The Application of Computer Tomography Technique (CT) in the Die Manufacture
In recent years, China die industrial have developed rapidly and already have international die tooling technology. The scale of the tooling making is the lead in the world. But it remains at the lower end of the relevant supporting testing technology, monotony and limitation.
Traditional test way only can do appearance size, hardness test and so on of the die and products. There is a lack of better testing method of the internal structure and quality, adaptability, risk assessment.
In consequence, a convenient a lossless testing way in all directions for interior and exterior of products and material quality is needed. A new research has a profound significance for improving the die and products manufacture, and that is industry computer tomography technique (CT) technology.
Industry CT is the most advanced non-destructively tech in the world. It is one of the important means to deal with measurement and statistics of internal and external defect, structure size measurement, design process improvement, update fabrication tech.
In the condition of no damage of product structure, CT testing is available that realizes test of flat and curved surface and internal physical dimension such as height, width and depth, areas, superficial area, that compares products with CAD model,
That analyses physical dimension and GD&T, and that implements lossless quality assessment and NDT (nondestructive testing) such as crack, bubble, inclusion, porosity, debonding, assemble defect, etc. CT testing also covers various texture and structure of die and products.
The application of industry CT tech
- Analysis of physical dimensionand GD&T
According to the designed drawing, CT test analyses the physical dimension and GD&T to meet the approval demand of production components, which is very useful and cost-efficient from the first piece sample to the mass production and significantly reduces testing cost of multi-cavity products.
Once CT dataset is formulated by the initial GD&T program, all data point can be fast conversion, and apply it to the subsequent product scan. Sometimes, outside surface of product is sealed by injection molding process, and its unknown if the internal parts meet the design demands such as tolerance, assemble, connecting quality. The traditional contact devices and optical equipments cannot deal with it because the probe and light cannot reach the internal part. Industry CT utilizes the X ray to pierce the surface of products and scan the interior to obtain the intact 3D image, and forms 4D image(X, Y, Z direction and time) on the monitor. It can be observed and measured from any section of three from the structure and the complete information is acquired clearly and accurately.
- Theanalysis of design and physicalmodel match degree
Product and CAD model rapidly contrastive analysis can be finished in several days after the first piece sample in using the way of Industry CT scan.
- Assemble analysis
Measurement, failure analysis, quality control in the fabrication and tolerance assessment aerie available while in the condition of assemble.
Shade coding is programmed by means of density value, and analysis the cross section layer by layer, the hide component in the assemble will be detected, and the defect and function parts are discovered easily.
- Density analysis
Industry CT is accompanied with prominent ability of density analysis, on/off the internal density scan, color code by means of density value and measurement. Quality CT image definition can be even higher than 0.1%
Thickness analysis is chiefly used in the injection mould and die casting mould. Rapidly and accurately measure the small change of the thickness so that adjust and optimize manufacture process to improve the quality in the NDT of complex parts.
In the casting process, the intricate interaction will generate defects that cannot identify from the exterior such as hole, pore, bubble, heat crack, size deviation and inclusion etc. This risk will be existed despite the best efforts. The application industry CT testing tech can expediently identify these defects.
Industry CT tech has high detection sensitivity of the defects in the composite materials such as inclusion, porosity, air pole, layering defect etc, So that the physical size and location of defects can be accurately confirmed.
To combine Industry CT tech with fabrication process of composite materials, the defect in the products can be detected timely, which is high practical significance of improving the process, products quality and production efficiency.
- Porosity of die casting measurement
As is well known, the porosity of die castings can seriously influence products working life. The measurement of the porosity location and distribution is very crucial to the die design. The film radiography way is adopted in common castings internal quality test, but not applies to the internal and external intricate and irregular parts.
Industry CT can detect the location and size of the porosity, air pole, sinkhole and crack despite of the structure, shape of the test part, which is very useful for the classification and assessment of the defects.
- Rapiddie amendment
When it comes to the intricate plastic products, the shrinkage problem is faced after the injection. The key to solve this problem is that predicts sufficiently the possible shrinkage in the die design and then amends the die to obtain the accurate products.
Based on the industry CT tech, the physical size and geometric tolerance assessment can be rapidly and accurately confirmed. Meanwhile, compared with CAD data, it can obtain the color deviation and deviation correction data, which greatly accelerates the speed of die amendment and shortens the injection, die development cycle.
- Reverse engineering
3D drawing can be obtained with the scan of industry CT from the given products, which can guide the die design, shorten the development cycle and improve the economic performance.
Much product data is not CAD digital model, and sometimes drawings is missing during in the design and develop of new product.
Entity 3D can be rebuilt in using of industry CT tech which is good for design and manufacture moulds such as calculation of die joint face and shrinkage rate.
In the process of test and modification, if the precision cannot meet the requirement, the die perhaps has to be redesigned. The reverse engineering can reduce the designer’s trouble. Through the surface data acquisition and technology innovation, design step can be reduced, and the product design process can be optimized.
(3) Repair die
Convert physical components to the actual match CAD models with measurements, and modify the CAD model for later processing, which can improve production efficiency.
(4) Usage and maintenance
In the process of production, work is often stopped because of a certain damaged parts. By means of reverse engineering, substitutes can be quickly fabricated for these parts, so as to improve the efficiency and service life of equipments.
- Measurement of coefficient of restitutionofstamping materials
Stamping rebound can affect its quality, which often directly cause the work piece to be scrapped. So the rebound problem has been plaguing the engineers. The key to accurate measurement of the coefficient of restitution is to solve rebound problem, Industrial CT is more accurate than three coordinates devices while measure values of R and R’, so that the measured values is closer to the real value.