APPLYING THE ISF TECHNOLOGY TO PRODUCE THE CAR PART MODELS

The paper presents an application the research results previously done by group on the influence of technological parameters to the deformation angle and finish surface quality in order to choose technology parameters for the incremental sheet forming (ISF) process to produce products for the purpose of rapid prototyping or single-batch production, including all steps from design and process 3D CAD model, calculate and select the technological parameters, setting up manufacturing and the stage of post-processing. The samples formed successfully showed high applicability of this technology to practical work, the complex products with the real size can be produced in industries: automotive, motorcycle, civil...


INTRODUCTION
Nowadays, the production of sheet products in small quantities, but the flexibility in change of design and size is a requirement in many fields such as automotive, aviationcosmic, medicine, household appliances... Market needs of rapid prototyping products also require a technology that can meet this demand (Truong Hai Auto Company...): a technology that can perform in the short term, does not require expensive machines and equipment, the process is simple. Traditional methods used in the current industry are hard to meet this demand because the expensive cost of mold and other relating equipment. The time to build a die for complex products is quite long [5].
In recent years, the field of sheet metal deformation was studied and introduced in order to reduce costs and production time. In particular, the ISF technology with the capability of meeting the above requirements is being researched strongly [1]. Although this technology is rather new in the world due to the only investment in research for several decades recently, but it has shown its potential development. The advantage of this method is that objects with asymmetric shape can be produced without using molds, saving time and costs, can change the product flexibly. Thus, the applicability of this technology is considerable [6].
Compared to other methods of forming sheets, this method has the advantage of significantly shortening the production time.   Step 1 Choosing diameter of forming tool Checking the maximum forming limit angle again Building the moving trajectory of forming tool Step 3 Step 4 Post processing to complete model Step 5 Creating CAM program in producing supporter and pressing sheet (TPIF) Producing supporter on CNC machine Fixing and producing model (TPIF) Step 6 Step 7 Science & Technology Development, Vol 13, No. K6-2010 Trang 94    Table 1. Choosing the producing parameters [5] Parts n (rpm) Step-down Hor.
Step -Increasing step depth to 0.5 mm compared with the optimal mode [5] in order to reduce processing time.

Post-processing and assembly
After producing (Fig. 9), components are separated from the Aluminum sheet by using a cutting tool mounted on CNC machine (Fig.   10). After that, we polish surfaces used in the assembly; connecting parts together; then grinding the welds to ensure the aesthetic issues and durability (Fig. 11). of about ± 0.8mm (Fig. 12). Such discrepancy is acceptable for the rapid prototyping process.

Science & Technology
We can improve accuracy by calculating the exact amount of compensation to fabricate gage and create a reasonable way to run appliances. Diagram comparing the advantages of two methods: ISF and stamping from level simple to complex products [5]. stamping [5] ISF cost depends on the geometry and material of parts. Currently, it shows that, for moderate complex parts, the model can be easily produced with ISF. According to these calculations and observations on the chart, we can see that ISF process will be profitable if the number of products is small. If more products are required, the mass-production methods (such as stamping) will be more profitable [5]. • Able to implement rapid prototyping or small production series; • The process without die; • Quickly and easily change the size of part, enabling high flexibility; • The process does not produce much noise.
In practical production, the process producing the product is very diverse and abundant; the process technology to create products contains many research achievements.
Producing with ISF technology will bring high economic efficiency for the products, which are produced in small batch, single or rapid prototyping.