, using computer and software, converting and processing data, understandable presentation of the information; also insight, experience, curiosity, and talent.The better the engineer at each stage of the chain understands what is requested from him/her and the more understandably he/she delivers his/her requests, the smother the following stages of product design go.This is also applicable to the ability of collecting data that later will be used for designing virtual 3D prototypes and further development of the products; and skills of creating and improving virtual 3D prototypes that later will be used for designing CNC and other programs and preparing questions and proposals.The most important aspects of the application of VR technologies [7,8] discussed in the article: Novelties: the article describes the method which allows accelerating many stages of product design, development, and manufacturing; putting into effect solutions that can hardly be actualised using classical methods.This method originated from multiple attempts to use VR technologies in the area of products design and develop in Mechanical Engineering Company; the result was achieved due to contact development of mechanical processing technologies, tight collaboration supported by an IDEF0 diagram of corporate specialists and divisions, and goodwilled cooperation between the manufacturer and the client [9].
Scientific value: cross-disciplinary communication enables developing new information, transferring and accepting knowledge and experience, acquiring and im-proving skills, accumulating experience and so on.Practical value: improved technical communication and more rapid generation of alternative ideas.Designing spherical elements and implementing them into the existing 2D drawings is complicated and time consuming process.It requires the creation of additional technologies that extend the time and increase the cost of production.Besides this, the 2D technology requires using several reference points that influence manifestation of setting (measurement) errors.

The relationship between physical and virtual prototypes
The usability of the user interface is a key aspect for the success of several industrial products.This assumption has led to the introduction of numerous design methodologies addressed to evaluate the user-friendliness of industrial products.Most of these methodologies follow the participatory design approach to involve the user in the design process [10].3D prototypes may be successfully used in various stages of product design and manufacturing: rapid design and improvement of work pieces; rapid design and improvement of surface geometry and preciseness; rapid generation of alternatives that would improve the structure and workability of the part or product; better cooperation between the manufacturer and the customers, the manufacturer and the consumers, and between various departments of the manufacturer.Virtual 3D prototype may be improved at any time by using software.The technological solution is implemented into a product at early production or design stages.The improved prototype is transferred to the programmer, who creates CNC program for mechanical processing of the product.Surface and geometry of the product remain unchanged, but there's achieved enhanced workability of the product.Simpler processing technology and reduced technological tooling reduce mechanical processing time thus enabling manufacturers to offer customers more competitive prices.
In a proposed case the manufacturer obtained primary 3D prototype from the customer (Fig. 1).It was a welded structure consisting of various length square tubes with wall thickness 3mm and plates of different geometrical forms and sizes.The plates were located at various original and complicated angles facing each other.Most of them should be mechanically processed aiming to obtain surfaces and holes of certain preciseness (tolerance T, Table 1).The development of the product, using VR technology, consists of the following stages:  the evaluation of geometrical, constructional and mechanical processing possibilities of the product;  development stage;  creation of the CNC numerical control program.The examination of 3D prototype is presented on the monitor.Making decision on the improvement of the prototype is proposed, aiming to improve workability of the product.Such improvement enables to maintain customers' requirements after implemented changes.Deciding on what actions shall be taken in order to implement the idea and performing them.Choosing necessary 3D and 2D CAD software and measurement tools for the implementation of idea is discussed.
Fig. 1 Primary virtual 3D prototype of the product This method was necessary since CNC machine was capable of processing elements not larger than overall dimensions 1700×1000×350 mm.Sometimes the manufacturers get orders exceeding the capabilities of CNC machines.In such case inquiry or even order must be cancelled facing technical capabilities of the manufacturer.Cancelation of inquiries and orders may to lead for losing customers.In order to retain competitiveness manufacturer must put in one's best efforts as possible performing gotten orders.In the described case, the overall dimensions of the product were 2100×1400×206 mm.Such welded structure is processed applying tool machine with bigger work table but less possibility of spindle positioning the tilting and turning in respect to coordinate system of machined welded structure.In such cases, manufacturers used to produce specific technological tooling that served as a starting point or a compensation of tilting or turning of the element or spindle.The production of such technological tooling required additional time, machinery, high quality specialists, materials, and energy.In addition, such technological tooling might not be enough for establishing one reference point and machining the welded structure because the manufacturers must use several reference points making more complicated chain of measurements and increasing the probability of setting errors.Designer's input to the improvement of the product depends on his/her knowledge of manufacturing technology and design skills.In a development stage, the main designer's output is an alternative 3D prototype.Virtual 3D prototype of the product becomes the intermediary between the customer, the designer, the technologist, and the operator.The described method has been developed aiming to improve mechanical processing technology, saving expenses of producing additional technological facility, and reducing the number of actual production actions and the number of reference points thus avoiding the errors.Product development diagram, gener-alising the applied method, is delivered in (Fig. 2.) Fig. 2

IDEF0 diagram of 3D model generation in VR environment
Aiming to improve the workability of the product, spherical element, delivered in (Fig. 3), was used.That tooling is fixed in a rectangular tube.As technological fixing feature for spherical element a M6 3 mm depth hole is used.Spherical elements perform significant roles in manufacturing of the products with prevailing precise and geometrically intrinsically to each other located surfaces.This element combines its mechanical functions with the idea of a technologist improving the workability of the product and creating better opportunities to design CNC program for manufacturing of the product reducing the amount of technological tooling and the probability of setting (measurement) errors.Aiming to develop 3D prototype delivered by the customer to the level that satisfies the requirements of a production technologist and programmer, the designer created virtual 3D prototype of a spherical element (Fig. 4).
Virtual 3D CAD prototype of the spherical element has been created on a basis of the sketch in communication with 3D design program (Fig. 5).Data for the sketch Table 2 was obtained having measured physical model of the spherical element in a measurement laboratory.The process of developing a 3D prototype of the Virtual 3D spherical element was integrated in a VR into virtual 3D model, sent by the customer, making an additional M6 3 mm deph hole.The location of the technological feature was selected by the programmer emploing his/her knowlewdge on the manufacturing technology and properties of the machinery that will be used for mechnical processing of the developed product.The sketch with required dimensions was delivered to the designer (Fig. 6).The sketch involved the indication of the type and the location of the hole in a primary model of the product.Then the designer emploing his design skills integrated the hole to the virtual 3D prototype (Fig.  After the improvement of virtual 3D prototype, integrating an additional spheric element (Fig. 8), new projections of the product in 2D environment were made.This data was used for the developmdent of CNC program to produce an actual product (Fig. 9).

Conclusions
In response to scientific value: possibility of facing, designing, and integrating virtual prototypes is a good basis for firming already possessed and acquiring new, specific, knowledge on the implementation of virtual prototypes in the area of product design and manufacturing.Such experience also helps to maintain and improve one's innovative, adaptive, and competitive potential.
In response to practical value: the integration of VR technologies enhances the possibilities of manufacturers to implement various technological solutions and make this process faster.It helps to transfer the knowledge acquired into the processes and products as well as provides better opportunities for using the information collected at early stages of product or process development.
Novelties: the applied method connects classical and VR technologies.The use of VR technologies accelerated the integration of a spherical element into a 3D prototype and the preparation of CNC program.The paper deals with application of virtual reality (VR) technologies for accelerating new product and process design.Significant benefits on efficiency and flexibi lity of processes as well as functionality of new products are available to get applying such technologies.The article describes the method, which allows speeding up the industrial production.This method originated from multiple attempts to use VR technologies in the area of mechanical engineering products and processes design and develop.The result was achieved due to tight collaboration of corporate specialists and divisions, and good-willed cooperation between the manufacturer and the client.Scientific value is expressed as cross-disciplinary communication that enables developing new information, transferring and accepting knowledge and experience, acquiring and improving skills, accumulating experience and so on.The practical value is improved the technical communication and more rapid generation of alternative ideas.Designing spherical elements and implementing them into the existing 2D drawings decreased the time consuming process.

Fig. 7
Fig. 7 Appointment of spherical element positioning in the 3D model

Table 1
Geometrical and mechanical characteristics of the product

Table 2
Data for integration of spherical element into primary product